Exhibit 10.1

X4 Pharmaceuticals, Inc.

2019 INDUCEMENT EQUITY INCENTIVE PLAN

(Adopted June 17, 2019)

The purpose of this 2019 Inducement Equity Incentive Plan (the “ Plan ”) of X4 Pharmaceuticals, Inc., a Delaware corporation (the “ Company ”), is to advance the interests of the Company’s stockholders by enhancing the Company’s ability to attract new employees who are expected to make important contributions to the Company and by providing such persons with equity ownership opportunities that are intended to better align the interests of such persons with those of the Company’s stockholders. The Company intends that the Plan be reserved for persons to whom the Company may issue securities without stockholder approval as an inducement pursuant to Listing Rule 5635(c)(4) of the corporate governance rules of the Nasdaq Stock Market (“ Nasdaq ”). Except where the context otherwise requires, the term “ Company ” shall include any of the Company’s present or future parent or subsidiary corporations as defined in Sections 424(e) or (f) of the Internal Revenue Code of 1986, as amended, and any regulations thereunder (the “ Code ”) and any other business venture (including, without limitation, joint venture or limited liability company) in which the Company has a controlling interest, as determined by the Board.

The Board will, in its sole discretion, name the Participants in the Plan; provided, however , that each Participant must be an employee of the Company or of an affiliate of the Company at the time the Award is granted. All of the Company’s employees are eligible to be granted Awards under the Plan. Each person who is granted an Award under the Plan is deemed a “ Participant .” “ Award ” means Options (as defined in Section 5), SARs (as defined in Section 6), Restricted Stock (as defined in Section 7), Restricted Stock Units (as defined in Section 7) and Other Stock-Based Awards (as defined in Section 8).

(a) Administration by Board of Directors . The Plan will be administered by the Board. The Board shall have authority to grant Awards and to adopt, amend and repeal such administrative rules, guidelines and practices relating to the Plan as it shall deem advisable. The Board may construe and interpret the terms of the Plan and any Award agreements entered into under the Plan. The Board may correct any defect, supply any omission or reconcile any inconsistency in the Plan or any Award in the manner and to the extent it shall deem expedient and it shall be the sole and final judge of such expediency. All decisions by the Board shall be made in the Board’s sole discretion and shall be final and binding on all persons having or claiming any interest in the Plan or in any Award.

(b) Appointment of Committees. The Board may delegate any or all of its powers under the Plan to the compensation committee of the Board (the “ Committee ”), as constituted in compliance with Rule 5605(d)(2) of the Nasdaq Listing Rules in order to comply with the exemption from the stockholder approval requirement for “inducement grants” provided under Rule 5635(c)(4) of the Nasdaq Listing Rules. All references in the Plan to the “ Board ” shall mean the Board or the Committee to the extent that the Board’s powers or authority under the Plan have been delegated to such Committee. Notwithstanding the foregoing, any grants of Awards under the Plan made by the Board must be approved by the majority of the Company’s independent directors (as defined in Rule 5605(a)(2) of the Nasdaq Listing Rules) in order to comply with Nasdaq Listing Rule 5635(c)(4).

(a) Number of Shares; Share Counting .

(1) Authorized Number of Shares . Subject to adjustment under Section 9, Awards may be made under the Plan for up to 150,000 shares of common stock, $0.001 par value per share, of the Company (the “ Common Stock ”). Shares issued under the Plan may consist in whole or in part of authorized but unissued shares or treasury shares.

(2) Share Counting . For purposes of counting the number of shares available for the grant of Awards under the

(A) all shares of Common Stock covered by SARs shall be counted against the number of shares available for the grant of Awards under the Plan; provided, however , that (i) SARs that may be settled only in cash shall not be so counted and (ii) if the Company grants an SAR in tandem with an Option for the same number of shares of Common Stock and provides that only one such Award may be exercised (a “ Tandem SAR ”), only the shares covered by the Option, and not the shares covered by the Tandem SAR, shall be so counted, and the expiration of one in connection with the other’s exercise will not restore shares to the Plan;

(B) if any Award (i) expires or is terminated, surrendered or canceled without having been fully exercised or is forfeited in whole or in part (including as the result of shares of Common Stock subject to such Award being repurchased by the Company at the original issuance price pursuant to a contractual repurchase right) or (ii) results in any Common Stock not being issued (including as a result of an SAR that was settleable either in cash or in stock actually being settled in cash), the unused Common Stock covered by such Award shall again be available for the grant of Awards; provided, however , that (1) in the case of the exercise of an SAR, the number of shares counted against the shares available under the Plan shall be the full number of shares subject to the SAR multiplied by the percentage of the SAR actually exercised, regardless of the number of shares actually used to settle such SAR upon exercise and (2) the shares covered by a Tandem SAR shall not again become available for grant upon the expiration or termination of such Tandem SAR; and

(C) shares of Common Stock delivered (by actual delivery, attestation, or net exercise) to the Company by a Participant to (i) purchase shares of Common Stock upon the exercise of an Award or (ii) satisfy tax withholding obligations with respect to Awards (including shares retained from the Award creating the tax obligation) shall be added back to the number of shares available for the future grant of Awards.

(b) Substitute Awards . To the extent such awards would be in compliance with Nasdaq Listing Rule 5635(c)(4), in connection with a merger or consolidation of an entity with the Company or the acquisition by the Company of property or stock of an entity, the Board may grant Awards in substitution for any options or other stock or stock-based awards granted by such entity or an affiliate thereof. Substitute Awards may be granted on such terms as the Board deems appropriate in the circumstances, notwithstanding any limitations on Awards contained in the Plan. Substitute Awards shall not count against the overall share limit set forth in Section 4(a)(1).

(a) General . The Board may grant options to purchase Common Stock that are not intended to qualify as incentive stock options under Section 422 of the Code (each, an “ Option ”) and determine the number of shares of Common Stock to be covered by each Option, the exercise price of each Option and the conditions and limitations applicable to the exercise of each Option, including conditions relating to applicable federal or state securities laws, as it considers necessary or advisable.

(b) Exercise Price . The Board shall establish the exercise price of each Option or the formula by which such exercise price will be determined. The exercise price shall be specified in the applicable Option agreement. The exercise price shall be not less than 100% of the Grant Date Fair Market Value (as defined below) of the Common Stock on the date the Option is granted; provided that if the Board approves the grant of an Option with an exercise price to be determined on a future date, the exercise price shall be not less than 100% of the Grant Date Fair Market Value on such future date. “ Grant Date Fair Market Value ” of a share of Common Stock for purposes of the Plan will be determined as follows:

(1) if the Common Stock trades on a national securities exchange, the closing sale price (for the primary trading session) on the date of grant; or

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(2) if the Common Stock does not trade on any such exchange, the average of the closing bid and asked prices on the date of grant as reported by an over-the-counter marketplace designated by the Board; or

(3) if the Common Stock is not publicly traded, the Board will determine the Grant Date Fair Market Value for purposes of the Plan using any measure of value it determines to be appropriate (including, as it considers appropriate, relying on appraisals) in a manner consistent with the valuation principles under Code Section 409A, except as the Board may expressly determine otherwise.

For any date that is not a trading day, the Grant Date Fair Market Value of a share of Common Stock for such date will be determined by using the closing sale price or average of the bid and asked prices, as appropriate, for the immediately preceding trading day and with the timing in the formulas above adjusted accordingly. The Board can substitute a particular time of day or other measure of “closing sale price” or “bid and asked prices” if appropriate because of exchange or market procedures or can, in its sole discretion, use weighted averages either on a daily basis or such longer period as complies with Code Section 409A.

The Board has sole discretion to determine the Grant Date Fair Market Value for purposes of the Plan, and all Awards are conditioned on the Participants’ agreement that the Administrator’s determination is conclusive and binding even though others might make a different determination.

(c) Duration of Options . Each Option shall be exercisable at such times and subject to such terms and conditions as the Board may specify in the applicable option agreement; provided, however , that no Option will be granted with a term in excess of 10 years.

(d) Exercise of Options . Options may be exercised by delivery to the Company of a notice of exercise in a form (which may be electronic) approved by the Company, together with payment in full (in the manner specified in Section 5(e)) of the exercise price for the number of shares for which the Option is exercised. Shares of Common Stock subject to the Option will be delivered by the Company as soon as practicable following exercise.

(e) Payment Upon Exercise. Common Stock purchased upon the exercise of an Option granted under the Plan shall be paid for as follows:

(1) in cash or by check, payable to the order of the Company;

(2) except as may otherwise be provided in the applicable Option agreement or approved by the Board, by (i) delivery of an irrevocable and unconditional undertaking by a creditworthy broker to deliver promptly to the Company sufficient funds to pay the exercise price and any required tax withholding or (ii) delivery by the Participant to the Company of a copy of irrevocable and unconditional instructions to a creditworthy broker to deliver promptly to the Company cash or a check sufficient to pay the exercise price and any required tax withholding;

(3) to the extent provided for in the applicable Option agreement or approved by the Board, by delivery (either by actual delivery or attestation) of shares of Common Stock owned by the Participant valued at their fair market value (valued in the manner determined by (or in a manner approved by) the Board), provided (i) such method of payment is then permitted under applicable law, (ii) such Common Stock, if acquired directly from the Company, was owned by the Participant for such minimum period of time, if any, as may be established by the Board and (iii) such Common Stock is not subject to any repurchase, forfeiture, unfulfilled vesting or other similar requirements;

(4) to the extent provided for in the applicable Option agreement or approved by the Board in its sole discretion, by delivery of a notice of “net exercise” to the Company, as a result of which the Participant would receive (i) the number of shares underlying the portion of the Option being exercised, less (ii) such number of shares as is equal to (A) the aggregate exercise price for the portion of the Option being exercised divided by (B) the fair market value of the Common Stock (valued in the manner determined by (or in a manner approved by) the Board) on the date of exercise;

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(5) to the extent permitted by applicable law and provided for in the applicable Option agreement or approved by the Board by payment of such other lawful consideration as the Board may determine; or

(6) by any combination of the above permitted forms of payment.

(f) Limitation on Repricing. Unless such action is approved by the Company’s stockholders, the Company may not (except as provided for under Section 9): (1) amend any outstanding Option granted under the Plan to provide an exercise price per share that is lower than the then-current exercise price per share of such outstanding Option, (2) cancel any outstanding option (whether or not granted under the Plan) and grant in substitution therefor new Awards under the Plan (other than Awards granted pursuant to Section 4(b)) covering the same or a different number of shares of Common Stock and having an exercise price per share lower than the then-current exercise price per share of the cancelled option, (3) cancel in exchange for a cash payment any outstanding Option with an exercise price per share above the then-current fair market value of the Common Stock (valued in the manner determined by (or in the manner approved by) the Board) or (4) take any other action under the Plan that constitutes a “repricing” within the meaning of the rules of Nasdaq.

(a) General . The Board may grant Awards consisting of stock appreciation rights (“ SARs ”) entitling the holder, upon exercise, to receive an amount of Common Stock or cash or a combination thereof (such form to be determined by the Board) determined by reference to appreciation, from and after the date of grant, in the fair market value of a share of Common Stock (valued in the manner determined by (or in the manner approved by) the Board) over the measurement price established pursuant to Section 6(b). The date as of which such appreciation is determined shall be the exercise date.

(b) Measurement Price . The Board shall establish the measurement price of each SAR and specify it in the applicable SAR agreement. The measurement price shall not be less than 100% of the Grant Date Fair Market Value of the Common Stock on the date the SAR is granted; provided that if the Board approves the grant of an SAR effective as of a future date, the measurement price shall be not less than 100% of the Grant Date Fair Market Value on such future date.

(c) Duration of SARs . Each SAR shall be exercisable at such times and subject to such terms and conditions as the Board may specify in the applicable SAR agreement; provided, however , that no SAR will be granted with a term in excess of 10 years.

(d) Exercise of SARs . SARs may be exercised by delivery to the Company of a notice of exercise in a form (which may be electronic) approved by the Company, together with any other documents required by the Board.

(e) Limitation on Repricing . Unless such action is approved by the Company’s stockholders, the Company may not (except as provided for under Section 9): (1) amend any outstanding SAR granted under the Plan to provide a measurement price per share that is lower than the then-current measurement price per share of such outstanding SAR, (2) cancel any outstanding SAR (whether or not granted under the Plan) and grant in substitution therefor new Awards under the Plan (other than Awards granted pursuant to Section 4(b)) covering the same or a different number of shares of Common Stock and having an exercise or measurement price per share lower than the then-current measurement price per share of the cancelled SAR, (3) cancel in exchange for a cash payment any outstanding SAR with a measurement price per share above the then-current fair market value of the Common Stock (valued in the manner determined by (or in a manner approved by) the Board) or (4) take any other action under the Plan that constitutes a “repricing” within the meaning of the rules of Nasdaq.

(a) General . The Board may grant Awards entitling recipients to acquire shares of Common Stock (“ Restricted Stock ”), subject to the right of the Company to repurchase all or part of such shares at their issue price or other stated or formula price (or to require forfeiture of such shares if issued at no cost) from the recipient in the event that conditions specified by the Board in the applicable Award are not satisfied prior to the end of the applicable

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restriction period or periods established by the Board for such Award. The Board may also grant Awards entitling the recipient to receive shares of Common Stock or cash to be delivered at the time such Award vests or is settled (“ Restricted Stock Units ”) (Restricted Stock and Restricted Stock Units are each referred to herein as a “ Restricted Stock Award ”).

(b) Terms and Conditions for All Restricted Stock Awards . The Board shall determine the terms and conditions of a Restricted Stock Award, including the conditions for vesting and repurchase (or forfeiture) and the issue price, if any.

(c) Additional Provisions Relating to Restricted Stock.

(1) Dividends . Unless otherwise provided in the applicable Award agreement, any dividends (whether paid in cash, stock or property) declared and paid by the Company with respect to shares of Restricted Stock (“ Accrued Dividends ”) shall be paid to the Participant only if and when such shares become free from the restrictions on transferability and forfeitability that apply to such shares. Each payment of Accrued Dividends will be made no later than the end of the calendar year in which the dividends are paid to stockholders of that class of stock or, if later, the 15th day of the third month following the lapsing of the restrictions on transferability and the forfeitability provisions applicable to the underlying shares of Restricted Stock.

(2) Stock Certificates . The Company may require that any stock certificates issued in respect of shares of Restricted Stock, as well as dividends or distributions paid on such Restricted Stock, shall be deposited in escrow by the Participant, together with a stock power endorsed in blank, with the Company (or its designee). At the expiration of the applicable restriction periods, the Company (or such designee) shall deliver the certificates no longer subject to such restrictions to the Participant or if the Participant has died, to his or her Designated Beneficiary. “ Designated Beneficiary ” means (i) the beneficiary designated, in a manner determined by the Board, by a Participant to receive amounts due or exercise rights of the Participant in the event of the Participant’s death or (ii) in the absence of an effective designation by a Participant, the Participant’s estate.

(d) Additional Provisions Relating to Restricted Stock Units.

(1) Settlement . Upon the vesting of and/or lapsing of any other restrictions (i.e., settlement) with respect to each Restricted Stock Unit, the Participant shall be entitled to receive from the Company such number of shares of Common Stock or (if so provided in the applicable Award agreement) an amount of cash equal to the fair market value (valued in the manner determined by (or in a manner approved by) the Board) of such number of shares of Common Stock as are set forth in the applicable Restricted Stock Unit agreement. The Board may provide that settlement of Restricted Stock Units shall be deferred, on a mandatory basis or at the election of the Participant in a manner that complies with Section 409A of the Code.

(2) Voting Rights . A Participant shall have no voting rights with respect to any Restricted Stock Units.

(3) Dividend Equivalents . The Award agreement for Restricted Stock Units may provide Participants with the right to receive an amount equal to any dividends or other distributions declared and paid on an equal number of outstanding shares of Common Stock (“ Dividend Equivalents ”). Dividend Equivalents may be settled in cash and/or shares of Common Stock and shall be subject to the same restrictions on transfer and forfeitability as the Restricted Stock Units with respect to which paid, in each case to the extent provided in the Award agreement.

(a) General . The Board may grant other Awards of shares of Common Stock, and other Awards that are valued in whole or in part by reference to, or are otherwise based on, shares of Common Stock or other property (“ Other Stock-Based Awards ”). Such Other Stock-Based Awards shall also be available as a form of payment in the settlement of other Awards granted under the Plan or as payment in lieu of compensation to which a Participant is otherwise entitled. Other Stock-Based Awards may be paid in shares of Common Stock or cash, as the Board shall determine.

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(b) Terms and Conditions . Subject to the provisions of the Plan, the Board shall determine the terms and conditions of each Other Stock-Based Award, including any purchase price applicable thereto.

(a) Changes in Capitalization . In the event of any stock split, reverse stock split, stock dividend, recapitalization, combination of shares, reclassification of shares, spin-off or other similar change in capitalization or event, or any dividend or distribution to holders of Common Stock other than an ordinary cash dividend, (i) the number and class of securities available under the Plan, (ii) the share counting rules set forth in Section 4(a), (iii) the number and class of securities and exercise price per share of each outstanding Option, (iv) the share and per-share provisions and the measurement price of each outstanding SAR, (v) the number of shares subject to and the repurchase price per share subject to each outstanding Restricted Stock Award and (vi) the share and per-share-related provisions and the purchase price, if any, of each outstanding Other Stock-Based Award, shall be equitably adjusted by the Company (or substituted Awards may be made, if applicable) in the manner determined by the Board. Without limiting the generality of the foregoing, in the event the Company effects a split of the Common Stock by means of a stock dividend and the exercise price of and the number of shares subject to an outstanding Option are adjusted as of the date of the distribution of the dividend (rather than as of the record date for such dividend), then an optionee who exercises an Option between the record date and the distribution date for such stock dividend shall be entitled to receive, on the distribution date, the stock dividend with respect to the shares of Common Stock acquired upon such Option exercise, notwithstanding the fact that such shares were not outstanding as of the close of business on the record date for such stock dividend.

(b) Reorganization Events.

(1) Definition . A “ Reorganization Event ” shall mean: (a) any merger or consolidation of the Company with or into another entity as a result of which all of the Common Stock of the Company is converted into or exchanged for the right to receive cash, securities or other property or is cancelled, (b) any transfer or disposition of all of the Common Stock of the Company for cash, securities or other property pursuant to a share exchange or other transaction or (c) any liquidation or dissolution of the Company.

(2) Consequences of a Reorganization Event on Awards Other than Restricted Stock .

(A) In connection with a Reorganization Event, the Board may take any one or more of the following actions as to all or any (or any portion of) outstanding Awards other than Restricted Stock on such terms as the Board determines (except to the extent specifically provided otherwise in an applicable Award agreement or another agreement between the Company and the Participant): (i) provide that such Awards shall be assumed, or substantially equivalent Awards shall be substituted, by the acquiring or succeeding corporation (or an affiliate thereof), (ii) upon written notice to a Participant, provide that all of the Participant’s unvested Awards will be forfeited immediately prior to the consummation of such Reorganization Event and/or unexercised Awards will terminate immediately prior to the consummation of such Reorganization Event unless exercised by the Participant (to the extent then exercisable) within a specified period following the date of such notice, (iii) provide that outstanding Awards shall become exercisable, realizable or deliverable, or restrictions applicable to an Award shall lapse, in whole or in part prior to or upon such Reorganization Event, (iv) in the event of a Reorganization Event under the terms of which holders of Common Stock will receive upon consummation thereof a cash payment for each share surrendered in the Reorganization Event (the “ Acquisition Price ”), make or provide for a cash payment to Participants with respect to each Award held by a Participant equal to (A) the number of shares of Common Stock subject to the vested portion of the Award (after giving effect to any acceleration of vesting that occurs upon or immediately prior to such Reorganization Event) multiplied by (B) the excess, if any, of (I) the Acquisition Price over (II) the exercise, measurement or purchase price of such Award and any applicable tax withholdings, in exchange for the termination of such Award, (v) provide that, in connection with a liquidation or dissolution of the Company, Awards shall convert into the right to receive liquidation proceeds (if applicable, net of the exercise, measurement or purchase price thereof and any applicable tax withholdings) and (vi) any combination of the foregoing. In taking any of the actions permitted under this Section 9(b)(2), the Board shall not be obligated by the Plan to treat all Awards, all Awards held by a Participant, or all Awards of the same type, identically.

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(B) Notwithstanding the terms of Section 9(b)(2)(A), in the case of outstanding Restricted Stock Units that are subject to Section 409A of the Code: (i) if the applicable Restricted Stock Unit agreement provides that the Restricted Stock Units shall be settled upon a “change in control event” within the meaning of Treasury Regulation Section 1.409A-3(i)(5)(i), and the Reorganization Event constitutes such a “change in control event”, then no assumption or substitution shall be permitted pursuant to Section 9(b)(2)(A)(i) and the Restricted Stock Units shall instead be settled in accordance with the terms of the applicable Restricted Stock Unit agreement; and (ii) the Board may only undertake the actions set forth in clauses (iii), (iv) or (v) of Section 9(b)(2)(A) if the Reorganization Event constitutes a “change in control event” as defined under Treasury Regulation Section 1.409A-3(i)(5)(i) and such action is permitted or required by Section 409A of the Code; if the Reorganization Event is not a “change in control event” as so defined or such action is not permitted or required by Section 409A of the Code, and the acquiring or succeeding corporation does not assume or substitute the Restricted Stock Units pursuant to clause (i) of Section 9(b)(2)(A), then the unvested Restricted Stock Units shall terminate immediately prior to the consummation of the Reorganization Event without any payment in exchange therefor.

(C) For purposes of Section 9(b)(2)(A)(i), an Award (other than Restricted Stock) shall be considered assumed if, following consummation of the Reorganization Event, such Award confers the right to purchase or receive pursuant to the terms of such Award, for each share of Common Stock subject to the Award immediately prior to the consummation of the Reorganization Event, the consideration (whether cash, securities or other property) received as a result of the Reorganization Event by holders of Common Stock for each share of Common Stock held immediately prior to the consummation of the Reorganization Event (and if holders were offered a choice of consideration, the type of consideration chosen by the holders of a majority of the outstanding shares of Common Stock); provided, however , that if the consideration received as a result of the Reorganization Event is not solely common stock of the acquiring or succeeding corporation (or an affiliate thereof), the Company may, with the consent of the acquiring or succeeding corporation, provide for the consideration to be received upon the exercise or settlement of the Award to consist solely of such number of shares of common stock of the acquiring or succeeding corporation (or an affiliate thereof) that the Board determines to be equivalent in value (as of the date of such determination or another date specified by the Board) to the per share consideration received by holders of outstanding shares of Common Stock as a result of the Reorganization Event.

(3) Consequences of a Reorganization Event on Restricted Stock . Upon the occurrence of a Reorganization Event other than a liquidation or dissolution of the Company, the repurchase and other rights of the Company with respect to outstanding Restricted Stock shall inure to the benefit of the Company’s successor and shall, unless the Board determines otherwise, apply to the cash, securities or other property which the Common Stock was converted into or exchanged for pursuant to such Reorganization Event in the same manner and to the same extent as they applied to such Restricted Stock; provided, however , that the Board may provide for termination or deemed satisfaction of such repurchase or other rights under the instrument evidencing any Restricted Stock or any other agreement between a Participant and the Company, either initially or by amendment. Upon the occurrence of a Reorganization Event involving the liquidation or dissolution of the Company, except to the extent specifically provided to the contrary in the instrument evidencing any Restricted Stock or any other agreement between a Participant and the Company, all restrictions and conditions on all Restricted Stock then outstanding shall automatically be deemed terminated or satisfied.

(a) Transferability of Awards . Awards shall not be sold, assigned, transferred, pledged or otherwise encumbered by the Participant, either voluntarily or by operation of law, except by will or the laws of descent and distribution or pursuant to a qualified domestic relations order, and, during the life of the Participant, shall be exercisable only by the Participant; provided, however , that, except with respect to Awards subject to Section 409A of the Code, the Board may permit or provide in an Award for the gratuitous transfer of the Award by the Participant to or for the benefit of any immediate family member, family trust or other entity established for the benefit of the Participant and/or an immediate family member thereof if the Company would be eligible to use a Form S-8 under the Securities Act of 1933, as amended for the registration of the sale of the Common Stock subject to such Award to such proposed transferee; provided further , that the Company shall not be required to recognize any such permitted transfer until such time as such permitted transferee shall, as a condition to such transfer, deliver to the Company a written instrument in form and substance satisfactory to the Company confirming that such transferee shall be bound by all of the terms and conditions of the Award. References to a Participant, to the extent relevant in the context, shall include references to authorized transferees. For the avoidance of doubt, nothing contained in this Section 10(a) shall be deemed to restrict a transfer to the Company.

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(b) Documentation . Each Award shall be evidenced in such form (written, electronic or otherwise) as the Board shall determine. Each Award may contain terms and conditions in addition to those set forth in the Plan.

(c) Board Discretion . Except as otherwise provided by the Plan, each Award may be made alone or in addition or in relation to any other Award. The terms of each Award need not be identical, and the Board need not treat Participants uniformly.

(d) Termination of Status . The Board shall determine the effect on an Award of the disability, death, termination or other cessation of employment, authorized leave of absence or other change in the employment or other status of a Participant and the extent to which, and the period during which, the Participant, or the Participant’s legal representative, conservator, guardian or Designated Beneficiary, may exercise rights under the Award.

(e) Withholding . The Participant must satisfy all applicable federal, state, and local or other income and employment tax withholding obligations before the Company will deliver stock certificates or otherwise recognize ownership of Common Stock under an Award. The Company may elect to satisfy the withholding obligations through additional withholding on salary or wages. If the Company elects not to or cannot withhold from other compensation, the Participant must pay the Company the full amount, if any, required for withholding or have a broker tender to the Company cash equal to the withholding obligations. Payment of withholding obligations is due before the Company will issue any shares on exercise, vesting or release from forfeiture of an Award or at the same time as payment of the exercise or purchase price, unless the Company determines otherwise. If provided for in an Award or approved by the Committee, a Participant may satisfy the tax obligations in whole or in part by delivery (either by actual delivery or attestation) of shares of Common Stock, including shares retained from the Award creating the tax obligation, valued at their fair market value (valued in the manner determined by (or in a manner approved by) the Company); provided, however , except as otherwise provided by the Committee, that the total tax withholding where stock is being used to satisfy such tax obligations cannot exceed the Company’s minimum statutory withholding obligations (based on minimum statutory withholding rates for federal and state tax purposes, including payroll taxes, that are applicable to such supplemental taxable income), except that, to the extent that the Company is able to retain shares of Common Stock having a fair market value (determined by, or in a manner approved by, the Company) that exceeds the statutory minimum applicable withholding tax without financial accounting implications or the Company is withholding in a jurisdiction that does not have a statutory minimum withholding tax, the Company may retain such number of shares of Common Stock (up to the number of shares having a fair market value equal to the maximum individual statutory rate of tax (determined by, or in a manner approved by, the Company)) as the Company shall determine in its sole discretion to satisfy the tax liability associated with any Award. Shares used to satisfy tax withholding requirements cannot be subject to any repurchase, forfeiture, unfulfilled vesting or other similar requirements.

(f) Amendment of Award . Except as otherwise provided in Sections 5(g) and 6(e) with respect to repricings and Section 11(d) with respect to actions requiring stockholder approval, the Board may amend, modify or terminate any outstanding Award, including but not limited to, substituting therefor another Award of the same or a different type, changing the date of exercise or realization. The Participant’s consent to such action shall be required unless (i) the Board determines that the action, taking into account any related action, does not materially and adversely affect the Participant’s rights under the Plan or (ii) the change is permitted under Section 9.

(g) Conditions on Delivery of Stock . The Company will not be obligated to deliver any shares of Common Stock pursuant to the Plan or to remove restrictions from shares previously issued or delivered under the Plan until (i) all conditions of the Award have been met or removed to the satisfaction of the Company, (ii) in the opinion of the Company’s counsel, all other legal matters in connection with the issuance and delivery of such shares have been satisfied, including any applicable securities laws and regulations and any applicable stock exchange or stock market rules and regulations and (iii) the Participant has executed and delivered to the Company such representations or agreements as the Company may consider appropriate to satisfy the requirements of any applicable laws, rules or regulations.

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(h) Acceleration . The Board may at any time provide that any Award shall become immediately exercisable in whole or in part, free from some or all restrictions or conditions, or otherwise realizable in whole or in part, as the case may be.

(a) No Right To Employment or Other Status . No person shall have any claim or right to be granted an Award by virtue of the adoption of the Plan, and the grant of an Award shall not be construed as giving a Participant the right to continued employment or any other relationship with the Company. The Company expressly reserves the right at any time to dismiss or otherwise terminate its relationship with a Participant free from any liability or claim under the Plan, except as expressly provided in the applicable Award.

(b) No Rights As Stockholder; Clawback Policy . Subject to the provisions of the applicable Award, no Participant or Designated Beneficiary shall have any rights as a stockholder with respect to any shares of Common Stock to be issued with respect to an Award until becoming the record holder of such shares. In accepting an Award under the Plan, a Participant agrees to be bound by any clawback policy the Company has in effect or may adopt in the future.

(c) Term of Plan . No Awards shall be granted under the Plan after the expiration of 10 years from the date of the Board’s adoption of the Plan, but Awards previously granted may extend beyond that date.

(d) Amendment of Plan . The Board may amend, suspend or terminate the Plan or any portion thereof at any time provided that no amendment that would require stockholder approval under the rules of Nasdaq may be made effective unless and until the Company’s stockholders approve such amendment. Unless otherwise specified in the amendment, any amendment to the Plan adopted in accordance with this Section 11(d) shall apply to, and be binding on the holders of, all Awards outstanding under the Plan at the time the amendment is adopted, provided the Board determines that such amendment, taking into account any related action, does not materially and adversely affect the rights of Participants under the Plan. No Award shall be made that is conditioned upon stockholder approval of any amendment to the Plan unless the Award provides that (i) it will terminate or be forfeited if stockholder approval of such amendment is not obtained within no more than 12 months from the date of grant and (2) it may not be exercised or settled (or otherwise result in the issuance of Common Stock) prior to such stockholder approval.

(e) Authorization of Sub-Plans (including for Grants to non-U.S. Employees) . The Board may from time to time establish one or more sub-plans under the Plan for purposes of satisfying applicable securities, tax or other laws of various jurisdictions. The Board shall establish such sub-plans by adopting supplements to the Plan containing (i) such limitations on the Board’s discretion under the Plan as the Board deems necessary or desirable or (ii) such additional terms and conditions not otherwise inconsistent with the Plan as the Board shall deem necessary or desirable. All supplements adopted by the Board shall be deemed to be part of the Plan, but each supplement shall apply only to Participants within the affected jurisdiction and the Company shall not be required to provide copies of any supplement to Participants in any jurisdiction which is not the subject of such supplement.

(f) Compliance with Section 409A of the Code . If and to the extent (i) any portion of any payment, compensation or other benefit provided to a Participant pursuant to the Plan in connection with his or her employment termination constitutes “nonqualified deferred compensation” within the meaning of Section 409A of the Code and (ii) the Participant is a specified employee as defined in Section 409A(a)(2)(B)(i) of the Code, in each case as determined by the Company in accordance with its procedures, by which determinations the Participant (through accepting the Award) agrees thathe or she is bound, such portion of the payment, compensation or other benefit shall not be paid before the day that is six months plus one day after the date of “separation from service” (as determined under Section 409A of the Code) (the “ New Payment Date ”), except as Section 409A of the Code may then permit. The aggregate of any payments that otherwise would have been paid to the Participant during the period between the date of separation from service and the New Payment Date shall be paid to the Participant in a lump sum on such New Payment Date, and any remaining payments will be paid on their original schedule.

The Company makes no representations or warranty and shall have no liability to the Participant or any other person if any provisions of or payments, compensation or other benefits under the Plan are determined to constitute nonqualified deferred compensation subject to Section 409A of the Code but do not to satisfy the conditions of that section.

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(g) Limitations on Liability . Notwithstanding any other provisions of the Plan, no individual acting as a director, officer, employee or agent of the Company will be liable to any Participant, former Participant, spouse, beneficiary, or any other person for any claim, loss, liability, or expense incurred in connection with the Plan, nor will such individual be personally liable with respect to the Plan because of any contract or other instrument he or she executes in his or her capacity as a director, officer, employee or agent of the Company. The Company will indemnify and hold harmless each director, officer, employee or agent of the Company to whom any duty or power relating to the administration or interpretation of the Plan has been or will be delegated, against any cost or expense (including attorneys’ fees) or liability (including any sum paid in settlement of a claim with the Board’s approval) arising out of any act or omission to act concerning the Plan unless arising out of such person’s own fraud or bad faith.

(h) Governing Law . The provisions of the Plan and all Awards made hereunder shall be governed by and interpreted in accordance with the laws of the State of Delaware, excluding choice-of-law principles of the law of such state that would require the application of the laws of a jurisdiction other than the State of Delaware.

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Exhibit 10.2

FORM FOR X4 PHARMACEUTICALS, INC. 2019 INDUCEMENT EQUITY INCENTIVE PLAN

(JUNE 2019)

X4 PHARMACEUTICALS, INC.

INDUCEMENT EQUITY STOCK OPTION AGREEMENT

X4 Pharmaceuticals, Inc. (the “ Company ”) hereby grants the following stock option pursuant to its 2019 Inducement Equity Incentive Plan. The terms and conditions attached hereto are also a part hereof.

Notice of Grant

Vesting Schedule:

This option satisfies in full all commitments that the Company has to the Participant with respect to the issuance of stock, stock options or other equity securities.

X4 PHARMACEUTICALS, INC.

Inducement Equity Stock Option Agreement

Incorporated Terms and Conditions

(Non-Qualified Stock Option)

1. Grant of Option .

This agreement evidences the grant by the Company, on the grant date(the “ Grant Date ”) set forth in the Notice of Grant that forms part of this agreement (the “ Notice of Grant ”), to the Participant of an option to purchase, in whole or in part, on the terms provided herein and in the Company’s 2019 Inducement Equity Incentive Plan (the “ Plan ”), the number of Shares set forth in the Notice of Grant of common stock, $0.001 par value per share, of the Company (“ Common Stock ”), at the exercise price per Share set forth in the Notice of Grant. Unless earlier terminated, this option shall expire at 5:00 p.m., Eastern time, on the Final Exercise Date set forth in the Notice of Grant (the “ Final Exercise Date ”).

The Company and the Participant understand and agree that the option shall be granted in compliance with Nasdaq Listing Rule 5635(c)(4) as a material inducement to the Participant entering into employment with the Company

2. Vesting Schedule .

This option will become exercisable (“ vest ”) in accordance with the vesting schedule set forth in the Notice of Grant.

The right of exercise shall be cumulative so that to the extent the option is not exercised in any period to the maximum extent permissible it shall continue to be exercisable, in whole or in part, with respect to all Shares for which it is vested until the earlier of the Final Exercise Date or the termination of this option under Section 3 hereof or the Plan.

3. Exercise of Option .

(a) Form of Exercise . Each election to exercise this option shall be in writing, in the form of the Stock Option Exercise Notice attached as Annex A , signed by the Participant, and received by the Company at its principal office, accompanied by this agreement, or in such other form (which may be electronic) as is approved by the Company, together with payment in full in the manner provided in the Plan. The Participant may purchase less than the number of shares covered hereby, provided that no partial exercise of this option may be for any fractional share.

(b) Continuous Relationship with the Company Required . Except as otherwise provided in this Section 3, this option may not be exercised unless the Participant, at the time he or she exercises this option, is, and has been at all times since the Grant Date, an employee of the Company or any other entity the employees of which are eligible to receive option grants under the Plan (an “ Eligible Participant ”).

(c) Termination of Relationship with the Company . If the Participant ceases to be an Eligible Participant for any reason, then, except as provided in paragraphs (d), (e) and (f) below, the right to exercise this option shall terminate three months after such cessation (but in no event after the Final Exercise Date), provided that this option shall be exercisable only to the extent that the Participant was entitled to exercise this option on the date of such cessation. Notwithstanding the foregoing, if the Participant, prior to the Final Exercise Date, violates the restrictive covenants (including, without limitation, the non-competition, non-solicitation, or confidentiality provisions) of any employment contract, the Non-Competition, Non-Solicitation, Confidentiality and Assignment of Inventions agreement to which the Participant is a party, if any, or any other agreement between the Participant and the Company, the right to exercise this option shall terminate immediately upon such violation.

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(d) Exercise Period Upon Death or Disability . If the Participant dies or becomes disabled (within the meaning of Section 22(e)(3) of the Code) prior to the Final Exercise Date while he or she is an Eligible Participant and the Company has not terminated such relationship for “cause” as specified in paragraph (e) below, this option shall be exercisable, within the period of one year following the date of death or disability of the Participant, by the Participant (or in the case of death by an authorized transferee), provided that this option shall be exercisable only to the extent that this option was exercisable by the Participant on the date of his or her death or disability, and further provided that this option shall not be exercisable after the Final Exercise Date.

(e) Termination for Cause . If, prior to the Final Exercise Date, the Participant’s employment is terminated by the Company for Cause (as defined in below), the right to exercise this option shall terminate immediately upon the effective date of such termination of employment. If, prior to the Final Exercise Date, the Participant is given notice by the Company of the termination of his or her employment by the Company for Cause, and the effective date of such employment termination is subsequent to the date of delivery of such notice, the right to exercise this option shall be suspended from the time of the delivery of such notice until the earlier of (i) such time as it is determined or otherwise agreed that the Participant’s employment shall not be terminated for Cause as provided in such notice or (ii) the effective date of such termination of employment (in which case the right to exercise this option shall, pursuant to the preceding sentence, terminate upon the effective date of such termination of employment). If the Participant is subject to an individual employment agreement with the Company or eligible to participate in a Company severance plan or arrangement, in any case which agreement, plan or arrangement contains a definition of “cause” for termination of employment, “ Cause ” shall have the meaning ascribed to such term in such agreement, plan or arrangement. Otherwise, “ Cause ” shall mean, with respect to the Participant (a) dishonesty with respect to the Company or any affiliate, (b) insubordination, substantial malfeasance or non-feasance of duty, (c) unauthorized disclosure of confidential information, (d) breach by the Participant of any provision of any employment, consulting, advisory, nondisclosure, non-competition or similar agreement between the Participant and the Company or any affiliate, and (e) conduct substantially prejudicial to the business of the Company or any affiliate. The determination of the administrator of the Plan as to the existence of Cause will be conclusive on the Participant and the Company. The Participant’s employment shall be considered to have been terminated for Cause if the Company determines, within 30 days after the Participant’s resignation, that termination for Cause was warranted.

(f) Consultants . If the Participant ceases to be an Eligible Participant of the Company but continues after termination of employment to provide services to the Company as a consultant to the Company, this option shall continue to vest in accordance with Section 2 above as if the option had not terminated until the Participant is no longer providing such services to the Company. In such case, this option shall continue on the same terms and conditions set forth herein until such Participant is no longer providing such services to the Company.

4. Withholding . No Shares will be issued pursuant to the exercise of this option unless and until the Participant pays to the Company, or makes provision satisfactory to the Company for payment of, any federal, state or local withholding taxes required by law to be withheld in respect of this option.

5. Transfer Restrictions; Clawback .

(a) This option may not be sold, assigned, transferred, pledged or otherwise encumbered by the Participant, either voluntarily or by operation of law, except by will or the laws of descent and distribution, and, during the lifetime of the Participant, this option shall be exercisable only by the Participant.

(b) In accepting this option, the Participant agrees to be bound by any clawback policy that the Company has in effect or may adopt in the future.

6. Provisions of the Plan .

This option is subject to the provisions of the Plan (including the provisions relating to amendments to the Plan), a copy of which is furnished to the Participant with this option.

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ANNEX A

X4 PHARMACEUTICALS, INC.

Stock Option Exercise Notice

X4 Pharmaceuticals, Inc.

955 Massachusetts Avenue, 4th Floor

Cambridge, MA 02139

Dear Sir or Madam:

I, (the “ Participant ”), hereby irrevocably exercise the right to purchase              shares of the Common Stock, $0.001 par value per share (the “ Shares ”), of X4 Pharmaceuticals, Inc. (the “ Company ”) at $              per share pursuant to the Company’s 2019 Inducement Equity Incentive Plan and a stock option agreement with the Company dated              (the “ Option Agreement ”). Enclosed herewith is a payment of $              , the aggregate purchase price for the Shares. The certificate for the Shares should be registered in my name as it appears below or, if so indicated below, jointly in my name and the name of the person designated below, with right of survivorship.

Dated:                                 

Signature

Print Name:

Address:                                          

Name and address of persons in whose name the Shares are to be jointly registered (if applicable):

Exhibit 10.3

FORM FOR X4 PHARMACEUTICALS, INC. 2019 INDUCEMENT EQUITY INCENTIVE PLAN

(JUNE 2019)

X4 PHARMACEUTICALS, INC.

RESTRICTED STOCK AGREEMENT

X4 Pharmaceuticals, Inc. (the “ Company ”) has selected you to receive the following restricted stock award pursuant to its 2019 Inducement Equity Incentive Plan. The terms and conditions attached hereto are also a part hereof.

Notice of Grant

Please confirm your acceptance of this restricted stock award and of the terms and conditions of this Agreement by signing a copy of this Agreement where indicated below.

X4 PHARMACEUTICALS, INC.

Restricted Stock Agreement

Incorporated Terms and Conditions

The terms and conditions of the award of shares of restricted common stock of the Company (the “ Restricted Shares ”) made to the Recipient, as set forth in the Notice of Grant that forms part of this agreement (the “ Notice of Grant ”), are as follows:

1. Issuance of Restricted Shares .

(a) The Restricted Shares are issued to the Recipient, effective as of the Grant Date set forth in the Notice of Grant, in consideration of services rendered and to be rendered by the Recipient to the Company.

(b) The Restricted Shares will initially be issued by the Company in book entry form only, in the name of the Recipient. Following the vesting of any Restricted Shares pursuant to Section 2 below, the Company shall, if requested by the Recipient, issue and deliver to the Recipient a certificate representing the vested Restricted Shares. The Recipient agrees that the Restricted Shares shall be subject to the forfeiture provisions set forth in Section 3 of this Agreement and the restrictions on transfer set forth in Section 4 of this Agreement.

(c) The Company and the Recipient understand and agree that the Restricted Shares are being granted in compliance with Nasdaq Listing Rule 5635(c)(4) as a material inducement to the Recipient entering into employment with the Company.

2. Vesting .

Unless otherwise provided in this Agreement, in the X4 Pharmaceuticals, Inc. 2019 Inducement Equity Incentive Plan (the “ Plan ”) or in another agreement between the Recipient and the Company, the Restricted Shares shall vest in accordance with the vesting schedule set forth in the Notice of Grant. Any fractional number of Restricted Shares resulting from the application of the vesting schedule shall be rounded down to the nearest whole number of Restricted Shares.

3. Forfeiture of Unvested Restricted Shares Upon Employment Termination .

Subject to the provisions of the Notice of Grant, in the event that the Recipient ceases to be employed by the Company for any reason or no reason, with or without cause, all of the Restricted Shares that are unvested as of the time of such employment termination shall be forfeited immediately and automatically to the Company, without the payment of any consideration to the Recipient, effective as of such termination of employment. The Recipient shall have no further rights with respect to any Restricted Shares that are so forfeited. If the Recipient is employed by a subsidiary of the Company, any references in this Agreement to employment with the Company shall instead be deemed to refer to employment with such subsidiary.

4. Restrictions on Transfer .

Except as set forth in the Plan, the Recipient shall not sell, assign, transfer, pledge, hypothecate or otherwise dispose of, by operation of law or otherwise (collectively “ transfer ”) any Restricted Shares, or any interest therein, until such Restricted Shares have vested. The Company shall not be required (i) to transfer on its books any of the Restricted Shares which have been transferred in violation of any of the provisions of this Agreement or the Plan or (ii) to treat as owner of such Restricted Shares or to pay dividends to any transferee to whom such Restricted Shares have been transferred in violation of any of the provisions of this Agreement or the Plan.

5. Restrictive Legends .

The book entry account reflecting the issuance of the Restricted Shares in the name of the Recipient shall bear a legend or other notation upon substantially the following terms:

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“These shares of stock are subject to forfeiture provisions and restrictions on transfer set forth in a certain Restricted Stock Agreement between the corporation and the registered owner of these shares (or his or her predecessor in interest), and such Agreement is available for inspection without charge at the office of the Secretary of the corporation.”

6. Rights as a Shareholder .

Except as otherwise provided in this Agreement, for so long as the Recipient is the registered owner of the Restricted Shares, the Recipient shall have all rights as a shareholder with respect to the Restricted Shares, whether vested or unvested, including, without limitation, rights to vote the Restricted Shares and act in respect of the Restricted Shares at any meeting of shareholders; provided that, as provided in the Plan, the payment of dividends on unvested Restricted Shares shall be deferred until the vesting of such shares.

7. Provisions of the Plan .

This Agreement is subject to the provisions of the Plan, a copy of which is furnished to the Recipient with this Agreement.

8. Tax Matters .

(a) Acknowledgments; Section 83(b) Election . The Recipient acknowledges that he or she is responsible for obtaining the advice of the Recipient’s own tax advisors with respect to the acquisition of the Restricted Shares and the Recipient is relying solely on such advisors and not on any statements or representations of the Company or any of its agents with respect to the tax consequences relating to the Restricted Shares. The Recipient understands that the Recipient (and not the Company) shall be responsible for the Recipient’s tax liability that may arise in connection with the acquisition, vesting and/or disposition of the Restricted Shares. The Recipient acknowledges that he or she has been informed of the availability of making an election under Section 83(b) of the Internal Revenue Code, as amended (a “ Section 83(b) Election ”) with respect to the issuance of the Restricted Shares. The Recipient agrees to promptly deliver written notice to the Company in the event the Recipient makes a Section 83(b) Election with respect to the Restricted Shares.

(b) Withholding . The Recipient acknowledges and agrees that the Company has the right to deduct from payments of any kind otherwise due to the Recipient any federal, state, local or other taxes of any kind required by law to be withheld with respect to the issuance or vesting of the Restricted Shares.

9. Miscellaneous .

(a) No Right to Continued Employment . The Recipient acknowledges and agrees that, notwithstanding the fact that the vesting of the Restricted Shares is contingent upon his or her continued employment by the Company, this Agreement does not constitute an express or implied promise of continued employment or confer upon the Recipient any rights with respect to continued employment by the Company.

(b) Governing Law . This Agreement shall be construed, interpreted and enforced in accordance with the internal laws of the State of Delaware without regard to any applicable conflicts of laws provisions.

(c) Recipient’s Acknowledgments . The Recipient acknowledges that he or she has read this Agreement, has received and read the Plan, and understands the terms and conditions of this Agreement and the Plan.

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Exhibit 10.4

FORM FOR X4 PHARMACEUTICALS, INC. 2019 INDUCEMENT EQUITY INCENTIVE PLAN

(JUNE 2019)

Restricted Stock Unit No.             

X4 PHARMACEUTICALS, INC.

RESTRICTED STOCK UNIT AWARD GRANT AGREEMENT

X4 Pharmaceuticals, Inc. (the “Company”) hereby grants the following restricted stock unit pursuant to its 2019 Inducement Equity Incentive Plan. The terms and conditions attached hereto are also a part hereof.

Notice of Grant

Vesting Schedule:

This Restricted Stock Unit Award shall vest as follows provided the Participant is an Eligible Participant on the applicable vesting date:

[Notwithstanding the foregoing, 100% of the unvested portion of this Restricted Stock Unit Award shall vest upon the termination of the Participant’s employment by the Company without Cause upon or at any time within 12 months following a Change of Control.

For purposes of this Agreement, a “ Change of Control ” shall mean the occurrence of any of the following events: (i) any “Person” (as such term is used in Sections 13(d) and 14(d) of the Exchange Act) becomes the “Beneficial Owner” (as defined in Rule 13d-3 under the Securities Exchange Act), directly or indirectly, of securities of the Company representing fifty percent (50%) or more of the total voting power represented by the Company’s then outstanding voting securities (excluding for this purpose any such voting securities held by the Company, or any affiliate, parent or subsidiary of the Company, or by any employee benefit plan of the Company)

pursuant to a transaction or a series of related transactions which the Board does not approve; or (ii) (A) A merger or consolidation of the Company whether or not approved by the Board, other than a merger or consolidation which would result in the voting securities of the Company outstanding immediately prior thereto continuing to represent (either by remaining outstanding or by being converted into voting securities of the surviving entity or the parent of such entity) at least fifty percent (50%) of the total voting power represented by the voting securities of the Company or such surviving entity or parent of such entity, as the case may be, outstanding immediately after such merger or consolidation; or (B) the sale or disposition by the Company of all or substantially all of the Company’s assets. For purposes of this Agreement, if the Participant is subject to an individual employment agreement with the Company or eligible to participate in a Company severance plan or arrangement, in any case which agreement, plan or arrangement contains a definition of “cause” for termination of employment, “ Cause ” shall have the meaning ascribed to such term in such agreement, plan or arrangement, otherwise, “ Cause ” shall mean, with respect to the Participant (a) dishonesty with respect to the Company or any affiliate, (b) insubordination, substantial malfeasance or non-feasance of duty, (c) unauthorized disclosure of confidential information, (d) breach by the recipient of any provision of any employment, consulting, advisory, nondisclosure, non-competition or similar agreement between the Participant and the Company or any affiliate, and (e) conduct substantially prejudicial to the business of the Company or any affiliate, with the determination of the administrator of the Plan as to the existence of Cause will be conclusive on the Participant and the Company. The Participant’s employment shall be considered to have been terminated for Cause if the Company determines, within 30 days after the Participant’s resignation, that termination for Cause was warranted.]

The Company and the Participant acknowledge receipt of this Restricted Stock Unit Award Notice of Grant and agree to the terms of the Restricted Stock Unit Agreement attached hereto and incorporated by reference herein, the Company’s 2019 Inducement Equity Incentive Plan and the terms of this Restricted Stock Unit Award as set forth above.

X4 PHARMACEUTICALS, INC.

Restricted Stock Unit Agreement

INCORPORATED TERMS AND CONDITIONS

AGREEMENT made as of the Grant Date set forth in the Restricted Stock Unit Award Notice of Grant between the Company and the Participant.

WHEREAS, the Company has adopted the 2019 Inducement Equity Incentive Plan (the “ Plan ”) to promote the interests of the Company by providing an incentive for employees of the Company or of any other entity the employees of which are eligible to receive grants of equity under the Plan;

WHEREAS, pursuant to the provisions of the Plan, the Company desires to grant to the Participant restricted stock units (“ RSUs ”) related to the Company’s common stock, $0.001 par value per share (“ Common Stock ”), in accordance with the provisions of the Plan, all on the terms and conditions hereinafter set forth;

WHEREAS, the Company and the Participant understand and agree that the RSUs being granted pursuant to this Agreement are being granted in compliance with Nasdaq Listing Rule 5635(c)(4) as a material inducement to the Participant entering into employment with the Company; and

WHEREAS, the Company and the Participant understand and agree that any terms used and not defined herein have the meanings ascribed to such terms in the Plan.

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

1. Grant of Award . The Company hereby grants to the Participant an award for the number of RSUs set forth in the Restricted Stock Unit Award Notice of Grant (the “ Award ”). Each RSU represents a contingent entitlement of the Participant to receive one share of Common Stock, on the terms and conditions and subject to all the limitations set forth herein and in the Plan, which is incorporated herein by reference. The Participant acknowledges receipt of a copy of the Plan.

2. Vesting of Award .

(a) Subject to the terms and conditions set forth in this Agreement and the Plan, the Award granted hereby shall vest as set forth in the Restricted Stock Unit Award Notice of Grant and is subject to the other terms and conditions of this Agreement and the Plan. On each vesting date set forth in the Restricted Stock Unit Award Notice of Grant, the Participant shall be entitled to receive such number of shares of Common Stock equivalent to the number of RSUs as set forth in the Restricted Stock Unit Award Notice of Grant provided that the Participant is, and has been at all times since the Grant Date, an employee of the Company or any other entity the employees of which are eligible to receive RSUs under the Plan (an “ Eligible Participant ”). Such shares of Common Stock shall thereafter be delivered by the Company to the Participant within five days of the applicable vesting date and in accordance with this Agreement and the Plan.

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(b) Except as otherwise set forth in this Agreement and the Notice of Grant, if the Participant ceases to be an Eligible Participant (the “ Termination ”) prior to a vesting date set forth in the Restricted Stock Unit Award Notice of Grant, then as of the date on which the Participant’s employment or service terminates, all unvested RSUs shall immediately be forfeited to the Company and this Agreement shall terminate and be of no further force or effect.

3. Prohibitions on Transfer and Sale . This Award (including any additional RSUs received by the Participant as a result of stock dividends, stock splits or any other similar transaction affecting the Company’s securities without receipt of consideration) shall not be transferable by the Participant otherwise than (i) by will or by the laws of descent and distribution, or (ii) pursuant to a qualified domestic relations order as defined by the Internal Revenue Code or Title I of the Employee Retirement Income Security Act or the rules thereunder. Except as provided in the previous sentence, the shares of Common Stock to be issued pursuant to this Agreement shall be issued, during the Participant’s lifetime, only to the Participant (or, in the event of legal incapacity or incompetence, to the Participant’s guardian or representative). This Award shall not be assigned, pledged or hypothecated in any way (whether by operation of law or otherwise) and shall not be subject to execution, attachment or similar process. Any attempted transfer, assignment, pledge, hypothecation or other disposition of this Award or of any rights granted hereunder contrary to the provisions of this Section 3, or the levy of any attachment or similar process upon this Award shall be null and void.

4. Adjustments . The Plan contains provisions covering the treatment of RSUs and shares of Common Stock in a number of contingencies such as stock splits. Provisions in the Plan for adjustment with respect to this Award and the related provisions with respect to successors to the business of the Company are hereby made applicable hereunder and are incorporated herein by reference.

5. Securities Law Compliance . The Participant specifically acknowledges and agrees that any sales of shares of Common Stock shall be made in accordance with the requirements of the Securities Act of 1933, as amended. The Company currently has an effective registration statement on file with the Securities and Exchange Commission with respect to the Common Stock to be granted hereunder. The Company intends to maintain this registration statement but has no obligation to do so. If the registration statement ceases to be effective for any reason, Participant will not be able to transfer or sell any of the shares of Common Stock issued to the Participant pursuant to this Agreement unless exemptions from registration or filings under applicable securities laws are available. Furthermore, despite registration, applicable securities laws may restrict the ability of the Participant to sell his or her Common Stock, including due to the Participant’s affiliation with the Company. The Company shall not be obligated to either issue the Common Stock or permit the resale of any shares of Common Stock if such issuance or resale would violate any applicable securities law, rule or regulation.

6. Rights as a Stockholder . The Participant shall have no right as a stockholder, including voting and dividend rights, with respect to the RSUs subject to this Agreement.

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7. Incorporation of the Plan . The Participant specifically understands and agrees that the RSUs and the shares of Common Stock to be issued under the Plan will be issued to the Participant pursuant to the Plan, a copy of which Plan the Participant acknowledges he or she has read and understands and by which Plan he or she agrees to be bound. The provisions of the Plan are incorporated herein by reference.

8. Tax Liability of the Participant and Payment of Taxes . The Participant acknowledges and agrees that any income or other taxes due from the Participant with respect to this Award or the shares of Common Stock to be issued pursuant to this Agreement or otherwise sold shall be the Participant’s responsibility. Without limiting the foregoing, the Participant agrees that, if under applicable law the Participant will owe taxes at each vesting date on the portion of the Award then vested, the Company shall be entitled to immediate payment from the Participant of the amount of any tax or other amounts required to be withheld by the Company by applicable law or regulation. Any taxes or other amounts due shall be paid, at the option of the Administrator, as follows:

(a) through reducing the number of shares of Common Stock entitled to be issued to the Participant on the applicable vesting date in an amount equal to the statutory minimum of the Participant’s total tax and other withholding obligations due and payable by the Company. Fractional shares will not be retained to satisfy any portion of the Company’s withholding obligation. Accordingly, the Participant agrees that in the event that the amount of withholding required would result in a fraction of a share being owed, that amount will be satisfied by withholding the fractional amount from the Participant’s paycheck;

(b) requiring the Participant to deposit with the Company an amount of cash equal to the amount determined by the Company to be required to be withheld with respect to the statutory minimum amount of the Participant’s total tax and other withholding obligations due and payable by the Company or otherwise withholding from the Participant’s paycheck an amount equal to such amounts due and payable by the Company; or

(c) if the Company believes that the sale of shares can be made in compliance with applicable securities laws, authorizing, at a time when the Participant is not in possession of material nonpublic information, the sale by the Participant on the applicable vesting date of such number of shares of Common Stock as the Company instructs a registered broker to sell to satisfy the Company’s withholding obligation, after deduction of the broker’s commission, and the broker shall be required to remit to the Company the cash necessary in order for the Company to satisfy its withholding obligation. To the extent the proceeds of such sale exceed the Company’s withholding obligation, the Company agrees to pay such excess cash to the Participant as soon as practicable. In addition, if such sale is not sufficient to pay the Company’s withholding obligation, the Participant agrees to pay to the Company as soon as practicable, including through additional payroll withholding, the amount of any withholding obligation that is not satisfied by the sale of shares of Common Stock. The Participant agrees to hold the Company and the broker harmless from all costs, damages or expenses relating to any such sale. The Participant acknowledges that the Company and the broker are under no obligation to arrange for such sale at any particular price. In connection with such sale of shares of Common Stock, the Participant shall execute any such documents requested by the broker in order to effectuate the sale of shares of Common Stock and payment of the withholding obligation to the Company. The Participant acknowledges that this paragraph is intended to comply with Section 10b5-1(c)(1(i)(B) under the Securities Exchange Act of 1934, as amended.

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It is the Company’s intention that the Participant’s tax obligations under this Section 8 shall be satisfied through the procedure of Subsection (c) above, unless the Company provides notice of an alternative procedure under this Section, in its discretion. The Company shall not deliver any shares of Common Stock to the Participant until it is satisfied that all required withholdings have been made.

9. Participant Acknowledgements and Authorizations .

The Participant acknowledges the following:

(a) He or she has read this Agreement, has read the Plan, and understands the terms and conditions of this Agreement and the Plan.

(b) The Company is not by the Plan or this Award obligated to continue the Participant as an employee of the Company or an affiliate.

(c) The Plan is discretionary in nature and may be suspended or terminated by the Company at any time.

(d) The grant of this Award is considered a one-time benefit and does not create a contractual or other right to receive any other award under the Plan, benefits in lieu of awards or any other benefits in the future.

(e) The Plan is a voluntary program of the Company and future awards, if any, will be at the sole discretion of the Company, including, but not limited to, the timing of any grant, the amount of any award, vesting provisions and the purchase price, if any.

(f) The value of this Award is an extraordinary item of compensation outside of the scope of the Participant’s employment or consulting contract, if any. As such the Award is not part of normal or expected compensation for purposes of calculating any severance, resignation, redundancy, end of service payments, bonuses, long-service awards, pension or retirement benefits or similar payments. The future value of the shares of Common Stock is unknown and cannot be predicted with certainty.

(g) The Participant (i) authorizes the Company and each affiliate and any agent of the Company or any affiliate administering the Plan or providing Plan recordkeeping services, to disclose to the Company or any of its affiliates such information and data as the Company or any such Affiliate shall request in order to facilitate the grant of the Award and the administration of the Plan; and (ii) authorizes the Company and each affiliate to store and transmit such information in electronic form for the purposes set forth in this Agreement.

(h) In accepting this Award, the Participant agrees to be bound by any clawback policy that the Company has in effect or may adopt in the future.

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10. Consultants . If the Participant ceases to be an Eligible Participant of the Company but continues after termination of employment to provide services to the Company as a consultant to the Company, this Award shall continue to vest in accordance with Section 2 above as if the Award had not terminated until the Participant is no longer providing such services to the Company. In such case, this Award shall continue on the same terms and conditions set forth herein until such Participant is no longer providing such services to the Company.

11. Assignment and Successors .

(a) This Agreement is personal to the Participant and without the prior written consent of the Company shall not be assignable by the Participant otherwise than by will or the laws of descent and distribution. This Agreement shall inure to the benefit of and be enforceable by the Participant’s legal representatives.

(b) This Agreement shall inure to the benefit of and be binding upon the Company and its successors and assigns.

12. Governing Law . This Agreement shall be construed, interpreted and enforced in accordance with the internal laws of the State of Delaware without regard to any applicable conflicts of laws provisions.

13. Severability . If any provision of this Agreement is held to be invalid or unenforceable by a court of competent jurisdiction, then such provision or provisions shall be modified to the extent necessary to make such provision valid and enforceable, and to the extent that this is impossible, then such provision shall be deemed to be excised from this Agreement, and the validity, legality and enforceability of the rest of this Agreement shall not be affected thereby.

14. Entire Agreement . This Agreement, together with the Plan, constitutes the entire agreement and understanding between the parties hereto with respect to the subject matter hereof and supersedes all prior oral or written agreements and understandings relating to the subject matter hereof. No statement, representation, warranty, covenant or agreement not expressly set forth in this Agreement shall affect or be used to interpret, change or restrict the express terms and provisions of this Agreement provided, however, in any event, this Agreement shall be subject to and governed by the Plan.

15. Modifications and Amendments; Waivers and Consents . The terms and provisions of this Agreement may be modified or amended as provided in the Plan. Except as provided in the Plan, the terms and provisions of this Agreement may be waived, or consent for the departure therefrom granted, only by written document executed by the party entitled to the benefits of such terms or provisions. No such waiver or consent shall be deemed to be or shall constitute a waiver or consent with respect to any other terms or provisions of this Agreement, whether or not similar. Each such waiver or consent shall be effective only in the specific instance and for the purpose for which it was given, and shall not constitute a continuing waiver or consent.

16. Section 409A . The Award of RSUs evidenced by this Agreement is intended to be exempt from the nonqualified deferred compensation rules of Section 409A of the Code as a “short term deferral” (as that term is used in the final regulations and other guidance issued under Section 409A of the Code, including Treasury Regulation Section 1.409A-1(b)(4)(i)), and shall be construed accordingly.

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17. Data Privacy . By entering into this Agreement, the Participant: (i) authorizes the Company and each affiliate, and any agent of the Company or any affiliate administering the Plan or providing Plan recordkeeping services, to disclose to the Company or any of its Affiliates such information and data as the Company or any such affiliate shall request in order to facilitate the grant of options and the administration of the Plan; (ii) to the extent permitted by applicable law waives any data privacy rights he or she may have with respect to such information, and (iii) authorizes the Company and each affiliate to store and transmit such information in electronic form for the purposes set forth in this Agreement.

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Exhibit 10.5

FORM FOR ARSANIS, INC. 2017 EQUITY INCENTIVE PLAN

(JUNE 2019)

Restricted Stock Unit No.             

X4 PHARMACEUTICALS, INC.

RESTRICTED STOCK UNIT AWARD GRANT AGREEMENT

X4 Pharmaceuticals, Inc. (the “ Company ”) hereby grants the following restricted stock unit pursuant to its 2017 Equity Incentive Plan (the Arsanis, Inc. 2017 Equity Incentive Plan). The terms and conditions attached hereto are also a part hereof.

Notice of Grant

Vesting Schedule:

This Restricted Stock Unit Award shall vest as follows provided the Participant is an Eligible Participant on the applicable vesting date:

[Notwithstanding the foregoing, 100% of the unvested portion of this Restricted Stock Unit Award shall vest upon the termination of the Participant’s employment by the Company without Cause upon or at any time within 12 months following a Change of Control.

For purposes of this Agreement, a “ Change of Control ” shall mean the occurrence of any of the following events: (i) any “Person” (as such term is used in Sections 13(d) and 14(d) of the Exchange Act) becomes the “Beneficial Owner” (as defined in Rule 13d-3 under the Securities Exchange Act), directly or indirectly, of securities of the Company representing fifty percent (50%) or more of the total voting power represented by the Company’s then outstanding voting securities (excluding for this purpose any such voting securities held by the Company, or any affiliate, parent or subsidiary of the Company, or by any employee benefit plan of the Company) pursuant to a transaction or a series of related transactions which the Board does not approve; or (ii) (A) A merger or consolidation of the Company whether or not approved by the Board, other than a merger or consolidation which would result in the voting securities of the Company outstanding immediately prior thereto continuing to represent (either by remaining outstanding or

by being converted into voting securities of the surviving entity or the parent of such entity) at least fifty percent (50%) of the total voting power represented by the voting securities of the Company or such surviving entity or parent of such entity, as the case may be, outstanding immediately after such merger or consolidation; or (B) the sale or disposition by the Company of all or substantially all of the Company’s assets. For purposes of this Agreement, if the Participant is subject to an individual employment agreement with the Company or eligible to participate in a Company severance plan or arrangement, in any case which agreement, plan or arrangement contains a definition of “cause” for termination of employment, “ Cause ” shall have the meaning ascribed to such term in such agreement, plan or arrangement, otherwise, “ Cause ” shall mean, with respect to the Participant (a) dishonesty with respect to the Company or any affiliate, (b) insubordination, substantial malfeasance or non-feasance of duty, (c) unauthorized disclosure of confidential information, (d) breach by the recipient of any provision of any employment, consulting, advisory, nondisclosure, non-competition or similar agreement between the Participant and the Company or any affiliate, and (e) conduct substantially prejudicial to the business of the Company or any affiliate, with the determination of the administrator of the Plan as to the existence of Cause will be conclusive on the Participant and the Company. The Participant’s employment shall be considered to have been terminated for Cause if the Company determines, within 30 days after the Participant’s resignation, that termination for Cause was warranted.]

The Company and the Participant acknowledge receipt of this Restricted Stock Unit Award Notice of Grant and agree to the terms of the Restricted Stock Unit Agreement attached hereto and incorporated by reference herein, the Company’s 2017 Equity Incentive Plan and the terms of this Restricted Stock Unit Award as set forth above.

X4 PHARMACEUTICALS, INC.

Restricted Stock Unit Agreement

INCORPORATED TERMS AND CONDITIONS

AGREEMENT made as of the Grant Date set forth in the Restricted Stock Unit Award Notice of Grant between the Company and the Participant.

WHEREAS, the Company has adopted the 2017 Equity Incentive Plan (the “ Plan ”) to promote the interests of the Company by providing an incentive for employees of the Company or of any other entity the employees of which are eligible to receive grants of equity under the Plan;

WHEREAS, pursuant to the provisions of the Plan, the Company desires to grant to the Participant restricted stock units (“ RSUs ”) related to the Company’s common stock, $0.001 par value per share (“ Common Stock ”), in accordance with the provisions of the Plan, all on the terms and conditions hereinafter set forth; and

WHEREAS, the Company and the Participant understand and agree that any terms used and not defined herein have the meanings ascribed to such terms in the Plan.

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

1. Grant of Award . The Company hereby grants to the Participant an award for the number of RSUs set forth in the Restricted Stock Unit Award Notice of Grant (the “ Award ”). Each RSU represents a contingent entitlement of the Participant to receive one share of Common Stock, on the terms and conditions and subject to all the limitations set forth herein and in the Plan, which is incorporated herein by reference. The Participant acknowledges receipt of a copy of the Plan.

2. Vesting of Award .

(a) Subject to the terms and conditions set forth in this Agreement and the Plan, the Award granted hereby shall vest as set forth in the Restricted Stock Unit Award Notice of Grant and is subject to the other terms and conditions of this Agreement and the Plan. On each vesting date set forth in the Restricted Stock Unit Award Notice of Grant, the Participant shall be entitled to receive such number of shares of Common Stock equivalent to the number of RSUs as set forth in the Restricted Stock Unit Award Notice of Grant provided that the Participant is, and has been at all times since the Grant Date, an employee of the Company or any other entity the employees of which are eligible to receive RSUs under the Plan (an “ Eligible Participant ”). Such shares of Common Stock shall thereafter be delivered by the Company to the Participant within five days of the applicable vesting date and in accordance with this Agreement and the Plan.

(b) Except as otherwise set forth in this Agreement and the Notice of Grant, if the Participant ceases to be an Eligible Participant (the “ Termination ”) prior to a vesting date set forth in the Restricted Stock Unit Award Notice of Grant, then as of the date on which the Participant’s employment or service terminates, all unvested RSUs shall immediately be forfeited to the Company and this Agreement shall terminate and be of no further force or effect.

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3. Prohibitions on Transfer and Sale . This Award (including any additional RSUs received by the Participant as a result of stock dividends, stock splits or any other similar transaction affecting the Company’s securities without receipt of consideration) shall not be transferable by the Participant otherwise than (i) by will or by the laws of descent and distribution, or (ii) pursuant to a qualified domestic relations order as defined by the Internal Revenue Code or Title I of the Employee Retirement Income Security Act or the rules thereunder. Except as provided in the previous sentence, the shares of Common Stock to be issued pursuant to this Agreement shall be issued, during the Participant’s lifetime, only to the Participant (or, in the event of legal incapacity or incompetence, to the Participant’s guardian or representative). This Award shall not be assigned, pledged or hypothecated in any way (whether by operation of law or otherwise) and shall not be subject to execution, attachment or similar process. Any attempted transfer, assignment, pledge, hypothecation or other disposition of this Award or of any rights granted hereunder contrary to the provisions of this Section 3, or the levy of any attachment or similar process upon this Award shall be null and void.

4. Adjustments . The Plan contains provisions covering the treatment of RSUs and shares of Common Stock in a number of contingencies such as stock splits. Provisions in the Plan for adjustment with respect to this Award and the related provisions with respect to successors to the business of the Company are hereby made applicable hereunder and are incorporated herein by reference.

5. Securities Law Compliance . The Participant specifically acknowledges and agrees that any sales of shares of Common Stock shall be made in accordance with the requirements of the Securities Act of 1933, as amended. The Company currently has an effective registration statement on file with the Securities and Exchange Commission with respect to the Common Stock to be granted hereunder. The Company intends to maintain this registration statement but has no obligation to do so. If the registration statement ceases to be effective for any reason, Participant will not be able to transfer or sell any of the shares of Common Stock issued to the Participant pursuant to this Agreement unless exemptions from registration or filings under applicable securities laws are available. Furthermore, despite registration, applicable securities laws may restrict the ability of the Participant to sell his or her Common Stock, including due to the Participant’s affiliation with the Company. The Company shall not be obligated to either issue the Common Stock or permit the resale of any shares of Common Stock if such issuance or resale would violate any applicable securities law, rule or regulation.

6. Rights as a Stockholder . The Participant shall have no right as a stockholder, including voting and dividend rights, with respect to the RSUs subject to this Agreement.

7. Incorporation of the Plan . The Participant specifically understands and agrees that the RSUs and the shares of Common Stock to be issued under the Plan will be issued to the Participant pursuant to the Plan, a copy of which Plan the Participant acknowledges he or she has read and understands and by which Plan he or she agrees to be bound. The provisions of the Plan are incorporated herein by reference.

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8. Tax Liability of the Participant and Payment of Taxes . The Participant acknowledges and agrees that any income or other taxes due from the Participant with respect to this Award or the shares of Common Stock to be issued pursuant to this Agreement or otherwise sold shall be the Participant’s responsibility. Without limiting the foregoing, the Participant agrees that, if under applicable law the Participant will owe taxes at each vesting date on the portion of the Award then vested, the Company shall be entitled to immediate payment from the Participant of the amount of any tax or other amounts required to be withheld by the Company by applicable law or regulation. Any taxes or other amounts due shall be paid, at the option of the Administrator, as follows:

(a) through reducing the number of shares of Common Stock entitled to be issued to the Participant on the applicable vesting date in an amount equal to the statutory minimum of the Participant’s total tax and other withholding obligations due and payable by the Company. Fractional shares will not be retained to satisfy any portion of the Company’s withholding obligation. Accordingly, the Participant agrees that in the event that the amount of withholding required would result in a fraction of a share being owed, that amount will be satisfied by withholding the fractional amount from the Participant’s paycheck;

(b) requiring the Participant to deposit with the Company an amount of cash equal to the amount determined by the Company to be required to be withheld with respect to the statutory minimum amount of the Participant’s total tax and other withholding obligations due and payable by the Company or otherwise withholding from the Participant’s paycheck an amount equal to such amounts due and payable by the Company; or

(c) if the Company believes that the sale of shares can be made in compliance with applicable securities laws, authorizing, at a time when the Participant is not in possession of material nonpublic information, the sale by the Participant on the applicable vesting date of such number of shares of Common Stock as the Company instructs a registered broker to sell to satisfy the Company’s withholding obligation, after deduction of the broker’s commission, and the broker shall be required to remit to the Company the cash necessary in order for the Company to satisfy its withholding obligation. To the extent the proceeds of such sale exceed the Company’s withholding obligation, the Company agrees to pay such excess cash to the Participant as soon as practicable. In addition, if such sale is not sufficient to pay the Company’s withholding obligation, the Participant agrees to pay to the Company as soon as practicable, including through additional payroll withholding, the amount of any withholding obligation that is not satisfied by the sale of shares of Common Stock. The Participant agrees to hold the Company and the broker harmless from all costs, damages or expenses relating to any such sale. The Participant acknowledges that the Company and the broker are under no obligation to arrange for such sale at any particular price. In connection with such sale of shares of Common Stock, the Participant shall execute any such documents requested by the broker in order to effectuate the sale of shares of Common Stock and payment of the withholding obligation to the Company. The Participant acknowledges that this paragraph is intended to comply with Section 10b5-1(c)(1(i)(B) under the Securities Exchange Act of 1934, as amended.

It is the Company’s intention that the Participant’s tax obligations under this Section 8 shall be satisfied through the procedure of Subsection (c) above, unless the Company provides notice of an alternative procedure under this Section, in its discretion. The Company shall not deliver any shares of Common Stock to the Participant until it is satisfied that all required withholdings have been made.

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9. Participant Acknowledgements and Authorizations .

The Participant acknowledges the following:

(a) He or she has read this Agreement, has read the Plan, and understands the terms and conditions of this Agreement and the Plan.

(b) The Company is not by the Plan or this Award obligated to continue the Participant as an employee, director or consultant of the Company or an affiliate.

(c) The Plan is discretionary in nature and may be suspended or terminated by the Company at any time.

(d) The grant of this Award is considered a one-time benefit and does not create a contractual or other right to receive any other award under the Plan, benefits in lieu of awards or any other benefits in the future.

(e) The Plan is a voluntary program of the Company and future awards, if any, will be at the sole discretion of the Company, including, but not limited to, the timing of any grant, the amount of any award, vesting provisions and the purchase price, if any.

(f) The value of this Award is an extraordinary item of compensation outside of the scope of the Participant’s employment or consulting contract, if any. As such the Award is not part of normal or expected compensation for purposes of calculating any severance, resignation, redundancy, end of service payments, bonuses, long-service awards, pension or retirement benefits or similar payments. The future value of the shares of Common Stock is unknown and cannot be predicted with certainty.

(g) The Participant (i) authorizes the Company and each affiliate and any agent of the Company or any affiliate administering the Plan or providing Plan recordkeeping services, to disclose to the Company or any of its affiliates such information and data as the Company or any such Affiliate shall request in order to facilitate the grant of the Award and the administration of the Plan; and (ii) authorizes the Company and each affiliate to store and transmit such information in electronic form for the purposes set forth in this Agreement.

(h) In accepting this Award, the Participant agrees to be bound by any clawback policy that the Company has in effect or may adopt in the future.

10. Assignment and Successors .

(a) This Agreement is personal to the Participant and without the prior written consent of the Company shall not be assignable by the Participant otherwise than by will or the laws of descent and distribution. This Agreement shall inure to the benefit of and be enforceable by the Participant’s legal representatives.

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(b) This Agreement shall inure to the benefit of and be binding upon the Company and its successors and assigns.

11. Governing Law . This Agreement shall be construed, interpreted and enforced in accordance with the internal laws of the State of Delaware without regard to any applicable conflicts of laws provisions.

12. Severability . If any provision of this Agreement is held to be invalid or unenforceable by a court of competent jurisdiction, then such provision or provisions shall be modified to the extent necessary to make such provision valid and enforceable, and to the extent that this is impossible, then such provision shall be deemed to be excised from this Agreement, and the validity, legality and enforceability of the rest of this Agreement shall not be affected thereby.

13. Entire Agreement . This Agreement, together with the Plan, constitutes the entire agreement and understanding between the parties hereto with respect to the subject matter hereof and supersedes all prior oral or written agreements and understandings relating to the subject matter hereof. No statement, representation, warranty, covenant or agreement not expressly set forth in this Agreement shall affect or be used to interpret, change or restrict the express terms and provisions of this Agreement provided, however, in any event, this Agreement shall be subject to and governed by the Plan.

14. Modifications and Amendments; Waivers and Consents . The terms and provisions of this Agreement may be modified or amended as provided in the Plan. Except as provided in the Plan, the terms and provisions of this Agreement may be waived, or consent for the departure therefrom granted, only by written document executed by the party entitled to the benefits of such terms or provisions. No such waiver or consent shall be deemed to be or shall constitute a waiver or consent with respect to any other terms or provisions of this Agreement, whether or not similar. Each such waiver or consent shall be effective only in the specific instance and for the purpose for which it was given, and shall not constitute a continuing waiver or consent.

15. Section 409A . The Award of RSUs evidenced by this Agreement is intended to be exempt from the nonqualified deferred compensation rules of Section 409A of the Code as a “short term deferral” (as that term is used in the final regulations and other guidance issued under Section 409A of the Code, including Treasury Regulation Section 1.409A-1(b)(4)(i)), and shall be construed accordingly.

16. Data Privacy . By entering into this Agreement, the Participant: (i) authorizes the Company and each affiliate, and any agent of the Company or any affiliate administering the Plan or providing Plan recordkeeping services, to disclose to the Company or any of its Affiliates such information and data as the Company or any such affiliate shall request in order to facilitate the grant of options and the administration of the Plan; (ii) to the extent permitted by applicable law waives any data privacy rights he or she may have with respect to such information, and (iii) authorizes the Company and each affiliate to store and transmit such information in electronic form for the purposes set forth in this Agreement.

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Exhibit 10.6

FORM FOR X4 PHARMACEUTICALS, INC. 2015 EMPLOYEE, DIRECTOR AND

CONSULTANT EQUITY INCENTIVE PLAN

(JUNE 2019)

Restricted Stock Unit No.             

X4 PHARMACEUTICALS, INC.

RESTRICTED STOCK UNIT AWARD GRANT AGREEMENT

X4 Pharmaceuticals, Inc. (the “Company”) hereby grants the following restricted stock unit pursuant to its 2015 Employee, Director and Consultant Equity Incentive Plan. The terms and conditions attached hereto are also a part hereof.

Notice of Grant

Vesting Schedule:

This Restricted Stock Unit Award shall vest as follows provided the Participant is an Employee, director or Consultant of the Company or of an Affiliate on the applicable vesting date:

[Notwithstanding the foregoing, 100% of the unvested portion of this Restricted Stock Unit Award shall vest upon the termination of the Participant’s employment by the Company without Cause (as defined in the Plan) upon or at any time within 12 months following a Change of Control. The Participant’s employment shall be considered to have been terminated by the Company for Cause if the Company determines, within 30 days after the Participant’s resignation, that determination for Cause was warranted.

For purposes of this Agreement, a “ Change of Control ” shall mean the occurrence of any of the following events: (i) any “Person” (as such term is used in Sections 13(d) and 14(d) of the Exchange Act) becomes the “Beneficial Owner” (as defined in Rule 13d-3 under the Securities Exchange Act), directly or indirectly, of securities of the Company representing fifty percent (50%) or more of the total voting power represented by the Company’s then outstanding voting securities (excluding for this purpose any such voting securities held by the Company, or any affiliate, parent or subsidiary of the Company, or by any employee benefit plan of the Company) pursuant to a transaction or a series of related transactions which the Board does not approve; or (ii) (A) A merger or consolidation of the Company whether or not approved by the Board, other than a merger or consolidation which would result in the voting securities of the Company

outstanding immediately prior thereto continuing to represent (either by remaining outstanding or by being converted into voting securities of the surviving entity or the parent of such entity) at least fifty percent (50%) of the total voting power represented by the voting securities of the Company or such surviving entity or parent of such entity, as the case may be, outstanding immediately after such merger or consolidation; or (B) the sale or disposition by the Company of all or substantially all of the Company’s assets.]

The Company and the Participant acknowledge receipt of this Restricted Stock Unit Award Notice of Grant and agree to the terms of the Restricted Stock Unit Agreement attached hereto and incorporated by reference herein, the Company’s 2017 Equity Incentive Plan and the terms of this Restricted Stock Unit Award as set forth above.

X4 PHARMACEUTICALS, INC.

Restricted Stock Unit Agreement

INCORPORATED TERMS AND CONDITIONS

AGREEMENT made as of the Grant Date set forth in the Restricted Stock Unit Award Notice of Grant between the Company and the Participant.

WHEREAS, the Company has adopted the 2015 Employee, Director and Consultant Equity Incentive Plan (the “ Plan ”) to promote the interests of the Company by providing an incentive for Employees, directors and Consultants of the Company and its Affiliates;

WHEREAS, pursuant to the provisions of the Plan, the Company desires to grant to the Participant restricted stock units (“ RSUs ”) related to the Company’s common stock, $0.001 par value per share (“ Common Stock ”), in accordance with the provisions of the Plan, all on the terms and conditions hereinafter set forth; and

WHEREAS, the Company and the Participant understand and agree that any terms used and not defined herein have the meanings ascribed to such terms in the Plan.

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

1. Grant of Award . The Company hereby grants to the Participant an award for the number of RSUs set forth in the Restricted Stock Unit Award Notice of Grant (the “ Award ”). Each RSU represents a contingent entitlement of the Participant to receive one share of Common Stock, on the terms and conditions and subject to all the limitations set forth herein and in the Plan, which is incorporated herein by reference. The Participant acknowledges receipt of a copy of the Plan.

2. Vesting of Award .

(a) Subject to the terms and conditions set forth in this Agreement and the Plan, the Award granted hereby shall vest as set forth in the Restricted Stock Unit Award Notice of Grant and is subject to the other terms and conditions of this Agreement and the Plan. On each vesting date set forth in the Restricted Stock Unit Award Notice of Grant, the Participant shall be entitled to receive such number of shares of Common Stock equivalent to the number of RSUs as set forth in the Restricted Stock Unit Award Notice of Grant provided that the Participant is employed or providing service to the Company or an Affiliate on such vesting date. Such shares of Common Stock shall thereafter be delivered by the Company to the Participant within five days of the applicable vesting date and in accordance with this Agreement and the Plan.

(b) Except as otherwise set forth in this Agreement and the Notice of Grant, if the Participant ceases to be employed by or to provide services to the Company or an Affiliate for any reason (the “ Termination ”) prior to a vesting date set forth in the Restricted Stock Unit Award Notice of Grant, then as of the date on which the Participant’s employment or service terminates, all unvested RSUs shall immediately be forfeited to the Company and this Agreement shall terminate and be of no further force or effect.

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3. Prohibitions on Transfer and Sale . This Award (including any additional RSUs received by the Participant as a result of stock dividends, stock splits or any other similar transaction affecting the Company’s securities without receipt of consideration) shall not be transferable by the Participant otherwise than (i) by will or by the laws of descent and distribution, or (ii) pursuant to a qualified domestic relations order as defined by the Internal Revenue Code or Title I of the Employee Retirement Income Security Act or the rules thereunder. Except as provided in the previous sentence, the shares of Common Stock to be issued pursuant to this Agreement shall be issued, during the Participant’s lifetime, only to the Participant (or, in the event of legal incapacity or incompetence, to the Participant’s guardian or representative). This Award shall not be assigned, pledged or hypothecated in any way (whether by operation of law or otherwise) and shall not be subject to execution, attachment or similar process. Any attempted transfer, assignment, pledge, hypothecation or other disposition of this Award or of any rights granted hereunder contrary to the provisions of this Section 3, or the levy of any attachment or similar process upon this Award shall be null and void.

4. Adjustments . The Plan contains provisions covering the treatment of RSUs and shares of Common Stock in a number of contingencies such as stock splits. Provisions in the Plan for adjustment with respect to this Award and the related provisions with respect to successors to the business of the Company are hereby made applicable hereunder and are incorporated herein by reference.

5. Securities Law Compliance . The Participant specifically acknowledges and agrees that any sales of shares of Common Stock shall be made in accordance with the requirements of the Securities Act of 1933, as amended. The Company currently has an effective registration statement on file with the Securities and Exchange Commission with respect to the Common Stock to be granted hereunder. The Company intends to maintain this registration statement but has no obligation to do so. If the registration statement ceases to be effective for any reason, Participant will not be able to transfer or sell any of the shares of Common Stock issued to the Participant pursuant to this Agreement unless exemptions from registration or filings under applicable securities laws are available. Furthermore, despite registration, applicable securities laws may restrict the ability of the Participant to sell his or her Common Stock, including due to the Participant’s affiliation with the Company. The Company shall not be obligated to either issue the Common Stock or permit the resale of any shares of Common Stock if such issuance or resale would violate any applicable securities law, rule or regulation.

6. Rights as a Stockholder . The Participant shall have no right as a stockholder, including voting and dividend rights, with respect to the RSUs subject to this Agreement.

7. Incorporation of the Plan . The Participant specifically understands and agrees that the RSUs and the shares of Common Stock to be issued under the Plan will be issued to the Participant pursuant to the Plan, a copy of which Plan the Participant acknowledges he or she has read and understands and by which Plan he or she agrees to be bound. The provisions of the Plan are incorporated herein by reference.

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8. Tax Liability of the Participant and Payment of Taxes . The Participant acknowledges and agrees that any income or other taxes due from the Participant with respect to this Award or the shares of Common Stock to be issued pursuant to this Agreement or otherwise sold shall be the Participant’s responsibility. Without limiting the foregoing, the Participant agrees that, if under applicable law the Participant will owe taxes at each vesting date on the portion of the Award then vested, the Company shall be entitled to immediate payment from the Participant of the amount of any tax or other amounts required to be withheld by the Company by applicable law or regulation. Any taxes or other amounts due shall be paid, at the option of the Administrator, as follows:

(a) through reducing the number of shares of Common Stock entitled to be issued to the Participant on the applicable vesting date in an amount equal to the statutory minimum of the Participant’s total tax and other withholding obligations due and payable by the Company. Fractional shares will not be retained to satisfy any portion of the Company’s withholding obligation. Accordingly, the Participant agrees that in the event that the amount of withholding required would result in a fraction of a share being owed, that amount will be satisfied by withholding the fractional amount from the Participant’s paycheck;

(b) requiring the Participant to deposit with the Company an amount of cash equal to the amount determined by the Company to be required to be withheld with respect to the statutory minimum amount of the Participant’s total tax and other withholding obligations due and payable by the Company or otherwise withholding from the Participant’s paycheck an amount equal to such amounts due and payable by the Company; or

(c) if the Company believes that the sale of shares can be made in compliance with applicable securities laws, authorizing, at a time when the Participant is not in possession of material nonpublic information, the sale by the Participant on the applicable vesting date of such number of shares of Common Stock as the Company instructs a registered broker to sell to satisfy the Company’s withholding obligation, after deduction of the broker’s commission, and the broker shall be required to remit to the Company the cash necessary in order for the Company to satisfy its withholding obligation. To the extent the proceeds of such sale exceed the Company’s withholding obligation, the Company agrees to pay such excess cash to the Participant as soon as practicable. In addition, if such sale is not sufficient to pay the Company’s withholding obligation, the Participant agrees to pay to the Company as soon as practicable, including through additional payroll withholding, the amount of any withholding obligation that is not satisfied by the sale of shares of Common Stock. The Participant agrees to hold the Company and the broker harmless from all costs, damages or expenses relating to any such sale. The Participant acknowledges that the Company and the broker are under no obligation to arrange for such sale at any particular price. In connection with such sale of shares of Common Stock, the Participant shall execute any such documents requested by the broker in order to effectuate the sale of shares of Common Stock and payment of the withholding obligation to the Company. The Participant acknowledges that this paragraph is intended to comply with Section 10b5-1(c)(1(i)(B) under the Securities Exchange Act of 1934, as amended.

It is the Company’s intention that the Participant’s tax obligations under this Section 8 shall be satisfied through the procedure of Subsection (c) above, unless the Company provides notice of an alternative procedure under this Section, in its discretion. The Company shall not deliver any shares of Common Stock to the Participant until it is satisfied that all required withholdings have been made.

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9. Participant Acknowledgements and Authorizations .

The Participant acknowledges the following:

(a) He or she has read this Agreement, has read the Plan, and understands the terms and conditions of this Agreement and the Plan.

(b) The Company is not by the Plan or this Award obligated to continue the Participant as an Employee, director or consultant of the Company or an Affiliate.

(c) The Plan is discretionary in nature and may be suspended or terminated by the Company at any time.

(d) The grant of this Award is considered a one-time benefit and does not create a contractual or other right to receive any other award under the Plan, benefits in lieu of awards or any other benefits in the future.

(e) The Plan is a voluntary program of the Company and future awards, if any, will be at the sole discretion of the Company, including, but not limited to, the timing of any grant, the amount of any award, vesting provisions and the purchase price, if any.

(f) The value of this Award is an extraordinary item of compensation outside of the scope of the Participant’s employment or consulting contract, if any. As such the Award is not part of normal or expected compensation for purposes of calculating any severance, resignation, redundancy, end of service payments, bonuses, long-service awards, pension or retirement benefits or similar payments. The future value of the shares of Common Stock is unknown and cannot be predicted with certainty.

(g) The Participant (i) authorizes the Company and each Affiliate and any agent of the Company or any Affiliate administering the Plan or providing Plan recordkeeping services, to disclose to the Company or any of its Affiliates such information and data as the Company or any such Affiliate shall request in order to facilitate the grant of the Award and the administration of the Plan; and (ii) authorizes the Company and each Affiliate to store and transmit such information in electronic form for the purposes set forth in this Agreement.

10. Assignment and Successors .

(a) This Agreement is personal to the Participant and without the prior written consent of the Company shall not be assignable by the Participant otherwise than by will or the laws of descent and distribution. This Agreement shall inure to the benefit of and be enforceable by the Participant’s legal representatives.

(b) This Agreement shall inure to the benefit of and be binding upon the Company and its successors and assigns.

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11. Governing Law . This Agreement shall be construed, interpreted and enforced in accordance with the internal laws of the State of Delaware without regard to any applicable conflicts of laws provisions.

12. Severability . If any provision of this Agreement is held to be invalid or unenforceable by a court of competent jurisdiction, then such provision or provisions shall be modified to the extent necessary to make such provision valid and enforceable, and to the extent that this is impossible, then such provision shall be deemed to be excised from this Agreement, and the validity, legality and enforceability of the rest of this Agreement shall not be affected thereby.

13. Entire Agreement . This Agreement, together with the Plan, constitutes the entire agreement and understanding between the parties hereto with respect to the subject matter hereof and supersedes all prior oral or written agreements and understandings relating to the subject matter hereof. No statement, representation, warranty, covenant or agreement not expressly set forth in this Agreement shall affect or be used to interpret, change or restrict the express terms and provisions of this Agreement provided, however, in any event, this Agreement shall be subject to and governed by the Plan.

14. Modifications and Amendments; Waivers and Consents . The terms and provisions of this Agreement may be modified or amended as provided in the Plan. Except as provided in the Plan, the terms and provisions of this Agreement may be waived, or consent for the departure therefrom granted, only by written document executed by the party entitled to the benefits of such terms or provisions. No such waiver or consent shall be deemed to be or shall constitute a waiver or consent with respect to any other terms or provisions of this Agreement, whether or not similar. Each such waiver or consent shall be effective only in the specific instance and for the purpose for which it was given, and shall not constitute a continuing waiver or consent.

15. Section 409A . The Award of RSUs evidenced by this Agreement is intended to be exempt from the nonqualified deferred compensation rules of Section 409A of the Code as a “short term deferral” (as that term is used in the final regulations and other guidance issued under Section 409A of the Code, including Treasury Regulation Section 1.409A-1(b)(4)(i)), and shall be construed accordingly.

16. Data Privacy . By entering into this Agreement, the Participant: (i) authorizes the Company and each Affiliate, and any agent of the Company or any Affiliate administering the Plan or providing Plan recordkeeping services, to disclose to the Company or any of its Affiliates such information and data as the Company or any such Affiliate shall request in order to facilitate the grant of options and the administration of the Plan; (ii) to the extent permitted by applicable law waives any data privacy rights he or she may have with respect to such information, and (iii) authorizes the Company and each Affiliate to store and transmit such information in electronic form for the purposes set forth in this Agreement.

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