Exhibit 10.1

EMPLOYMENT AGREEMENT

     THIS EMPLOYMENT AGREEMENT (this “Agreement”) is entered into as of December 15th, 2000 (the “Effective Date”) by and between UP Subsidiary Corporation (the “Company”) and Darlene Walley, Ph.D. (the “Executive”).

     WHEREAS, the Company desires to obtain the services of the Executive, and the Executive is willing to render such services to the Company, upon the terms and conditions herein set forth;

     NOW, THEREFORE, in consideration of the promises and mutual covenants contained herein, and for other good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties hereto agree as follows.

     1.     Employment. Upon the other terms and conditions hereinafter stated, the Company agrees to employ the Executive and the Executive agrees to accept employment by the Company for the term set forth in Section 2 hereof and in the position and with the duties and responsibilities set forth in Section 3 hereof. Executive warrants that she is under no restriction that would prevent her from entering into this Agreement and from complying with all of its provisions to their fullest extent.

     2.     Term. The employment of the Executive by the Company will commence on the Effective Date and end on the third anniversary of such date (the “Initial Term”), and thereafter shall continue from year to year for additional one-year terms (the “Additional Terms”), unless and until either party shall give notice of such party’s intent to terminate not less than 30 days prior to the end of the then-current Initial Term or Additional Term, which termination shall be effective at the expiration of said term, or until sooner terminated as hereinafter set forth.

     3.     Position and Duties. The Executive shall serve as President, with such duties and responsibilities as are normally performed by the President of a medical foods company and as otherwise assigned by the Board of Directors from time to time that are not inconsistent with duties and responsibilities as are normally performed by the President. Executive shall report directly to Barry Kanarek, Ph.D. of United Therapeutics. The Executive shall at all times exert her best efforts and loyalty on behalf of the Company and shall devote full time and attention to such employment. The Executive agrees to abide by all employment guidelines and policies as may be developed from time to time by the Company, including, without limitation, the United Therapeutics Corporation Company Manual, the United Therapeutics Corporation Securities Trades by Company Personnel Policy and the United Therapeutics Corporation Media and Analysts Policy.

     4.     Compensation and Related Matters.

               (a)     For services rendered under this Agreement, the Company shall pay to the Executive an annual base salary of Two Hundred Thousand Dollars ($200,000) (the

“Base Salary”), subject to increase, as determined by the Board of Directors of the Company, in its sole discretion, on or before any anniversary date of this Agreement, but such increase to be not less than 10% of Executive’s Base Salary per year. The Base Salary shall be payable semi-monthly or in such other installments as shall be consistent with the Company’s payroll procedures. The Company shall deduct and withhold all necessary social security and withholding taxes and any other similar sums required by law or authorized by the Executive with respect to payment of the Base Salary and all other amounts and benefits payable under this Agreement.

               (b)     The Executive shall be entitled to participate in any group life, disability and medical insurance or other benefit plan or arrangement available generally to the employees of the Company as determined by the Board of Directors.

               (c)     Executive shall be entitled to participate in United Therapeutics Corporation’s employee bonus plan.

               (d)     Executive shall also receive a cash bonus equal to 2% of CP sales based on revenues received by CP from invoiced sales less (i) credits, allowances, discounts and rebates to, and chargebacks from the account of, third parties for spoiled, damaged, obsolete, outdated, rejected or returned product and for retroactive price reductions in lieu of returned product; (ii) actual shipping and handling, freight and insurance costs incurred in transporting such product in final form to such third parties; (iii) cash, quantity, and trade discounts; (iv) sales, use, excise, value-added and other taxes or governmental charges incurred in connection with the sale, exportation or importation, transportation, or delivery of such product in final form; and (v) bad debts or uncollectible accounts. Such bonus amounts due shall be paid within 60 days after the end of each quarter.

               (e)     CP shall also lease an automobile for Executive’s use and pay related monthly insurance premiums in an amount not to exceed $1,000 per month.

               (f)     As an inducement to Executive to enter into this Agreement, within 30 days of signing this Agreement Executive shall be granted an option to purchase 60,000 shares of the common stock of United Therapeutics Corporation priced at the NASDAQ closing price on the date of the grant and vesting in one-third increments on each anniversary of this Agreement. Executive shall enter into a separate stock option agreement with United Therapeutics Corporation setting forth the terms of this option grant.

     5.     Expenses. The Executive shall be reimbursed by the Company for reasonable travel and other expenses, as approved from time to time by the Board of Directors, which are incurred and accounted for in accordance with the Company’s normal practices.

     6.     Vacation. The Executive shall be entitled to vacation at such time or times and for such period or periods as shall be mutually agreed upon by the Executive and the Board of Directors.

     7.     Termination of Employment.

               (a)     Termination Without Cause or With Good Reason. In the event that Executive is terminated by the Company without Cause or Executive voluntarily terminates her employment with the Company for Good Reason, and Executive signs and does not revoke a release of claims in the reasonable form provided to Executive by the Company (which will include a release by the Company of the Executive in reasonable form), then, Executive will be entitled to receive:

                         (i)     Earned and Unpaid Base Salary. All earned but unpaid Base Salary otherwise owed to the Executive under the terms of this Agreement through the date of termination, payable in a lump sum within thirty (30) days of the date of Executive’s termination.

                         (ii)     Base Salary. Executive shall receive severance pay in an amount equal to (A) twelve (12) months of Executive’s Base Salary (at the then current level), if such termination occurs during the first Employment Year hereunder, or (B) six (6) months of Executive’s Base Salary (at the then current level), if such termination occurs following the first Employment Year hereunder, in either case payable in a manner consistent with the Company’s then current payroll procedures, with appropriate tax withholding and deductions, and for so long as Executive is not in breach of her obligations under Section 10 below.

                         (iii)     Vacation Pay. Executive shall receive a payment equal to all accrued but unused vacation pay, as determined on the termination date, and such sum shall be payable in a lump sum within thirty (30) days of Executive’s termination.

               (b)     Voluntary Termination or Termination for Cause. In the event that Executive is terminated by the Company for “Cause,” or in the event that Executive voluntarily terminates her employment without Good Reason, then (i) all vesting of her options will terminate immediately and all payments of compensation by the Company to Executive hereunder will terminate immediately (except as to amounts already earned which amounts shall be paid to Executive within thirty (30) days of such termination), and (ii) Executive will only be eligible for severance benefits in accordance with the Company’s established policies as then in effect.

               (c)     Death or Disability. Executive’s employment will automatically terminate upon her death. Upon Executive’s Disability (as defined herein), the Company may terminate Executive’s employment hereunder by written notice to Executive which termination shall be effective on the thirtieth (30th) day after such notice; provided , that the Executive shall not have returned to the performance of the Executive’s duties on a full-time basis during such thirty (30) day period. In the event of Executive’s death or Disability (as defined herein), the Executive or her estate, as applicable, shall be entitled to receive the payments and benefits set forth in Section 7(a)(i) above and all other unpaid amounts, if any, to which the Executive is entitled as of such date in connection with any fringe benefits or under any incentive compensation plan or program of the Company pursuant to Sections 4 hereof, at the time such payments are due. The Executive or her estate, as applicable, shall be permitted to exercise her options, to the extent vested as of the date of her termination, in

accordance with the terms of the Executive’s stock option agreements. Executive’s options will cease to vest on the date of her termination due to death or Disability.

               (d)     Expenses. On termination of Executive’s employment hereunder for any reason, the Company shall reimburse the Executive for any reasonable expenses incurred by the Executive prior to the date of termination in accordance with Section 5 hereof, promptly following Executive’s compliance with the Company’s policies and terms described therein.

     8.     Definitions.

               (a)     Cause. For purposes of this Agreement, the Company shall have “Cause” to terminate the Executive’s employment hereunder upon the (A) failure of the Executive (other than for reasons described in Sections 7(c) hereof) to perform or observe any of the material terms or provisions of this Agreement; (B) negligent or unsatisfactory performance of the Executive’s duties under this Agreement and the failure of the Executive, within 10 days after receipt of notice from the Company setting forth in reasonable detail the nature of the Executive’s negligent or unsatisfactory performance, (i) to provide the Company with a reasonably satisfactory explanation of the Executive’s actions (or inaction) and (ii) to correct to the satisfaction of the Company any reasonably identified deficiencies; (C) employment- or profession-related misconduct on the part of the Executive; (D) conviction of the Executive of a crime involving a felony, fraud, embezzlement or the like; or (E) misappropriation of the Company funds or misuse of the Company’s assets by Executive.

               (b)     Disability. For purposes of this Agreement, “Disability” shall mean Executive’s mental or physical impairment that has prevented Executive from performing the responsibilities and duties of her position for three months or more in the aggregate during any six-month period. Any question as to the existence or extent of Executive’s disability shall be resolved by a qualified independent physician who is an acknowledged expert in the area of the mental or physical impairment, selected in good faith by the Board; provided, however, such selection must be reasonably acceptable to the Executive.

               (c)     Good Reason. For purposes of this Agreement, “Good Reason” means that the Executive voluntarily terminates employment with the Company after any of the following are undertaken without the Executive’s express written consent: (i) material breach of any provision of this Agreement by the Company, which breach shall not have been cured by the Company within thirty (30) days of receipt of written notice specifying in reasonable detail the nature of such material breach; (ii) any action by the Company that results in a material diminution of Executive’s position, authority, duties or responsibilities, which action shall not have been cured by the Company within thirty (30) days of receipt of written notice specifying in reasonable detail the nature of such material diminution of Executive’s position, authority, duties or responsibilities; or (iii) the requirement that Executive relocate more than fifty (50) miles from the current location of the Company’s principal executive offices.

     9.     Intellectual Property Rights. Because of the highly specialized and technical nature of the business of the Company and the nature and scope of Executive’s employment, Executive agrees that any and all rights, title, and interest, including but not limited to domestic and foreign patents, copyrights, trademarks and trade secrets, in and to all inventions, processes, computer programs, photographic, written or artistic works, or other forms of intellectual property (“Intellectual Property”) which employee makes, conceives, reduces to practice or develops, in whole or in part, during the term of this Agreement in the furtherance of the Company’s business and in connection with specific Company projects as defined in Paragraph 9 below (whether or not made during the hours of employment or with the use of Company’s materials, facilities or personnel, either solely or jointly with others), or after termination of employment if such Intellectual Property is based upon Confidential Information, shall be the sole and exclusive property of the Company, and its respective successors, licensees, and assigns. In full consideration of the compensation provided to Executive by the Company, Executive agrees to each and all of the following:

               (a)     Work Made for Hire. Executive acknowledges and agrees that all works of authorship created by Executive as an employee of the Company is a commissioned “work for hire” within the meaning of United States copyright law which will be owned solely and exclusively by the Company. If the work is determined not to be a “work for hire” or such doctrine is not effective, Executive hereby irrevocably assigns, conveys and otherwise transfers to the Company, and its respective successors, licensees, and assigns, all right, title and interest worldwide in and to the work and all proprietary rights therein, including, without limitation, all copyrights, trademarks, design patents, trade secret rights, moral rights, and all contract and licensing rights, and all claims and causes of action with respect to any of the foregoing, whether now known or hereafter to become known. In the event that Executive has any right in the work which cannot be assigned, Executive agrees to waive enforcement worldwide of such right against the Company, its distributors and licensees or, if necessary, exclusively license such right, worldwide to the Company with the right to sublicense. These rights are assignable by the Company. Executive has not and hereby does not transfer any Intellectual Property rights owned or held solely by Executive to the Company relating to periods prior to the date of this Agreement and retains all rights to same provided, however, that Executive acknowledges that Intellectual Property rights that she created as an employee of the Cooke Pharma prior to the date of this Agreement, and not otherwise previously assigned or transferred prior to the date of this Agreement pursuant to the attached schedule, are solely owned by the Company as a work made for hire.

               (b)     Original Work. Executive agrees that Executive will not include any copyrighted or patented material owned by a third party in any written, copyrightable or patentable material furnished or delivered by Executive under this Agreement without the unconditional written consent of the copyright or patent owner unless specific written approval of the Company for inclusions of such copyrighted or patented material is secured in advance. Executive also agrees that all work (or tangible expression of an idea) that Executive creates or contributes to the Company in the course of Executive’s employment hereunder will be created solely by Executive, will be original to Executive, and will be free of any third party claims or interests.

               (c)     Applications for Patent, Copyrights and Trademarks. Executive shall, if the Company so decides at its sole discretion and expense, apply for United States and foreign letters patent, copyrights, and/or trademarks, either in Executive’s name or as the Company in its sole discretion may direct. Executive hereby grants the Company the exclusive right, and appoints the Company as Executive’s attorney-in-fact, to execute and prosecute an application for domestic and/or foreign patent or other statutory protection, and Executive shall execute and deliver to the Company, without charge to the Company but at the Company’s expense, such other documents of registration and recordation, and do such other acts, such as give testimony in support of Executive’s inventorship, as may be necessary in the opinion of the Company to vest in the Company or any other party nominated by the Company, or otherwise to protect, the exclusive rights conveyed and/or granted to the Company pursuant to this Agreement. Executive’s duty to support the Company’s claim of rights in patents, copyrights, or trademarks claimed by the Company, and resulting from Executive’s service to the Company as its employee, shall continue for the life of any such patent, copyright or trademark.

               (d)     Assignment Except as otherwise may be agreed by the parties in a signed writing, Executive agrees to assign to the Company and its respective successors, licensees, and assigns, all of Executive’s rights, title and interests in and to the Intellectual Property governed by this Agreement and all rights, title, and interests in and to United States and foreign letters patent, copyrights, and trademarks resulting therefrom. Executive acknowledges this provision and understands fully its implications and meaning.

               (e)     Use. The Company and its respective successors, licensees, and assigns, shall have the sole and exclusive right to practice, or to make, use or sell products, processes or services derived from any discoveries or creations within the scope of this Agreement or created by Executive and covered by the terms of this Agreement, whether or not patentable or copyrightable under the laws of any jurisdiction, or protected by the trade secret laws of any jurisdiction.

               (f)     Trade Secret Protection. In the event that the Company decides not to pursue patent, copyright or trademark protection for any discovery or creation made by Executive, and instead decides to protect the discovery or creation pursuant to the trade secret laws of any jurisdiction, such decision shall not be construed as a waiver of the Company’s rights pursuant to this Agreement. At the Company’s expense, Executive shall also take whatever steps are necessary to sustain the Company’s claim to such trade secrets, including but not limited to: (a) maintaining the confidential nature of any such discoveries or creations; and (b) testifying and providing other support and substantiation for the Company’s claims with regard to the discovery or creation.

               (g)     Reports. With respect to discoveries made by Executive covered by the terms of this Agreement, Executive shall maintain notebooks and other records adequate to describe such discovery to others conversant in the subject of the technology and to establish the date and circumstances of Executive’s discovery. Executive shall notify the Company’s General Counsel of any such discoveries and shall make copies of all documents or reports relating to such discoveries available to the Company. Any such discovery shall be reported to the Company’s General Counsel regardless of whether, in Executive’s opinion, a

given discovery is of value to the Company, or is protectable under patent, copyright or the laws of any jurisdiction.

               (h)     Infringement Actions. In the event that the Company shall bring an infringement suit against any third parties or shall be sued by any third parties as a result of Executive’s authorship or creation, including any addition and/or modification of the aforementioned items of Confidential Information, Executive agrees to cooperate reasonably without charge to the Company, but at its request and expense, in defending against or prosecuting any such suit. This right shall be cumulative to any other rights of the Company hereunder.

     10.     Obligation of Confidentiality and Non-Competition. Executive agrees that Executive has a fiduciary duty to the Company and that Executive shall hold in confidence and shall not, except in the course of performing Executive’s employment obligations or pursuant to written authorization from the Company, at any time during or for three years after termination of Executive’s relationship with the Company knowingly (a) directly or indirectly reveal, report, publish, disclose or transfer the Confidential Information or any part thereof to any person or entity; (b) use any of the Confidential Information or any part thereof for any purpose other than for the benefit of the Company; (c) assist any person or entity other than the Company to secure any benefit from the Confidential Information or any part thereof or (d) solicit (on Executive’s behalf or on behalf of any third party) any employee of the Company for the purpose of providing services or products which Executive is prohibited from providing hereunder.

     Furthermore, Executive agrees that all Confidential Information, as defined below, shall belong exclusively and without any additional compensation to the Company. For the purposes of this Agreement, “Confidential Information” shall mean each of the following: (a) any information or material proprietary to the Company or designated as confidential either orally or in writing by the Company; and (b) any information not generally known by non- Company personnel; and (c) any information which Executive should know the Company would not care to have revealed to others or used in competition with the Company; and (d) any information which Executive made or makes, conceived or conceives, developed or develops or obtained or obtains knowledge or access through or as a result of Executive’s relationship with the Company (including information received, originated, discovered or developed in whole or in part by Executive) from the initial date of Executive’s employment with the Company.

     Furthermore, Executive agrees not to accept employment, consultancy or other business relationships with a business which directly competes with the Company’s then existing or planned business for twelve months following Executive’s last receipt of compensation from the Company. For the purpose of this paragraph, the Company’s business as of the date of this Agreement shall be defined as medical foods development and marketing. The parties acknowledge that the Company’s business after the date of this Agreement may evolve into other or additional areas and activities. Executive and Company agree that the terms of this Section 11 relating to non-competition are reasonable in scope and length and are necessary for the protection of the Company. In the event that a court finds the scope of this provision to be unreasonably broad or if the length of time of this provision is

found to be unreasonably long, an arbitrator or court, as applicable, shall narrow the scope or shorten the length of time to the extent required to render the provision reasonable and enforceable and shall enforce the provision as so narrowed.

     While employed by the Company and for a period of twelve months after the cessation of employment for any reason, Executive shall not induce or attempt to influence, either directly or indirectly any other employee or contractor of the Company to terminate his or her employment or relationship with the Company or to work for Executive or any other person or entity.

     11.     Miscellaneous.

               (a)     Entire Agreement. This Agreement contains the entire agreement between the parties hereto relating to the subject matter hereof, and this Agreement supersedes all prior understandings and agreements, whether oral or written, relating to the employment of the Executive by the Company.

               (b)     Assignment. This Agreement shall not be assignable or otherwise transferable by either party hereto, but any amounts owing to Executive upon the Executive’s death shall inure to the benefit of the Executive’s heirs, legatees, legal representatives, executor or administrator. Notwithstanding the foregoing, this Agreement applies with the prior written consent of the Executive, which consent shall not be unreasonably withheld. This Agreement shall be binding upon and shall inure to the benefit of the parties hereto and any such respective heirs, legatees, executors, administrators, representatives, successors and assigns.

               (c)     Notices. All notices, demands, requests or other communications which may be, or are required to be given, served or sent by any party to any party pursuant to this Agreement shall be in writing and shall be mailed by first class, registered or certified mail, return receipt requested, postage prepaid, or transmitted by hand delivery, telegram or telex and addressed as follows:

               (d)     Amendment; Waiver. This Agreement shall not be amended, altered, modified or discharged except by an instrument in writing duly executed by the Executive and the Company. Neither the waiver by the parties hereto of a breach of, or default under, any of the provisions of this Agreement, nor the failure of either of the parties, on one or more occasions, to enforce any of the provisions of this Agreement or to exercise any right or privilege hereunder, shall thereafter be construed as a waiver of any such provisions, rights or privileges hereunder.

               (e)     Severability. The invalidity or unenforceabilty of any provision or provisions of this Agreement shall not affect the validity or enforceability of any other provisions of this Agreement, which shall remain in full force and effect.

               (f)     Applicable Law. This Agreement and the rights and obligations of the parties under this Agreement shall be construed, interpreted and enforced in accordance with the laws of the State of Maryland, exclusive of the choice-of-laws rules thereunder.

               (g)     Survival. It is the express intention and agreement of the parties hereto that the provisions of Sections 8 7, 9, 10 and 11 hereof shall survive the termination of employment of the Executive. In addition, all obligations of the Company to make payments hereunder shall survive any termination of this Agreement on the terms and conditions set forth.

               (h)     Execution. To facilitate execution, this Agreement may be executed in as many counterparts as may be required; and it shall not be necessary that the signatures of, or on behalf of, each party, or that the signatures of all persons required to bind any party, appear on each counterpart; but it shall be sufficient that the signature of, or on behalf of, each party, or that the signatures of the persons required to bind any party, appear on one or more of the counterparts. All counterparts shall collectively constitute a single agreement. It shall not be necessary in making proof of this Agreement to produce or account for more than a number of counterparts containing the respective signatures of, or on behalf of, all of the parties hereto.

     IN WITNESS WHEREOF, the undersigned have duly executed this Agreement, or have caused this Agreement to be duly executed on their behalf, as of the date first above written.

Exhibit 10.2

EMPLOYMENT AGREEMENT

     THIS EMPLOYMENT AGREEMENT (this “Agreement”) is entered into as of December 29, 2000 by and between UTSC Sub Acquisition, Inc. (the “Company”) and Ricardo A. Balda (the “Executive”).

     WHEREAS, the Company desires to obtain the services of the Executive, and the Executive is willing to render such services to the Company, upon the terms and conditions herein set forth;

     NOW, THEREFORE, in consideration of the promises and mutual covenants contained herein; and for other good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties hereto agree as follows:

     1.     Employment. Upon the other terms and conditions hereinafter stated, the Company agrees to employ the Executive and the Executive agrees to accept employment by the Company for the term set forth in Section 2 hereof and in the position and with the duties and responsibilities set forth in Section 3 hereof. Executive warrants that he is under no restriction that would prevent him from entering into this Agreement and from complying with all of its provisions to their fullest extent.

     2.     Term. The employment of the Executive by the Company will commence on January 2, 2001 and end on the fifth anniversary of such date (the “Initial Term”), and thereafter shall continue from year to year for additional one-year terms (the “Additional Terms”), unless and until either party shall give notice of such party’s intent to terminate not less than 90 days prior to the end of the then-current Initial Term or Additional Term, which termination shall be effective at the expiration of said term, or until sooner terminated as hereinafter set forth.

     3.     Positions and Duties.

               (a)     The Executive shall serve as co-Chief Executive Officer of the Company, with such duties and responsibilities as are normally performed by the Chief Executive Officer of a medical device/telemedicine services company and as otherwise assigned by the Board of Directors from time to time that are consistent with duties and responsibilities as are normally performed by the Chief Executive Officer. The Executive shall at all times exert his best efforts and loyalty on behalf of the Company. Unless otherwise provided herein, the Executive agrees to abide by all employment guidelines and policies as may be developed from time to time by the Company, including, without limitation, the United Therapeutics Corporation Company Manual, the United Therapeutics Corporation Securities Trades by Company Personnel Policy and the United Therapeutics Corporation Media and Analysts Policy. Martine Rothblatt, the Chairman and CEO of United Therapeutics Corporation, will serve as the Company’s other co-CEO. In the event that Martine Rothblatt ceases to serve as

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Chairman or CEO of UT, then the Executive shall serve as the sole CEO of the Company.

               (b)     United Therapeutics Corporation shall cause the number of members of its Board of Directors to be increased by one and shall cause the Executive to be appointed to fill such newly created directorship.

     4.     Compensation and Related Matters.

               (a)     For services rendered under this Agreement, the Company shall pay to the Executive an initial annual base salary of Two Hundred Thousand Dollars ($200,000) (the “Base Salary’), subject to increase, which shall be considered and determined by the Board of Directors of the Company, in its sole discretion, on or before any anniversary date of this Agreement. The Base Salary shall be payable semi-monthly or in such other installments as shall be consistent with the Company’s payroll procedures, but not less often than monthly. The Company shall deduct and withhold all necessary social security and withholding taxes and any other similar sums required by law or authorized by the Executive with respect to payment of the Base Salary and all other amounts and benefits payable under this Agreement.

               (b)     The Executive shall be entitled to participate in any group life, disability and medical insurance or other benefit plan or arrangement available generally to the employees of the Company as determined by the Board of Directors; provided however, the Company shall allow Employee to become eligible to participate in such programs under the shortest eligibility period allowable under the relevant documents or other applicable laws. Unless otherwise provided herein, the Executive shall be entitled to participate in other benefit plans as are generally provided by United Therapeutics Corporation to Chief Executive Officers of its subsidiaries and to its Board of Directors, including, but not limited to, other cash and stock option bonus plans.

               (c)     As an inducement to executive to enter into this Agreement, Executive shall be granted within thirty days of Closing an option to purchase 40,000 shares of the common stock of United Therapeutics Corporation outside of the Company’s Equity Incentive Plan priced at the NASDAQ closing price on the date of this Agreement, with vesting in one-fourth increments on each anniversary of this Agreement. Executive shall enter into a separate stock option agreement with United Therapeutics Corporation setting forth the terms of this option grant.

               (d)     The Executive shall be entitled to participate in the Company’s Employee Incentive Bonus Pool adopted by the Company as of the date of this Agreement and contemplated by that Employee Incentive Bonus Pool Agreement dated December 28, 2000. Executive shall be entitled to receive one-third of the amounts funded and/or paid under paragraph 1 of the Employee Incentive Bonus Pool Agreement dated December 28, 2000. Executive shall also be entitled to participate in any other bonus compensation program as are generally provided by United

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Therapeutics Corporation to its Chief Executive Officers, Board of Directors or employees.

     5.     Expenses. The Executive shall be reimbursed by the Company for reasonable and ordinary business expenses incurred by the Executive in the performance of his responsibilities and the promotion of the Company’s businesses and accounted for in accordance with the Company’s normal practices, including, without limitation, travel and lodging, parking at or near the Company’s offices, phone charges, club memberships and dues, meals and other expenses, as approved from time to time by the Board of Directors. In addition, the Company shall also provide the Executive with a monthly automobile allowance equal to the amount of the Executive’s lease payments on his current automobile, a BMW540, which lease matures in December 2000, but not to exceed $1,000 per month. Thereafter, the Company shall lease a comparable automobile for use of the Executive through the end of the Initial Term or, if applicable, the end of any Additional Terms. The Company shall also pay the reasonable and ordinary fees for The Executive Committee, a support organization for CEOs.

     6     Vacation. The Executive shall be entitled to five (5) weeks of vacation each year at such time or times and for such period or periods as shall be mutually agreed upon by the Executive and the Company.

     7.     Termination of Employment.

               (a)     The Executive’s employment hereunder shall terminate upon the Executive’s death.

               (b)     The Company may terminate the Executive’s employment hereunder as set forth in Section 2 above, and under the following circumstances:

                         (i)     If, as a result of the Executive’s incapacity due to physical or mental illness, the Executive shall have been unable to perform all of the Executive’s material duties hereunder by reason of illness, or physical or mental disability or other similar capacity, which inability shall continue for more than three (3) consecutive months, the Company may terminate the Executive’s employment hereunder.

                         (ii)     The Company may terminate the Executive’s employment hereunder for “Cause.” For purposes of this Agreement, the Company shall have “Cause” to terminate the Executive’s employment hereunder upon the (A) negligence, malfeasance, willful misconduct or fraud on the part of the Executive in the performance of his Duties hereunder and the failure of the Executive, within 10 days after receipt of notice from the Company setting forth in reasonable detail the nature of the Executive’s alleged negligence, malfeasance, willful misconduct or fraud, (i) to provide the Company with a reasonably satisfactory explanation of the Executive’s actions (or inaction) and (ii) to reasonably correct to the satisfaction of the Company any such misconduct; (B) conviction of the Executive of a crime involving a felony,

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fraud, embezzlement or the like; or (C) misappropriation of the Company funds or misuse of the Company’s assets by Executive.

               (c)     The Executive may terminate his employment hereunder for “Good Reason.” For purposes of this Agreement, the Executive shall have “Good Reason” to terminate his employment hereunder upon (A) the change in control of United Therapeutics Corporation or the Company by any means including, but not limited to, any company or companies acquiring, directly or indirectly, all or substantially all of the assets of United Therapeutics Corporation or the Company, whether by merger, consolidation, purchase, lease or otherwise; or (B) the filing for bankruptcy or dissolution proceedings by United Therapeutics Corporation or the Company.

               (d)     Any termination of the Executive’s employment by the Company or by the Executive (other than pursuant to Section 7(a) hereof) shall be communicated by written “Notice of Termination” to the other party hereto in accordance with Section 12(c) hereof, which shall indicate the specific termination provision in this Agreement relied upon, if any, and shall set forth in reasonable detail the facts and circumstances claimed to provide a basis for termination of the Executive’s employment under the provision so indicated.

               (e)     For purposes of this Agreement, the “Date of Termination” shall mean (i) if the Executive’s employment is terminated by the Executive’s death, the date of the Executive’s death; (ii) if the Executive’s employment is terminated pursuant to Section 7(b)(i) hereof, thirty (30) days after the Notice of Termination; provided, that the Executive shall not have returned to the performance of the Executive’s duties on a full-time basis during such thirty (30) day period; (iii) if the Executive’s employment is terminated pursuant to Section 7(b)(ii) hereof, the date specified in the Notice of Termination which date, in the case of termination for negligent performance, shall not be sooner than thirty (30) days from the date of the Notice of Termination; and (iv) if the Executive’s employment is terminated for any other reason, the date on which the Notice of Termination is given; provided however, the date provided in such Notice of Termination shall not be less than 90 days after the Notice of Termination is sent pursuant to Section 12(c) hereof.

     8.     Compensation Upon Termination.

               (a)     If the Executive’s employment is terminated by the Executive’s death, the Company shall continue to pay to the Executive’s estate or as may be directed by the legal representatives of such estate, the Executive’s full Base Salary through the end of the calendar year following the Executive’s death at the rate in effect at the time of the Executive’s death and all other unpaid amounts, if any, to which the Executive is entitled as of such date in connection with any fringe benefits or under any incentive compensation plan or program of the Company pursuant to Section 4 hereof, at the time such payments are due.

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               (b)     During any period that the Executive fails to perform the Executive’s duties hereunder solely as a result of incapacity due to physical or mental illness (“disability period”), the Executive shall continue to receive the Executive’s full base salary through the Date of Termination at the rate in effect at the time the Notice of Termination is given and all other unpaid amounts, if any, to which the Executive is entitled as of the Date of Termination in connection with any fringe benefits or under any incentive compensation plan or program of the Company, at the time such payments are due; provided that payments so made to the Executive during the disability period shall be reduced by the sum of the amounts, if any, payable to the Executive at or prior to the time of any such payment under disability benefit plans of the Company and which amounts were not previously applied to reduce any such payment.

               (c)     If the Executive shall terminate the Executive’s employment other than for Good Reason as provided in Section 7(c) hereof or the Company terminates the Executive’s employment for Cause as provided in Section 7(b)(ii) hereof, the Company shall pay the Executive the Executive’s full Base Salary through the Date of Termination at the rate in effect at the time the Notice of Termination is given, and the Company shall have no further obligations to the Executive under this Agreement. If the Company terminates the Executive’s employment other than for Cause as provided in Section 7(b)(ii) hereof, Executive shall continue to receive payments under the Company’s Employee Incentive Bonus Pool for the full term the Pool is in existence.

               (d)     If the Company terminates this Agreement without Cause or if the Executive terminates this Agreement for Good Reason as provided for in paragraph 7 above, then the Executive shall receive the following termination benefits: (1) an amount equal to the Executive’s then current Base Salary, plus (2) the greater of $70,000 or the amount of Executive’s most recent annual bonus paid under Section 4(d) (collectively (1) and (2) hereinafter referenced as “Termination Benefits”) for each year of the period ending on the earlier of (i) five (5) years from the date of such termination, or (ii) the tenth (10th) anniversary date following the execution of this Agreement by both parties. The Termination Benefits shall be paid in such manner as normally and customarily are paid by the Company. If the Company terminates this Agreement at the end of the Initial Term or at the end of any Additional Term, then the Executive shall be entitled to receive the Termination Benefits for each year of the period between such termination and January 1, 2011.

     9.     Intellectual Property Rights. Because of the highly specialized and technical nature of the business of the Company and the nature and scope of Executive’s employment, Executive agrees that any and all rights, title, and interest, including but not limited to domestic and foreign patents, copyrights, trademarks and trade secrets, in and to all inventions, processes, computer programs, photographic, written or artistic works, or other forms of intellectual property (“Intellectual Property”) which employee makes, conceives, reduces to practice or develops, in whole or in part, during the term of this Agreement in the furtherance of the Company’s business and in connection with specific Company projects as defined in Paragraph 10 below (whether or not made during the hours of employment or with the use of

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Company’s materials, facilities or personnel, either solely or jointly with others), or after termination of employment if such Intellectual Property is based upon Confidential Information, shall be the sole and exclusive property of the Company, and its respective successors, licensees, and assigns. Neither this Paragraph nor any of its subparts shall apply to any invention developed entirely on Executive’s own time without using the Company’s equipment, supplies, facilities or Confidential Information, except for those items and inventions that either: (i) relate, at the time of conception or reduction to practice of the invention, to the Company’s business or any of the products or services being developed, manufactured, sold or licensed by the Company or which may conveniently be used in relation therewith, or actual, or demonstrably anticipated research or development of the Company, or (ii) result from any work performed by Executive for the Company. In full consideration of the compensation provided to Executive by the Company, Executive agrees to each and all of the following:

               (a)     Work Made for Hire. Executive acknowledges and agrees that all works of authorship created by Executive as an employee of the Company is a commissioned “work for hire” within the meaning of United States copyright law which will be owned solely and exclusively by the Company. If the work is determined not to be a “work for hire” or such doctrine is not effective, Executive hereby irrevocably assigns, conveys and otherwise transfers to the Company, and its respective successors, licensees, and assigns, all right, title and interest worldwide in and to the work and all proprietary rights therein, including, without limitation, all copyrights, trademarks, design patents, trade secret rights, moral rights, and all contract and licensing rights, and all claims and causes of action with respect to any of the foregoing, whether now known or hereafter to become known. In the event that Executive has any right in the work which cannot be assigned, Executive agrees to waive enforcement worldwide of such right against the Company, its distributors and licensees or, if necessary, exclusively license such right, worldwide to the Company with the right to sublicense. These rights are assignable by the Company. Executive has not and hereby does not transfer any Intellectual Property rights owned or held solely by Executive to the Company relating to periods prior to the date of this Agreement and retains all rights to same provided, however, that Executive acknowledges that Intellectual Property rights that he created as an employee of Medicomp, Inc, or Telemedical Procedures, LLC. prior to the date of this Agreement, and not otherwise previously assigned or transferred prior to the date of this Agreement pursuant to the attached schedule, are solely owned by the Company as a work made for hire.

               (b)     Original Work. Executive agrees that Executive will not include any copyrighted or patented material owned by a third party in any written, copyrightable or patentable material furnished or delivered by Executive under this Agreement without the unconditional written consent of the copyright or patent owner unless specific written approval of the Company for inclusions of such copyrighted or patented material is secured in advance. Executive also agrees that all work (or tangible expression of an idea) that Executive creates or contributes to the Company in the course of Executive’s employment hereunder will be created solely by Executive, will be original to Executive, and will be free of any third party claims or interests.

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               (c)     Applications for Patent, Copyrights and Trademarks. Executive shall, if the Company so decides at its sole discretion and expense, apply for United States and foreign letters patent, copyrights, and/or trademarks, either in Executive’s name or as the Company in its sole discretion may direct. Executive hereby grants the Company the exclusive right, and appoints the Company as Executive’s attorney-in-fact, to execute and prosecute an application for domestic and/or foreign patent or other statutory protection, and Executive shall execute and deliver to the Company, without charge to the Company but at the Company’s expense, such other documents of registration and recordation, and do such other acts, such as give testimony in support of Executive’s inventorship, as may be necessary in the opinion of the Company to vest in the Company or any other party nominated by the Company, or otherwise to protect, the exclusive rights conveyed and/or granted to the Company pursuant to this Agreement. Executive’s duty to support the Company’s claim of rights in patents, copyrights, or trademarks claimed by the Company, and resulting from Executive’s service to the Company as its employee, shall continue for the life of any such patent, copyright or trademark.

               (d)     Assignment. Except as otherwise may be agreed by the parties in a signed writing, Executive agrees to assign to the Company and its respective successors, licensees, and assigns, all of Executive’s rights, title and interests in and to the Intellectual Property governed by this Agreement and all rights, title, and interests in and to United States and foreign letters patent, copyrights, and trademarks resulting therefrom. Executive acknowledges this provision and understands fully its implications and meaning.

               (e)     Use. The Company and its respective successors, licensees, and assigns, shall have the sole and exclusive right to practice, or to make, use or sell products, processes or services derived from any discoveries or creations within the scope of this Agreement or created by Executive and covered by the terms of this Agreement, whether or not patentable or copyrightable under the laws of any jurisdiction, or protected by the trade secret laws of any jurisdiction.

               (f)     Trade Secret Protection. In the event that the Company decides not to pursue patent, copyright or trademark protection for any discovery or creation made by Executive, and instead decides to protect the discovery or creation pursuant to the trade secret laws of any jurisdiction, such decision shall not be construed as a waiver of the Company’s rights pursuant to this Agreement. At the Company’s expense, Executive shall also take whatever steps are necessary to sustain the Company’s claim to such trade secrets, including but not limited to: (a) maintaining the confidential nature of any such discoveries or creations; and (b) testifying and providing other support and substantiation for the Company’s claims with regard to the discovery or creation.

               (g)     Reports. With respect to discoveries made by Executive covered by the terms of this Agreement, Executive shall maintain notebooks and other records adequate to describe such discovery to others conversant in the subject of the technology and to establish the date and circumstances of Executive’s discovery.

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     Executive shall notify the Company’s General Counsel of any such discoveries and shall make copies of all documents or reports relating to such discoveries available to the Company. Any such discovery shall be reported to the Company’s General Counsel regardless of whether, in Executive’s opinion, a given discovery is of value to the Company, or is protectable under patent, copyright or the laws of any jurisdiction.

               (h)     Infringement Actions. In the event that the Company shall bring an infringement suit against any third parties or shall be sued by any third parties as a result of Executive’s authorship or creation, including any addition and/or modification of the aforementioned items of Confidential Information, Executive agrees to cooperate reasonably without charge to the Company, except for reimbursement for reasonable expenses incurred by Executive for activities authorized in advance by Company, in defending against or prosecuting any such suit. This right shall be cumulative to any other rights of the Company hereunder.

     10.     Obligation of Confidentiality and Non-Competition. Executive agrees that Executive has a fiduciary duty to the Company and that Executive shall hold in confidence and shall not, except in the course of performing Executive’s employment obligations or pursuant to written authorization from the Company, at any time during or for three years after termination of Executive’s employment with the Company knowingly (a) directly or indirectly reveal, report, publish, disclose or transfer the Confidential Information or any part thereof to any person or entity; (b) use any of the Confidential Information or any part thereof for any purpose other than for the benefit of the Company; (c) assist any person or entity other than the Company to secure any benefit from the Confidential Information or any part thereof.

     Furthermore, Executive agrees that all Confidential Information, as defined below, shall belong exclusively and without any additional compensation to the Company. For the purposes of this Agreement, “Confidential Information” shall mean each of the following: (a) any information or material proprietary to the Company or designated as confidential either orally or in writing by the Company; and (b) any information not generally known by non-Company personnel; and (c) any information which Executive should know the Company would not care to have revealed to others or used in competition with the Company discovered or developed in whole or in part by Executive) from the initial date of Executive’s employment with the Company.

     Furthermore, Executive agrees not to accept employment, consultancy or other business relationships with a business which directly competes with the Company’s then existing or planned business for twelve months following Executive’s last receipt of compensation from the Company; provided however, the Executive shall have the right to waive his right to receive any further compensation from the Company after the five year period immediately following the termination of his employment with the Company. For the purpose of this paragraph, the Company’s business as of the date of this Agreement shall be defined as telemedicine devices and telemedicine services produced, sold, conducted, developed, or in the process of development by the Company on the date of termination. The parties acknowledge that the Company’s business after the date of this Agreement may evolve into other or additional areas and activities.

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Executive and Company agree that the terms of this Section 10 relating to non-competition are reasonable in scope and length and are necessary for the protection of the Company. In the event that a court finds the scope of this provision to be unreasonably broad or if the length of time of this provision is found to be unreasonably long, an arbitrator or court, as applicable, shall narrow the scope or shorten the length of time to the extent required to render the provision reasonable and enforceable and shall enforce the provision as so narrowed.

     While employed by the Company and for a period of twelve months after the cessation of employment for any reason, Executive shall not induce or attempt to influence, either directly or indirectly any other employee or contractor of the Company to terminate his or her employment or relationship with the Company or to work for Executive or any other person or entity.

     11.     Indemnification. The Company shall indemnify, defend and hold and save Executive, his heirs, administrators and executors, and each of them, harmless for any and all actions and causes of action, claims, demands, liabilities, losses, damages or expenses, of whatsoever kind and nature, including judgments, interest and attorneys’ fees and all other reasonable costs, expenses and charges which he, his heirs, administrators and executors, or any of them shall or may be at any time, or from time to time, subsequent to the date of this Agreement sustain or incur, or become subject to by reason of any claim or claims against him, his heirs, administrators or executors or any of them for any reason related to his or his heirs, administrators or executors, or any of them, carrying out the terms and conditions of his responsibilities under this Agreement, except for willful misconduct or criminal acts under U.S. law, and provided further that Executive, his heirs, administrators, executors, or any one of them promptly notifies the Company and its general counsel of adverse claims or threatened or actual lawsuits. United Therapeutics Corporation shall purchase and maintain adequate insurance for this such indemnification coverage from a carrier mutually acceptable to United Therapeutics Corporation and the Executive.

     12     Miscellaneous.

               (a)     Entire Agreement. This Agreement contains the entire agreement between the parties hereto relating to the subject matter hereof, and this Agreement supersedes all prior understandings and agreements, whether oral or written, relating to the employment of the Executive by the Company.

               (b)     Assignment. Neither this Agreement, nor any of Executive’s rights, powers, duties or obligations hereunder may be assigned by Employee; provided however, any amounts owing to Executive upon the Executive’s death shall inure to the benefit of the Executive’s heirs, legatees, legal representatives, executor or administrator. Successors of the Company shall include, without limitation, any company or companies acquiring, directly or indirectly, all or substantially all of the assets of the Company, whether by merger, consolidation, purchase, lease or otherwise, and such successor shall thereafter be deemed “the Company” for the purpose hereof.

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               (c)     Notices. All notices, demands, requests or other communications which may be, or are required to be given, served or sent by any party to any party pursuant to this Agreement shall be in writing and shall be mailed by first class, registered or certified mail, return receipt requested, postage prepaid, or transmitted by hand delivery, telegram or telex and addressed as follows:

If to the Executive:

Personal & Confidential—To Be Opened by Addressee Only Ricardo Balda 7845 Ellis Road Melbourne, Florida 32904

                                      If to the Company:

UTSC Sub Acquisition, Inc. c/o United Therapeutics Corporation 1110 Spring Street Silver Spring, MD 20910 Attn: CEO

With a copy to:

Paul A. Mahon, Esq. United Therapeutics Corporation 1110 Spring Street Silver Spring, Maryland 20910

               (d)     Amendment; Waiver. This Agreement shall not be amended, altered, modified or discharged except by an instrument in writing duly executed by the Executive and the Company. Neither the waiver by the parties hereto of a breach of, or default under, any of the provisions of this Agreement, nor the failure of either of the parties, on one or more occasions, to enforce any of the provisions of this Agreement or to exercise any right or privilege hereunder, shall thereafter be construed as a waiver of any such provisions, rights or privileges hereunder.

               (e)     Severability. The invalidity or unenforceability of any provision or provisions of this Agreement shall not affect the validity or enforceability of any other provisions of this Agreement, which shall remain in full force and effect.

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               (f)     Applicable Law. This Agreement and the rights and obligations of the parties under this Agreement shall be construed, interpreted and enforced in accordance with the laws of the State of Florida, exclusive of the choice-of-laws rules thereunder. Each of the parties hereto hereby irrevocably consents and submits to jurisdiction of the Circuit Court of the 18th Judicial Circuit in and for Brevard County, Florida and United States District Court the Middle District of Florida in connection with any suit, action or other proceeding concerning the interpretation or enforcement of this Agreement. Each party waives and agrees not to assert any defense that the court lacks jurisdiction, venue is improper, inconvenient forum or otherwise.

               (g)     Attorneys Fees. If either party initiates proceedings for the other’s breach of this Employment Agreement, the prevailing party shall recover its/his reasonable attorneys’ fees and costs, including such fees and costs of any enforcement or appeal proceedings.

               (h)     Survival. It is the express intention and agreement of the parties hereto that the provisions of Sections 8, 9, 10, 11 and 12 hereof shall survive the termination of employment of the Executive. In addition, all obligations of the Company to make payments hereunder shall survive any termination of this Agreement on the terms and conditions set forth herein. All obligations of the Company to make payments hereunder shall also be binding upon successors of the Company whether by merger, consolidation, purchase, lease or otherwise.

               (i)     Execution. To facilitate execution, this Agreement may be executed in as many counterparts as may be required; and it shall not be necessary that the signatures of, or on behalf of, each party, or that the signatures of all persons required to bind any party, appear on each counterpart; but it shall be sufficient that the signature of, or on behalf of, each party, or that the signatures of the persons required to bind any party, appear on one or more of the counterparts. All counterparts shall collectively constitute a single agreement. It shall not be necessary in making proof of this Agreement to produce or account for more than a number of counterparts containing the respective signatures of, or on behalf of, all of the parties hereto.

     IN WITNESS WHEREOF, the undersigned have duly executed this Agreement, or have caused this Agreement to be duly executed on their behalf, as of the date first above written.

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Exhibit 10.3

EMPLOYMENT AGREEMENT

     THIS EMPLOYMENT AGREEMENT (this “Agreement”) is entered into as of October 1, 2001 by and between United Therapeutics Corporation (the “Company”) and Barry Kanarek, Ph.D. (“Executive”).

     WHEREAS, the Company currently employs Executive as the President of its Unither Pharmaceuticals, Inc. subsidiary, and Executive shall continue in this capacity subject to the terms and conditions contained herein; and

     WHEREAS, the parties desire this Agreement to supersede and replace all previous agreements for employment entered into between the Company and Executive.

     NOW, THEREFORE, in consideration of the promises and mutual covenants contained herein, and for other good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties hereto agree as follows.

     1.     Employment. Company agrees to continue to employ Executive and Executive agrees to accept such continuing employment by the Company for the term set forth in Section 2 hereof and in the position and with the duties and responsibilities set forth in Section 3 hereof. Executive warrants that he is under no restriction that would prevent him from entering into this Agreement and from complying with all of its provisions to their fullest extent.

     2.     Term. The employment of Executive by the Company will commence on October 1, 2001 and end on the third anniversary of such date (the “Initial Term”), and thereafter shall continue from year to year for additional one-year terms (the “Additional Terms”), unless and until either party shall give notice of such party’s intent to terminate not less than 30 days prior to the end of the then-current Initial Term or Additional Term, which termination shall be effective at the expiration of said term, or until sooner terminated as hereinafter set forth.

     3.     Position and Duties. Executive shall continue to serve as President of Unither Pharmaceuticals, Inc., or such other Executive Position as the CEO determines, with such duties and responsibilities as are normally performed by the President of a biotechnology company or as otherwise assigned by the CEO of the Company. Executive shall have primary responsibility for the operations of the Company’s subsidiaries Unither Pharmaceuticals, Inc., Cooke Pharma, Inc., and Medicomp, Inc. These duties shall include, without limitation, the management of the Company’s iminosugar drug development program, and serving as Chief Operating Officer of Cooke Pharma, Inc. and Medicomp, Inc. Executive shall at all times exert his best efforts and loyalty on behalf of the Company and shall devote full time and attention to such employment. Executive agrees to abide by all employment guidelines and policies as may be developed from time to time by the Company, including, without limitation, the United Therapeutics Corporation Company Manual, the United Therapeutics Corporation Securities Trades by

Company Personnel Policy, and the United Therapeutics Corporation Media & Analyst Communication Policy.

     4.     Compensation and Related Matters. Effective October 1, 2001, the Company shall provide the following compensation and benefits to Executive:

             (a)     The Company shall pay to Executive an annual base salary of Two Hundred Thousand Dollars ($200,000) (the “Base Salary”). The Base Salary shall be payable semi-monthly or in such other installments as shall be consistent with the Company’s payroll procedures. The Company shall deduct and withhold all necessary social security and withholding taxes and any other similar sums required by law or authorized by Executive with respect to payment of the Base Salary and all other amounts and benefits payable under this Agreement.

             (b)     Executive shall be entitled to participate in any group life, disability and medical insurance or other benefit plan or arrangement available generally to the employees of the Company as determined by the Board of Directors.

             (c)     Executive shall be entitled to receive bonus compensation according to the following schedule:

                       (i)     For 2002, Executive shall be entitled to receive $10,000 and options to purchase 10,000 shares of the Company’s common stock for each calendar quarter that Medicomp is cash-flow positive, and $10,000 and options to purchase 10,000 shares of the Company’s common stock for each calendar quarter that Cooke Pharma is cash-flow positive;

                       (ii)     For 2003, Executive shall be entitled to receive $10,000 and options to purchase 10,000 shares of the Company’s common stock for each calendar quarter that Medicomp produces revenue at a $10 million annualized rate, and $10,000 and options to purchase 10,000 shares of the Company’s common stock for each calendar quarter that Cooke Pharma concludes with 10,000 paying subscribers at $49.99/month or more;

                       (iii)    For 2004, Executive shall be entitled to receive $10,000 and options to purchase 10,000 shares of the Company’s common stock for each calendar quarter that Medicomp produces at least ten cents per share of the Company’s earnings, and $10,000 and options to purchase 10,000 shares of the Company’s common stock for each calendar quarter that Cooke Pharma produces at least ten cents per share of the Company’s earnings;

                       (iv)    The exercise price of all options to purchase shares of the Company’s common stock granted in this Section 4(c) shall be at the NASDAQ closing price of the Company’s common stock on January 1, 2002;

                       (v)     Options granted in this Section 4(c) shall vest as follows: 50% of the options allocable to each calendar quarter shall vest upon achievement of the corresponding milestone, and 50% shall vest 12 months from achievement of the milestone. The Company shall make the determination of whether or not a particular milestone has been

achieved based upon information contained in the Company’s Quarterly Report filed with the SEC on Form 10-Q and such other books and records of the Company maintained in the ordinary course of business. Cash bonuses earned hereunder shall be payable to Executive upon the Company’s determination that a corresponding option grant has vested.

             (d)     All options previously awarded Executive, whether under any prior agreement or otherwise, shall be unaffected by this Agreement.

     5.     Expenses. Executive shall be reimbursed by the Company for reasonable travel and other expenses that are incurred and accounted for in accordance with the Company’s normal practices and policies.

     6.     Vacation. Executive shall be entitled to vacation at such time or times and for such period or periods as shall be mutually agreed upon by Executive and the CEO, with the number of vacation days determined in accordance with the Company’s employee manual.

     7.     Termination of Employment.

             (a)     Executive’s employment hereunder shall terminate upon Executive’s death.

             (b)     The Company may terminate Executive’s employment hereunder as set forth in Section 2 above, and under the following circumstances:

                       (i)     If, as a result of Executive’s incapacity due or other disability owing to physical or mental illness, Executive shall have been unable to perform all of Executive’s material duties hereunder by reason of illness, or physical or mental disability or other similar capacity, which inability shall continue for more than two (2) consecutive months, the Company may terminate Executive’s employment hereunder.

                       (ii)     The Company may terminate Executive’s employment hereunder for “Cause.” For purposes of this Agreement, the Company shall have “Cause” to terminate Executive’s employment hereunder upon the (A) failure of Executive (other than for reasons described in Sections 7(a) and 7(b)(i) hereof) to perform or observe any of the material terms or provisions of this Agreement; (B) negligent or unsatisfactory performance of Executive’s duties under this Agreement and the failure of Executive, within 10 days after receipt of notice from the Company setting forth in reasonable detail the nature of Executive’s negligent or unsatisfactory performance, (i) to provide the Company with a reasonably satisfactory explanation of Executive’s actions (or inaction) and (ii) to correct to the satisfaction of the Company any reasonably identified deficiencies; (C) employment- or profession-related misconduct or other employment- or profession-related similar action on the part of Executive; (D) conviction of Executive of a crime involving a felony, fraud, embezzlement or the like; or (E) misappropriation of the Company funds or misuse of the Company’s assets by Executive, or other act of dishonesty by Executive.

             (c)     Any termination of Executive’s employment by the Company or by Executive (other than pursuant to Section 7(a) hereof) shall be communicated by written

“Notice of Termination” to the other party hereto in accordance with Section 10(c) hereof, which shall indicate the specific termination provision in this Agreement relied upon, if any, and shall set forth in reasonable detail the facts and circumstances claimed to provide a basis for termination of Executive’s employment under the provision so indicated.

             (d)     For purposes of this Agreement, the “Date of Termination” shall mean (i) if Executive’s employment is terminated by Executive’s death, the date of Executive’s death; (ii) if Executive’s employment is terminated pursuant to Section 7(b)(i) hereof, thirty (30) days after the Notice of Termination; provided , that Executive shall not have returned to the performance of Executive’s duties on a full-time basis during such thirty (30) day period; (iii) if Executive’s employment is terminated pursuant to Section 7(b)(ii) hereof, the date specified in the Notice of Termination (which date, in the case of termination of Executive’s employment solely pursuant to clause (B) of Section 7(b)(ii) by reason of inadequate performance, shall not be sooner than thirty (30) days from the date of the Notice of Termination); and (iv) if Executive’s employment is terminated for any other reason, the date on which the Notice of Termination is given.

             (e)     Following termination of this Agreement, Executive shall promptly make himself reasonably available to assist the Company with any information or other requests.

             (f)     For a period of 91 days following termination of this Agreement, Executive shall not trade in the Company’s stock and shall not make and corresponding filings with the SEC without obtaining advance written permission of the Company’s General Counsel.

     8.     Compensation Upon Termination.

             (a)     If Executive’s employment is terminated by Executive’s death, the Company shall pay to Executive’s estate or as may be directed by the legal representatives of such estate, Executive’s full Base Salary through the Date of Termination at the rate in effect at the time of Executive’s death and all other unpaid amounts, if any, to which Executive is entitled as of such date in connection with any fringe benefits or under any incentive compensation plan or program of the Company pursuant to Section 4(c) hereof, at the time such payments are due.

             (b)     During any period that Executive fails to perform Executive’s duties hereunder solely as a result of incapacity due to physical or mental illness (“Disability Period”), Executive shall continue to receive Executive’s full base salary through the Date of Termination at the rate in effect at the time the Notice of Termination is given and all other unpaid amounts, if any, to which Executive is entitled as of the Date of Termination in connection with any fringe benefits or under any incentive compensation plan or program of the Company hereof, at the time such payments are due; provided that payments so made to Executive during the Disability Period shall be reduced by the sum of the amounts, if any, payable to Executive at or prior to the time of any such payment under disability benefit plans of the Company and which amounts were not previously applied to reduce any such payment.

             (c)     If Executive shall terminate Executive’s employment or the Company terminates Executive’s employment for Cause as provided in Section 7(b)(ii) hereof, the Company shall pay Executive Executive’s full Base Salary through the Date of Termination at the rate in effect at the time the Notice of Termination is given, and the Company shall have no further obligations to the to Executive under this Agreement.

             (d)     Subject to Section 8(e) below, if the Company terminates Executive’s employment without Cause, the Company shall pay to Executive an amount equal to 180 days of Executive’s Base Salary, payable in semi-monthly installments and as is otherwise consistent with the Company’s payroll procedures.

             (e)     If Executive chooses to terminate his employment or the Company terminates Executive’s employment without Cause solely as a result of either (i) the transfer of control of the Company by acquisition, merger, or hostile takeover, or (ii) if the Company’s current CEO Martine Rothblatt leaves employment with the Company and Executive then chooses to leave employment with the Company or is terminated without Cause, then the Company shall pay to Executive an amount equal to 360 days of Executive’s Base Salary, payable in semi-monthly installments and as is otherwise consistent with the Company’s payroll procedures.

             (f)     Compensation to Executive upon termination described in this Section 8 shall be and is hereby made expressly contigent upon Executive’s ongoing compliance with non-competition, confidentiality, non-solicitation, continuing cooperation and all other obligations of Executive that survive termination of this Agreement.

     9.     Intellectual Property Rights. Because of the highly specialized and technical nature of the business of the Company and the nature and scope of Executive’s employment, Executive agrees that any and all rights, title, and interest, including but not limited to domestic and foreign patents, copyrights, trademarks and trade secrets, in and to all inventions, processes, computer programs, photographic, written or artistic works, or other forms of intellectual property (“Intellectual Property”) which employee makes, conceives, reduces to practice or develops, in whole or in part, during the term of this Agreement in the furtherance of the Company’s business and in connection with specific Company projects as defined in this Section 9 (whether or not made during the hours of employment or with the use of Company’s materials, facilities or personnel, either solely or jointly with others), or after termination of employment if such Intellectual Property is based upon Confidential Information, shall be the sole and exclusive property of the Company, and its respective successors, licensees, and assigns. In full consideration of the compensation provided to Executive by the Company, Executive agrees to each and all of the following:

             (a)     Work Made for Hire. Executive acknowledges and agrees that all works of authorship created by Executive as an employee of the Company is a commissioned “work for hire” within the meaning of United States copyright law which will be owned solely and exclusively by the Company. If the work is determined not to be a “work for hire” or such doctrine is not effective, Executive hereby irrevocably assigns, conveys and otherwise transfers to the Company, and its respective successors, licensees, and assigns, all right, title and interest worldwide in and to the work and all proprietary rights therein, including,

without limitation, all copyrights, trademarks, design patents, trade secret rights, moral rights, and all contract and licensing rights, and all claims and causes of action with respect to any of the foregoing, whether now known or hereafter to become known. In the event that Executive has any Intellectual Property right that cannot be assigned, Executive agrees to waive enforcement worldwide of such right against the Company, its distributors and licensees or, if necessary, exclusively license such right, worldwide to the Company with the right to sublicense. These rights are assignable by the Company. Executive has not and hereby does not transfer any Intellectual Property rights owned or held solely by Executive to the Company relating to periods prior to the date of this Agreement and retains all rights to same provided, however, that Executive acknowledges that Intellectual Property rights that he created as an employee of the United Therapeutics Corporation prior to the date of this Agreement, and not otherwise previously assigned or transferred prior to the date of this Agreement are solely owned by the Company as a work made for hire.

             (b)     Original Work. Executive agrees that Executive will not include any copyrighted or patented material owned by a third party in any written, copyrightable or patentable material furnished or delivered by Executive under this Agreement without the unconditional written consent of the copyright or patent owner unless specific written approval of the Company for inclusions of such copyrighted or patented material is secured in advance. Executive also agrees that all work (or tangible expression of an idea) that Executive creates or contributes to the Company in the course of Executive’s employment hereunder will be created solely by Executive, will be original to Executive, and will be free of any third party claims or interests.

             (c)     Applications for Patent, Copyrights and Trademarks. Executive shall, if the Company so decides at its sole discretion and expense, apply for United States and foreign letters patent, copyrights, and/or trademarks, either in Executive’s name or as the Company in its sole discretion may direct. Executive hereby grants the Company the exclusive right, and appoints the Company as Executive’s attorney-in-fact, to execute and prosecute an application for domestic and/or foreign patent or other statutory protection, and Executive shall execute and deliver to the Company, without charge to the Company but at the Company’s expense, such other documents of registration and recordation, and do such other acts, such as give testimony in support of Executive’s inventorship, as may be necessary in the opinion of the Company to vest in the Company or any other party nominated by the Company, or otherwise to protect, the exclusive rights conveyed and/or granted to the Company pursuant to this Agreement. Executive’s duty to support the Company’s claim of rights in patents, copyrights, or trademarks claimed by the Company, and resulting from Executive’s service to the Company as its employee, shall continue for the life of any such patent, copyright or trademark.

             (d)     Assignment Except as otherwise may be agreed by the parties in a signed writing, Executive agrees to assign to the Company and its respective successors, licensees, and assigns, all of Executive’s rights, title and interests in and to the Intellectual Property governed by this Agreement and all rights, title, and interests in and to United States and foreign letters patent, copyrights, and trademarks resulting therefrom. Executive acknowledges this provision and understands fully its implications and meaning.

             (e)     Use. The Company and its respective successors, licensees, and assigns, shall have the sole and exclusive right to practice, or to make, use or sell products, processes or services derived from any discoveries or creations within the scope of this Agreement or created by Executive and covered by the terms of this Agreement, whether or not patentable or copyrightable under the laws of any jurisdiction, or protected by the trade secret laws of any jurisdiction.

             (f)     Trade Secret Protection. In the event that the Company decides not to pursue patent, copyright or trademark protection for any discovery or creation made by Executive, and instead decides to protect the discovery or creation pursuant to the trade secret laws of any jurisdiction, such decision shall not be construed as a waiver of the Company’s rights pursuant to this Agreement. At the Company’s expense, Executive shall also take whatever steps are necessary to sustain the Company’s claim to such trade secrets, including but not limited to: (a) maintaining the confidential nature of any such discoveries or creations; and (b) testifying and providing other support and substantiation for the Company’s claims with regard to the discovery or creation.

             (g)     Reports. With respect to discoveries made by Executive covered by the terms of this Agreement, Executive shall maintain notebooks and other records adequate to describe such discovery to others conversant in the subject of the technology and to establish the date and circumstances of Executive’s discovery. Executive shall notify the Company’s General Counsel of any such discoveries and shall make copies of all documents or reports relating to such discoveries available to the Company. Any such discovery shall be reported to the Company’s General Counsel regardless of whether, in Executive’s opinion, a given discovery is of value to the Company, or is protectable under patent, copyright or the laws of any jurisdiction.

             (h)     Infringement Actions. In the event that the Company shall bring an infringement suit against any third parties or shall be sued by any third parties as a result of Executive’s authorship or creation, including any addition and/or modification of the aforementioned items of Confidential Information, Executive agrees to cooperate reasonably without charge to the Company, but at its request and expense, in defending against or prosecuting any such suit. This right shall be cumulative to any other rights of the Company hereunder.

     10.   Obligation of Confidentiality and Non-Competition.

             (a)     Executive agrees that Executive has a fiduciary duty to the Company and that Executive shall hold in confidence and shall not, except in the course of performing Executive’s employment obligations or pursuant to written authorization from the Company, at any time during or for five years after termination of Executive’s relationship with the Company knowingly (a) directly or indirectly reveal, report, publish, disclose or transfer the Confidential Information or any part thereof to any person or entity; (b) use any of the Confidential Information or any part thereof for any purpose other than for the benefit of the Company; (c) assist any person or entity other than the Company to secure any benefit from the Confidential Information or any part thereof or (d) solicit (on Executive’s behalf or on

behalf of any third party) any employee of the Company for the purpose of providing services or products which Executive is prohibited from providing hereunder.

             (b)     Executive agrees that all Confidential Information, as defined below, shall belong exclusively and without any additional compensation to the Company. For the purposes of this Agreement, “Confidential Information” shall mean each of the following: (a) any information or material proprietary to the Company or designated as confidential either orally or in writing by the Company; and (b) any information not generally known by non- Company personnel; and (c) any information which Executive should know the Company would not care to have revealed to others or used in competition with the Company; and (d) any information which Executive made or makes, conceived or conceives, developed or develops or obtained or obtains knowledge or access through or as a result of Executive’s relationship with the Company (including information received, originated, discovered or developed in whole or in part by Executive) from the initial date of Executive’s employment with the Company.

             (c)     Executive agrees not to accept employment from, nor render services in any capacity for, nor have any other business relationships with, nor engage in any business activity in which it would be useful or helpful to Executive or others with whom he is associated for Executive to use or disclose Confidential Information of the Company with, a person or entity engaged in a business located anywhere in the world which directly competes with the Company’s then existing or planned business a period of one (1) year following Executive’s last receipt of compensation from the Company, whether the termination of Executive’s employment by either party was with or without Cause. A person or entity directly competes with the Company’s then existing or planned business if such individual or entity is engaged in, or about to become engaged in, research on, or development, production, manufacture, marketing, merchandising, leasing, selling, licensing, servicing or promotion of a Competing Product. As used in this Agreement, a “Competing Product” means any product, technology, process, system or service, in existence or under development, of any person or organization other than the Company which is the same as, similar to, competes with or has a usage allied to a product, technology, process, system or service in existence or planned by the Company as of the termination of Executive’s employment hereunder. The parties acknowledge that the Company’s business after the date of this Agreement may evolve into other or additional areas and activities. Executive and the Company agree that the terms of this Section 10(c) relating to non-competition are reasonable in scope and length and are necessary for the protection of the Company. In the event that a court finds the scope of this provision to be unreasonably broad or if the length of time of this provision is found to be unreasonably long, an arbitrator or court, as applicable, shall narrow the scope or shorten the length of time to the extent required to render the provision reasonable and enforceable and shall enforce the provision as so narrowed.

             (d)     While employed by the Company and for a period of one (1) year following Executive’s last receipt of compensation from the Company, whether the termination of Executive’s employment by either party was with or without Cause, Executive will not hire, induce, attempt to hire, assist in hiring, or cause to be hired, directly or indirectly, by another person or organization, any person who was an employee or a contractor of the Company. In addition, for the same period, Executive shall not identify, or

furnish any information about, any other employee of the Company to any other person or organization for the purpose of assisting or facilitating the hiring efforts of such other person or organization.

     11.   Miscellaneous.

             (a)     Entire Agreement. This Agreement contains the entire agreement between the parties hereto relating to the subject matter hereof, and this Agreement supersedes all prior understandings and agreements, whether oral or written, relating to the employment of Executive by the Company.

             (b)     Assignment. This Agreement shall not be assignable or otherwise transferable by either party hereto, but any amounts owing to Executive upon Executive’s death shall inure to the benefit of Executive’s heirs, legatees, legal representatives, executor or administrator. Notwithstanding the foregoing, this Agreement applies with the prior written consent of Executive, which consent shall not be unreasonably withheld. This Agreement shall be binding upon and shall inure to the benefit of the parties hereto and any such respective heirs, legatees, executors, administrators, representatives, successors and assigns.

             (c)     Notices. All notices, demands, requests or other communications which may be, or are required to be given, served or sent by any party to any party pursuant to this Agreement shall be in writing and shall be mailed by first class, registered or certified mail, return receipt requested, postage prepaid, or transmitted by hand delivery, telegram or telex and addressed as follows:

If to Executive:		Barry Kanarek, Ph.D.
		If to the Company:
		United Therapeutics Corporation 1110 Spring Street Silver Spring, Maryland 20910
		Attn: Martine A. Rothblatt, CEO
		With a copy to:
		Paul A. Mahon, Esq. United Therapeutics Corporation 1735 Connecticut Avenue, N.W. Washington, D.C. 20009

             (d)     Amendment; Waiver. This Agreement shall not be amended, altered, modified or discharged except by an instrument in writing duly executed by Executive and the Company. Neither the waiver by the parties hereto of a breach of, or default under, any of the provisions of this Agreement, nor the failure of either of the parties, on one or more occasions, to enforce any of the provisions of this Agreement or to exercise any right or privilege hereunder, shall thereafter be construed as a waiver of any such provisions, rights or privileges hereunder.

             (e)     Severability. The invalidity or unenforceabilty of any provision or provisions of this Agreement shall not affect the validity or enforceability of any other provisions of this Agreement, which shall remain in full force and effect.

             (f)     Applicable Law. This Agreement and the rights and obligations of the parties under this Agreement shall be construed, interpreted and enforced in accordance with the laws of the State of Maryland, exclusive of the choice-of-laws rules thereunder. The parties hereby irrevocably consent and submit to the exclusive jurisdiction of the courts located in the State of Maryland in connection with any suit, action or other proceeding concerning the interpretation or enforcement of this Agreement. Each party waives and agrees not to assert any defense that such courts lack jurisdiction, venue is improper, inconvenient forum or otherwise.

             (g)     Survival. It is the express intention and agreement of the parties hereto that the provisions of Sections 7, 8, 9, and 10 hereof shall survive the termination of employment of Executive. In addition, all obligations of the Company to make payments hereunder shall survive any termination of this Agreement on the terms and conditions set forth.

             (h)     Execution. To facilitate execution, this Agreement may be executed in as many counterparts as may be required; and it shall not be necessary that the signatures of, or on behalf of, each party, or that the signatures of all persons required to bind any party, appear on each counterpart; but it shall be sufficient that the signature of, or on behalf of, each party, or that the signatures of the persons required to bind any party, appear on one or more of the counterparts. All counterparts shall collectively constitute a single agreement. It shall not be necessary in making proof of this Agreement to produce or account for more than a number of counterparts containing the respective signatures of, or on behalf of, all of the parties hereto.

     IN WITNESS WHEREOF, the undersigned have duly executed this Agreement, or have caused this Agreement to be duly executed on their behalf, as of the date first above written.

		UNITED THERAPEUTICS CORPORATION
/s/ Barry Kanarek		/s/ Martine Rothblatt
Barry Kanarek, Ph.D.		Martine A. Rothblatt, CEO

Exhibit 10.4

EMPLOYMENT AGREEMENT

     THIS EMPLOYMENT AGREEMENT (this “Agreement”) is entered into as of June 16, 2001 by and between United Therapeutics Corporation (the “Company”) and Paul A. Mahon (the “Executive”).

     WHEREAS, the Executive currently serves as outside General Counsel and Assistant Secretary of the Company; and

     WHEREAS, the Company desires to employ Executive as its Senior Vice President and General Counsel, subject to the terms and conditions herein set forth;

     NOW, THEREFORE, in consideration of the promises and mutual covenants contained herein, and for other good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties hereto agree as follows.

     1.     Employment. Upon the other terms and conditions hereinafter stated, the Company agrees to employ the Executive and the Executive agrees to accept employment by the Company for the term set forth in Section 2 hereof and in the position and with the duties and responsibilities set forth in Section 3 hereof. Executive warrants that he is under no restriction that would prevent him from entering into this Agreement and from complying with all of its provisions to their fullest extent.

     2.     Term. The employment of the Executive by the Company will commence on June 16, 2001 for a term of five (5) years continuing to and including June 14, 2006. The term (as herein extended) shall automatically be extended by one (1) additional year at the end of each year unless at least six (6) months prior to the end of the term or any anniversary thereof, the Company shall deliver to Executive or Executive shall deliver to the Company written notice that the term shall not be so extended.

     3.     Position and Duties. Executive shall serve as Senior Vice President and General Counsel, with such duties and responsibilities as are normally performed by the Senior Vice President and General Counsel of a biotechnology company and as otherwise assigned by the CEO from time to time that are not inconsistent with duties and responsibilities as are normally performed by the Senior Vice President and General Counsel. The Executive shall at all times exert his best efforts and loyalty on behalf of the Company and shall devote full time and attention to such employment, provided, however, that it shall not be a violation of this Agreement for Executive to continue representing legal clients through the law firm of Mahon Patusky Rothblatt & Fisher, Chartered so long as such activities do not conflict or materially interfere with the performance of Executive’s duties hereunder. Executive shall perform his duties from the Company’s offices located in Washington, D.C. The Executive agrees to abide by all employment guidelines and policies as may be developed from time to time by the Company, including, without limitation, the United Therapeutics Corporation Company

Manual and the United Therapeutics Corporation Securities Trades by Company Personnel Policy.

     4.     Compensation and Related Matters. The Company shall provide the following compensation and benefits to the Executive:

             (a)     The Company shall pay to the Executive an annual base salary of Three Hundred Thousand Dollars ($300,000) (the “Base Salary”), such annual base salary to be subject to review and increase at least annually by Compensation Committee of the Company’s Board of Directors, with the first such review to occur not later than December 31, 2001. The Base Salary shall be payable semi-monthly or in such other installments as shall be consistent with the Company’s payroll procedures. The Company shall deduct and withhold all necessary social security and withholding taxes and any other similar sums required by law or authorized by the Executive with respect to payment of the Base Salary and all other amounts and benefits payable under this Agreement.

             (b)     The Executive shall be entitled to participate in any group life, disability and medical insurance or other benefit plan or arrangement available generally to the employees of the Company as determined by the Board of Directors.

             (c)     The Executive shall be entitled to receive one hundred thousand (100,000) incentive stock options at the NASDAQ closing price of the Company’s common stock on June 15, 2001, vesting 20% on each of the next five anniversaries of the commencement date of Executive’s employment with the Company.

             (d)     All Options previously awarded Executive, whether under any prior agreement or otherwise, shall be unaffected by this Agreement.

     5.     Expenses.

             (a)     The Executive shall be reimbursed by the Company for reasonable travel and other expenses which are incurred and accounted for in accordance with the Company’s normal practices.

             (b)     The Company shall reimburse the Executive for all professional license fees and continuing legal education requirements that may be required of Executive in order to maintain his license to practice law in the jurisdictions in which he is licensed or may become licensed.

     6.     Vacation. The Executive shall be entitled to vacation at such time or times and for such period or periods as shall be mutually agreed upon by the Executive and the CEO, with the number of vacation days determined in accordance with the Company’s employee manual in recognition of Executive’s services to the Company since 1996.

     7.     Termination of Employment.

             (a)     The Executive’s employment hereunder shall terminate upon the Executive’s death.

             (b)     The Company may terminate the Executive’s employment hereunder as set forth in Section 2 above, and under the following circumstances:

                       (i)     If, as a result of the Executive’s incapacity due or other disability owing to physical or mental illness, the Executive shall have been unable to perform all of the Executive’s material duties hereunder by reason of illness, or physical or mental disability or other similar capacity, which inability shall continue for more than two (2) consecutive months, the Company may terminate the Executive’s employment hereunder.

                       (ii)     The Company may terminate the Executive’s employment hereunder for “Cause.” For purposes of this Agreement, the Company shall have “Cause” to terminate the Executive’s employment hereunder upon the (A) failure of the Executive (other than for reasons described in Sections 7(a) and 7(b)(i) hereof) to perform or observe any of the material terms or provisions of this Agreement; (B) negligent or unsatisfactory performance of the Executive’s duties under this Agreement and the failure of the Executive, within 10 days after receipt of notice from the Company setting forth in reasonable detail the nature of the Executive’s negligent or unsatisfactory performance, (i) to provide the Company with a reasonably satisfactory explanation of the Executive’s actions (or inaction) and (ii) to correct to the satisfaction of the Company any reasonably identified deficiencies; (C) employment- or profession-related misconduct or other employment- or profession-related similar action on the part of the Executive; (D) conviction of the Executive of a crime involving a felony, fraud, embezzlement or the like; or (E) misappropriation of the Company funds or misuse of the Company’s assets by Executive.

             (c)     Any termination of the Executive’s employment by the Company or by the Executive (other than pursuant to Section 7(a) hereof) shall be communicated by written “Notice of Termination” to the other party hereto in accordance with Section 10(c) hereof, which shall indicate the specific termination provision in this Agreement relied upon, if any, and shall set forth in reasonable detail the facts and circumstances claimed to provide a basis for termination of the Executive’s employment under the provision so indicated.

             (d)     For purposes of this Agreement, the “Date of Termination” shall mean (i) if the Executive’s employment is terminated by the Executive’s death, the date of the Executive’s death; (ii) if the Executive’s employment is terminated pursuant to Section 7(b)(i) hereof, thirty (30) days after the Notice of Termination; provided , that the Executive shall not have returned to the performance of the Executive’s duties on a full-time basis during such thirty (30) day period; (iii) if the Executive’s employment is terminated pursuant to Section 7(b)(ii) hereof, the date specified in the Notice of Termination (which date, in the case of termination of Executive’s employment solely pursuant to clause (B) of Section 7(b)(ii) by reason of inadequate performance, shall not be sooner than thirty (30) days from the date of the Notice of Termination); and (iv) if the Executive’s employment is terminated for any other reason, the date on which the Notice of Termination is given.

     8.     Compensation Upon Termination.

             (a)     If the Executive’s employment is terminated by the Executive’s death, the Company shall pay to the Executive’s estate or as may be directed by the legal representatives of such estate, the Executive’s full Base Salary through the Date of Termination at the rate in effect at the time of the Executive’s death and all other unpaid amounts, if any, to which the Executive is entitled as of such date in connection with any fringe benefits or under any incentive compensation plan or program of the Company pursuant to Section 4(c) hereof, at the time such payments are due.

             (b)     During any period that the Executive fails to perform the Executive’s duties hereunder solely as a result of incapacity due to physical or mental illness (“disability period”), the Executive shall continue to receive the Executive’s full base salary through the Date of Termination at the rate in effect at the time the Notice of Termination is given and all other unpaid amounts, if any, to which the Executive is entitled as of the Date of Termination in connection with any fringe benefits or under any incentive compensation plan or program of the Company hereof, at the time such payments are due; provided that payments so made to the Executive during the disability period shall be reduced by the sum of the amounts, if any, payable to the Executive at or prior to the time of any such payment under disability benefit plans of the Company and which amounts were not previously applied to reduce any such payment.

             (c)     If the Executive shall terminate the Executive’s employment or the Company terminates the Executive’s employment for Cause as provided in Section 7(b)(ii) hereof, the Company shall pay the Executive the Executive’s full Base Salary through the Date of Termination at the rate in effect at the time the Notice of Termination is given, and the Company shall have no further obligations to the to the Executive under this Agreement.

             (d)     If (i) the Company terminates the Executive’s employment without Cause, or (ii) the Executive’s employment is terminated as a result of the transfer of control of the Company by acquisition, merger, hostile takeover or for any other reason whatsoever, or (iii) Executive’s authority and responsibilities are materially diminished without cause relating to the performance of Executive’s services hereunder and Executive terminates this Agreement as a result of such unjustified diminution of authority, then should any of the foregoing events occur, the Company shall pay to Executive a lump-sum amount equal to the greater of either (a) the amount Executive would have been entitled to receive in Base Salary for the time remaining in Executive’s then current term of employment, or (b) an amount equal to two years of Base Salary. Such payment shall be fully due and payable to Executive in a lump sum upon Executive’s Date of Termination. Additionally, in the event of termination contemplated in this Section 8(d), all options granted to Executive pursuant to Section 4(c) shall immediately vest in Executive.

     9.     Intellectual Property Rights. Because of the highly specialized and technical nature of the business of the Company and the nature and scope of Executive’s employment, Executive agrees that any and all rights, title, and interest, including but not limited to domestic and foreign patents, copyrights, trademarks and trade secrets, in and to all inventions, processes, computer programs, photographic, written or artistic works, or other

forms of intellectual property (“Intellectual Property”) which employee makes, conceives, reduces to practice or develops, in whole or in part, during the term of this Agreement in the furtherance of the Company’s business and in connection with specific Company projects as defined in Paragraph 9 below (whether or not made during the hours of employment or with the use of Company’s materials, facilities or personnel, either solely or jointly with others), or after termination of employment if such Intellectual Property is based upon Confidential Information, shall be the sole and exclusive property of the Company, and its respective successors, licensees, and assigns. In full consideration of the compensation provided to Executive by the Company, Executive agrees to each and all of the following:

             (a)     Work Made for Hire. Executive acknowledges and agrees that all works of authorship created by Executive as an employee of the Company is a commissioned “work for hire” within the meaning of United States copyright law which will be owned solely and exclusively by the Company. If the work is determined not to be a “work for hire” or such doctrine is not effective, Executive hereby irrevocably assigns, conveys and otherwise transfers to the Company, and its respective successors, licensees, and assigns, all right, title and interest worldwide in and to the work and all proprietary rights therein, including, without limitation, all copyrights, trademarks, design patents, trade secret rights, moral rights, and all contract and licensing rights, and all claims and causes of action with respect to any of the foregoing, whether now known or hereafter to become known. In the event that Executive has any right in the work which cannot be assigned, Executive agrees to waive enforcement worldwide of such right against the Company, its distributors and licensees or, if necessary, exclusively license such right, worldwide to the Company with the right to sublicense. These rights are assignable by the Company. Executive has not and hereby does not transfer any Intellectual Property rights owned or held solely by Executive to the Company relating to periods prior to the date of this Agreement and retains all rights to same provided, however, that Executive acknowledges that Intellectual Property rights that he created as an employee of the United Therapeutics Corporation prior to the date of this Agreement, and not otherwise previously assigned or transferred prior to the date of this Agreement are solely owned by the Company as a work made for hire.

             (b)     Original Work. Executive agrees that Executive will not include any copyrighted or patented material owned by a third party in any written, copyrightable or patentable material furnished or delivered by Executive under this Agreement without the unconditional written consent of the copyright or patent owner unless specific written approval of the Company for inclusions of such copyrighted or patented material is secured in advance. Executive also agrees that all work (or tangible expression of an idea) that Executive creates or contributes to the Company in the course of Executive’s employment hereunder will be created solely by Executive, will be original to Executive, and will be free of any third party claims or interests.

             (c)     Applications for Patent, Copyrights and Trademarks. Executive shall, if the Company so decides at its sole discretion and expense, apply for United States and foreign letters patent, copyrights, and/or trademarks, either in Executive’s name or as the Company in its sole discretion may direct. Executive hereby grants the Company the exclusive right, and appoints the Company as Executive’s attorney-in-fact, to execute and prosecute an application for domestic and/or foreign patent or other statutory protection, and

Executive shall execute and deliver to the Company, without charge to the Company but at the Company’s expense, such other documents of registration and recordation, and do such other acts, such as give testimony in support of Executive’s inventorship, as may be necessary in the opinion of the Company to vest in the Company or any other party nominated by the Company, or otherwise to protect, the exclusive rights conveyed and/or granted to the Company pursuant to this Agreement. Executive’s duty to support the Company’s claim of rights in patents, copyrights, or trademarks claimed by the Company, and resulting from Executive’s service to the Company as its employee, shall continue for the life of any such patent, copyright or trademark.

             (d)     Assignment Except as otherwise may be agreed by the parties in a signed writing, Executive agrees to assign to the Company and its respective successors, licensees, and assigns, all of Executive’s rights, title and interests in and to the Intellectual Property governed by this Agreement and all rights, title, and interests in and to United States and foreign letters patent, copyrights, and trademarks resulting therefrom. Executive acknowledges this provision and understands fully its implications and meaning.

             (e)     Use. The Company and its respective successors, licensees, and assigns, shall have the sole and exclusive right to practice, or to make, use or sell products, processes or services derived from any discoveries or creations within the scope of this Agreement or created by Executive and covered by the terms of this Agreement, whether or not patentable or copyrightable under the laws of any jurisdiction, or protected by the trade secret laws of any jurisdiction.

             (f)     Trade Secret Protection. In the event that the Company decides not to pursue patent, copyright or trademark protection for any discovery or creation made by Executive, and instead decides to protect the discovery or creation pursuant to the trade secret laws of any jurisdiction, such decision shall not be construed as a waiver of the Company’s rights pursuant to this Agreement. At the Company’s expense, Executive shall also take whatever steps are necessary to sustain the Company’s claim to such trade secrets, including but not limited to: (a) maintaining the confidential nature of any such discoveries or creations; and (b) testifying and providing other support and substantiation for the Company’s claims with regard to the discovery or creation.

             (g)     Reports. With respect to discoveries made by Executive covered by the terms of this Agreement, Executive shall maintain notebooks and other records adequate to describe such discovery to others conversant in the subject of the technology and to establish the date and circumstances of Executive’s discovery. Executive shall notify the Company’s General Counsel of any such discoveries and shall make copies of all documents or reports relating to such discoveries available to the Company. Any such discovery shall be reported to the Company’s General Counsel regardless of whether, in Executive’s opinion, a given discovery is of value to the Company, or is protectable under patent, copyright or the laws of any jurisdiction.

             (h)     Infringement Actions. In the event that the Company shall bring an infringement suit against any third parties or shall be sued by any third parties as a result of Executive’s authorship or creation, including any addition and/or modification of the

aforementioned items of Confidential Information, Executive agrees to cooperate reasonably without charge to the Company, but at its request and expense, in defending against or prosecuting any such suit. This right shall be cumulative to any other rights of the Company hereunder.

     10.     Obligation of Confidentiality and Non-Competition.

             (a)     Executive agrees that Executive has a fiduciary duty to the Company and that Executive shall hold in confidence and shall not, except in the course of performing Executive’s employment obligations or pursuant to written authorization from the Company, at any time during or for three years after termination of Executive’s relationship with the Company knowingly (a) directly or indirectly reveal, report, publish, disclose or transfer the Confidential Information or any part thereof to any person or entity; (b) use any of the Confidential Information or any part thereof for any purpose other than for the benefit of the Company; (c) assist any person or entity other than the Company to secure any benefit from the Confidential Information or any part thereof or (d) solicit (on Executive’s behalf or on behalf of any third party) any employee of the Company for the purpose of providing services or products which Executive is prohibited from providing hereunder.

             (b)     Executive agrees that all Confidential Information, as defined below, shall belong exclusively and without any additional compensation to the Company. For the purposes of this Agreement, “Confidential Information” shall mean each of the following: (a) any information or material proprietary to the Company or designated as confidential either orally or in writing by the Company; and (b) any information not generally known by non- Company personnel; and (c) any information which Executive should know the Company would not care to have revealed to others or used in competition with the Company; and (d) any information which Executive made or makes, conceived or conceives, developed or develops or obtained or obtains knowledge or access through or as a result of Executive’s relationship with the Company (including information received, originated, discovered or developed in whole or in part by Executive) from the initial date of Executive’s employment with the Company.

             (c)     Executive agrees not to accept employment from, nor render services in any capacity for, nor have any other business relationships with, nor engage in any business activity in which it would be useful or helpful to Executive or others with whom he is associated for Executive to use or disclose Confidential Information of the Company with, a person or entity engaged in a business located anywhere in the world which directly competes with the Company’s then existing or planned business a period of one (1) year following Executive’s last receipt of compensation from the Company, whether the termination of Executive’s employment by either party was with or without Cause. A person or entity directly competes with the Company’s then existing or planned business if such individual or entity is engaged in, or about to become engaged in, research on, or development, production, manufacture, marketing, merchandising, leasing, selling, licensing, servicing or promotion of a Competing Product. As used in this Agreement, a “Competing Product” means any product, technology, process, system or

service, in existence or under development, of any person or organization other than the Company which is the same as, similar to, competes with or has a usage allied to a product, technology, process, system or service in existence or planned by the Company as of the termination of Executive’s employment hereunder. The parties acknowledge that the Company’s business after the date of this Agreement may evolve into other or additional areas and activities. Executive and the Company agree that the terms of this Section 10(c) relating to non-competition are reasonable in scope and length and are necessary for the protection of the Company. In the event that a court finds the scope of this provision to be unreasonably broad or if the length of time of this provision is found to be unreasonably long, an arbitrator or court, as applicable, shall narrow the scope or shorten the length of time to the extent required to render the provision reasonable and enforceable and shall enforce the provision as so narrowed.

             (d)     While employed by the Company and for a period of one (1) year following Executive’s last receipt of compensation from the Company, whether the termination of Executive’s employment by either party was with or without Cause, the Executive will not hire, induce, attempt to hire, assist in hiring, or cause to be hired, directly or indirectly, by another person or organization, any person who was an employee or a contractor of the Company. In addition, for the same period, the Executive shall not identify, or furnish any information about, any other employee of the Company to any other person or organization for the purpose of assisting or facilitating the hiring efforts of such other person or organization.

     11.     Miscellaneous.

             (a)     Entire Agreement. This Agreement contains the entire agreement between the parties hereto relating to the subject matter hereof, and this Agreement supersedes all prior understandings and agreements, whether oral or written, relating to the employment of the Executive by the Company.

             (b)     Assignment. This Agreement shall not be assignable or otherwise transferable by either party hereto, but any amounts owing to Executive upon the Executive’s death shall inure to the benefit of the Executive’s heirs, legatees, legal representatives, executor or administrator. Notwithstanding the foregoing, this Agreement applies with the prior written consent of the Executive, which consent shall not be unreasonably withheld. This Agreement shall be binding upon and shall inure to the benefit of the parties hereto and any such respective heirs, legatees, executors, administrators, representatives, successors and assigns.

             (c)     Notices. All notices, demands, requests or other communications which may be, or are required to be given, served or sent by any party to any party pursuant to this Agreement shall be in writing and shall be mailed by first class, registered or certified mail, return receipt requested, postage prepaid, or transmitted by hand delivery, telegram or telex and addressed as follows:

If to the Executive:		Paul A. Mahon
		3703 Northampton Street, N.W.
		Washington, D.C. 20016
If to the Company:		United Therapeutics Corporation

             (d)     Amendment; Waiver. This Agreement shall not be amended, altered, modified or discharged except by an instrument in writing duly executed by the Executive and the Company. Neither the waiver by the parties hereto of a breach of, or default under, any of the provisions of this Agreement, nor the failure of either of the parties, on one or more occasions, to enforce any of the provisions of this Agreement or to exercise any right or privilege hereunder, shall thereafter be construed as a waiver of any such provisions, rights or privileges hereunder.

             (e)     Severability. The invalidity or unenforceabilty of any provision or provisions of this Agreement shall not affect the validity or enforceability of any other provisions of this Agreement, which shall remain in full force and effect.

             (f)     Applicable Law. This Agreement and the rights and obligations of the parties under this Agreement shall be construed, interpreted and enforced in accordance with the laws of the District of Columbia, exclusive of the choice-of-laws rules thereunder.

             (g)     Survival. It is the express intention and agreement of the parties hereto that the provisions of Sections 7, 8, 9, and 10 hereof shall survive the termination of employment of the Executive. In addition, all obligations of the Company to make payments hereunder shall survive any termination of this Agreement on the terms and conditions set forth.

             (h)     Execution. To facilitate execution, this Agreement may be executed in as many counterparts as may be required; and it shall not be necessary that the signatures of, or on behalf of, each party, or that the signatures of all persons required to bind any party, appear on each counterpart; but it shall be sufficient that the signature of, or on behalf of, each party, or that the signatures of the persons required to bind any party, appear on one or more of the counterparts. All counterparts shall collectively constitute a single agreement. It shall not be necessary in making proof of this Agreement to produce or account for more than a number of counterparts containing the respective signatures of, or on behalf of, all of the parties hereto.

     IN WITNESS WHEREOF, the undersigned have duly executed this Agreement, or have caused this Agreement to be duly executed on their behalf, as of the date first above written.

Exhibit 10.5

AMENDMENT

     THIS AMENDMENT is made as of the 21st day of December, 2000 to the Executive Employment Agreement (the “Agreement”) between Martine Rothblatt (“Executive”) and United Therapeutics Corporation (“UT”) dated April 2, 1999.

     WHEREAS, the Board of Directors of UT unanimously approved an amendment to the Agreement at its December 14, 2000 board meeting;

     NOW THEREFORE, the parties hereby amend the Agreement as follows:

     1.     Section 3.2(a) of the Agreement shall be replaced in its entirety by the following new Section 3.2(a):

                       “Annual Incentive Compensation. During each year of the term of this Agreement, options to purchase such number of shares, exercisable for ten years at 110% of the fair market price at the time of grant, as is equal to, for the first year, the quotient of one percent of the difference in UT market capitalization from the date of IPO to the one year anniversary thereof divided by $18.00. For each year thereafter, commencing with the period beginning December, 2000 and with the next option grant to be made on January 2, 2002, an option to purchase such number of shares, valid for ten years and exercisable at 110% of the fair market price at the time of grant, as is the quotient of one percent of the rise in market capitalization of UT from December 2000 to December 2001 calculated using the average Nasdaq closing price during the month of December of each year, divided by $18.00. Incentive compensation shall be vested when earned. The maximum incentive compensation that may be earned shall be capped by the projected market capitalization of UT at the end of each year under the January 1999 UT Business Plan.”

     In witness whereof, the parties have executed this Amendment effective as of the date first written above.

Exhibit 10.6

EMPLOYMENT AGREEMENT

     THIS EMPLOYMENT AGREEMENT (this “Agreement”) is entered into as of January 3, 2000 by and between United Therapeutics Corporation, a Delaware corporation having its principal offices at 1110 Spring Street, Silver Spring, Maryland 20910 (“United Therapeutics”) and Fred Hadeed, CPA (the “Executive”).

     WHEREAS, United Therapeutics desires to obtain the services of the Executive, and the Executive is willing to render such services to United Therapeutics, upon the terms and conditions herein set forth;

     NOW, THEREFORE, in consideration of the promises and mutual covenants contained herein, and for other good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties hereto agree as follows.

     1.     Definitions

             (a)     As used in this Agreement, “Confidential Information” means any information of whatever kind or form, including without limitation: an idea, invention, concept, formula, computer program, algorithm, research, device, method, technique, design, manufacturing process, know how, internal procedure or method of operation, process, plan, project, picture, drawing, lists of customers, contracts, contractors or vendors, business or financial data, plans or accounts, pricing strategies, purchasing data and/or reports, marketing data and/or reports, business relationships, contractual rights, lists of actual or prospective investors, industrial or strategic partners and consultants, trade secrets and other proprietary information of United Therapeutics that becomes known to Executive, or is developed, examined, enhanced or modified by Executive as a result of or during the course of Executive’s employment with United Therapeutics, regardless of source, except to the extent of the following: (i) information that is or becomes known to the general public without breach of the nondisclosure obligations of this Agreement; (ii) information that is customarily disclosed to others without restriction on subsequent disclosure; (iii) information that is obtained by Executive from a third party without breach of a nondisclosure obligation and without restriction on subsequent disclosure; and (iv) information to the limited extent that disclosure is expressly required by judicial or administrative order, or otherwise is required by law, provided that Executive gives immediate notice to United Therapeutics prior to disclosure of such information.

             (b)     As used in this Agreement, “Competing Product” means any product, system or service, in existence or under development, of any person or organization other than United Therapeutics which is the same as, similar to, competes with or has a usage allied to a product, process, system or service upon which Executive worked (in either a sales or a non-sales capacity) during the last three years of his or her employment by United Therapeutics, or about which Executive acquired Confidential Information in the course of his or her employment with United Therapeutics.

             (c)     As used in this Agreement, “Competing Organization” means any person or organization which is engaged in, or about to become engaged in, research on, or development, production, marketing, leasing, selling, licensing or servicing of, a Competing Product.

             (d)     As used in this Agreement, “Intellectual Property” means any and all rights, title, and interest, including but not limited to domestic and foreign patents, copyrights, trademarks, trade secrets and all Confidential Information relating to any of the foregoing, in and to all inventions, processes, computer programs, formulae, photographic, written or artistic works, or other forms of Intellectual Property which Executive makes, conceives, reduces to practice or develops, in whole or in part, during the term of this Agreement or after termination of Executive’s employment with United Therapeutics if the Intellectual Property is based upon or derived from United Therapeutics’ Confidential Information.

     2.     Employment. Upon the other terms and conditions hereinafter stated, United Therapeutics agrees to employ the Executive and the Executive agrees to accept employment by United Therapeutics for the term set forth in Section 3 hereof and in the position and with the duties and responsibilities set forth in Section 4 hereof. Executive warrants that he is under no restriction that would prevent him from entering into this Agreement and from complying with all of its provisions to their fullest extent. If Executive is enjoined or otherwise prevented by judicial or administrative determination from complying with the terms of this Agreement, then United Therapeutics may terminate this Agreement immediately without incurring any further liability.

     3.     Term. The employment of the Executive by United Therapeutics will commence on January 31, 2000 and end on the second anniversary of such date (the “Initial Term”), and thereafter shall continue for two additional two-year terms (the “Additional Terms”), unless and until either party shall give notice of such party’s intent to terminate not less than 60 days prior to the end of the then-current Initial Term or Additional Term, which termination shall be effective at the expiration of said term, or until sooner terminated as hereinafter set forth.

     4.     Position and Duties.

             (a)     The Executive shall serve as Chief Financial Officer of United Therapeutics, reporting to United Therapeutics’ CEO, with such duties and responsibilities as are normally performed by the Chief Financial Officer and with such additional duties and responsibilities as may be assigned from time to time by United Therapeutics’ CEO.

             (b)     The Executive shall at all times exert his best efforts and loyalty on behalf of United Therapeutics and shall devote full time and attention to such employment. The Executive agrees to abide by all employment guidelines and policies as may be developed from time to time by United Therapeutics, including, without limitation, the attached United

Therapeutics, Inc. Company Manual, United Therapeutics Corporation Securities Trades by Company Personnel Policy, and the United Therapeutics Corporation Media and Analysts Policy.

     5.     Compensation and Related Matters.

             (a)     For services rendered under this Agreement, United Therapeutics shall pay to the Executive an annual base salary of One Hundred Forty Thousand Dollars ($140,000) (the “Base Salary”), subject to annual increases as determined by the Board of Directors of United Therapeutics, in its sole discretion, in an amount not less than ten percent of the then-current Base Salary. The Base Salary shall be payable semi-monthly or in such other installments as shall be consistent with United Therapeutics’ payroll procedures. United Therapeutics shall deduct and withhold all necessary social security and withholding taxes and any other similar sums required by law or authorized by the Executive with respect to payment of the Base Salary and all other amounts and benefits payable under this Agreement.

             (b)     The Executive shall be entitled to participate in any group life, disability and medical insurance or other benefit plan or arrangement available generally to the employees of United Therapeutics as determined by the Board of Directors.

             (c)     The Executive shall be entitled to receive reimbursement for relocation expenses according to the United Therapeutics Corporation Relocation Expense Reimbursement Policy.

             (d)     The Executive shall receive a grant of stock options to purchase shares of the Common Stock of United Therapeutics Corporation pursuant to the United Therapeutics Corporation Amended and Restated Equity Incentive Plan in such number as may be recommended by the Compensation Committee of the Board of Directors and vesting as follows: twenty percent (20%) on commencement of employment and twenty percent (20%) per year on each anniversary of the commencement of Executive’s employment. Executive will enter into a separate Equity Incentive Plan Award Agreement to effect this grant. The Compensation Committee of the United Therapeutics Board of Directors may, in its sole discretion, award additional incentive stock option grants to Executive during the term of this Agreement.

     6.     Expenses. The Executive shall be reimbursed by United Therapeutics for reasonable travel and other expenses, as approved from time to time by the Board of Directors, which are incurred and accounted for in accordance with United Therapeutics’ normal practices.

     7.     Vacation. The Executive shall be entitled during the term of employment hereunder to three calendar weeks of vacation annually, which vacation shall be at such time or times and for such period or periods as shall be mutually agreed upon by the Executive and United Therapeutics’ CEO. The Executive shall also be entitled to all public holidays observed by United Therapeutics.

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     8.     Termination of Employment.

             (a)     The Executive’s employment hereunder shall terminate upon the Executive’s death.

             (b)     United Therapeutics may terminate the Executive’s employment hereunder under the following circumstances:

                       (i)     If, as a result of the Executive’s incapacity due or other disability owing to physical or mental illness, the Executive shall have been unable to perform all of the Executive’s material duties hereunder by reason of illness, or physical or mental disability or other similar capacity, which inability shall continue for more than four (4) consecutive months, United Therapeutics may terminate the Executive’s employment hereunder.

                       (ii)     United Therapeutics may terminate the Executive’s employment hereunder for “Cause.” For purposes of this Agreement, United Therapeutics shall have “Cause” to terminate the Executive’s employment hereunder upon the (A) failure of the Executive (other than for reasons described in Sections 8(a) and 8(b)(i) hereof) to perform or observe any of the material terms or provisions of this Agreement; (B) negligent or unsatisfactory performance of the Executive’s duties under this Agreement and the failure of the Executive, within 30 days after receipt of notice from United Therapeutics setting forth in reasonable detail the nature of the Executive’s negligent or unsatisfactory performance, (i) to provide United Therapeutics with a reasonably satisfactory explanation of the Executive’s actions (or inaction) and (ii) to correct to the satisfaction of United Therapeutics any reasonably identified deficiencies; (C) employment- or profession-related misconduct or other employment- or profession-related similar action on the part of the Executive; (D) conviction of the Executive of a crime involving a felony, fraud, embezzlement or the like; or (E) misappropriation of United Therapeutics funds or misuse of United Therapeutics’ assets by Executive.

             (c)     Any termination of the Executive’s employment by United Therapeutics or by the Executive (other than pursuant to Section 8(a) hereof) shall be communicated by written “Notice of Termination” to the other party hereto in accordance with Section 19(f) hereof, which shall indicate the specific termination provision in this Agreement relied upon, if any, and shall set forth in reasonable detail the facts and circumstances claimed to provide a basis for termination of the Executive’s employment under the provision so indicated.

             (d)     For purposes of this Agreement, the “Date of Termination” shall mean (i) if the Executive’s employment is terminated by the Executive’s death, the date of the Executive’s death; (ii) if the Executive’s employment is terminated pursuant to Section 8(b)(i) hereof, thirty (30) days after the Notice of Termination; provided , that the Executive shall not have returned to the performance of the Executive’s duties on a full-time basis

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during such thirty (30) day period; (iii) if the Executive’s employment is terminated pursuant to Section 8(b)(ii) hereof, the date specified in the Notice of Termination (which date, in the case of termination of Executive’s employment solely pursuant to clause (B) of Section 8(b)(ii) by reason of inadequate performance, shall not be sooner than nine months from the date of the Notice of Termination); and (iv) if the Executive’s employment is terminated for any other reason, the date on which the Notice of Termination is given.

     9.     Compensation Upon Termination.

             (a)     If the Executive’s employment is terminated by the Executive’s death, United Therapeutics shall pay to the Executive’s estate or as may be directed by the legal representatives of such estate, the Executive’s full Base Salary through the Date of Termination at the rate in effect at the time of the Executive’s death and all other unpaid amounts, if any, to which the Executive is entitled as of such date in connection with any fringe benefits or under any incentive compensation plan or program of United Therapeutics pursuant to Section 5(c) or 5(d) hereof, at the time such payments are due.

             (b)     During any period that the Executive fails to perform the Executive’s duties hereunder solely as a result of incapacity due to physical or mental illness (“disability period”), the Executive shall continue to receive the Executive’s full base salary through the Date of Termination at the rate in effect at the time the Notice of Termination is given and all other unpaid amounts, if any, to which the Executive is entitled as of the Date of Termination in connection with any fringe benefits or under any incentive compensation plan or program of United Therapeutics pursuant to Section 5(c) or 5(d) hereof, at the time such payments are due; provided that payments so made to the Executive during the disability period shall be reduced by the sum of the amounts, if any, payable to the Executive at or prior to the time of any such payment under disability benefit plans of United Therapeutics and which amounts were not previously applied to reduce any such payment.

             (c)     If the Executive shall terminate the Executive’s employment or United Therapeutics terminates the Executive’s employment for Cause as provided in Section 8(b)(ii) hereof, United Therapeutics shall pay the Executive the Executive’s full Base Salary through the Date of Termination at the rate in effect at the time the Notice of Termination is given, and United Therapeutics shall have no further obligations to the to the Executive under this Agreement.

             (d)     In the event that Executive’s employment with United Therapeutics is terminated for any reason within twelve months of its commencement, then, (i) Executive agrees to reimburse United Therapeutics for the amount of any signing bonus which Executive received and relocation expense reimbursement as provided herein paid to Executive or on Executive’s behalf, and (ii) Executive acknowledges that any stock options granted to Executive, whether vested or unvested, shall immediately terminate upon the termination of Executive’s employment.

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     10.   Confidentiality and Nondisclosure.

             (a)     As a material inducement to United Therapeutics to engage Executive’s services and to pay to Executive compensation for such services to be rendered to United Therapeutics by Executive (it being understood and agreed by Executive that such compensation shall also be paid and received in consideration hereof), Executive covenants and agrees that during the term of this Agreement, and for a period as long as the Confidential Information shall be maintained in confidence by United Therapeutics, Executive shall maintain all Confidential Information in strictest secrecy and guard against unauthorized disclosure, and Executive shall not directly or indirectly use, sell, transfer, convey, disseminate, disclose, divulge, publish, copy, duplicate or communicate any Confidential Information for any purpose other than the purposes of United Therapeutics, except as generally allowed in the conduct of United Therapeutics’ business or with the prior written consent of United Therapeutics.

             (b)     Executive shall obtain the written permission of United Therapeutics prior to disclosure of any Confidential Information to any person who previously has not been expressly authorized by United Therapeutics to receive such Confidential Information. Executive’s duty to obtain United Therapeutics’ consent prior to disclosure shall survive the term of this Agreement and shall continue until such time as United Therapeutics notifies Executive that United Therapeutics no longer considers specific information to be confidential.

             (c)     Executive agrees that Executive will not take with Executive any Confidential Information that is in written, machine readable, model or other form, including sound or video recordings, computer disks, or any other medium capable of physical delivery, upon or after the termination of Executive’s employment with United Therapeutics, for any reason whatsoever, without the prior written consent of United Therapeutics. Executive also agrees, upon termination of his employment with United Therapeutics to promptly deliver all such materials in Executive’s possession or under Executive’s control to United Therapeutics. Executive further agrees that, upon termination of Executive’s employment with United Therapeutics, Executive will return to United Therapeutics any property of United Therapeutics within Executive’s possession or control, including all work created by Executive or others. The nature of Executive’s work is such that Executive will be undertaking time-sensitive projects for United Therapeutics. Such projects cannot easily be re-created by others. A delay or inability to complete such projects could jeopardize United Therapeutics’ client relations and goodwill. If Executive’s association with United Therapeutics terminates for any reason, Executive agrees that even if there is any subsequent dispute between United Therapeutics and Executive, Executive shall, pendente lite , deliver to United Therapeutics all copies of any Confidential Information, documents, computer disks, computer files, or other such material in Executive’s possession to which United Therapeutics claims title. United Therapeutics also shall be entitled to other preliminary mandatory relief, including a writ of replevin or injunction to recover possession of its property, on such terms as a court deems equitable under the circumstances.

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             (d)     Executive agrees to report in writing to United Therapeutics, promptly and in reasonable detail, any notice or claim received by Executive with respect to any information or Confidential Information disclosed, delivered or produced under this Agreement.

     11.   Intellectual Property Rights. Because of the highly specialized and technical nature of the business of United Therapeutics and the nature and scope of Executive’s employment, Executive agrees that any and all rights, title, and interest in United Therapeutics’ Intellectual Property shall be the sole and exclusive property of United Therapeutics, and its respective successors, licensees, and assigns. In full consideration of the compensation provided to Executive by United Therapeutics, Executive agrees to each and all of the following:

             (a)     Work Made for Hire. Executive acknowledges and agrees that all work performed by Executive as an employee of United Therapeutics is a commissioned “work for hire” within the meaning of United States copyright law which will be owned solely and exclusively by United Therapeutics. If the work is determined not to be a “work for hire” or such doctrine is not effective, Executive hereby irrevocably assigns, conveys and otherwise transfers to United Therapeutics, and its respective successors, licensees, and assigns, all right, title and interest worldwide in and to the work and all proprietary rights therein, including, without limitation, all copyrights, trademarks, design patents, trade secret rights, moral rights, and all contract and licensing rights, and all claims and causes of action with respect to any of the foregoing, whether now known or hereafter to become known. In the event that Executive has any right in the work which cannot be assigned, Executive agrees to waive enforcement worldwide of such right against United Therapeutics, its distributors and licensees or, if necessary, to license such right exclusively, worldwide to United Therapeutics with the right to sublicense. These rights are assignable by United Therapeutics.

             (b)     Original Work. Executive agrees that Executive will not include any copyrighted or patented material owned by a third party in any written, copyrightable or patentable material furnished or delivered by Executive under this Agreement without the unconditional written consent of the copyright or patent owner unless specific written approval of United Therapeutics for inclusions of such copyrighted or patented material is secured in advance. Executive also agrees that all work (or tangible expression of an idea) that Executive creates or contributes to United Therapeutics in the course of Executive’s employment hereunder will be created solely by Executive, will be original to Executive, and will be free of any third party claims or interests.

             (c)     Applications for Patent, Copyrights and Trademarks. Executive shall, if United Therapeutics so decides at its sole discretion and expense, apply for United States and foreign letters patent, copyrights, and/or trademarks, either in Executive’s name or as United Therapeutics in its sole discretion may direct. Executive hereby grants United Therapeutics the exclusive right, and appoints United Therapeutics as Executive’s attorney-in-fact, to execute and prosecute an application for domestic and/or foreign patent or other statutory protection, and Executive shall execute and deliver to United Therapeutics, without

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charge to United Therapeutics but at United Therapeutics’ expense, such other documents of registration and recordation, and do such other acts, such as give testimony in support of Executive’s inventorship, as may be necessary in the opinion of United Therapeutics to vest in United Therapeutics or any other party nominated by United Therapeutics, or otherwise to protect, the exclusive rights conveyed and/or granted to United Therapeutics pursuant to this Agreement. Executive’s duty to support United Therapeutics’ claim of rights in patents, copyrights, or trademarks claimed by United Therapeutics, and resulting from Executive’s service to United Therapeutics as its employee, shall continue for the life of any such patent, copyright or trademark.

             (d)     Assignment Executive agrees to assign to United Therapeutics and its respective successors, licensees, and assigns, all of Executive’s rights, title and interests in and to the Intellectual Property governed by this Agreement, and all rights, title, and interests in and to United States and foreign letters patent, copyrights, and trademarks resulting therefrom. Executive acknowledges this provision and understands fully its implications and meaning.

             (e)     Use. United Therapeutics and its respective successors, licensees, and assigns, shall have the sole and exclusive right to practice, or to make, use or sell products, processes or services derived from any discoveries or creations within the scope of this Agreement, whether or not patentable or copyrightable under the laws of any jurisdiction, or protected by the trade secret laws of any jurisdiction.

             (f)     Trade Secret Protection. In the event that United Therapeutics decides not to pursue patent, copyright or trademark protection for any discovery or creation made by Executive, and instead decides to protect the discovery or creation pursuant to the trade secret laws of any jurisdiction, such decision shall not be construed as a waiver of United Therapeutics’ rights pursuant to this Agreement. At United Therapeutics’ expense, Executive shall also take whatever steps are necessary to sustain United Therapeutics’ claim to such trade secrets, including but not limited to: (i) maintaining the confidential nature of any such discoveries or creations; and (ii) testifying and providing other support and substantiation for United Therapeutics’ claims with regard to the discovery or creation.

             (g)     Reports. With respect to discoveries made by Executive, Executive shall maintain notebooks and other records adequate to describe such discovery to others conversant in the subject of the technology and to establish the date and circumstances of Executive’s discovery. Executive shall notify United Therapeutics’ CEO of any such discoveries and shall make copies of all documents or reports relating to such discoveries available to United Therapeutics. Any discovery shall be reported to United Therapeutics’ CEO regardless of whether, in Executive’s opinion, a given discovery is of value to United Therapeutics, or is protectable under patent, copyright or the laws of any jurisdiction.

             (h)     Infringement Actions. In the event that United Therapeutics shall bring an infringement suit against any third parties or shall be sued by any third parties as a result of Executive’s authorship or creation, including any addition and/or modification of the aforementioned items of Confidential Information, Executive agrees to cooperate

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reasonably without charge to United Therapeutics, but at its request and expense, in defending against or prosecuting any such suit. This right shall be cumulative to any other rights of United Therapeutics hereunder.

     12.   Covenant of Further Assurances. Upon the request of United Therapeutics, Executive shall execute and deliver such documents and take such actions as may be reasonably requested in order to carry out the intent and purposes of this Agreement, including but not limited to executing all documents necessary or desirable to protect United Therapeutics’ rights in and title to any work (or tangible expression of an idea) that Executive creates or contributes to United Therapeutics in the course of Executive’s employment hereunder.

     13.   Restrictive Covenants. As a material inducement to United Therapeutics to employ Executive and to disclose United Therapeutics’ Confidential Information to Executive, Executive agrees as follows:

             (a)     While employed by United Therapeutics and for a period of one (1) year following the termination of Executive’s employment with United Therapeutics by either party, with or without cause, Executive will not accept employment from, nor render services for, in any capacity whatsoever within the United States, any Competing Organization, or otherwise engage in any business activity in which it would be useful or helpful to Executive or others with whom he is associated, for Executive to use or disclose any Confidential Information of United Therapeutics, except that Executive may accept employment with a large Competing Organization whose business is diversified and which has separate and distinct operating divisions, and which as to part of its business is not a Competing Organization, provided that, prior to Executive’s acceptance of such employment, United Therapeutics shall receive separate written assurances satisfactory, in its sole discretion, to United Therapeutics from such Competing Organization and from Executive, that Executive will not be employed by such Competing Organization in a division which, in any aspect of its operation, develops, produces, markets or sells a Competing Product and that Executive will not have any responsibilities with respect to which it would be useful or helpful to Executive or others within said Competing Organization for Executive to use or disclose any Confidential Information of United Therapeutics.

             (b)     While employed by United Therapeutics and for a period of one (1) year following the termination of Executive’s employment with United Therapeutics by either party, with or without cause, Executive will not accept employment from, or render services to, any Competing Organization in connection with the development, manufacture, marketing, sale, merchandising, leasing, licensing, servicing or promotion of any Competing Product to any customer or potential customer of United Therapeutics with which Executive dealt personally or with respect to which Executive rendered services during his or her employment with United Therapeutics.

             (c)     While employed by United Therapeutics and for a period of one (1) year following the termination of Executive’s employment with United Therapeutics by either party, with or without cause, Executive will not hire, attempt to hire, assist in hiring, or

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cause to be hired by another person or organization, any person who was an employee of United Therapeutics at any time after Executive first had contact with another person or organization, whether such contact was initiated by Executive or such other person or organization, concerning the possible employment of Executive or others employed by United Therapeutics at that time by any person or organization other than United Therapeutics. In addition, for the same period, Executive shall not identify, or furnish any information about, any other employee of United Therapeutics to any other person or organization for the purpose of assisting or facilitating the hiring efforts of such other person or organization.

     14.     Notification of Agreement. Executive agrees that, in the event he seeks or is offered employment with any other person or organization which, as to all or any part of its business, is a Competing Organization, prior to the expiration of the one (1) year period following the termination of Executive’s employment with United Therapeutics, Executive shall advise such person or organization of the existence of this Agreement and shall immediately provide such other person or organization with a complete and accurate copy of this Agreement. Executive further agrees that United Therapeutics may, in its sole discretion, notify any such other person or organization of United Therapeutics’ understanding of the requirements of this Agreement and of such steps, if any, as United Therapeutics may take to ensure compliance with or enforcement of this Agreement.

     15.     Assignment. Neither this Agreement nor any of the rights and obligations of the parties under this Agreement may be assigned, transferred or otherwise disposed of by Executive without United Therapeutics’ prior written consent.

     16.     Absence of Conflict. Executive represents that Executive’s performance of all the terms of this Agreement as an employee of United Therapeutics does not and will not breach any agreement to keep in confidence proprietary information acquired by Executive in confidence prior to Executive’s employment by United Therapeutics.

               Executive has not entered into, and Executive agrees that Executive will not enter into, any agreement either oral or written in actual or potential conflict with any provision of this Agreement. Executive will promptly report any actual or potential conflict to United Therapeutics’ CEO.

     17.     Injunctive Relief. Executive acknowledges that United Therapeutics will be irreparably harmed if Executive’s obligations under this Agreement are not specifically enforced, including but not limited to a breach of the covenants in Sections 10 or 13 above, and that United Therapeutics would not have an adequate remedy at law in the event of an actual or threatened violation by Executive of Executive’s obligations. Therefore, Executive agrees that United Therapeutics shall be entitled to an injunction or any appropriate decree of specific performance for any actual or threatened violations or breaches by Executive without the necessity of United Therapeutics showing actual damages or that monetary damages would not afford an adequate remedy. Notwithstanding the foregoing, a court shall have the proper power to modify any of the restrictive covenants in Section 13 above if it is deemed necessary to achieve an equitable result.

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     18.   Indemnification. Executive agrees to indemnify and hold United Therapeutics and its officers, directors, licensees and distributors harmless from and against any and all claims, losses, liabilities, damages, expenses and costs (including United Therapeutics’ reasonable attorney’s fees and costs) that result from Executive’s breach of this Agreement.

     19.   Miscellaneous.

             (a)     This agreement constitutes the entire agreement and understanding between United Therapeutics and Executive concerning the subject matter hereof. No modification, amendment, termination or waiver of this Agreement shall be binding unless in writing and signed by a duly authorized officer of United Therapeutics. Failure of United Therapeutics to insist upon strict compliance with any of the terms, covenants or conditions hereof shall not be deemed a waiver of such terms, covenants and conditions.

             (b)     This Agreement shall be binding upon Executive irrespective of the duration of Executive’s employment with United Therapeutics or the amount of Executive’s salary or wages.

             (c)     Executive understands, acknowledges and agrees that any violation by Executive of any of the terms of this Agreement may result in Executive’s immediate termination.

             (d)     This Agreement shall be construed, interpreted, and applied in accordance with the laws of the State of Maryland, applying to contracts fully executed and performed in the State of Maryland. Any action or proceeding brought to enforce or construe this Agreement or in any way arising out of or relating to its performance shall be brought in the State of Maryland. Each party consents to personal jurisdiction and venue in the State of Maryland and waives any objection thereto. In the event of any such action or proceeding between the parties, the prevailing party shall be entitled to recover, in addition to any other relief awarded or granted, its costs and expenses (including reasonable attorney’s fees) incurred in any such proceeding.

             (e)     Should a court deem any term or provision of this Agreement too broad, such term or provision will nevertheless be valid and enforceable to the extent deemed reasonable under the circumstances and the court is empowered to modify such provision to the extent necessary to accomplish that objective. The validity or unenforceability of any term or provision of this Agreement will in no way affect the validity or enforceability of any other term or provision.

             (f)     Notices. All notices, demands, requests or other communications which may be, or are required to be given, served or sent by any party to any party pursuant to this Agreement shall be in writing and shall be mailed by first class, registered or certified mail, return receipt requested, postage prepaid, or transmitted by hand delivery, telegram or telex and addressed as follows:

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     20.     Executive hereby acknowledges receipt of a duplicate copy of this Agreement.

     IN WITNESS WHEREOF the parties have executed this Agreement the date first above written.

     EXECUTIVE ACKNOWLEDGES THAT BEFORE SIGNING EXECUTIVE HAS HAD AN ADEQUATE OPPORTUNITY TO READ THIS AGREEMENT AND THAT EXECUTIVE HAS DONE SO AND UNDERSTAND ITS TERMS AND CONDITIONS. EXECUTIVE ENTERS INTO THIS AGREEMENT WITH THE INTENT TO BE BOUND BY IT.

FRED HADEED, CPA

/s/ Fred Hadeed

UNITED THERAPEUTICS CORPORATION

/s/ Martine Rothblatt Martine Rothblatt, CEO

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Exhibit 10.7

Amendment to Employment Agreement

This amendment is made to the employment agreement dated January 3, 2000 by and between Fred T. Hadeed (Executive) and United Therapeutics Corporation (Company) and is effective as of August 16, 2001. The following paragraph is added to Executive’s employment agreement.

8(e) If (i) the Company terminates Executive’s employment without Cause, or (ii) the Executive’s employment is terminated as a result of the transfer of control of the Company by acquisition, merger, hostile takeover or for any other reason whatsoever, or (iii) Executive’s authority and responsibilities are materially diminished without cause relating to the performance of Executive’s services hereunder and Executive terminates this Agreement as a result of such unjustified diminution of authority, then should any of the foregoing events occur, the Company shall pay to Executive a lump-sum amount equal to the greater of either (a) the amount Executive would have been entitled to receive in current Base Salary for the time remaining in Executive’s then current term of employment, or (b) an amount equal to two years of current Base Salary. Such payment shall be fully due and payable to Executive in a lump sum upon Executive’s Date of Termination. Additionally, in the event of termination contemplated in this Section 8(e), all options granted to Executive shall immediately vest in Executive.

IN WITNESS WHEREOF, the undersigned have duly executed this Amendment, or have caused this Amendment to be duly executed on their behalf, as of the date above.

UNITED THERAPEUTICS CORPORATION

Exhibit 10.8

EMPLOYMENT AGREEMENT

     THIS EMPLOYMENT AGREEMENT (this “Agreement”) is entered into as of October 22, 1999 by and between SynQuest, Inc., an Illinois corporation having its principal offices at 2225 W. Harrison, Chicago, Illinois 60612 (the “Company”) and David Walsh, Ph.D. (the “Executive”).

     WHEREAS, the Company desires to obtain the services of the Executive, and the Executive is willing to render such services to the Company, upon the terms and conditions herein set forth;

     WHEREAS, the Company and Executive desire this Agreement to supersede and replace all previous or existing agreements between the Company and Executive relating to the subject matter covered by this Agreement;

     NOW, THEREFORE, in consideration of the promises and mutual covenants contained herein, and for other good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties hereto agree as follows.

     1.     Employment. Upon the other terms and conditions hereinafter stated, the Company agrees to employ the Executive and the Executive agrees to accept employment by the Company for the term set forth in Section 2 hereof and in the position and with the duties and responsibilities set forth in Section 3 hereof. Executive warrants that he is under no restriction that would prevent him from entering into this Agreement and from complying with all of its provisions to their fullest extent. If Executive is enjoined or otherwise prevented by judicial or administrative determination from complying with the terms of this Agreement, then the Company may terminate this Agreement immediately without incurring any further liability.

     2.     Term. The employment of the Executive by the Company will commence on December 1, 1999 and end on the first anniversary of such date (the “Initial Term”), and thereafter shall continue from year to year for additional one-year terms (the “Additional Terms”), unless and until either party shall give notice of such party’s intent to terminate not less than 30 days prior to the end of the then-current Initial Term or Additional Term, which termination shall be effective at the expiration of said term, or until sooner terminated as hereinafter set forth.

     3.     Position and Duties. The Executive shall serve as Vice President, Operations, with such duties and responsibilities as are normally performed by the Vice President of a chemical research and manufacturing company and as otherwise assigned by the Board of Directors from time to time. The Executive shall at all times exert his best efforts and loyalty on behalf of the Company and shall devote full time and attention to such employment. The Executive agrees to abide by all employment guidelines and policies as may be developed from time to time by the Company, including, without limitation, the attached United Therapeutics Corporation Company Manual, United

Therapeutics Corporation Securities Trades by Company Personnel Policy, and the United Therapeutics Corporation Media and Analysts Policy.

     4.     Compensation and Related Matters.

           (a)   For services rendered under this Agreement, the Company shall pay to the Executive an annual base salary of One Hundred Fifty Thousand Dollars ($150,000) (the “Base Salary”), subject to increase, as determined by the Board of Directors of the Company, in its sole discretion, on or before any anniversary date of this Agreement. The Base Salary shall be payable semi-monthly or in such other installments as shall be consistent with the Company’s payroll procedures. The Company shall deduct and withhold all necessary social security and withholding taxes and any other similar sums required by law or authorized by the Executive with respect to payment of the Base Salary and all other amounts and benefits payable under this Agreement.

           (b)   The Executive shall be entitled to participate in any group life, disability and medical insurance or other benefit plan or arrangement available generally to the employees of the Company as determined by the Board of Directors.

           (c)   The Executive shall receive a grant of up to 40,000 incentive stock options to purchase shares of the Common Stock of United Therapeutics Corporation pursuant to the United Therapeutics Corporation Amended and Restated Equity Incentive Plan, effective as of January 1, 2000 and vesting at a rate of twenty-five percent (25%) per year on each anniversary of the effective date. Executive will enter into a separate Equity Incentive Plan Award Agreement to effect this grant.

     5.     Expenses. The Executive shall be reimbursed by the Company for reasonable travel and other expenses, as approved from time to time by the Board of Directors, which are incurred and accounted for in accordance with the Company’s normal practices.

     6.     Vacation. The Executive shall be entitled during the term of employment hereunder to four weeks of vacation annually, which vacation shall be at such time or times and for such period or periods as shall be mutually agreed upon by the Executive and the Board of Directors. The Executive shall also be entitled to all public holidays observed by the Company.

     7.     Termination of Employment.

           (a)   The Executive’s employment hereunder shall terminate upon the Executive’s death.

           (b)   The Company may terminate the Executive’s employment hereunder under the following circumstances:

                 (i)   If, as a result of the Executive’s incapacity due or other disability owing to physical or mental illness, the Executive shall have been unable to perform all of the Executive’s material duties hereunder by reason of illness, or physical or

mental disability or other similar capacity, which inability shall continue for more than four (4) consecutive months, the Company may terminate the Executive’s employment hereunder.

                 (ii)   The Company may terminate the Executive’s employment hereunder for “Cause.” For purposes of this Agreement, the Company shall have “Cause” to terminate the Executive’s employment hereunder upon the (A) failure of the Executive (other than for reasons described in Sections 7(a) and 7(b)(i) hereof) to perform or observe any of the material terms or provisions of this Agreement; (B) negligent or unsatisfactory performance of the Executive’s duties under this Agreement and the failure of the Executive, within 30 days after receipt of notice from the Company setting forth in reasonable detail the nature of the Executive’s negligent or unsatisfactory performance, (i) to provide the Company with a reasonably satisfactory explanation of the Executive’s actions (or inaction) and (ii) to correct to the satisfaction of the Company any reasonably identified deficiencies; (C) employment- or profession-related misconduct or other employment- or profession-related similar action on the part of the Executive; (D) conviction of the Executive of a crime involving a felony, fraud, embezzlement or the like; or (E) misappropriation of the Company funds or misuse of the Company’s assets by Executive.

           (c)   Any termination of the Executive’s employment by the Company or by the Executive (other than pursuant to Section 7(a) hereof) shall be communicated by written “Notice of Termination” to the other party hereto in accordance with Section 10(c) hereof, which shall indicate the specific termination provision in this Agreement relied upon, if any, and shall set forth in reasonable detail the facts and circumstances claimed to provide a basis for termination of the Executive’s employment under the provision so indicated.

           (d)   For purposes of this Agreement, the “Date of Termination” shall mean (i) if the Executive’s employment is terminated by the Executive’s death, the date of the Executive’s death; (ii) if the Executive’s employment is terminated pursuant to Section 7(b)(i) hereof, thirty (30) days after the Notice of Termination; provided , that the Executive shall not have returned to the performance of the Executive’s duties on a full-time basis during such thirty (30) day period; (iii) if the Executive’s employment is terminated pursuant to Section 7(b)(ii) hereof, the date specified in the Notice of Termination (which date, in the case of termination of Executive’s employment solely pursuant to clause (B) of Section 7(b)(ii) by reason of inadequate performance, shall not be sooner than nine months from the date of the Notice of Termination); and (iv) if the Executive’s employment is terminated for any other reason, the date on which the Notice of Termination is given.

     8.     Compensation Upon Termination.

           (a)   If the Executive’s employment is terminated by the Executive’s death, the Company shall pay to the Executive’s estate or as may be directed by the legal representatives of such estate, the Executive’s full Base Salary through the Date of Termination at the rate in effect at the time of the Executive’s death and all other unpaid amounts, if any, to which the Executive is entitled as of such date in connection with any fringe benefits or under any incentive compensation plan or program of the Company pursuant to Section 4(c) or 4(d) hereof, at the time such payments are due.

           (b)   During any period that the Executive fails to perform the Executive’s duties hereunder solely as a result of incapacity due to physical or mental illness (“disability period”), the Executive shall continue to receive the Executive’s full base salary through the Date of Termination at the rate in effect at the time the Notice of Termination is given and all other unpaid amounts, if any, to which the Executive is entitled as of the Date of Termination in connection with any fringe benefits or under any incentive compensation plan or program of the Company pursuant to Section 4(c) or 4(d) hereof, at the time such payments are due; provided that payments so made to the Executive during the disability period shall be reduced by the sum of the amounts, if any, payable to the Executive at or prior to the time of any such payment under disability benefit plans of the Company and which amounts were not previously applied to reduce any such payment.

           (c)   If the Executive shall terminate the Executive’s employment or the Company terminates the Executive’s employment for Cause as provided in Section 7(b)(ii) hereof, the Company shall pay the Executive the Executive’s full Base Salary through the Date of Termination at the rate in effect at the time the Notice of Termination is given, and the Company shall have no further obligations to the to the Executive under this Agreement.

           (d)   In the event that Executive’s employment with the Company is terminated for any reason within twelve months of its commencement, then, (i) Executive agrees to reimburse the Company for the amount of any signing bonus which Executive received and relocation allowance (including moving and co-paid expenses incurred for sale or purchase of a home) paid to Executive or on Executive’s behalf, and (ii) Executive acknowledges that any stock options granted to Executive, whether vested or unvested, shall immediately terminate upon the termination of Executive’s employment.

     9.     Intellectual Property Rights. Because of the highly specialized and technical nature of the business of the Company and the nature and scope of Executive’s employment, Executive agrees that any and all rights, title, and interest, including but not limited to domestic and foreign patents, copyrights, trademarks and trade secrets, in and to all inventions, processes, computer programs, photographic, written or artistic works, or other forms of intellectual property (“Intellectual Property”) which employee makes, conceives, reduces to practice or develops, in whole or in part, during the term of this Agreement in the furtherance of the Company’s business and in connection with specific Company projects as defined in Paragraph 9 below (whether or not made during the hours of employment or with the use of Company’s materials, facilities or personnel, either solely or jointly with others), or after termination of employment if such Intellectual Property is based upon Confidential Information, shall be the sole and exclusive property of the Company, and its respective successors, licensees, and assigns. In full consideration of the compensation provided to Executive by the Company, Executive agrees to each and all of the following:

           (a)   Work Made for Hire. Executive acknowledges and agrees that all works of authorship created by Executive as an employee of the Company is a commissioned “work for hire” within the meaning of United States copyright law which will be owned solely and exclusively by the Company. If the work is determined not to be a “work for hire” or such doctrine is not effective, Executive hereby irrevocably assigns, conveys and otherwise transfers to the Company, and its respective successors, licensees, and assigns, all right, title

and interest worldwide in and to the work and all proprietary rights therein, including, without limitation, all copyrights, trademarks, design patents, trade secret rights, moral rights, and all contract and licensing rights, and all claims and causes of action with respect to any of the foregoing, whether now known or hereafter to become known. In the event that Executive has any right in the work which cannot be assigned, Executive agrees to waive enforcement worldwide of such right against the Company, its distributors and licensees or, if necessary, exclusively license such right, worldwide to the Company with the right to sublicense. These rights are assignable by the Company. Executive has not and hereby does not transfer any Intellectual Property rights owned or held solely by Executive to the Company relating to periods prior to the date of this Agreement and retains all rights to same provided, however, that Executive acknowledges that Intellectual Property rights that he created as an employee of the Company prior to the date of this Agreement, and not otherwise previously assigned or transferred prior to the date of this Agreement pursuant to the attached schedule, are solely owned by the Company as a work made for hire.

           (b)   Original Work. Executive agrees that Executive will not include any copyrighted or patented material owned by a third party in any written, copyrightable or patentable material furnished or delivered by Executive under this Agreement without the unconditional written consent of the copyright or patent owner unless specific written approval of the Company for inclusions of such copyrighted or patented material is secured in advance. Executive also agrees that all work (or tangible expression of an idea) that Executive creates or contributes to the Company in the course of Executive’s employment hereunder will be created solely by Executive, will be original to Executive, and will be free of any third party claims or interests.

           (c)   Applications for Patent, Copyrights and Trademarks. Executive shall, if the Company so decides at its sole discretion and expense, apply for United States and foreign letters patent, copyrights, and/or trademarks, either in Executive’s name or as the Company in its sole discretion may direct. Executive hereby grants the Company the exclusive right, and appoints the Company as Executive’s attorney-in-fact, to execute and prosecute an application for domestic and/or foreign patent or other statutory protection, and Executive shall execute and deliver to the Company, without charge to the Company but at the Company’s expense, such other documents of registration and recordation, and do such other acts, such as give testimony in support of Executive’s inventorship, as may be necessary in the opinion of the Company to vest in the Company or any other party nominated by the Company, or otherwise to protect, the exclusive rights conveyed and/or granted to the Company pursuant to this Agreement. Executive’s duty to support the Company’s claim of rights in patents, copyrights, or trademarks claimed by the Company, and resulting from Executive’s service to the Company as its employee, shall continue for the life of any such patent, copyright or trademark.

           (d)   Assignment Except as otherwise may be agreed by the parties in a signed writing, Executive agrees to assign to the Company and its respective successors, licensees, and assigns, all of Executive’s rights, title and interests in and to the Intellectual Property governed by this Agreement and all rights, title, and interests in and to United States and foreign letters patent, copyrights, and trademarks resulting therefrom. Executive acknowledges this provision and understands fully its implications and meaning.

           (e)   Use. The Company and its respective successors, licensees, and assigns, shall have the sole and exclusive right to practice, or to make, use or sell products, processes or services derived from any discoveries or creations within the scope of this Agreement or created by Executive and covered by the terms of this Agreement, whether or not patentable or copyrightable under the laws of any jurisdiction, or protected by the trade secret laws of any jurisdiction.

           (f)   Trade Secret Protection. In the event that the Company decides not to pursue patent, copyright or trademark protection for any discovery or creation made by Executive, and instead decides to protect the discovery or creation pursuant to the trade secret laws of any jurisdiction, such decision shall not be construed as a waiver of the Company’s rights pursuant to this Agreement. At the Company’s expense, Executive shall also take whatever steps are necessary to sustain the Company’s claim to such trade secrets, including but not limited to: (a) maintaining the confidential nature of any such discoveries or creations; and (b) testifying and providing other support and substantiation for the Company’s claims with regard to the discovery or creation.

           (g)   Reports. With respect to discoveries made by Executive covered by the terms of this Agreement, Executive shall maintain notebooks and other records adequate to describe such discovery to others conversant in the subject of the technology and to establish the date and circumstances of Executive’s discovery. Executive shall notify the Company’s General Counsel of any such discoveries and shall make copies of all documents or reports relating to such discoveries available to the Company. Any such discovery shall be reported to the Company’s General Counsel regardless of whether, in Executive’s opinion, a given discovery is of value to the Company, or is protectable under patent, copyright or the laws of any jurisdiction.

           (h)   Infringement Actions. In the event that the Company shall bring an infringement suit against any third parties or shall be sued by any third parties as a result of Executive’s authorship or creation, including any addition and/or modification of the aforementioned items of Confidential Information, Executive agrees to cooperate reasonably without charge to the Company, but at its request and expense, in defending against or prosecuting any such suit. This right shall be cumulative to any other rights of the Company hereunder.

     10.     Obligation of Confidentiality and Non-Competition. Executive agrees that Executive has a fiduciary duty to the Company and that Executive shall hold in confidence and shall not, except in the course of performing Executive’s employment obligations or pursuant to written authorization from the Company, at any time during or for three years after termination of Executive’s relationship with the Company knowingly (a) directly or indirectly reveal, report, publish, disclose or transfer the Confidential Information or any part thereof to any person or entity; (b) use any of the Confidential Information or any part thereof for any purpose other than for the benefit of the Company; (c) assist any person or entity other than the Company to secure any benefit from the Confidential Information or any part thereof or (d) solicit (on Executive’s behalf or on behalf of any third party) any employee of

the Company for the purpose of providing services or products which Executive is prohibited from providing hereunder.

     Furthermore, Executive agrees that all Confidential Information, as defined below, shall belong exclusively and without any additional compensation to the Company. For the purposes of this Agreement, “Confidential Information” shall mean each of the following: (a) any information or material proprietary to the Company or designated as confidential either orally or in writing by the Company; and (b) any information not generally known by non- Company personnel; and (c) any information which Executive should know the Company would not care to have revealed to others or used in competition with the Company; and (d) any information which Executive made or makes, conceived or conceives, developed or develops or obtained or obtains knowledge or access through or as a result of Executive’s relationship with the Company (including information received, originated, discovered or developed in whole or in part by Executive) from the initial date of Executive’s employment with the Company.

     Furthermore, Executive agrees not to accept employment, consultancy or other business relationships with a business which directly competes with the Company’s then existing or planned business for twelve months following Executive’s last receipt of compensation from the Company. For the purpose of this paragraph, the Company’s business as of the date of this Agreement shall be defined as complex specialized chemical syntheses and complex specialized organic syntheses for pharmaceutical and neutraceutical applications for which the Company shall be developing, producing, testing, and/or applying for Intellectual Property Rights and shall hold Intellectual Property Rights. The parties acknowledge that the Company’s business after the date of this Agreement may evolve into other or additional areas and activities. Executive and Company agree that the terms of this Section 10 relating to non-competition are reasonable in scope and length and are necessary for the protection of the Company. In the event that a court finds the scope of this provision to be unreasonably broad or if the length of time of this provision is found to be unreasonably long, an arbitrator or court, as applicable, shall narrow the scope or shorten the length of time to the extent required to render the provision reasonable and enforceable and shall enforce the provision as so narrowed.

     While employed by the Company and for a period of twelve months after the cessation of employment for any reason, Executive shall not induce or attempt to influence, either directly or indirectly any other employee or contractor of the Company to terminate his or her employment or relationship with the Company or to work for Executive or any other person or entity.

     11.     Miscellaneous.

           (a)   Entire Agreement. This Agreement contains the entire agreement between the parties hereto relating to the subject matter hereof, and this Agreement supersedes all prior understandings and agreements, whether oral or written, relating to the employment of the Executive by the Company.

           (b)   Assignment. This Agreement shall not be assignable or otherwise transferable by either party hereto, but any amounts owing to Executive upon the Executive’s death shall inure to the benefit of the Executive’s heirs, legatees, legal representatives, executor or administrator. Notwithstanding the foregoing, this Agreement applies with the prior written consent of the Executive, which consent shall not be unreasonably withheld. This Agreement shall be binding upon and shall inure to the benefit of the parties hereto and any such respective heirs, legatees, executors, administrators, representatives, successors and assigns.

           (c)   Notices. All notices, demands, requests or other communications which may be, or are required to be given, served or sent by any party to any party pursuant to this Agreement shall be in writing and shall be mailed by first class, registered or certified mail, return receipt requested, postage prepaid, or transmitted by hand delivery, telegram or telex and addressed as follows:

           (d)   Amendment; Waiver. This Agreement shall not be amended, altered, modified or discharged except by an instrument in writing duly executed by the Executive and the Company. Neither the waiver by the parties hereto of a breach of, or default under, any of the provisions of this Agreement, nor the failure of either of the parties, on one or more occasions, to enforce any of the provisions of this Agreement or to exercise any right or privilege hereunder, shall thereafter be construed as a waiver of any such provisions, rights or privileges hereunder.

           (e)   Severability. The invalidity or unenforceabilty of any provision or provisions of this Agreement shall not affect the validity or enforceability of any other provisions of this Agreement, which shall remain in full force and effect.

           (f)   Applicable Law. This Agreement and the rights and obligations of the parties under this Agreement shall be construed, interpreted and enforced in accordance with the laws of the State of Illinois, exclusive of the choice-of-laws rules thereunder.

           (g)   Survival. It is the express intention and agreement of the parties hereto that the provisions of Sections 8, 9, 10 and 11 hereof shall survive the termination of employment of the Executive. In addition, all obligations of the Company to make payments hereunder shall survive any termination of this Agreement on the terms and conditions set forth.

           (h)   Execution. To facilitate execution, this Agreement may be executed in as many counterparts as may be required; and it shall not be necessary that the signatures of, or on behalf of, each party, or that the signatures of all persons required to bind any party, appear on each counterpart; but it shall be sufficient that the signature of, or on behalf of, each party, or that the signatures of the persons required to bind any party, appear on one or more of the counterparts. All counterparts shall collectively constitute a single agreement. It shall not be necessary in making proof of this Agreement to produce or account for more than a number of counterparts containing the respective signatures of, or on behalf of, all of the parties hereto.

     IN WITNESS WHEREOF, the undersigned have duly executed this Agreement, or have caused this Agreement to be duly executed on their behalf, as of the date first above written.

SYNQUEST, INC.

Exhibit 10.9

EMPLOYMENT AGREEMENT

     THIS EMPLOYMENT AGREEMENT (this “Agreement”) is entered into as of November 29, 2000 by and between United Therapeutics Corporation (the “Company”) and Roger Jeffs, Ph.D. (the “Executive”).

     WHEREAS, the Company currently employs the Executive as its Vice President of Research, Development & Medical and Executive shall continue in this capacity until commencement of the Initial Term in accordance with Section 2 below;

     WHEREAS, the Company desires to promote the Executive, and the Executive is willing to accept such promotion from the Company, subject to the terms and conditions herein set forth; and

     WHEREAS, the parties desire this Agreement to supersede and replace all previous agreements for employment entered into between the Company and Executive.

     NOW, THEREFORE, in consideration of the promises and mutual covenants contained herein, and for other good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties hereto agree as follows.

     1.     Employment. Upon the other terms and conditions hereinafter stated, the Company agrees to employ the Executive and the Executive agrees to accept employment by the Company for the term set forth in Section 2 hereof and in the position and with the duties and responsibilities set forth in Section 3 hereof. Executive warrants that he is under no restriction that would prevent him from entering into this Agreement and from complying with all of its provisions to their fullest extent.

     2.     Term. The employment of the Executive by the Company will commence immediately upon the retirement of James W. Crow, Ph.D. from his position as President and COO of the Company and end on the fifth anniversary of such date (the “Initial Term”), and thereafter shall continue from year to year for additional one-year terms (the “Additional Terms”), unless and until either party shall give notice of such party’s intent to terminate not less than 30 days prior to the end of the then-current Initial Term or Additional Term, which termination shall be effective at the expiration of said term, or until sooner terminated as hereinafter set forth.

     3.     Position and Duties. Prior to commencement of the Initial Term, the Executive shall continue to provide services as the Company’s Vice President of Research, Development & Medical. Upon commencement of the Initial Term, Executive shall serve as President and COO, with such duties and responsibilities as are normally performed by the President and COO of a biotechnology company and as otherwise assigned by the Board of Directors from time to time that are not inconsistent with duties and responsibilities as are normally performed by the President and COO. The Executive shall have primary responsibility for the operations of the Company’s Research Triangle

Park, N.C. office and management of all prostacyclin drug development programs. Executive is expected to continue the Company’s development of its UT-15 and Beraprost compounds for PH and PVD, as well as follow-on sustained release and pegylated molecules for PH, PVD and one new major indication to be determined by the Company. The Executive shall at all times exert his best efforts and loyalty on behalf of the Company and shall devote full time and attention to such employment. The Executive agrees to abide by all employment guidelines and policies as may be developed from time to time by the Company, including, without limitation, the United Therapeutics Corporation Company Manual and the United Therapeutics Corporation Securities Trades by Company Personnel Policy.

     4.     Compensation and Related Matters. Effective January 1, 2001, the Company shall provide the following compensation and benefits to the Executive:

           (a)    The Company shall pay to the Executive an annual base salary of Two Hundred Fifty Thousand Dollars ($250,000) (the “Base Salary”), such annual base salary to be increased by a minimum of 10% on each anniversary of the term of Executive’s employment hereunder. The Base Salary shall be payable semi-monthly or in such other installments as shall be consistent with the Company’s payroll procedures. The Company shall deduct and withhold all necessary social security and withholding taxes and any other similar sums required by law or authorized by the Executive with respect to payment of the Base Salary and all other amounts and benefits payable under this Agreement.

           (b)    The Executive shall be entitled to participate in any group life, disability and medical insurance or other benefit plan or arrangement available generally to the employees of the Company as determined by the Board of Directors.

           (c)    The Executive shall be entitled to receive 125,000 incentive stock options at the NASDAQ closing price of the Company’s common stock on January 2, 2001, vesting as follows:

	(i)     25,000 shares shall immediately vest as of January 1, 2001;
	(ii)    25,000 shares on each of the next four anniversaries of the commencement of the Initial Term.

           (d)    All Options previously awarded Executive, whether under any prior agreement or otherwise, shall be unaffected by this Agreement.

           (e)    The Company shall lease for Executive’s use a luxury class car of Executive’s choosing, with a monthly lease payment not to exceed $1,000.

           (f)    The Company shall recommend to the Board of Directors that Executive be elected to the Board of Directors to fill the next employee-director vacancy that occurs.

     5.     Expenses. The Executive shall be reimbursed by the Company for reasonable travel and other expenses which are incurred and accounted for in accordance with the Company’s normal practices.

     6.     Vacation. The Executive shall be entitled to vacation at such time or times and for such period or periods as shall be mutually agreed upon by the Executive and the Board of Directors.

     7.     Termination of Employment.

           (a)    The Executive’s employment hereunder shall terminate upon the Executive’s death.

           (b)    The Company may terminate the Executive’s employment hereunder as set forth in Section 2 above, and under the following circumstances:

                 (i)    If, as a result of the Executive’s incapacity due or other disability owing to physical or mental illness, the Executive shall have been unable to perform all of the Executive’s material duties hereunder by reason of illness, or physical or mental disability or other similar capacity, which inability shall continue for more than two (2) consecutive months, the Company may terminate the Executive’s employment hereunder.

                 (ii)    The Company may terminate the Executive’s employment hereunder for “Cause.” For purposes of this Agreement, the Company shall have “Cause” to terminate the Executive’s employment hereunder upon the (A) failure of the Executive (other than for reasons described in Sections 7(a) and 7(b)(i) hereof) to perform or observe any of the material terms or provisions of this Agreement; (B) negligent or unsatisfactory performance of the Executive’s duties under this Agreement and the failure of the Executive, within 10 days after receipt of notice from the Company setting forth in reasonable detail the nature of the Executive’s negligent or unsatisfactory performance, (i) to provide the Company with a reasonably satisfactory explanation of the Executive’s actions (or inaction) and (ii) to correct to the satisfaction of the Company any reasonably identified deficiencies; (C) employment- or profession-related misconduct or other employment- or profession-related similar action on the part of the Executive; (D) conviction of the Executive of a crime involving a felony, fraud, embezzlement or the like; or (E) misappropriation of the Company funds or misuse of the Company’s assets by Executive.

           (c)    Any termination of the Executive’s employment by the Company or by the Executive (other than pursuant to Section 7(a) hereof) shall be communicated by written “Notice of Termination” to the other party hereto in accordance with Section 10(c) hereof, which shall indicate the specific termination provision in this Agreement relied upon, if any, and shall set forth in reasonable detail the facts and circumstances claimed to provide a basis for termination of the Executive’s employment under the provision so indicated.

           (d)    For purposes of this Agreement, the “Date of Termination” shall mean (i) if the Executive’s employment is terminated by the Executive’s death, the date of the Executive’s death; (ii) if the Executive’s employment is terminated pursuant to Section

7(b)(i) hereof, thirty (30) days after the Notice of Termination; provided , that the Executive shall not have returned to the performance of the Executive’s duties on a full-time basis during such thirty (30) day period; (iii) if the Executive’s employment is terminated pursuant to Section 7(b)(ii) hereof, the date specified in the Notice of Termination (which date, in the case of termination of Executive’s employment solely pursuant to clause (B) of Section 7(b)(ii) by reason of inadequate performance, shall not be sooner than thirty (30) days from the date of the Notice of Termination); and (iv) if the Executive’s employment is terminated for any other reason, the date on which the Notice of Termination is given.

     8.     Compensation Upon Termination.

           (a)    If the Executive’s employment is terminated by the Executive’s death, the Company shall pay to the Executive’s estate or as may be directed by the legal representatives of such estate, the Executive’s full Base Salary through the Date of Termination at the rate in effect at the time of the Executive’s death and all other unpaid amounts, if any, to which the Executive is entitled as of such date in connection with any fringe benefits or under any incentive compensation plan or program of the Company pursuant to Section 4(c) hereof, at the time such payments are due.

           (b)    During any period that the Executive fails to perform the Executive’s duties hereunder solely as a result of incapacity due to physical or mental illness (“disability period”), the Executive shall continue to receive the Executive’s full base salary through the Date of Termination at the rate in effect at the time the Notice of Termination is given and all other unpaid amounts, if any, to which the Executive is entitled as of the Date of Termination in connection with any fringe benefits or under any incentive compensation plan or program of the Company hereof, at the time such payments are due; provided that payments so made to the Executive during the disability period shall be reduced by the sum of the amounts, if any, payable to the Executive at or prior to the time of any such payment under disability benefit plans of the Company and which amounts were not previously applied to reduce any such payment.

           (c)    If the Executive shall terminate the Executive’s employment or the Company terminates the Executive’s employment for Cause as provided in Section 7(b)(ii) hereof, the Company shall pay the Executive the Executive’s full Base Salary through the Date of Termination at the rate in effect at the time the Notice of Termination is given, and the Company shall have no further obligations to the to the Executive under this Agreement.

           (d)    If (i) the Company terminates the Executive’s employment without Cause, or (ii) the Executive’s employment is terminated as a result of the transfer of control of the Company by acquisition, merger, hostile takeover or for any other reason whatsoever, or (iii) Executive’s authority and responsibilities are materially diminished without cause relating to the performance of Executive’s services hereunder and Executive terminates this Agreement as a result of such unjustified diminution of authority, then should any of the foregoing events occur, the Company shall pay to Executive a lump-sum amount equal to the greater of either
(a)  the amount Executive would have been entitled to receive in Base Salary for the time remaining in Executive’s then current term of employment (either Initial Term or Additional

Term), or (b) an amount equal to two years of Base Salary. Such payment shall be fully due and payable to Executive in a lump sum upon Executive’s Date of Termination. Additionally, in the event of termination contemplated in this Section 8(d), all options granted to Executive pursuant to Section 4(c) shall immediately vest in Executive.

     9.     Intellectual Property Rights. Because of the highly specialized and technical nature of the business of the Company and the nature and scope of Executive’s employment, Executive agrees that any and all rights, title, and interest, including but not limited to domestic and foreign patents, copyrights, trademarks and trade secrets, in and to all inventions, processes, computer programs, photographic, written or artistic works, or other forms of intellectual property (“Intellectual Property”) which employee makes, conceives, reduces to practice or develops, in whole or in part, during the term of this Agreement in the furtherance of the Company’s business and in connection with specific Company projects as defined in Paragraph 9 below (whether or not made during the hours of employment or with the use of Company’s materials, facilities or personnel, either solely or jointly with others), or after termination of employment if such Intellectual Property is based upon Confidential Information, shall be the sole and exclusive property of the Company, and its respective successors, licensees, and assigns. In full consideration of the compensation provided to Executive by the Company, Executive agrees to each and all of the following:

           (a)    Work Made for Hire. Executive acknowledges and agrees that all works of authorship created by Executive as an employee of the Company is a commissioned “work for hire” within the meaning of United States copyright law which will be owned solely and exclusively by the Company. If the work is determined not to be a “work for hire” or such doctrine is not effective, Executive hereby irrevocably assigns, conveys and otherwise transfers to the Company, and its respective successors, licensees, and assigns, all right, title and interest worldwide in and to the work and all proprietary rights therein, including, without limitation, all copyrights, trademarks, design patents, trade secret rights, moral rights, and all contract and licensing rights, and all claims and causes of action with respect to any of the foregoing, whether now known or hereafter to become known. In the event that Executive has any right in the work which cannot be assigned, Executive agrees to waive enforcement worldwide of such right against the Company, its distributors and licensees or, if necessary, exclusively license such right, worldwide to the Company with the right to sublicense. These rights are assignable by the Company. Executive has not and hereby does not transfer any Intellectual Property rights owned or held solely by Executive to the Company relating to periods prior to the date of this Agreement and retains all rights to same provided, however, that Executive acknowledges that Intellectual Property rights that he created as an employee of the United Therapeutics Corporation prior to the date of this Agreement, and not otherwise previously assigned or transferred prior to the date of this Agreement are solely owned by the Company as a work made for hire.

           (b)    Original Work. Executive agrees that Executive will not include any copyrighted or patented material owned by a third party in any written, copyrightable or patentable material furnished or delivered by Executive under this Agreement without the unconditional written consent of the copyright or patent owner unless specific written approval of the Company for inclusions of such copyrighted or patented material is secured in advance. Executive also agrees that all work (or tangible expression of an idea) that

Executive creates or contributes to the Company in the course of Executive’s employment hereunder will be created solely by Executive, will be original to Executive, and will be free of any third party claims or interests.

           (c)    Applications for Patent, Copyrights and Trademarks. Executive shall, if the Company so decides at its sole discretion and expense, apply for United States and foreign letters patent, copyrights, and/or trademarks, either in Executive’s name or as the Company in its sole discretion may direct. Executive hereby grants the Company the exclusive right, and appoints the Company as Executive’s attorney-in-fact, to execute and prosecute an application for domestic and/or foreign patent or other statutory protection, and Executive shall execute and deliver to the Company, without charge to the Company but at the Company’s expense, such other documents of registration and recordation, and do such other acts, such as give testimony in support of Executive’s inventorship, as may be necessary in the opinion of the Company to vest in the Company or any other party nominated by the Company, or otherwise to protect, the exclusive rights conveyed and/or granted to the Company pursuant to this Agreement. Executive’s duty to support the Company’s claim of rights in patents, copyrights, or trademarks claimed by the Company, and resulting from Executive’s service to the Company as its employee, shall continue for the life of any such patent, copyright or trademark.

           (d)    Assignment Except as otherwise may be agreed by the parties in a signed writing, Executive agrees to assign to the Company and its respective successors, licensees, and assigns, all of Executive’s rights, title and interests in and to the Intellectual Property governed by this Agreement and all rights, title, and interests in and to United States and foreign letters patent, copyrights, and trademarks resulting therefrom. Executive acknowledges this provision and understands fully its implications and meaning.

           (e)    Use. The Company and its respective successors, licensees, and assigns, shall have the sole and exclusive right to practice, or to make, use or sell products, processes or services derived from any discoveries or creations within the scope of this Agreement or created by Executive and covered by the terms of this Agreement, whether or not patentable or copyrightable under the laws of any jurisdiction, or protected by the trade secret laws of any jurisdiction.

           (f)    Trade Secret Protection. In the event that the Company decides not to pursue patent, copyright or trademark protection for any discovery or creation made by Executive, and instead decides to protect the discovery or creation pursuant to the trade secret laws of any jurisdiction, such decision shall not be construed as a waiver of the Company’s rights pursuant to this Agreement. At the Company’s expense, Executive shall also take whatever steps are necessary to sustain the Company’s claim to such trade secrets, including but not limited to: (a) maintaining the confidential nature of any such discoveries or creations; and (b) testifying and providing other support and substantiation for the Company’s claims with regard to the discovery or creation.

           (g)    Reports. With respect to discoveries made by Executive covered by the terms of this Agreement, Executive shall maintain notebooks and other records adequate to describe such discovery to others conversant in the subject of the technology and to

establish the date and circumstances of Executive’s discovery. Executive shall notify the Company’s General Counsel of any such discoveries and shall make copies of all documents or reports relating to such discoveries available to the Company. Any such discovery shall be reported to the Company’s General Counsel regardless of whether, in Executive’s opinion, a given discovery is of value to the Company, or is protectable under patent, copyright or the laws of any jurisdiction.

           (h)    Infringement Actions. In the event that the Company shall bring an infringement suit against any third parties or shall be sued by any third parties as a result of Executive’s authorship or creation, including any addition and/or modification of the aforementioned items of Confidential Information, Executive agrees to cooperate reasonably without charge to the Company, but at its request and expense, in defending against or prosecuting any such suit. This right shall be cumulative to any other rights of the Company hereunder.

     10.     Obligation of Confidentiality and Non-Competition.

           (a)    Executive agrees that Executive has a fiduciary duty to the Company and that Executive shall hold in confidence and shall not, except in the course of performing Executive’s employment obligations or pursuant to written authorization from the Company, at any time during or for three years after termination of Executive’s relationship with the Company knowingly (a) directly or indirectly reveal, report, publish, disclose or transfer the Confidential Information or any part thereof to any person or entity; (b) use any of the Confidential Information or any part thereof for any purpose other than for the benefit of the Company; (c) assist any person or entity other than the Company to secure any benefit from the Confidential Information or any part thereof or (d) solicit (on Executive’s behalf or on behalf of any third party) any employee of the Company for the purpose of providing services or products which Executive is prohibited from providing hereunder.

           (b)    Executive agrees that all Confidential Information, as defined below, shall belong exclusively and without any additional compensation to the Company. For the purposes of this Agreement, “Confidential Information” shall mean each of the following: (a) any information or material proprietary to the Company or designated as confidential either orally or in writing by the Company; and (b) any information not generally known by non- Company personnel; and (c) any information which Executive should know the Company would not care to have revealed to others or used in competition with the Company; and (d) any information which Executive made or makes, conceived or conceives, developed or develops or obtained or obtains knowledge or access through or as a result of Executive’s relationship with the Company (including information received, originated, discovered or developed in whole or in part by Executive) from the initial date of Executive’s employment with the Company.

           (c)    Executive agrees not to accept employment from, nor render services in any capacity for, nor have any other business relationships with, nor engage in any business activity in which it would be useful or helpful to Executive or others with whom he is associated for Executive to use or disclose Confidential Information of the Company with, a person or entity engaged in a business located anywhere in the world which directly

competes with the Company’s then existing or planned business a period of one (1) year following Executive’s last receipt of compensation from the Company, whether the termination of Executive’s employment by either party was with or without Cause. A person or entity directly competes with the Company’s then existing or planned business if such individual or entity is engaged in, or about to become engaged in, research on, or development, production, manufacture, marketing, merchandising, leasing, selling, licensing, servicing or promotion of a Competing Product. As used in this Agreement, a “Competing Product” means any product, technology, process, system or service, in existence or under development, of any person or organization other than the Company which is the same as, similar to, competes with or has a usage allied to a product, technology, process, system or service in existence or planned by the Company as of the termination of Executive’s employment hereunder. The parties acknowledge that the Company’s business after the date of this Agreement may evolve into other or additional areas and activities. Executive and the Company agree that the terms of this Section 10(c) relating to non-competition are reasonable in scope and length and are necessary for the protection of the Company. In the event that a court finds the scope of this provision to be unreasonably broad or if the length of time of this provision is found to be unreasonably long, an arbitrator or court, as applicable, shall narrow the scope or shorten the length of time to the extent required to render the provision reasonable and enforceable and shall enforce the provision as so narrowed.

           (d)    While employed by the Company and for a period of one (1) year following Executive’s last receipt of compensation from the Company, whether the termination of Executive’s employment by either party was with or without Cause, the Executive will not hire, induce, attempt to hire, assist in hiring, or cause to be hired, directly or indirectly, by another person or organization, any person who was an employee or a contractor of the Company. In addition, for the same period, the Executive shall not identify, or furnish any information about, any other employee of the Company to any other person or organization for the purpose of assisting or facilitating the hiring efforts of such other person or organization.

     11.     Miscellaneous.

           (a)    Entire Agreement. This Agreement contains the entire agreement between the parties hereto relating to the subject matter hereof, and this Agreement supersedes all prior understandings and agreements, whether oral or written, relating to the employment of the Executive by the Company.

           (b)    Assignment. This Agreement shall not be assignable or otherwise transferable by either party hereto, but any amounts owing to Executive upon the Executive’s death shall inure to the benefit of the Executive’s heirs, legatees, legal representatives, executor or administrator. Notwithstanding the foregoing, this Agreement applies with the prior written consent of the Executive, which consent shall not be unreasonably withheld. This Agreement shall be binding upon and shall inure to the benefit of the parties hereto and any such respective heirs, legatees, executors, administrators, representatives, successors and assigns.

     (c)  Notices. All notices, demands, requests or other communications which may be, or are required to be given, served or sent by any party to any party pursuant to this Agreement shall be in writing and shall be mailed by first class, registered or certified mail, return receipt requested, postage prepaid, or transmitted by hand delivery, telegram or telex and addressed as follows:

           (d)    Amendment; Waiver. This Agreement shall not be amended, altered, modified or discharged except by an instrument in writing duly executed by the Executive and the Company. Neither the waiver by the parties hereto of a breach of, or default under, any of the provisions of this Agreement, nor the failure of either of the parties, on one or more occasions, to enforce any of the provisions of this Agreement or to exercise any right or privilege hereunder, shall thereafter be construed as a waiver of any such provisions, rights or privileges hereunder.

           (e)    Severability. The invalidity or unenforceabilty of any provision or provisions of this Agreement shall not affect the validity or enforceability of any other provisions of this Agreement, which shall remain in full force and effect.

           (f)    Applicable Law. This Agreement and the rights and obligations of the parties under this Agreement shall be construed, interpreted and enforced in accordance with the laws of the State of Maryland, exclusive of the choice-of-laws rules thereunder.

           (g)    Survival. It is the express intention and agreement of the parties hereto that the provisions of Sections 7, 8, 9, and 10 hereof shall survive the termination of employment of the Executive. In addition, all obligations of the Company to make payments hereunder shall survive any termination of this Agreement on the terms and conditions set forth.

           (h)    Execution. To facilitate execution, this Agreement may be executed in as many counterparts as may be required; and it shall not be necessary that the signatures of, or on behalf of, each party, or that the signatures of all persons required to bind any party, appear on each counterpart; but it shall be sufficient that the signature of, or on behalf of, each party, or that the signatures of the persons required to bind any party, appear on one or more of the counterparts. All counterparts shall collectively constitute a single agreement. It shall not be necessary in making proof of this Agreement to produce or account for more than a number of counterparts containing the respective signatures of, or on behalf of, all of the parties hereto.

     IN WITNESS WHEREOF, the undersigned have duly executed this Agreement, or have caused this Agreement to be duly executed on their behalf, as of the date first above written.

United Therapeutics Corporation

Exhibit 10.10

PROMISSORY NOTE

Section 1.  General.

     FOR VALUE RECEIVED, Roger Jeffs and Lisa Jeffs (collectively referred to as the “Borrowers”), jointly and severally promise to pay to the order of United Therapeutics Corporation (“Lender”) at 1110 Spring Street, Silver Spring, Maryland 20910, or at such other place as may be designated in writing by Lender, on or before that date that is five years from the date the Principal Amount is paid to the Borrowers, the principal sum of One Million Three Hundred Thousand Dollars ($1,300,000) (the “Principal Amount”) and accrued interest on the unpaid Principal Amount remaining from time to time from the date the Principal Amount is paid to the Borrowers until it is paid in full at the rate equivalent to six and one-half percent (6.5%) per annum, accrued in arrears, such payment of the Principal Amount and accrued interest to be repaid earlier in part or in full upon the occurrence of any of the events set forth in Section 2 below (the “Repayment Triggers”).

     This loan is being made to the Borrowers to assist them in acquiring a new residence at 3410 Forest Oaks Drive, Chapel Hill, NC 27514 (the “Property”). Borrowers hereby (i) pledge the Property as security for the loan as the first trust secured by the Property and (ii) pledge all United Therapeutics common stock now owned or in the future acquired by the Borrowers, whether individually or jointly, in accordance with the attached Security Agreement (the “Owned Shares”), until the loan is paid to Lender as provided herein, and Borrowers agree to execute all documents necessary to record Lender’s secured interest in the Property required by North Carolina law, such recordation to be at Borrower’s cost.

     In the event that Borrowers fail to repay the Principal Amount and accrued interest upon the occurrence of a Repayment Trigger, Lender may, at its sole discretion, elect to recover the Principal Amount and accrued interest using one or any combination of the following methods: (i) garnish Roger Jeff’s wages from United Therapeutics Corporation or the wages of the Borrowers from any subsequent employer; (ii) withhold any bonus or payment due Roger Jeffs from United Therapeutics Corporation; (iii) require the voluntary forfeiture by Roger Jeffs of Roger Jeffs’ vested options to purchase the common stock of United Therapeutics Corporation and issue stop transfer orders with respect to United Therapeutics’ shares owned by or on behalf of Borrowers, whether owned individually or jointly; or (iv) sell or transfer the Property and the Owned Shares in satisfaction of all payments due it hereunder; provided, however, that the

security interest will only apply against the Property and the Owned Shares in an amount equivalent to the outstanding Principal Amount plus accrued interest in accordance with this Note.

     Borrowers hereby consent to the actions and agree to cooperate with and not to oppose any attempt by Lender to recover the Principal Amount and accrued interest using these methods in the event Borrowers fails to repay the Principal Amount and accrued interest when due.

     Borrowers shall have the privilege of prepaying this Note in full at any time before maturity by paying Lender an amount equal to one hundred percent (100%) of the outstanding Principal Amount plus payment of accrued interest.

Section 2.  Repayment Triggers.

     If any one or more of the following events shall occur, they shall constitute a Repayment Trigger and the Principal Amount and accrued interest thereon shall immediately become due and payable in part or in full, without presentment, demand, notice of nonpayment, protest, notice of protest, or other notice of dishonor, all of which are expressly waived by the Borrowers:

     (a)  The sale of the Property or the Owned Shares;

     (b)  Each sale of United Therapeutics stock by the Borrowers, whether individually or jointly, until the Principal Amount and accrued interest on the unpaid balance is paid in full;

     (c)  The receipt by the Borrowers, whether individually or jointly, of a mortgage or other financing secured by the Property or the Owned Shares;

     (d)  The Borrowers shall fail to execute the documents necessary to perfect Lender’s secured interest in the Property; or

     (e)  The Borrowers shall (i) generally not pay their debts as such debts become due, (ii) become or otherwise declare themselves insolvent, (iii) file a voluntary petition for bankruptcy protection, (iv) make any assignment for the benefit of creditors, (v) have any custodian, receiver, trustee, liquidator, administrator or person with similar powers appointed against them or their properties, which appointment is not stayed or vacated within thirty (30) days from the date of any such appointment, or (vi) take any action to authorize, acquiesce in or for the purposes of effectuating any of the foregoing.

     If any payment of the Principal Amount and accrued interest is not made in full upon the occurrence of a repayment trigger, then the entire unpaid Principal Amount and accrued interest shall at the option of Lender become due and payable without notice, and failure to exercise that option shall not waive the right to exercise it in the event of a subsequent default. Borrowers, to the extent

legally permissible: (i) upon default promise to pay all collection costs, including a reasonable attorneys’ fees, whether incurred in connection with collection, trial, appeal, or otherwise; and, (ii) waive presentment, demand, protest of demand, protest, and nonpayment.

     Time is of the essence with respect to this Note and to all the payments and the performance required under this Note.

Section 3.  Assignment/Binding Effect.

     This Note shall be binding upon the Borrowers and inure to the benefit of the Lender, provided, that the Borrowers may not assign any rights or delegate any duties under this Note without the Lender’s prior written consent in the Lender’s sole discretion.

Section 4.  Headings.

     The headings used in this Note are for convenience only and are not intended to define or limit the contents or substance of any provision of this Note.

Section 5.  Severability.

     Each provision of this Note constitutes a separate and distinct undertaking, covenant, or provision of this Note. In the event that any provision of this Note shall finally be determined to be invalid or unenforceable, such provision shall be deemed limited by construction in scope and effect to the minimum extent necessary to render the same valid and enforceable, and, in the event such a limiting construction is impossible, such unlawful provision shall be deemed severed from this Note, but every other provision of this Note shall remain in full force and effect.

Section 6.  No Waivers.

     The remedies of Lender under this Note shall be cumulative and concurrent, and may be pursued singly, successively, or together, at the sole discretion of Lender, and may be exercised as often as occasion therefor shall arise. No act, omission, or commission of Lender, including, specifically, any failure to exercise any right, remedy, or recourse, shall be effective unless set forth in a written document executed by Lender and then only to the extent specifically recited in such written document. A waiver or release with reference to one event shall not be construed as continuing, as a bar to, or as a waiver or release of, any subsequent right, remedy, or recourse as to any subsequent event.