Transition Agreement and Release between the Registrant and David Hilbert, Ph.D., dated January 7, 2022

Exhibit 10.15

TRANSITION AGREEMENT AND RELEASE

This Transition Agreement and Release (“Agreement”) is made by and between David M. Hilbert, Ph.D. (“Employee”) and Arcellx, Inc. (the “Company”) (collectively referred to as the “Parties” or individually referred to as a “Party”).

RECITALS

WHEREAS, Employee was employed by the Company;

WHEREAS, Employee signed an offer letter with the Company on November 10, 2017, as amended on January 26, 2021 (the “Offer Letter”);

WHEREAS, Employee signed an At-Will Employment, Confidential Information, Invention Assignment, and Arbitration Agreement with the Company on March 29, 2015 (the “Confidentiality Agreement”);

WHEREAS, the Company and Employee have entered into stock option agreements dated June 26, 2017 (as amended on November 10, 2017), December 8, 2017, September 18, 2018, January 31, 2021, and June 9, 2021, in each case granting Employee the option to purchase shares of the Company’s common stock subject to the terms and conditions of the Company’s 2017 Equity Incentive Plan (the “Plan”) and the applicable stock option agreement (collectively the “Stock Agreements,” and such stock options, the “Options”);

WHEREAS, Employee’s employment with the Company ended without Cause (as defined in the Offer Letter) effective January 1, 2022 (the “Separation Date”); and

WHEREAS, the Parties wish to resolve any and all disputes, claims, complaints, grievances, charges, actions, petitions, and demands that the Employee may have against the Company and any of the Releasees as defined below, including, but not limited to, any and all claims arising out of or in any way related to Employee’s employment with or separation from the Company;

NOW, THEREFORE, in consideration of the mutual promises made herein, the Company and Employee hereby agree as follows:

COVENANTS

1. Consideration. In consideration of Employee’s execution of this Agreement and Employee’s fulfillment of all of its terms and conditions, and provided that Employee does not revoke the Agreement under Section 6 below, the Company agrees as follows:

a. Payment. The Company agrees to pay Employee (i) a lump sum equal to six (6) months of Employees’ base salary, less applicable withholdings, and (ii) a lump sum of $75,000, which is equal to your additional bonus award approved by the Board on March 17, 2021, subject to applicable withholdings and deductions. This payment will be made to Employee within ten (10) business days after the Effective Date of this Agreement. In addition, the Company agrees that Employee will remain eligible to receive a bonus award pursuant to Employee’s Offer Letter, which shall have a target amount of $166,400, which is equal to 40% of Employee’s annual base salary for fiscal year 2021, subject to applicable withholdings and deductions (the “Bonus Severance”). The amount of the Bonus Severance, which may be $0, will be determined by the Company’s board of directors in its sole discretion based on achievement of the Company’s corporate performance goals for the Company’s 2021 fiscal year. The Bonus Severance will be paid at the same time as all other executive bonus awards are paid for fiscal year 2021 (if any); provided, however that Employee must be continuing to provide consulting services pursuant to the Consulting Agreement (as defined below) at the time of payment in order to receive the Bonus Severance.

b. Consulting Agreement. The Company agrees to retain Employee to perform transition services for the Company as a consultant, in which role Employee shall provide ad hoc consulting services to the Company as an independent contractor, between January 2, 2022 and June 30, 2022, pursuant to the terms of the consulting agreement attached hereto as Exhibit A (the “Consulting Agreement”) (such period during which the Consulting Agreement is in effect

and hasn’t been terminated, the “Consulting Period”). The Consulting Period may be extended until December 31, 2022 by a mutual written agreement signed by the Parties. Nothing in this Agreement or the Consulting Agreement pertaining to Employee’s anticipated role as a consultant shall in any way be construed to constitute Employee as a continuing agent, officer, executive, or representative of the Company after the Separation Date, but Employee shall perform the services under the Consulting Agreement solely as an independent contractor.

c. COBRA. The Company will provide the Employee a taxable payment in an amount equal to the monthly Consolidated Omnibus Budget Reconciliation Act of 1985, as amended (“COBRA”) premium that the Employee would be required to pay to continue the Employee’s group health coverage in effect on the date of termination of employment (which amount will be based on the premium for the first month of COBRA coverage), which payments will be made regardless of whether the Employee elects COBRA continuation coverage and will commence in the month following the month of the Separation Date and continue for the period of twelve (12) months.

d. Supplemental Release Consideration/Extension of Option Post-Service Exercisability Period. If Employee remains employed with the Company through January 1, 2022, during such period the Company shall not involuntarily terminate Employee’s employment without Cause (as defined in the Offer Letter), continues to provide consulting services through the Consulting Period, and executes the Supplemental Release Agreement as set forth in Section 1.e., the post-service exercisability period of each of the Options pursuant to the Stock Agreements shall be extended such that each Option, to the extent vested, outstanding and exercisable as of the end of the Consulting Period, will be exercisable until the earlier of (i) twelve (12) months from the date of the end of the Consulting Period or (ii) the applicable Option’s expiration date, as set forth in the applicable Stock Agreement, unless otherwise earlier terminated in accordance with the Plan (the “Supplemental Release Consideration”). Employee acknowledges and agrees that this Agreement is a “modification” of each Option under the Internal Revenue Code of 1986, as amended (the “Code”) and, to the extent any Option or portion thereof is treated as an incentive stock option, entering into this Agreement with respect to such Options will result in converting the incentive stock options into nonstatutory stock options as of the Effective Date. Employee acknowledges and agrees that Employee remains solely responsible for all tax obligations associated with any exercise of the Options. Except as amended hereby, each Option will remain subject to the terms and conditions of the applicable Stock Agreement.

e. Supplemental Release Agreement. In exchange for the Supplemental Release Consideration, Employee agrees to execute, within seven (7) days of the termination of the Consulting Period, the Supplemental Release attached hereto as Exhibit B, which agreement will serve to cover the time period from the Effective Date of this Agreement through the Supplemental Release Effective Date; provided, however, the Parties agree to modify the Supplemental Release to comply with any new laws that become applicable prior to the termination of the Consulting Period. Employee understands and agrees that Employee will only be entitled to the consideration set forth in Section 1.d. if Employee executes the Supplemental Release within the time allotted in this Section 1.e. and does not revoke that agreement. If Employee fails to sign this Agreement or revokes his signature, the Company will not extend the exercise period of the Options.

f. General. Employee acknowledges that without this Agreement, Employee is otherwise not entitled to the consideration listed in this Section 1.

2. Stock. Company and Employee agree that Employee will continue to serve as a Service Provider (as defined in the Plan) during the term of the Consulting Agreement, and shall continue to vest during such period subject to the terms and conditions of the applicable Stock Agreements and the Plan. The Parties agree that for purposes of determining the number of shares of the Company’s common stock that have vested under the Options, Employee will be considered to have vested only up to the date Employee ceases to be a Service Provider pursuant to the Consulting Agreement. Except as provided in Section 1() above, each Option and the shares subject thereto shall continue to be governed by the terms and conditions of the applicable Stock Agreements.

3. Benefits. Employee’s health insurance benefits shall cease on January 31, 2022, subject to Employee’s right to continue Employee’s health insurance under COBRA. Employee’s participation in all benefits and incidents of employment, including, but not limited to, the accrual of bonuses, vacation, and paid time off, ceased as of the Separation Date.

4. Payment of Salary and Receipt of All Benefits. Employee acknowledges and represents that, other than the consideration set forth in this Agreement, the Company and its agents have paid or provided all salary, wages, bonuses, accrued vacation/paid time off, notice periods, premiums, leaves, housing allowances, relocation costs, interest, severance, outplacement costs, fees, reimbursable expenses, commissions, stock, stock options, vesting, and any and all other benefits and compensation due to Employee.

5. Release of Claims. Employee agrees that the foregoing consideration represents settlement in full of all outstanding obligations owed to Employee by the Company and its current and former: officers, directors, employees, agents, investors, attorneys, shareholders, administrators, affiliates, benefit plans, plan administrators, professional employer organization or co-employer, insurers, trustees, divisions, and subsidiaries, and predecessor and successor corporations and assigns (collectively, the “Releasees”). Employee, on Employee’s own behalf and on behalf of Employee’s respective heirs, family members, executors, agents, and assigns, hereby and forever releases the Releasees from, and agrees not to sue concerning, or in any manner to institute, prosecute, or pursue, any claim, complaint, charge, duty, obligation, demand, or cause of action relating to any matters of any kind, whether presently known or unknown, suspected or unsuspected, that Employee may possess against any of the Releasees arising from any omissions, acts, facts, or damages that have occurred up until and including the signature date of this Agreement, including, without limitation:

a. any and all claims relating to or arising from Employee’s employment relationship with the Company and the termination of that relationship;

b. any and all claims relating to, or arising from, Employee’s right to purchase, or actual purchase of shares of stock of the Company, including, without limitation, any claims for fraud, misrepresentation, breach of fiduciary duty, breach of duty under applicable state corporate law, and securities fraud under any state or federal law;

c. any and all claims for wrongful discharge of employment; termination in violation of public policy; discrimination; harassment; retaliation; breach of contract, both express and implied; breach of covenant of good faith and fair dealing, both express and implied; promissory estoppel; negligent or intentional infliction of emotional distress; fraud; negligent or intentional misrepresentation; negligent or intentional interference with contract or prospective economic advantage; unfair business practices; defamation; libel; slander; negligence; personal injury; assault; battery; invasion of privacy; false imprisonment; conversion; and disability benefits;

d. any and all claims for violation of any federal, state, or municipal statute, including, but not limited to, Title VII of the Civil Rights Act of 1964; the Civil Rights Act of 1991; the Rehabilitation Act of 1973; the Americans with Disabilities Act of 1990; the Equal Pay Act; the Fair Labor Standards Act; the Fair Credit Reporting Act; the Age Discrimination in Employment Act of 1967; the Older Workers Benefit Protection Act; the Employee Retirement Income Security Act of 1974; the Worker Adjustment and Retraining Notification Act; the Family and Medical Leave Act; the Uniformed Services Employment and Reemployment Rights Act; the Maryland Fair Employment Practices Act; the Maryland Human Relations Law; the Maryland Equal Pay For Equal Work Law; the Maryland False Claims Act; and the Maryland Parental Leave Act;

e. any and all claims for violation of the federal or any state constitution;

f. any and all claims arising out of any other laws and regulations relating to employment or employment discrimination;

g. any claim for any loss, cost, damage, or expense arising out of any dispute over the nonwithholding or other tax treatment of any of the proceeds received by Employee as a result of this Agreement; and

h. any and all claims for attorneys’ fees and costs.

Employee agrees that the release set forth in this section shall be and remain in effect in all respects as a complete general release as to the matters released. This release does not extend to any obligations incurred under this Agreement. This release does not release claims that cannot be released as a matter of law, including any Protected Activity (as defined below). This release does not extend to any right Employee may have to unemployment compensation benefits or workers’ compensation benefits. Employee represents that Employee has made no assignment or transfer of any right, claim, complaint, charge, duty, obligation, demand, cause of action, or other matter waived or released by this Section.

6. Acknowledgment of Waiver of Claims under ADEA. Employee acknowledges that Employee is waiving and releasing any rights Employee may have under the Age Discrimination in Employment Act of 1967 (“ADEA”), and that this waiver and release is knowing and voluntary. Employee agrees that this waiver and release does not apply to any rights or claims that may arise under the ADEA after the Effective Date of this Agreement. Employee acknowledges that the consideration given for this waiver and release is in addition to anything of value to which Employee was already entitled. Employee further acknowledges that Employee has been advised by this writing that: (a) Employee should consult with an attorney prior to executing this Agreement; (b) Employee has twenty-one (21) days within which to consider this Agreement; (c) Employee has seven (7) days following Employee’s execution of this Agreement to revoke this Agreement; (d) this Agreement shall not be effective until after the revocation period has expired; and (e) nothing in this Agreement prevents or precludes Employee from challenging or seeking a determination in good faith of the validity of this waiver under the ADEA, nor does it impose any condition precedent, penalties, or costs for doing so, unless specifically authorized by federal law. In the event Employee signs this Agreement and returns it to the Company in less than the 21-day period identified above, Employee hereby acknowledges that Employee has freely and voluntarily chosen to waive the time period allotted for considering this Agreement. Employee acknowledges and understands that revocation must be accomplished by a written notification to the undersigned Company representative that is received prior to the Effective Date. The Parties agree that changes, whether material or immaterial, do not restart the running of the 21-day period.

7. Unknown Claims. Employee acknowledges that Employee has been advised to consult with legal counsel and that Employee is familiar with the principle that a general release does not extend to claims that the releaser does not know or suspect to exist in Employee’s favor at the time of executing the release, which, if known by Employee, must have materially affected Employee’s settlement with the releasee. Employee, being aware of said principle, agrees to expressly waive any rights Employee may have to that effect, as well as under any other statute or common law principles of similar effect.

8. No Pending or Future Lawsuits. Employee represents that Employee has no lawsuits, claims, or actions pending in Employee’s name, or on behalf of any other person or entity, against the Company or any of the other Releasees. Employee also represents that Employee does not intend to bring any claims on Employee’s own behalf or on behalf of any other person or entity against the Company or any of the other Releasees.

9. Confidentiality. Employee agrees to maintain in complete confidence the existence of this Agreement, the contents and terms of this Agreement, and the consideration for this Agreement (hereinafter collectively referred to as “Separation Information”). Except as required by law, Employee may disclose Separation Information only to Employee’s immediate family members, the Court in any proceedings to enforce the terms of this Agreement, Employee’s counsel, and Employee’s accountant and any professional tax advisor to the extent that they need to know the Separation Information in order to provide advice on tax treatment or to prepare tax returns, and must prevent disclosure of any Separation Information to all other third parties. Employee agrees that Employee will not publicize, directly or indirectly, any Separation Information.

10. Trade Secrets and Confidential Information/Company Property. Employee reaffirms and agrees to observe and abide by the terms of the Confidentiality Agreement, specifically including the provisions therein regarding nondisclosure of the Company’s trade secrets and confidential and proprietary information, non-competition, and nonsolicitation of Company employees. Employee agrees that the above reaffirmation and agreement with the Confidentiality Agreement shall constitute a new and separately enforceable agreement to abide by the terms of the Confidentiality Agreement, entered and effective as of the Effective Date. Employee specifically acknowledges and agrees that any violation of the restrictive covenants in the Confidentiality Agreement shall constitute a material breach of this Agreement. Employee’s signature below constitutes Employee’s certification that Employee agrees to return all documents and other items provided to Employee by the Company, developed or obtained by Employee in connection with Employee’s service relationship with the Company, or otherwise belonging to the Company, including, but not limited to, all passwords to any software or other programs or data that Employee used in performing services for the Company, no later than Employee’s last day of service with the Company.

11. No Cooperation. Employee agrees that Employee will not knowingly encourage, counsel, or assist any attorneys or their clients in the presentation or prosecution of any disputes, differences, grievances, claims, charges, or complaints by any third party against any of the Releasees, unless under a subpoena or other court order to do so or as related directly to the ADEA waiver in this Agreement. Employee agrees both to immediately notify the Company upon receipt of any such subpoena or court order, and to furnish, within three (3) business days of its receipt, a copy of such subpoena or other court order. If approached by anyone for counsel or assistance in the presentation or prosecution of any disputes, differences, grievances, claims, charges, or complaints against any of the Releasees, Employee shall state no more than that Employee cannot provide counsel or assistance.

12. Nondisparagement. Employee agrees to refrain from any disparagement, defamation, libel, or slander of any of the Releasees, and agrees to refrain from any tortious interference with the contracts and relationships of any of the Releasees. Employee shall direct any inquiries by potential future employers to the Company’s human resources department.

13. Breach. In addition to the rights provided in the “Attorneys’ Fees” section below, Employee acknowledges and agrees that any material breach of this Agreement, unless such breach constitutes a legal action by Employee challenging or seeking a determination in good faith of the validity of the waiver herein under the ADEA, or of any provision of the Confidentiality Agreement shall entitle the Company immediately to recover and/or cease providing the consideration provided to Employee under this Agreement and to obtain damages, except as provided by law, provided, however, that the Company shall not recover One Hundred Dollars ($100.00) of the consideration already paid pursuant to this Agreement and such amount shall serve as full and complete consideration for the promises and obligations assumed by Employee under this Agreement and the Confidentiality Agreement.

14. No Admission of Liability. Employee understands and acknowledges that this Agreement constitutes a compromise and settlement of any and all actual or potential disputed claims by Employee. No action taken by the Company hereto, either previously or in connection with this Agreement, shall be deemed or construed to be (a) an admission of the truth or falsity of any actual or potential claims or (b) an acknowledgment or admission by the Company of any fault or liability whatsoever to Employee or to any third party.

15. Costs. The Parties shall each bear their own costs, attorneys’ fees, and other fees incurred in connection with the preparation of this Agreement.

16. ARBITRATION. THE PARTIES AGREE THAT ANY AND ALL DISPUTES ARISING OUT OF THE TERMS OF THIS AGREEMENT, THEIR INTERPRETATION, AND ANY OF THE MATTERS HEREIN RELEASED, SHALL BE SUBJECT TO ARBITRATION IN MONTGOMERY COUNTY, MARYLAND BEFORE THE JUDICIAL ARBITRATION AND MEDIATION SERVICE (“JAMS”) UNDER ITS COMPREHENSIVE ARBITRATION RULES (“JAMS RULES”) AND MARYLAND LAW. THE ARBITRATOR MAY GRANT INJUNCTIONS AND OTHER RELIEF IN SUCH DISPUTES. THE ARBITRATOR SHALL ADMINISTER AND CONDUCT ANY ARBITRATION IN ACCORDANCE WITH MARYLAND LAW, AND THE ARBITRATOR SHALL APPLY SUBSTANTIVE AND PROCEDURAL MARYLAND LAW TO ANY DISPUTE OR CLAIM, WITHOUT REFERENCE TO ANY CONFLICT-OF-LAW PROVISIONS OF ANY JURISDICTION. TO THE EXTENT THAT THE JAMS RULES CONFLICT WITH MARYLAND LAW, MARYLAND LAW SHALL TAKE PRECEDENCE. THE DECISION OF THE ARBITRATOR SHALL BE FINAL, CONCLUSIVE, AND BINDING ON THE PARTIES TO THE ARBITRATION. THE PARTIES AGREE THAT THE PREVAILING PARTY IN ANY ARBITRATION SHALL BE ENTITLED TO INJUNCTIVE RELIEF IN ANY COURT OF COMPETENT JURISDICTION TO ENFORCE THE ARBITRATION AWARD. THE PARTIES TO THE ARBITRATION SHALL EACH PAY HALF THE COSTS AND EXPENSES OF SUCH ARBITRATION, AND EACH PARTY SHALL SEPARATELY PAY FOR ITS RESPECTIVE COUNSEL FEES AND EXPENSES; PROVIDED, HOWEVER, THAT THE ARBITRATOR SHALL AWARD ATTORNEYS’ FEES AND COSTS TO THE PREVAILING PARTY, EXCEPT AS PROHIBITED BY LAW. THE PARTIES AGREE THAT PUNITIVE DAMAGES SHALL BE UNAVAILABLE IN ARBITRATION. THE PARTIES HEREBY AGREE TO WAIVE THEIR RIGHT TO HAVE ANY DISPUTE BETWEEN THEM RESOLVED IN A COURT OF LAW BY A JUDGE OR JURY. NOTWITHSTANDING THE FOREGOING, THIS SECTION WILL NOT PREVENT EITHER PARTY FROM SEEKING INJUNCTIVE RELIEF (OR ANY OTHER PROVISIONAL REMEDY) FROM ANY COURT HAVING JURISDICTION OVER THE PARTIES AND THE SUBJECT MATTER OF THEIR DISPUTE RELATING TO THIS AGREEMENT AND THE AGREEMENTS INCORPORATED HEREIN BY REFERENCE. SHOULD ANY PART OF THE ARBITRATION AGREEMENT CONTAINED IN THIS PARAGRAPH CONFLICT WITH ANY OTHER ARBITRATION AGREEMENT BETWEEN THE PARTIES, THE PARTIES AGREE THAT THIS ARBITRATION AGREEMENT SHALL GOVERN.

17. Tax Consequences. The Company makes no representations or warranties with respect to the tax consequences of the payments and any other consideration provided to Employee or made on Employee’s behalf under the terms of this Agreement. Employee agrees and understands that Employee is responsible for payment, if any, of local, state,

and/or federal taxes on the payments and any other consideration provided hereunder by the Company and any penalties or assessments thereon. Employee further agrees to indemnify and hold the Company harmless from any claims, demands, deficiencies, penalties, interest, assessments, executions, judgments, or recoveries by any government agency against the Company for any amounts claimed due on account of (a) Employee’s failure to pay, or Employee’s delayed payment of, federal or state taxes, or (b) damages sustained by the Company by reason of any such claims, including attorneys’ fees and costs.

18. Section 409A. It is intended that this Agreement comply with, or be exempt from, Code Section 409A and the final regulations and official guidance thereunder (“Section 409A”) and any ambiguities herein will be interpreted to so comply and/or be exempt from Section 409A. Each payment and benefit to be paid or provided under this Agreement is intended to constitute a series of separate payments for purposes of Section 1.409A-2(b)(2) of the Treasury Regulations. The Company and Employee will work together in good faith to consider either (i) amendments to this Agreement; or (ii) revisions to this Agreement with respect to the payment of any awards, which are necessary or appropriate to avoid imposition of any additional tax or income recognition prior to the actual payment to Employee under Section 409A. In no event will the Releasees reimburse Employee for any taxes that may be imposed on Employee as a result of Section 409A.

19. Authority. The Company represents and warrants that the undersigned has the authority to act on behalf of the Company and to bind the Company and all who may claim through it to the terms and conditions of this Agreement. Employee represents and warrants that Employee has the capacity to act on Employee’s own behalf and on behalf of all who might claim through Employee to bind them to the terms and conditions of this Agreement. Each Party warrants and represents that there are no liens or claims of lien or assignments in law or equity or otherwise of or against any of the claims or causes of action released herein.

20. Protected Activity. Employee understands that nothing in this Agreement shall in any way limit or prohibit Employee from engaging for a lawful purpose in any Protected Activity. For purposes of this Agreement, “Protected Activity” shall mean filing a charge, complaint, or report with, or otherwise communicating with, cooperating with or participating in any investigation or proceeding that may be conducted by, any federal, state or local government agency or commission, including the Securities and Exchange Commission, the Equal Employment Opportunity Commission, the Occupational Safety and Health Administration, and the National Labor Relations Board (“Government Agencies”). Employee understands that in connection with such Protected Activity, Employee is permitted to disclose documents or other information as permitted by law, and without giving notice to, or receiving authorization from, the Company. Notwithstanding the foregoing, Employee agrees to take all reasonable precautions to prevent any unauthorized use or disclosure of any information that may constitute Company confidential information under the Confidentiality Agreement to any parties other than the relevant Government Agencies. Employee further understands that “Protected Activity” does not include the disclosure of any Company attorney-client privileged communications, and that any such disclosure without the Company’s written consent shall constitute a material breach of this Agreement. In addition, pursuant to the Defend Trade Secrets Act of 2016, Employee is notified that an individual will not be held criminally or civilly liable under any federal or state trade secret law for the disclosure of a trade secret that (i) is made in confidence to a federal, state, or local government official (directly or indirectly) or to an attorney solely for the purpose of reporting or investigating a suspected violation of law, or (ii) is made in a complaint or other document filed in a lawsuit or other proceeding, if (and only if) such filing is made under seal. In addition, an individual who files a lawsuit for retaliation by an employer for reporting a suspected violation of law may disclose the trade secret to the individual’s attorney and use the trade secret information in the court proceeding, if the individual files any document containing the trade secret under seal and does not disclose the trade secret, except pursuant to court order.

21. No Representations. Employee represents that Employee has had an opportunity to consult with an attorney, and has carefully read and understands the scope and effect of the provisions of this Agreement. Employee has not relied upon any representations or statements made by the Company that are not specifically set forth in this Agreement.

22. Severability. In the event that any provision or any portion of any provision hereof or any surviving agreement made a part hereof becomes or is declared by a court of competent jurisdiction or arbitrator to be illegal, unenforceable, or void, this Agreement shall continue in full force and effect without said provision or portion of provision.

23. Attorneys’ Fees. Except with regard to a legal action challenging or seeking a determination in good faith of the validity of the waiver herein under the ADEA, in the event that either Party brings an action to enforce or effect its rights under this Agreement, the prevailing Party shall be entitled to recover its costs and expenses, including the costs of mediation, arbitration, litigation, court fees, and reasonable attorneys’ fees incurred in connection with such an action.

24. Entire Agreement. This Agreement represents the entire agreement and understanding between the Company and Employee concerning the subject matter of this Agreement and Employee’s employment with and separation from the Company and the events leading thereto and associated therewith, and supersedes and replaces any and all prior agreements and understandings concerning the subject matter of this Agreement and Employee’s relationship with the Company, including the Offer Letter, with the exception of the Confidentiality Agreement and the Stock Agreements.

25. No Oral Modification. This Agreement may only be amended in a writing signed by Employee and the Company’s Chief Executive Officer.

26. Governing Law. This Agreement shall be governed by the laws of the State of Maryland, without regard for choice-of-law provisions. Employee consents to personal and exclusive jurisdiction and venue in the State of Maryland.

27. Effective Date. Employee understands that this Agreement shall be null and void if not executed by Employee, and returned to the Company, within the twenty-one (21) days following the Separation Date. In no event shall Employee sign this Agreement earlier than the Separation Date. Each Party has seven (7) days after that Party signs this Agreement to revoke it. This Agreement will become effective on the eighth (8th) day after Employee signed this Agreement, so long as it has been signed by the Parties and has not been revoked by either Party before that date (the “Effective Date”).

28. Counterparts. This Agreement may be executed in counterparts and each counterpart shall be deemed an original and all of which counterparts taken together shall have the same force and effect as an original and shall constitute an effective, binding agreement on the part of each of the undersigned. The counterparts of this Agreement may be executed and delivered by facsimile, photo, email PDF, Docusign/Echosign or a similarly accredited secure signature service, or other electronic transmission or signature. This Agreement may be executed in one or more counterparts, and counterparts may be exchanged by electronic transmission (including by email), each of which will be deemed an original, but all of which together constitute one and the same instrument.

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29. Voluntary Execution of Agreement. Employee understands and agrees that Employee executed this Agreement voluntarily, without any duress or undue influence on the part or behalf of the Company or any third party, with the full intent of releasing all of Employee’s claims against the Company and any of the other Releasees. Employee acknowledges that:

IN WITNESS WHEREOF, the Parties have executed this Agreement on the respective dates set forth below.

EXHIBIT A

ARCELLX, INC. CONSULTING AGREEMENT

This Consulting Agreement (this “Agreement”) is by and between Arcellx, Inc. (the “Company”), and David M. Hilbert, Ph.D. (“Consultant”) (each herein referred to individually as a “Party,” or collectively as the “Parties”) and effective as of January 2, 2022 (the “Effective Date”).

The Company desires to retain Consultant as an independent contractor to perform consulting services for the Company, and Consultant is willing to perform such services, on the terms described below. In consideration of the mutual promises contained herein, the Parties agree as follows:

1. Services and Compensation

Consultant shall perform the services described in Exhibit A-1 (the “Services”) for the Company (or its designee), and the Company agrees to pay Consultant the compensation described in Exhibit A-1 for Consultant’s performance of the Services.

2. Confidentiality

A. Definition of Confidential Information. “Confidential Information” means any information (including any and all combinations of individual items of information) that relates to the actual or anticipated business and/or products, research or development of the Company, its affiliates or subsidiaries, or to the Company’s, its affiliates’ or subsidiaries’ technical data, trade secrets, or know-how, including, but not limited to, research, product plans, or other information regarding the Company’s, its affiliates’ or subsidiaries’ products or services and markets therefor, customer lists and customers (including, but not limited to, customers of the Company on whom Consultant called or with whom Consultant became acquainted during the term of this Agreement), software, developments, inventions, discoveries, ideas, processes, formulas, technology, designs, drawings, engineering, hardware configuration information, marketing, finances, and other business information disclosed by the Company, its affiliates or subsidiaries, either directly or indirectly, in writing, orally or by drawings or inspection of premises, parts, equipment, or other property of the Company, its affiliates or subsidiaries. Notwithstanding the foregoing, Confidential Information shall not include any such information which Consultant can establish (i) was publicly known or made generally available prior to the time of disclosure to Consultant; (ii) becomes publicly known or made generally available after disclosure to Consultant through no wrongful action or inaction of Consultant; or (iii) is in the rightful possession of Consultant, without confidentiality obligations, at the time of disclosure as shown by Consultant’s then-contemporaneous written records; provided that any combination of individual items of information shall not be deemed to be within any of the foregoing exceptions merely because one or more of the individual items are within such exception, unless the combination as a whole is within such exception.

B. Nonuse and Nondisclosure. During and after the term of this Agreement, Consultant will hold in the strictest confidence, and take all reasonable precautions to prevent any unauthorized use or disclosure of Confidential Information, and Consultant will not (i) use the Confidential Information for any purpose whatsoever other than as necessary for the performance of the Services on behalf of the Company, or (ii) subject to Consultant’s right to engage in Protected Activity (as defined below) disclose the Confidential Information to any third party without the prior written consent of an authorized representative of the Company, except that Consultant may disclose Confidential Information to the extent compelled by applicable law; provided however, prior to such disclosure, Consultant shall provide prior written notice to the Company and seek a protective order or such similar confidential protection as may be available under applicable law. Consultant agrees that no ownership of Confidential Information is conveyed to the Consultant. Without limiting the foregoing, Consultant shall not use or disclose any Company property, intellectual property rights, trade secrets or other proprietary know-how of the Company to invent, author, make, develop, design, or otherwise enable others to invent, author, make, develop, or design identical or substantially similar designs as those developed under this Agreement for any third party. Consultant agrees that Consultant’s obligations under this Section 2.B shall continue after the termination of this Agreement.

C. Other Client Confidential Information. Consultant agrees that Consultant will not improperly use, disclose, or induce the Company to use any proprietary information or trade secrets of any former or current employer of Consultant or other person or entity with which Consultant has an obligation to keep in confidence. Consultant also agrees that Consultant will not bring onto the Company’s premises or transfer onto the Company’s technology systems any unpublished document, proprietary information, or trade secrets belonging to any third party unless disclosure to, and use by, the Company has been consented to in writing by such third party.

D. Third Party Confidential Information. Consultant recognizes that the Company has received and in the future will receive from third parties their confidential or proprietary information subject to a duty on the Company’s part to maintain the confidentiality of such information and to use it only for certain limited purposes. Consultant agrees that at all times during the term of this Agreement and thereafter, Consultant owes the Company and such third parties a duty to hold all such confidential or proprietary information in the strictest confidence and not to use it or to disclose it to any person, firm, corporation, or other third party except as necessary in carrying out the Services for the Company consistent with the Company’s agreement with such third party.

3. Ownership

A. Assignment of Inventions. Consultant agrees that all right, title, and interest in and to any copyrightable material, notes, records, drawings, designs, inventions, improvements, developments, discoveries, ideas, and trade secrets conceived, discovered, authored, invented, developed or reduced to practice by Consultant, solely or in collaboration with others, during the term of this Agreement and arising out of, or in connection with, performing the Services under this Agreement and any copyrights, patents, trade secrets, mask work rights or other intellectual property rights relating to the foregoing (collectively, “Inventions”), are the sole property of the Company. Consultant also agrees to promptly make full written disclosure to the Company of any Inventions and to deliver and assign (or cause to be assigned) and hereby irrevocably assigns fully to the Company all right, title and interest in and to the Inventions.

B. Pre-Existing Materials. Subject to Section 3.A, Consultant will provide the Company with prior written notice if, in the course of performing the Services, Consultant incorporates into any Invention or utilizes in the performance of the Services any invention, discovery, idea, original works of authorship, development, improvements, trade secret, concept, or other proprietary information or intellectual property right owned by Consultant or in which Consultant has an interest, prior to, or separate from, performing the Services under this Agreement (“Prior Inventions”), and the Company is hereby granted a nonexclusive, royalty-free, perpetual, irrevocable, transferable, worldwide license (with the right to grant and authorize sublicenses) to make, have made, use, import, offer for sale, sell, reproduce, distribute, modify, adapt, prepare derivative works of, display, perform, and otherwise exploit such Prior Inventions, without restriction, including, without limitation, as part of or in connection with such Invention, and to practice any method related thereto. Consultant will not incorporate any invention, discovery, idea, original works of authorship, development, improvements, trade secret, concept, or other proprietary information or intellectual property right owned by any third party into any Invention without the Company’s prior written permission, including without limitation any free software or open source software.

C. Moral Rights. Any assignment to the Company of Inventions includes all rights of attribution, paternity, integrity, modification, disclosure and withdrawal, and any other rights throughout the world that may be known as or referred to as “moral rights,” “artist’s rights,” “droit moral,” or the like (collectively, “Moral Rights”). To the extent that Moral Rights cannot be assigned under applicable law, Consultant hereby waives and agrees not to enforce any and all Moral Rights, including, without limitation, any limitation on subsequent modification, to the extent permitted under applicable law.

D. Maintenance of Records. Consultant agrees to keep and maintain adequate, current, accurate, and authentic written records of all Inventions made by Consultant (solely or jointly with others) during the term of this Agreement, and for a period of three (3) years thereafter. The records will be in the form of notes, sketches, drawings, electronic files, reports, or any other format that is customary in the industry and/or otherwise specified by the Company. Such records are and remain the sole property of the Company at all times and upon the Company’s request, Consultant shall deliver (or cause to be delivered) the same.

E. Further Assurances. Consultant agrees to assist the Company, or its designee, at the Company’s expense, in every proper way to secure the Company’s rights in Inventions in any and all countries, including the disclosure to the Company of all pertinent information and data with respect thereto, the execution of all applications, specifications, oaths, assignments and all other instruments that the Company may deem necessary in order to apply for, register, obtain, maintain, defend, and enforce such rights, and in order to deliver, assign and convey to the Company, its successors, assigns and nominees the sole and exclusive right, title, and interest in and to all Inventions and testifying in a suit or other proceeding relating to such Inventions. Consultant further agrees that Consultant’s obligations under this Section 3.E shall continue after the termination of this Agreement.

F. Attorney-in-Fact. Consultant agrees that, if the Company is unable because of Consultant’s unavailability, dissolution, mental or physical incapacity, or for any other reason, to secure Consultant’s signature with respect to any Inventions, including, without limitation, for the purpose of applying for or pursuing any application for any United States or foreign patents or mask work or copyright registrations covering the Inventions assigned to the Company in Section 3.A, then Consultant hereby irrevocably designates and appoints the Company and its duly authorized officers and agents as Consultant’s agent and attorney-in-fact, to act for and on Consultant’s behalf to execute and file any papers and oaths and to do all other lawfully permitted acts with respect to such Inventions to further the prosecution and issuance of patents, copyright and mask work registrations with the same legal force and effect as if executed by Consultant. This power of attorney shall be deemed coupled with an interest, and shall be irrevocable.

4. Conflicting Obligations

A. Consultant represents and warrants that Consultant has no agreements, relationships, or commitments to any other person or entity that conflict with the provisions of this Agreement, Consultant’s obligations to the Company under this Agreement, and/or Consultant’s ability to perform the Services. Consultant will not enter into any such conflicting agreement during the term of this Agreement. Consultant acknowledges and agrees that regardless of this Agreement, Consultant is required to and will observe and abide by the continuing obligations set forth in the At-Will Employment, Confidential Information, Invention Assignment, and Arbitration Agreement entered into with the Company on March 29, 2015 (the “Confidentiality Agreement”).

B. Consultant shall require all Consultant’s employees, contractors, or other third-parties performing Services under this Agreement to execute a nondisclosure and intellectual property assignment agreement in the form provided by the Company, and promptly provide a copy of each such executed agreement to the Company. Consultant’s violation of this Section 4 will be considered a material breach under Section 6.B.

5. Return of Company Materials

Upon the termination of this Agreement, or upon the Company’s earlier request, Consultant will immediately deliver to the Company, and will not keep in Consultant’s possession, recreate, or deliver to anyone else, any and all Company property, including, but not limited to, Confidential Information, tangible embodiments of the Inventions, all devices and equipment belonging to the Company, all electronically-stored information and passwords to access such property, those records maintained pursuant to Section 3.D and any reproductions of any of the foregoing items that Consultant may have in Consultant’s possession or control.

6. Term and Termination

A. Term. The term of this Agreement will begin on the Effective Date of this Agreement and will continue until the earlier of (i) June 30, 2022 (unless the Consulting Period has been extended to December 31, 2022 by a mutual written agreement signed by the Parties, in which case such date shall be December 31, 2022), or (ii) termination as provided in Section 6.B.

B. Termination. The Company may terminate this Agreement immediately for any reason or no reason upon giving Consultant written notice of such termination pursuant to Section 11.G of this Agreement..

C. Survival. Upon any termination, all rights and duties of the Company and Consultant toward each other shall cease except:

(1) The Company will pay, within thirty (30) days after the effective date of termination, all amounts owing to Consultant for Services completed and accepted by the Company prior to the termination date and related reimbursable expenses, if any, submitted in accordance with the Company’s policies; and

(2) Section 2 (Confidentiality), Section 3 (Ownership), Section 4.B (Conflicting Obligations), Section 5 (Return of Company Materials), Section 6 (Term and Termination), Section 7 (Independent Contractor; Benefits), Section 8 (Indemnification), Section 9 (Limitation of Liability), Section 10 (Arbitration and Equitable Relief), and Section 11 (Miscellaneous) will survive termination or expiration of this Agreement in accordance with their terms.

7. Independent Contractor; Benefits

A. Independent Contractor. It is the express intention of the Company and Consultant that Consultant perform the Services as an independent contractor to the Company. Nothing in this Agreement shall in any way be construed to constitute Consultant as an agent, employee or representative of the Company. Without limiting the generality of the foregoing, Consultant is not authorized to bind the Company to any liability or obligation or to represent that Consultant has any such authority. Consultant agrees to furnish (or reimburse the Company for) all tools and materials necessary to accomplish this Agreement and shall incur all expenses associated with performance. Consultant acknowledges and agrees that Consultant is obligated to report as income all compensation received by Consultant pursuant to this Agreement. Consultant agrees to and acknowledges the obligation to pay all self-employment and other taxes on such income.

B. Benefits. The Company and Consultant agree that Consultant will receive no Company-sponsored benefits from the Company where benefits include, but are not limited to, paid vacation, sick leave, medical insurance and 401k participation. If Consultant is reclassified by a state or federal agency or court as the Company’s employee, Consultant will become a reclassified employee and will receive no benefits from the Company, except those mandated by state or federal law, even if by the terms of the Company’s benefit plans or programs of the Company in effect at the time of such reclassification, Consultant would otherwise be eligible for such benefits.

8. Indemnification

Consultant agrees to indemnify and hold harmless the Company and its affiliates and their directors, officers and employees from and against all taxes, losses, damages, liabilities, costs and expenses, including attorneys’ fees and other legal expenses, arising directly or indirectly from or in connection with (i) any negligent, reckless or intentionally wrongful act of Consultant or Consultant’s assistants, employees, contractors or agents, (ii) a determination by a court or agency that the Consultant is not an independent contractor, (iii) any breach by the Consultant or Consultant’s assistants, employees, contractors or agents of any of the covenants contained in this Agreement and any corresponding nondisclosure and intellectual property assignment agreement, (iv) any failure of Consultant to perform the Services in accordance with all applicable laws, rules and regulations, or (v) any violation or claimed violation of a third party’s rights resulting in whole or in part from the Company’s use of the Inventions or other deliverables of Consultant under this Agreement.

9. Limitation of Liability

IN NO EVENT SHALL THE COMPANY BE LIABLE TO CONSULTANT OR TO ANY OTHER PARTY FOR ANY INDIRECT, INCIDENTAL, SPECIAL OR CONSEQUENTIAL DAMAGES, OR DAMAGES FOR LOST PROFITS OR LOSS OF BUSINESS, HOWEVER CAUSED AND UNDER ANY THEORY OF LIABILITY, WHETHER BASED IN CONTRACT, TORT (INCLUDING NEGLIGENCE) OR OTHER THEORY OF LIABILITY, REGARDLESS OF WHETHER THE COMPANY WAS ADVISED OF THE POSSIBILITY OF SUCH DAMAGES AND NOTWITHSTANDING THE FAILURE OF ESSENTIAL PURPOSE OF ANY LIMITED REMEDY. IN NO EVENT SHALL THE COMPANY’S LIABILITY ARISING OUT OF OR IN CONNECTION WITH THIS AGREEMENT EXCEED THE AMOUNTS PAID BY THE COMPANY TO CONSULTANT UNDER THIS AGREEMENT FOR THE SERVICES, DELIVERABLES OR INVENTION GIVING RISE TO SUCH LIABILITY.

10. Arbitration and Equitable Relief

A. Arbitration. IN CONSIDERATION OF CONSULTANT’S CONSULTING RELATIONSHIP WITH THE COMPANY, ITS PROMISE TO ARBITRATE ALL DISPUTES RELATED TO CONSULTANT’S CONSULTING RELATIONSHIP WITH THE COMPANY AND CONSULTANT’S RECEIPT OF THE COMPENSATION AND OTHER BENEFITS PAID TO CONSULTANT BY THE COMPANY, AT PRESENT AND IN THE FUTURE, CONSULTANT AGREES THAT ANY AND ALL CONTROVERSIES, CLAIMS, OR DISPUTES WITH ANYONE (INCLUDING THE COMPANY AND ANY EMPLOYEE, OFFICER, DIRECTOR, SHAREHOLDER OR BENEFIT PLAN OF THE COMPANY IN THEIR CAPACITY AS SUCH OR OTHERWISE) ARISING OUT OF, RELATING TO, OR RESULTING FROM CONSULTANT’S CONSULTING OR OTHER RELATIONSHIP WITH THE COMPANY OR THE TERMINATION OF CONSULTANT’S CONSULTING OR OTHER RELATIONSHIP WITH THE COMPANY, INCLUDING ANY BREACH OF THIS AGREEMENT, SHALL BE SUBJECT TO BINDING ARBITRATION UNDER

THE FEDERAL ARBITRATION ACT (THE “FAA”) AND THAT THE FAA SHALL GOVERN AND APPLY TO THIS ARBITRATION AGREEMENT WITH FULL FORCE AND EFFECT. CONSULTANT FURTHER AGREES THAT, TO THE FULLEST EXTENT PERMITTED BY LAW, CONSULTANT MAY BRING ANY ARBITRATION PROCEEDING ONLY IN CONSULTANT’S INDIVIDUAL CAPACITY, AND NOT AS A PLAINTIFF, REPRESENTATIVE, OR CLASS MEMBER IN ANY PURPORTED CLASS, COLLECTIVE, OR REPRESENTATIVE LAWSUIT OR PROCEEDING. CONSULTANT AGREES TO ARBITRATE ANY AND ALL COMMON LAW AND/OR STATUTORY CLAIMS UNDER LOCAL, STATE, OR FEDERAL LAW, INCLUDING, BUT NOT LIMITED TO, CLAIMS UNDER MARYLAND STATE LAW, CLAIMS RELATING TO EMPLOYMENT OR INDEPENDENT CONTRACTOR STATUS, CLASSIFICATION, AND RELATIONSHIP WITH THE COMPANY, AND CLAIMS OF BREACH OF CONTRACT, EXCEPT AS PROHIBITED BY LAW. CONSULTANT ALSO AGREES TO ARBITRATE ANY AND ALL DISPUTES ARISING OUT OF OR RELATING TO THE INTERPRETATION OR APPLICATION OF THIS AGREEMENT TO ARBITRATE, BUT NOT TO DISPUTES ABOUT THE ENFORCEABILITY, REVOCABILITY OR VALIDITY OF THIS AGREEMENT TO ARBITRATE OR ANY PORTION HEREOF OR THE CLASS, COLLECTIVE AND REPRESENTATIVE PROCEEDING WAIVER HEREIN. WITH RESPECT TO ALL SUCH CLAIMS AND DISPUTES THAT CONSULTANT AGREES TO ARBITRATE, CONSULTANT HEREBY EXPRESSLY AGREES TO WAIVE, AND DOES WAIVE, ANY RIGHT TO A TRIAL BY JURY. CONSULTANT FURTHER UNDERSTANDS THAT THIS AGREEMENT TO ARBITRATE ALSO APPLIES TO ANY DISPUTES THAT THE COMPANY MAY HAVE WITH CONSULTANT.

B. Procedure. CONSULTANT AGREES THAT ANY ARBITRATION WILL BE ADMINISTERED BY JAMS PURSUANT TO ITS EMPLOYMENT ARBITRATION RULES & PROCEDURES (THE “JAMS RULES”), WHICH ARE AVAILABLE AT HTTP://WWW.JAMSADR.COM/RULES-EMPLOYMENT-ARBITRATION/. CONSULTANT AGREES THAT THE USE OF THE JAMS RULES DOES NOT CHANGE CONSULTANT’S CLASSIFICATION TO THAT OF AN EMPLOYEE. TO THE CONTRARY, CONSULTANT REAFFIRMS THAT CONSULTANT IS AN INDEPENDENT CONTRACTOR. THE ARBITRATION SHALL BE BEFORE A SINGLE ARBITRATOR WHO SHALL BE A FORMER FEDERAL OR STATE COURT JUDGE. THE ARBITRATION SHALL APPLY THE FEDERAL RULES OF CIVIL PROCEDURE, EXCEPT TO THE EXTENT SUCH RULES CONFLICT WITH THE JAMS RULES. CONSULTANT UNDERSTANDS THAT THE PARTIES TO THE ARBITRATION SHALL EACH PAY AN EQUAL SHARE OF THE COSTS AND EXPENSES OF SUCH ARBITRATION (“ARBITRATION COSTS”), EXCEPT AS PROHIBITED BY LAW, AND UNDERSTANDS THAT EACH PARTY SHALL SEPARATELY PAY ITS RESPECTIVE ATTORNEYS’ FEES AND COSTS. IN THE EVENT THAT JAMS FAILS, REFUSES, OR OTHERWISE DOES NOT ENFORCE THE AFOREMENTIONED ARBITRATION COSTS SHARING PROVISION, EITHER PARTY MAY COMMENCE AN ACTION TO RECOVER SUCH AMOUNTS AGAINST THE NON-PAYING PARTY IN COURT AND THE NON-PAYING PARTY SHALL REIMBURSE THE MOVING PARTY FOR THE ATTORNEYS’ FEES AND COSTS INCURRED IN CONNECTION WITH SUCH ACTION. CONSULTANT AGREES THAT THE ARBITRATOR SHALL CONSIDER AND SHALL HAVE THE POWER TO DECIDE ANY MOTIONS BROUGHT BY ANY PARTY TO THE ARBITRATION, INCLUDING MOTIONS FOR SUMMARY JUDGMENT AND/OR ADJUDICATION, AND MOTIONS TO DISMISS, PRIOR TO ANY ARBITRATION HEARING. CONSULTANT AGREES THAT THE ARBITRATOR SHALL ISSUE A WRITTEN DECISION ON THE MERITS. CONSULTANT ALSO AGREES THAT THE ARBITRATOR SHALL HAVE THE POWER TO AWARD ANY REMEDIES AVAILABLE UNDER APPLICABLE LAW. CONSULTANT AGREES THAT THE DECREE OR AWARD RENDERED BY THE ARBITRATOR MAY BE ENTERED AS A FINAL AND BINDING JUDGMENT IN ANY COURT HAVING JURISDICTION THEREOF. CONSULTANT AGREES THAT THE ARBITRATOR SHALL APPLY SUBSTANTIVE MARYLAND LAW TO ANY DISPUTE OR CLAIM, WITHOUT REFERENCE TO RULES OF CONFLICT OF LAW. TO THE EXTENT THAT THE JAMS RULES CONFLICT WITH SUBSTANTIVE MARYLAND LAW, MARYLAND LAW SHALL TAKE PRECEDENCE. CONSULTANT AGREES THAT ARBITRATION UNDER THIS AGREEMENT SHALL BE CONDUCTED IN MONTGOMERY COUNTY, MARYLAND.

C. Remedy. EXCEPT AS PROHIBITED BY LAW OR PROVIDED BY THIS AGREEMENT, ARBITRATION SHALL BE THE SOLE, EXCLUSIVE AND FINAL REMEDY FOR ANY DISPUTE BETWEEN CONSULTANT AND THE COMPANY. ACCORDINGLY, EXCEPT AS PROVIDED BY LAW OR THIS AGREEMENT, NEITHER CONSULTANT NOR THE COMPANY WILL BE PERMITTED TO PURSUE COURT ACTION REGARDING CLAIMS THAT ARE SUBJECT TO ARBITRATION. NOTWITHSTANDING, THE ARBITRATOR WILL NOT HAVE THE AUTHORITY TO DISREGARD OR REFUSE TO ENFORCE ANY LAWFUL COMPANY POLICY, AND THE ARBITRATOR SHALL NOT ORDER OR REQUIRE THE COMPANY TO ADOPT A POLICY NOT OTHERWISE REQUIRED BY LAW WHICH THE COMPANY HAS NOT ADOPTED.

D. Availability of Injunctive Relief. EITHER PARTY MAY ALSO PETITION THE COURT FOR INJUNCTIVE RELIEF WHERE EITHER PARTY ALLEGES OR CLAIMS A VIOLATION OF ANY AGREEMENT REGARDING TRADE SECRETS, OR CONFIDENTIAL INFORMATION, OR A BREACH OF ANY RESTRICTIVE COVENANT. IN THE EVENT EITHER PARTY SEEKS INJUNCTIVE RELIEF, THE PREVAILING PARTY SHALL BE ENTITLED TO RECOVER REASONABLE COSTS AND ATTORNEYS’ FEES.

E. Administrative Relief. CONSULTANT UNDERSTANDS THAT THIS AGREEMENT DOES NOT PROHIBIT CONSULTANT FROM PURSUING AN ADMINISTRATIVE CLAIM WITH A LOCAL, STATE OR FEDERAL ADMINISTRATIVE BODY SUCH AS THE MARYLAND COMMISSION ON CIVIL RIGHTS, THE EQUAL EMPLOYMENT OPPORTUNITY COMMISSION, THE NATIONAL LABOR RELATIONS BOARD, OR THE WORKERS’ COMPENSATION BOARD. THIS AGREEMENT DOES, HOWEVER, PRECLUDE CONSULTANT FROM PURSUING COURT ACTION REGARDING ANY SUCH CLAIM, EXCEPT AS PERMITTED BY LAW.

F. Voluntary Nature of Agreement. CONSULTANT ACKNOWLEDGES AND AGREES THAT CONSULTANT IS EXECUTING THIS AGREEMENT VOLUNTARILY AND WITHOUT ANY DURESS OR UNDUE INFLUENCE BY THE COMPANY OR ANYONE ELSE. CONSULTANT FURTHER ACKNOWLEDGES AND AGREES THAT CONSULTANT HAS CAREFULLY READ THIS AGREEMENT AND THAT CONSULTANT HAS ASKED ANY QUESTIONS NEEDED FOR CONSULTANT TO UNDERSTAND THE TERMS, CONSEQUENCES AND BINDING EFFECT OF THIS AGREEMENT AND FULLY UNDERSTAND IT, INCLUDING THAT CONSULTANT IS WAIVING CONSULTANT’S RIGHT TO A JURY TRIAL. FINALLY, CONSULTANT AGREES THAT CONSULTANT HAS BEEN PROVIDED AN OPPORTUNITY TO SEEK THE ADVICE OF AN ATTORNEY OF CONSULTANT’S CHOICE BEFORE SIGNING THIS AGREEMENT.

11. Miscellaneous

A. Governing Law; Consent to Personal Jurisdiction. With the exception of the arbitration requirements set forth herein, this Agreement shall be governed by the laws of the State of Maryland, without regard to the conflicts of law provisions of any jurisdiction. To the extent that any lawsuit is permitted under this Agreement, the Parties hereby expressly consent to the personal and exclusive jurisdiction and venue of the state and federal courts located in Maryland.

B. Assignability. This Agreement will be binding upon Consultant’s heirs, executors, assigns, administrators, and other legal representatives, and will be for the benefit of the Company, its successors, and its assigns. There are no intended third-party beneficiaries to this Agreement, except as expressly stated. Except as may otherwise be provided in this Agreement, Consultant may not sell, assign or delegate any rights or obligations under this Agreement. Notwithstanding anything to the contrary herein, the Company may assign this Agreement and its rights and obligations under this Agreement to any successor to all or substantially all of the Company’s relevant assets, whether by merger, consolidation, reorganization, reincorporation, sale of assets or stock, change of control or otherwise.

C. Entire Agreement. This Agreement constitutes the entire agreement and understanding between the Parties with respect to the subject matter herein and supersedes all prior written and oral agreements, discussions, or representations between the Parties. For the avoidance of doubt, the Confidentiality Agreement between the Parties remains in effect. Consultant represents and warrants that Consultant is not relying on any statement or representation not contained in this Agreement. To the extent any terms set forth in any exhibit or schedule conflict with the terms set forth in this Agreement, the terms of this Agreement shall control unless otherwise expressly agreed by the Parties in such exhibit or schedule.

D. Headings. Headings are used in this Agreement for reference only and shall not be considered when interpreting this Agreement.

E. Severability. If a court or other body of competent jurisdiction finds, or the Parties mutually believe, any provision of this Agreement, or portion thereof, to be invalid or unenforceable, such provision will be enforced to the maximum extent permissible so as to effect the intent of the Parties, and the remainder of this Agreement will continue in full force and effect.

F. Modification, Waiver. No modification of or amendment to this Agreement, nor any waiver of any rights under this Agreement, will be effective unless in a writing signed by the Parties. Waiver by the Company of a breach of any provision of this Agreement will not operate as a waiver of any other or subsequent breach.

G. Notices. Any notice or other communication required or permitted by this Agreement to be given to a Party shall be in writing and shall be deemed given (i) if delivered personally or by commercial messenger or courier service, (ii) when sent by email (so long as such email is not returned as undelivered), or (iii) if mailed by U.S. registered or certified mail (return receipt requested), to the Party at the Party’s address written below or at such other address as the Party may have previously specified by like notice. If by mail, delivery shall be deemed effective three business days after mailing in accordance with this Section 11.G. If by email, delivery shall be deemed effective as of the date it is sent.

25 W Watkins Mill Road

Gaithersburg, MD 20878

Attention: Chief Executive Officer

(2) If to Consultant, to the address for notice on the signature page to this Agreement or, if no such address is provided, to the last address of Consultant provided by Consultant to the Company.

H. Attorneys’ Fees. In any court action at law or equity that is brought by one of the Parties to this Agreement to enforce or interpret the provisions of this Agreement, the prevailing Party will be entitled to reasonable attorneys’ fees, in addition to any other relief to which that Party may be entitled.

I. Signatures. This Agreement may be signed in two counterparts, each of which shall be deemed an original, with the same force and effectiveness as though executed in a single document.

J. Protected Activity Not Prohibited. Consultant understands that nothing in this Agreement shall in any way limit or prohibit Consultant from engaging in any Protected Activity. For purposes of this Agreement, “Protected Activity” shall mean filing a charge, complaint, or report with, or otherwise communicating, cooperating, or participating in any investigation or proceeding that may be conducted by, any federal, state or local government agency or commission, including the Securities and Exchange Commission (“Government Agencies”). Consultant understands that in connection with such Protected Activity, Consultant is permitted to disclose documents or other information as permitted by law, and without giving notice to, or receiving authorization from, the Company. Notwithstanding the foregoing, Consultant agrees to take all reasonable precautions to prevent any unauthorized use or disclosure of any information that may constitute Company confidential information to any parties other than the Government Agencies. Consultant further understands that “Protected Activity” does not include the disclosure of any Company attorney-client privileged communications. Pursuant to the Defend Trade Secrets Act of 2016, Consultant is notified that an individual will not be held criminally or civilly liable under any federal or state trade secret law for the disclosure of a trade secret that (i) is made in confidence to a federal, state, or local government official (directly or indirectly) or to an attorney solely for the purpose of reporting or investigating a suspected violation of law, or (ii) is made in a complaint or other document filed in a lawsuit or other proceeding, if (and only if) such filing is made under seal. In addition, an individual who files a lawsuit for retaliation by an employer for reporting a suspected violation of law may disclose the trade secret to the individual’s attorney and use the trade secret information in the court proceeding, if the individual files any document containing the trade secret under seal and does not disclose the trade secret, except pursuant to court order.

IN WITNESS WHEREOF, the Parties hereto have executed this Consulting Agreement as of the Effective Date.

EXHIBIT A-1

SERVICES AND COMPENSATION

Name: Rami Elghandour

Title: Chief Executive Officer

Email: ***@***

A. During the Term of this Agreement, Consultant will continue to serve as a Company Service Provider and shall continue to vest in any outstanding stock options to purchase shares of the Company’s common stock held by the Consultant, subject to the terms and conditions of any applicable stock option and related agreements between Consultant and the Company and the Company’s 2017 Equity Incentive Plan.

This Exhibit A-1 is dated as of 12/31/2021.

EXHIBIT B

SUPPLEMENTAL RELEASE AGREEMENT

This Supplemental Release Agreement (“Supplemental Release”) is made by and between David M. Hilbert, Ph.D. (“Employee”) and Arcellx, Inc. (the “Company”) (jointly referred to as the “Parties” and individually referred to as a “Party”).

1. Consideration. In consideration for the Supplemental Release Consideration (as applicable) in Section 1.d. of the Transition Agreement and Release signed by Employee in or around January 2022 (the “Transition Agreement”), Employee hereby extends Employee’s release and waiver of claims to any claims that may have arisen between the Effective Date (as such term is defined in the Transition Agreement) and the Supplemental Release Effective Date (as defined below), all such claims shall be released insofar as they arise from any omissions, acts, facts, or damages that have occurred up until and including the Supplemental Release Effective Date.

2. Incorporation of Terms of Release Agreement. The undersigned Parties further acknowledge that the terms of the Transition Agreement, including, but not limited to, the Sections entitled Payment of Salary and Receipt of All Benefits, Release of Claims, Acknowledgement of Waiver of Claims Under ADEA, Trade Secrets and Confidential Information/Company Property, Nondisparagement, Breach, No Admission of Liability, Arbitration, and Protected Activity Not Prohibited shall apply to this Supplemental Release and are incorporated herein to the extent that they are not inconsistent with the express terms of this Supplemental Release.

4. Supplemental Release Effective Date. Employee understands that this Supplemental Release shall be null and void if not executed by Employee, and returned to the Company, within seven (7) days after the termination of the Consulting Period (as defined in the Transition Agreement). This Supplemental Release will become effective on the eighth (8th) day after Employee signs this Supplemental Release, so long as it has been signed by the Parties and has not been revoked by either Party before that date (the “Supplemental Release Effective Date”).

5. Voluntary Execution of Agreement. Employee understands and agrees that Employee executed this Supplemental Release voluntarily, without any duress or undue influence on the part or behalf of the Company or any third party, with the full intent of releasing all of Employee’s claims against the Company and any of the other Releasees. Employee acknowledges that:

IN WITNESS WHEREOF, the Parties have executed this Agreement on the respective dates set forth below.