Exhibit 10.1

ATTORNEY WORK PRODUCT

PRIVILEGED AND CONFIDENTIAL

ARCA biopharma, Inc.

10170 Church Ranch Way, Suite 100

Westminster, Colorado 80021

June 14, 2022

Cable Car Capital LLC

2261 Market Street #4307

San Francisco, California 94114

Attn: Jacob Ma-Weaver

Ladies and Gentlemen:

This letter (this “Agreement”) constitutes the agreement between (a) ARCA biopharma, Inc. (“Company”) and (b) Cable Car Capital LLC and each of the other related Persons (as defined below) set forth on the signature pages to this Agreement (collectively, the “CCC Signatories”). Company and the CCC Signatories are collectively referred to as the “Parties.” The CCC Signatories and each Affiliate (as defined below) and Associate (as defined below) of each CCC Signatory are collectively referred to as the “CCC Group.”

1.Board Matters.

(a)First Director Appointment. Effective upon the execution and delivery of this Agreement, Company’s board of directors (the “Board”) will take all action necessary (including increasing the size of the Board) to appoint Jacob Ma-Weaver (the “First Designee”) to the Board as a Class III director with a term expiring at Company’s 2024 Annual Meeting of Stockholders. The First Designee will be appointed to the Special Committee of the Board, and such other committees, if any, as determined from time to time by the Board.

(b)Second Director Appointment. Following the date of this Agreement, the Parties will begin a process to identify a mutually acceptable independent director to join Company’s slate of director nominees standing for election at the 2022 Annual Meeting (the “Second Designee”); provided, however, that the Company shall not unreasonably object to a designee proposed by CCC Group who satisfies the following conditions. The Second Designee will (i) be qualified to serve as a member of the Board under all applicable corporate governance policies or guidelines of Company and the Board and applicable legal and regulatory requirements; (ii) not be party to any voting agreement, arrangement or understanding, written or oral, with any member of the CCC Group regarding the Second Designee’s service on the Board; (iii) meet the independence requirements with respect to Company of the listing rules of Company’s principal securities exchange and the Securities and Exchange Commission (the “SEC”); and (iv) have complied with Company’s procedures (as in effect from time to time) for director candidates (including the completion of Company’s standard form of a directors and officers questionnaire, successfully undergoing a customary background check arranged by Company, and participating in interviews with, as requested, the members of the Nominating and Corporate Governance Committee (including any successor committee) of the Board. Upon joining Company’s slate of director nominees, the Second Designee will execute an appropriate joinder to this Agreement (in

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a form reasonably acceptable to Company). The First Designee and the Second Designee are referred to as the “Designees.”

(c)Termination of Certain Obligations. Company’s obligations under this paragraph 1 will immediately terminate upon the earliest of: (a) the CCC Group no longer beneficially owning shares of Company’s common stock (which shares are determined to be Net Long Shares (as defined below)) representing in the aggregate at least 10 percent of Company’s then-outstanding common stock; (b) any Restricted Person (as defined below) breaching this Agreement and such breach not being cured (if capable of being cured) within 15 days after receipt by the CCC Signatories from Company of written notice specifying the breach; or (c) the submission by any Restricted Person during the Restricted Period of any director nominations in connection with any meeting of Company’s stockholders. In connection with any termination of Company’s obligations under this paragraph 1, the CCC Signatories will cause the Designees to offer to resign from the Board (it being understood that the decision of whether to accept such resignation will be in the discretion of the Board).

2.Recusal. The CCC Signatories understand and agree that the Board or any of its committees, in the exercise of its fiduciary duties, may require that either or both of the Designees be recused from (and may restrict access to information of Company in respect of) any Board or committee meeting or portion thereof at which the Board or any such committee is evaluating or taking action with respect to (a) this Agreement; (b) any action taken or proposed by any Restricted Person with respect to Company; or (c) any proposed transaction between Company and any Restricted Person.

3.Compliance with Laws and Company Policies. The CCC Signatories acknowledge that the Designees will each be subject to the same laws, policies, procedures, processes, codes, rules, standards and guidelines applicable to members of the Board, including Company’s corporate governance guidelines and code of conduct, and Company’s director resignation, insider trading, related party transaction, Regulation FD and disclosure policies, in each case in effect and as modified from time to time, that are applicable to all of Company’s non-employee directors (collectively, the “Laws and Company Policies”).

4.No Fiduciary Restriction. Notwithstanding anything to the contrary in this Agreement, but subject to the Law and Company Policies, Company and the CCC Signatories acknowledge that neither of the Designees, during such Designee’s service as a director of Company, will not be prohibited from acting in such Designee’s capacity as a director of Company or from complying with such Designee’s fiduciary duties as a director of Company (including voting as a director on any matter submitted for consideration by the Board or any committee of the Board on which such Designee serves, participating in deliberations or discussions of the Board or any committee of the Board on which such Designee serves, and making suggestions or raising any issues or recommendations to the Board or any committee of the Board on which such Designee serves).

5.Director Benefits. The Designees will each be entitled to the same director benefits as other non-employee members of the Board, including (a) compensation for such Designee’s service as a director and reimbursement of such Designee’s expenses on the same basis as all other non-employee directors of Company; (b) equity-based compensation grants and other benefits, if

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any, on the same basis as all other non-employee directors of Company; and (c) the same rights of indemnification and directors’ and officers’ liability insurance coverage as the other non-employee directors of Company as such rights may exist from time to time.

6.Standstill. During the Restricted Period, none of the CCC Signatories will, and each will cause the other Restricted Persons not to, in any way, directly or indirectly (in each case, except as expressly permitted by this Agreement):

(a)with respect to Company or the Voting Securities, (i) make, participate in or encourage any “solicitation” (as such term is used in the proxy rules of the SEC, including any solicitations of the type contemplated by Rule 14a-2(b) promulgated under the Securities Exchange Act of 1934 (the “Exchange Act”)) of proxies or consents with respect to the election or removal of directors or any other matter or proposal; (ii) become a “participant” (as such term is used in the proxy rules of the SEC) in any such solicitation of proxies or consents; (iii) seek to advise, encourage or influence any Person, or assist any Person in so encouraging, advising or influencing any Person, with respect to the giving or withholding of any proxy, consent or other authority to vote or act (other than such encouragement, advice or influence that is consistent with the Board’s recommendation in connection with such matter, if applicable); or (iv) initiate, encourage or participate, directly or indirectly, in any “vote no,” “withhold” or similar campaign;

(b)initiate, propose or otherwise “solicit” (as such term is used in the proxy rules of the SEC, including any solicitations of the type contemplated by Rule 14a-2(b) promulgated under the Exchange Act) Company’s stockholders for the approval of any stockholder proposal, whether made pursuant to Rule 14a-4 or Rule 14a-8 promulgated under the Exchange Act, or otherwise, or cause or encourage any Person to initiate or submit any such stockholder proposal;

(c)with respect to Company or the Voting Securities, (i) communicate with Company’s stockholders or others pursuant to Rule 14a-1(l)(2)(iv) promulgated under the Exchange Act; (ii) participate in, or take any action pursuant to, or encourage any Person to take any action pursuant to, any type of “proxy access”; or (iii) conduct any nonbinding referendum or hold a “stockholder forum”;

(d)(i) seek, alone or in concert with others, election or appointment to, or representation on, the Board; (ii) nominate or propose the nomination of, or recommend the nomination of, or encourage any Person to nominate or propose the nomination of or recommend the nomination of, any candidate to the Board; or (iii) seek, alone or in concert with others, or encourage any Person to seek, the removal of any member of the Board;

(e)(i) call or seek to call a special meeting of stockholders, or encourage any Person to call a special meeting of stockholders; (ii) act or seek to act by written consent of stockholders; or (iii) make a request for any stockholder list or other books and records of Company;

(f)other than solely with other Restricted Persons with respect to Voting Securities now or subsequently owned by them, (i) form, join (whether or not in writing), encourage, influence, advise or participate in a partnership, limited partnership, syndicate or other

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group, including a “group” as defined pursuant to Section 13(d) of the Exchange Act, with respect to any Voting Securities; (ii) deposit any Voting Securities into a voting trust, arrangement or agreement; or (iii) subject any Voting Securities to any voting trust, arrangement or agreement (other than granting proxies in solicitations approved by the Board);

(g)(i) make any offer or proposal (with or without conditions) with respect to any tender offer, exchange offer, merger, amalgamation, consolidation, acquisition, business combination, recapitalization, consolidation, restructuring, liquidation, dissolution or similar extraordinary transaction involving Company, any of its subsidiaries or any of their respective securities or assets (each, an “Extraordinary Transaction”) and any Restricted Person; (ii) knowingly solicit any Person not a party to this Agreement (a “Third Party”) to, on an unsolicited basis, make an offer or proposal (with or without conditions) with respect to any Extraordinary Transaction, or encourage, initiate or support any Third Party in making such an offer or proposal; (iii) participate in any way in, either alone or in concert with others, any Extraordinary Transaction; or (iv) prior to Company announcing an Extraordinary Transaction, publicly comment on any proposal regarding any Extraordinary Transaction (it being understood that this clause (g) will not restrict any Restricted Person from (A) publicly commenting on an Extraordinary Transaction involving any Third Party after Company has announced such Extraordinary Transaction; or (C) tendering shares, receiving payment for shares or otherwise participating in any such Extraordinary Transaction on the same basis as other stockholders of Company);

(h)institute, solicit, assist or join, as a party, any litigation, arbitration or other proceeding against or involving Company, its Affiliates or any of their respective current or former directors or officers (including derivative actions), except that the foregoing will not prevent any Restricted Person from (i) bringing litigation to enforce the provisions of this Agreement instituted in accordance with this Agreement; (ii) making counterclaims with respect to any proceeding initiated by, or on behalf of, Company or its Affiliates against a Restricted Person; (iii) bringing bona fide commercial disputes that do not in any manner relate to the subject matter of this Agreement; (iv) exercising statutory appraisal rights; or (v) responding to or complying with a validly issued legal process;

(i)take any action in support of, or make any proposal or request that constitutes: (i) controlling, changing or influencing the Board or management of Company, including any plans or proposals to change the number or term of directors or to fill any vacancies on the Board; (ii) controlling, changing or influencing the capitalization, stock repurchase programs and practices, capital allocation programs and practices, or dividend policy of Company; (iii) controlling, changing or influencing Company’s management, business or corporate structure; (iv) seeking to have Company waive or make amendments or modifications to its certificate of incorporation or bylaws; (v) causing a class of securities of Company to be delisted from, or to cease to be authorized to be quoted on, any securities exchange; or (vi) causing a class of securities of Company to become eligible for termination of registration pursuant to Section 12(g)(4) of the Exchange Act;

(j)sell, offer or agree to sell to any Third Party, through swap or hedging transactions, derivative agreements or otherwise, any voting rights decoupled from the underlying Voting Securities;

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(k)engage in any short sale or similar transaction with respect to any security (other than a broad-based market basket or index) that includes, relates to or derives any significant part of its value from a decline in the market price or value of the securities of Company (it being understood that the restrictions in this clause (k) will not apply to the sale of put options or other option-related contracts);

(l)other than through non-public communications that would not reasonably be expected to trigger public disclosure obligations for any Party, make or disclose any statement regarding any intent, purpose, plan or proposal with respect to the Board, Company or its management, policies, affairs or assets, or the Voting Securities or this Agreement, that is inconsistent with the provisions of this Agreement, including any intent, purpose, plan or proposal that is conditioned on, or that would require, the waiver, amendment, nullification or invalidation of any provision of this Agreement, or take any action that could require Company to make any public disclosure relating to any such intent, purpose, plan, proposal or condition;

(m)enter into any economic relationship with any Person in respect of Company, or compensate or enter into any agreement, arrangement or understanding, whether written or oral, to compensate any person for his or her service as a director of Company with any cash, securities (including any rights or options convertible into or exercisable for or exchangeable into securities or any profit sharing agreement or arrangement) or other form of compensation directly or indirectly related to Company or its securities;

(n)other than with other Restricted Persons, enter into any negotiations, agreements (whether written or oral), arrangements or understandings with, or advise, finance, assist or encourage, any Third Party to take any action that the Restricted Persons are prohibited from taking pursuant to this Agreement;

(o)without the prior consent of the Board, including a determination that there is no material non-public information regarding the Company, acquire, offer, agree or propose to acquire, whether by purchase, tender or exchange offer, through the acquisition of control of another Person, by joining a partnership, limited partnership, syndicate or other group (including a “group” as defined pursuant to Section 13(d) of the Exchange Act), through swap or hedging transactions, or otherwise, or direct any Third Party in the acquisition of, any securities of Company or any rights decoupled from the underlying securities of Company that would result in the CCC Group in the aggregate owning, controlling or otherwise having any beneficial or other ownership interest of more than 19.9 percent of the then-outstanding Voting Securities (including, for purpose of this calculation, all Voting Securities that a member of the CCC Group has the right to acquire pursuant to the exercise of any rights in connection with any securities or any agreement, regardless of when such rights may be exercised and whether they are conditional and including economic ownership pursuant to a cash settled call option or other derivative security, contract or instrument primarily related to the price of Voting Securities, provided that options disclosed to the Company and outstanding as of the date hereof shall be excluded from such calculation); or

(p)other than through open market broker sale transactions where the identity of the purchaser is not known and in underwritten widely dispersed public offerings, sell, offer or agree to sell, through swap or hedging transactions or otherwise, the securities of Company to any Third Party that, to the knowledge of any member of the CCC Group (after due inquiry in

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connection with a private, non-open market transaction, it being understood that such knowledge will be deemed to exist with respect to any publicly available information, including information in documents filed with the SEC), would result in such Third Party, together with its Affiliates and Associates, owning, controlling or otherwise having any beneficial or other ownership interest of more than 4.9 percent of the then-outstanding Voting Securities or that would increase the beneficial or other ownership interest of any Third Party who, together with its Affiliates and Associates, has a beneficial or other ownership interest of more than 4.9 percent of the then-outstanding Voting Securities (it being understood that the restrictions in this clause (q) will not apply to any Third Party that is a Schedule 13G filer and is a mutual fund, pension fund, index fund or investment fund manager with no known history of activism or known plans to engage in activism).

7.Mutual Non-Disparagement. During the Restricted Period, (a) the CCC Signatories shall not, and shall cause the Restricted Persons not to make, or cause to be made, by press release or other public statement to the press or media, any statement or announcement that constitutes an ad hominem attack on, or otherwise disparages, the Company, its officers or its directors or any person who has served as an officer or director of the Company in the past and (b) the Company shall not, and shall cause its directors, officers, partners, members, employees, agents (in each case, acting in such capacity) and Affiliates not to, make, or cause to be made, by press release or other public statement to the press or media, any statement or announcement that constitutes an ad hominem attack on, or otherwise disparages, the CCC Group, any of their respective Affiliates, Associates, subsidiaries, successors or assigns, or any of its or their respective current or former officers, directors, employees, stockholders, agents, attorneys, advisors or representatives. The foregoing shall not restrict the ability of any Person to (a) comply with any subpoena or other legal process or respond to a request for information from any governmental authority with jurisdiction over such Person; or (b) enforce such Person’s rights pursuant to this Agreement.

8.Compliance with this Agreement. The CCC Signatories will cause the other Restricted Persons to comply with the terms of this Agreement and will be responsible for any breach of the terms of this Agreement by any Restricted Person (even if such Restricted Person is not a party to this Agreement).

9.Expenses. All fees, costs and expenses incurred in connection with this Agreement will be paid by the Person incurring such fee, cost or expense.

10.Public Disclosure.

(a)Press Release. No later than 7:00 a.m., Mountain time, on June 21, 2022, Company will issue a press release in the form reasonably acceptable to the First Designee and the Company (the “Press Release”). Neither Company nor any member of the CCC Group will (i) make any public statements with respect to the matters covered by this Agreement (or in any other filing with the SEC, any other regulatory or governmental agency, any stock exchange or in any materials that would reasonably be expected to be filed with the SEC) that are inconsistent with, or otherwise contrary to, the statements in the Press Release; or (ii) speak on the record or on background with the press, media or any analysts about the other Party or any of its respective Affiliates, Associates, subsidiaries, successors or assigns, or any of its or their respective current or former officers, directors, employees, stockholders, agents, attorneys, advisors or

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representatives. Prior to the issuance of the Press Release, neither Company nor any member of the CCC Group will issue any press release or public announcement regarding this Agreement or take any action that would require public disclosure of this Agreement.

(b)Form 8-K. Company will promptly prepare and file (but not before the issuance of the Press Release) with the SEC a Current Report on Form 8-K (the “Form 8-K”) reporting the entry into this Agreement. All disclosure in the Form 8-K will be consistent with this Agreement. Company will provide the CCC Signatories and their counsel with a reasonable opportunity to review and comment on the Form 8-K prior to filing, and will consider in good faith any changes proposed by the CCC Signatories or their counsel.

(c)Schedule 13D. The CCC Signatories will promptly prepare and file (but not before the issuance of the Press Release) with the SEC an amendment to their Schedule 13D (such amendment, the “Amended Schedule 13D”) reporting the entry into this Agreement. All disclosure in the Amended Schedule 13D will be consistent with this Agreement. The CCC Signatories will provide Company and its counsel with a reasonable opportunity to review and comment on the Amended Schedule 13D prior to filing, and will consider in good faith any changes proposed by Company or its counsel.

11.Definitions. As used in this Agreement, the following terms have the following meanings:

(a)“Affiliate” has the meaning set forth in Rule 12b-2 promulgated under the Exchange Act and will include Persons who become Affiliates of any Person after the date of this Agreement.

(b)“Associate” has the meaning set forth in Rule 12b-2 promulgated under the Exchange Act and will include Persons who become Associates of any Person after the date of this Agreement, but will exclude any Person not controlled by or under common control with the related Person.

(c)“beneficially own,” “beneficially owned” and “beneficial ownership” has the meaning set forth in Rule 13d-3 and Rule 13d-5(b)(1) promulgated under the Exchange Act.

(d)“Business Day” means any day other than a Saturday, Sunday or a day on which the Federal Reserve Bank of Kansas City is closed.

(e)“Net Long Shares” will be limited to the number of shares of Company’s common stock that are beneficially owned by any Person that constitute such Person’s net long position as defined in Rule 14e-4 promulgated under the Exchange Act (except that for purposes of such definition, the date that the tender offer is first announced will instead refer to the date for determining or documenting such Person’s Net Long Shares and the reference to the highest tender price will refer to the market price on such date) and, to the extent not covered by such definition, reduced by any shares as to which such Person does not have the right to vote or direct the vote as of the date for determining or documenting or as to which such Person has entered into a derivative or other agreement, arrangement or understanding that hedges or transfers, in whole or in part, directly or indirectly, any of the economic consequences of ownership of such shares, it being

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understood that whether shares constitute Net Long Shares will be decided by the Board in its reasonable determination.

(f)“Person” will be interpreted broadly to include, among others, any individual, general or limited partnership, corporation, limited liability or unlimited liability company, joint venture, estate, trust, group, association or other entity of any kind or structure

(g)“Restricted Persons” means the members of the CCC Group and the principals, directors, general partners, officers, employees, agents and representatives of each member of the CCC Group.

(h)“Restricted Period” means the period from the date of this Agreement until the earlier to occur of (i) 11:59 p.m., Mountain time, on the 180th day after the First Designee is no longer serving as a director of Company and (ii) 11:59 p.m., Mountain time, on the 90^th day prior to the 2023 annual meeting of stockholders (it being understood that paragraphs 9, 11, and 12 through 24 will survive the end of the Restricted Period and any termination of this Agreement).

(i)“Voting Securities” means the shares of Company’s capital stock and any other securities of Company entitled to vote in the election of directors, or securities convertible into, or exercisable or exchangeable for, such shares or other securities, whether or not subject to the passage of time or other contingencies.

12.Interpretations. The words “include,” “includes” and “including” will be deemed to be followed by the words “without limitation.” Unless the context requires otherwise, “or” is not exclusive. The definitions contained in this Agreement are applicable to the singular as well as the plural forms of such terms. Any agreement, instrument, law, rule or statute defined or referred to in this Agreement means, unless otherwise indicated, such agreement, instrument, law, rule or statute as from time to time amended, modified or supplemented. The measure of a period of one month or year for purposes of this Agreement will be the day of the following month or year corresponding to the starting date. If no corresponding date exists, then the end date of such period being measured will be the next actual day of the following month or year (for example, one month following February 18 is March 18 and one month following March 31 is May 1).

13.Representations of the CCC Signatories. Each of the CCC Signatories, severally and not jointly, represents that (a) its authorized signatory set forth on the signature page of this Agreement has the power and authority to execute this Agreement and any other documents or agreements to be entered into in connection with this Agreement and to bind such Person; (b) this Agreement has been duly authorized, executed and delivered by it and is a valid and binding obligation of such Person, enforceable against it in accordance with its terms, except as enforcement thereof may be limited by applicable bankruptcy, insolvency, reorganization, moratorium, fraudulent conveyance or similar laws generally affecting the rights of creditors and subject to general equity principles; (c) this Agreement does not and will not violate any law, any order of any court or other agency of government, its organizational documents or any provision of any agreement or other instrument to which it or any of its properties or assets is bound, or conflict with, result in a material breach of or constitute (with due notice or lapse of time or both) a default under any such agreement or other instrument to which any member of the CCC Group is bound, or result in the creation or imposition of, or give rise to, any material lien, charge,

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restriction, claim, encumbrance or adverse penalty of any nature whatsoever; (d) it has not, and no member of the CCC Group has, directly or indirectly, compensated or entered into any agreement, arrangement or understanding to compensate any person for his or her service as a director of Company with any cash, securities (including any rights or options convertible into or exercisable for or exchangeable into securities or any profit sharing agreement or arrangement) or other form of compensation directly or indirectly related to Company or its securities; and (e) as of the date of this Agreement, the CCC Signatories (i) are the beneficial owners of an aggregate of 2,580,452 shares of Company’s common stock, (ii) have voting authority over such shares, and (iii) own no other equity or equity-related interest in Company.

14.Representations of Company. Company represents that (a) its authorized signatory set forth on the signature page to this Agreement has the power and authority to execute this Agreement and any other documents or agreements to be entered into in connection with this Agreement and to bind Company, (b) this Agreement has been duly authorized, executed and delivered by it and is a valid and binding obligation of Company, enforceable against Company in accordance with its terms, except as enforcement thereof may be limited by applicable bankruptcy, insolvency, reorganization, moratorium, fraudulent conveyance or similar laws generally affecting the rights of creditors and subject to general equity principles; (b) this Agreement does not require the approval of the stockholders of Company; and (c) this Agreement does not and will not violate any law, any order of any court or other agency of government, Company’s certificate of incorporation or bylaws, each as amended from time to time, or any provision of any agreement or other instrument to which Company or any of its properties or assets is bound, or conflict with, result in a material breach of or constitute (with due notice or lapse of time or both) a default under any such agreement or other instrument to which Company is bound, or result in the creation or imposition of, or give rise to, any material lien, charge, restriction, claim, encumbrance or adverse penalty of any nature whatsoever. Company has not taken any actions with respect to any matters related to this Agreement that require disclosure on a Current Report on Form 8-K prior to the date of this Agreement that have not previously been disclosed.

15.Specific Performance. Each Party acknowledges and agrees that money damages would not be a sufficient remedy for any breach (or threatened breach) of this Agreement by it and that, in the event of any breach or threatened breach of this Agreement, (a) the Party seeking specific performance will be entitled seek injunctive and other equitable relief, without proof of actual damages; (b) the Party against whom specific performance is sought will not plead in defense that there would be an adequate remedy at law; and (c) the Party against whom specific performance is sought agrees to waive any applicable right or requirement that a bond be posted. Such remedies will not be the exclusive remedies for a breach of this Agreement and will be in addition to all other remedies available at law or in equity.

16.Entire Agreement; Binding Nature; Assignment; Waiver. This Agreement constitutes the only agreement between the Parties with respect to the subject matter of this Agreement and it supersedes all prior agreements, understandings, negotiations and discussions, whether oral or written. This Agreement binds, and will inure to the benefit of, the Parties and their respective successors and permitted assigns. No Party may assign or otherwise transfer either this Agreement or any of its rights, interests, or obligations under this Agreement without the prior written approval of the other Party. Any purported transfer requiring consent without such consent is void. No amendment, modification, supplement or waiver of any provision of this Agreement

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will be effective unless it is in writing and signed by the affected Party, and then only in the specific instance and for the specific purpose stated in such writing. Any waiver by any Party of a breach of any provision of this Agreement will not operate as or be construed to be a waiver of any other breach of such provision or of any breach of any other provision of this Agreement. The failure of a Party to insist upon strict adherence to any term of this Agreement on one or more occasions will not be considered a waiver or deprive that Party of the right to insist upon strict adherence to that term or any other term of this Agreement in the future.

17.Severability. If any provision of this Agreement is held invalid or unenforceable by any court of competent jurisdiction, then the other provisions of this Agreement will remain in full force and effect. Any provision of this Agreement that is held invalid or unenforceable only in part or degree will remain in full force and effect to the extent not held invalid or unenforceable, and this Agreement will otherwise be construed so as to effectuate the original intention of the Parties reflected in this Agreement. The Parties further agree to replace such invalid or unenforceable provision of this Agreement with a valid and enforceable provision that will achieve, to the extent possible, the purposes of such invalid or unenforceable provision.

18.Governing Law; Forum. This Agreement is governed by and will be construed in accordance with the laws of the State of Delaware. Each of the Parties (a) irrevocably and unconditionally consents to the exclusive personal jurisdiction and venue of the Court of Chancery of the State of Delaware and any appellate court thereof (unless the federal courts have exclusive jurisdiction over the matter, in which case the United States District Court for the District of Delaware and any appellate court thereof will have exclusive personal jurisdiction); (b) agrees that it will not challenge such personal jurisdiction by motion or other request for leave from any such court; (c) agrees that it will not bring any action relating to this Agreement or otherwise in any court other than the such courts; and (d) waives any claim of improper venue or any claim that those courts are an inconvenient forum. The Parties agree that mailing of process or other papers in connection with any such action or proceeding in the manner provided in paragraph 22 or in such other manner as may be permitted by applicable law, will be valid and sufficient service thereof.

19.Waiver of Jury Trial. EACH OF THE PARTIES, AFTER CONSULTING OR HAVING HAD THE OPPORTUNITY TO CONSULT WITH COUNSEL, KNOWINGLY, VOLUNTARILY AND INTENTIONALLY WAIVES ANY RIGHT THAT SUCH PARTY MAY HAVE TO A TRIAL BY JURY IN ANY LITIGATION BASED UPON OR ARISING OUT OF THIS AGREEMENT OR ANY COURSE OF CONDUCT, DEALING, STATEMENTS (WHETHER ORAL OR WRITTEN), OR ACTIONS OF ANY OF THEM. No Party will seek to consolidate, by counterclaim or otherwise, any action in which a jury trial has been waived with any other action in which a jury trial cannot be or has not been waived.

20.Third Party Beneficiaries. This Agreement is solely for the benefit of the Parties and is not enforceable by any other Person.

21.Notices. All notices and other communications under this Agreement must be in writing and will be deemed to have been duly delivered and received (a) four Business Days after being sent by registered or certified mail, return receipt requested, postage prepaid; (b) one Business Day after being sent for next Business Day delivery, fees prepaid, via a reputable

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nationwide overnight courier service; (c) immediately upon delivery by hand; or (d) on the date sent by email (except that notice given by email will not be effective unless either (i) a duplicate copy of such email notice is promptly given by one of the other methods described in this paragraph 22 or (ii) the receiving Party delivers a written confirmation of receipt of such notice either by email or any other method described in this paragraph 22 (excluding “out of office” or other automated replies)). The addresses for such communications are as follows. At any time, any Party may, by notice given to the other Parties in accordance with this paragraph 22, provide updated information for notices pursuant to this Agreement.

If to Company:

ARCA biopharma, Inc.

10170 Church Ranch Way, Suite 100

Westminster, Colorado 80021

Attn:Accounting/General Counsel

with a copy (which will not constitute notice) to:

Wilson Sonsini Goodrich & Rosati

Professional Corporation

1881 9th Street

Boulder, Colorado 80302

Attn:Brent D. Fassett

Douglas K. Schnell

If to the CCC Signatories:

Cable Car Capital LLC

2261 Market Street #4307

San Francisco, California 94114

with a copy (which will not constitute notice) to:

Olshan Frome Wolosky LLP

1325 Avenue of the Americas

New York, New York 10019

Attn:Andrew Freedman

22.Representation by Counsel. Each of the Parties acknowledges that it has been represented by counsel of its choice throughout all negotiations that have preceded the execution of this Agreement, and that it has executed this Agreement with the advice of such counsel. Each Party and its counsel cooperated and participated in the drafting and preparation of this Agreement,

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and any and all drafts of this Agreement exchanged among the Parties will be deemed the work product of all of the Parties and may not be construed against any Party by reason of its drafting or preparation. Accordingly, any rule of law or any legal decision that would require interpretation of any ambiguities in this Agreement against any Party that drafted or prepared it is of no application and is expressly waived by each of the Parties, and any controversy over interpretations of this Agreement will be decided without regard to events of drafting or preparation.

23.Counterparts. This Agreement and any amendments to this Agreement may be executed in one or more textually identical counterparts, all of which will be considered one and the same agreement and will become effective when one or more counterparts have been signed by each of the Parties and delivered to the other Parties, it being understood that all Parties need not sign the same counterpart. Any such counterpart, to the extent delivered by fax or .pdf, .tif, .gif, .jpg or similar attachment to electronic mail or by an electronic signature service (any such delivery, an “Electronic Delivery”), will be treated in all manner and respects as an original executed counterpart and will be considered to have the same binding legal effect as if it were the original signed version thereof delivered in person. No Party may raise the use of an Electronic Delivery to deliver a signature, or the fact that any signature or agreement or instrument was transmitted or communicated through the use of an Electronic Delivery, as a defense to the formation of a contract, and each Party forever waives any such defense, except to the extent that such defense relates to lack of authenticity.

24.Headings. The headings set forth in this Agreement are for convenience of reference purposes only and will not affect or be deemed to affect in any way the meaning or interpretation of this Agreement or any term or provision of this Agreement.

[Signature page follows.]

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Exhibit 10.1

ATTORNEY WORK PRODUCT

PRIVILEGED AND CONFIDENTIAL

Very truly yours,

ARCA BIOPHARMA, INC.

ACCEPTED AND AGREED

as of the date written above:

CABLE CAR CAPITAL LLC

THE FUNICULAR FUND, LP

FUNICULAR FUNDS, LP

JACOB MA-WEAVER

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