Consulting and Employment Separation Agreement effective as of July 1, 2024 between the Registrant and Kenneth T. Mills

Agreement

This Consulting and Employment Separation Agreement (the “Agreement”) is entered into as of June 12, 2024, by and between REGENXBIO Inc. (“REGENXBIO”), a Delaware corporation with offices at 9804 Medical Center Drive, Rockville, Maryland 20850, and Ken Mills (“Mr. Mills”), (each a “Party” and collectively the “Parties”).

WHEREAS, Mr. Mills will voluntarily resign from his role of President and Chief Executive Officer of REGENXBIO effective July 1, 2024, but has recently been named Chairman of the Board of Directors of REGENXBIO.

WHEREAS, in addition to his roles as a member and Chairman of the board of directors of REGENXBIO (the “Board”), REGENXBIO desires to retain Mr. Mills as an independent contractor to perform consulting services for REGENXBIO, and Mr. Mills is willing to perform such services, on the terms described herein.

NOW, THEREFORE, in consideration of the mutual promises contained herein, the Parties agree as follows:

During the Term of this Agreement, Mr. Mills shall perform the services set forth in the Scope of Work attached hereto as Exhibit A as a consultant, which is incorporated by reference herein, as reasonably requested by REGENXBIO (the “Services”). Nothing in this Agreement or PIIA (as defined below) shall require Mr. Mills to disclose any information that is otherwise subject to a non-disclosure agreement, confidentiality agreement, or similar agreement, or to violate Mr. Mills’ fiduciary obligations to another company/organization. Further, to the extent permitted by Section 122(17) of the Delaware General Corporation Law or any other applicable law in the event that the applicable entity is not incorporated, formed or organized as a corporation in the State of Delaware, REGENXBIO (for itself and on behalf of each of its wholly-owned subsidiaries) hereby renounces any interest or expectancy to participate in any corporate opportunities that are presented to Mr. Mills in connection with Mr. Mills’ role as Chief Executive Officer and a member of the board of directors of other companies that are not directly competitive with REGENXBIO (collectively, the “Permitted Activities”), and waives any claim against Mr. Mills and shall indemnify Mr. Mills against any claim that Mr. Mills is liable to REGENXBIO for breach of any fiduciary duty solely by reason of Mr. Mills’ participation in any such corporate opportunity arising out of any such Permitted Activity and to the extent otherwise in compliance with the terms of this Agreement and the PIIA.

REGENXBIO and Mr. Mills entered into a Proprietary Information and Inventions Agreement effective as of May 18, 2015 (the “PIIA”), which shall be incorporated into and made part of this Agreement. Notwithstanding any terms or conditions to the contrary in the PIIA, all rights, obligations and restrictions pursuant to the PIIA shall be interpreted to continue in full force and effect during the term of this Agreement as if Mr. Mills were an employee of the Company during such term; provided, however, nothing created or learned by Mr. Mills in connection with the Permitted Activities, shall be subject to or covered by the PIIA.

It is understood and agreed that effective July 1, 2024, Mr. Mills is an independent contractor and is not an employee of REGENXBIO or any of REGENXBIO’s affiliates and that REGENXBIO will not make any deductions for any statutory withholdings, such as income tax, pension plans, unemployment insurance or worker’s compensation. Other than as specified herein, Mr. Mills will not be entitled to participate in any medical, dental, extended health or group life insurance plans of REGENXBIO. Mr. Mills is not and shall not hold himself out to be an agent, legal representative, partner, subsidiary, joint venturer or employee of REGENXBIO, and Mr. Mills shall have no right or power to, and shall not bind or obligate REGENXBIO in any manner whatsoever or represent that Mr. Mills has any right to do so.

Mr. Mills shall retain the right to perform work for others during the term of this Agreement, provided, however, that, Mr. Mills will not provide consulting services or other services to another company engaged in developing competitive gene therapy related products.

Neither Party may use the name of the other Party, or any variation thereon or adaptation thereof, in any endorsement, advertising, promotional sales literature or other publicity without the prior written approval of such other Party, such approval not to be unreasonably withheld, conditioned or delayed.

Mr. Mills represents, warrants and covenants to the best of his knowledge that the performance of the Services contemplated by this Agreement (a) does not and will not violate any agreements or undertakings of Mr. Mills with any other third party; (b) Mr. Mills has full authority to grant to REGENXBIO all rights granted hereunder; (c) Mr. Mills shall perform all Services in accordance with all applicable laws, rules, regulations and guidelines, including without limitation and to the extent applicable those relating to privacy and data protection; and (d) Mr. Mills is not debarred under Section 306 of the Federal Food, Drug & Cosmetic Act, or otherwise debarred, suspended, excluded, disqualified, or otherwise restricted from working on, providing services for, or participating in any U.S. Food and Drug Administration-regulated activity or federally-funded contract, grant, cooperative agreement, health care program, or research activity, or from practicing before any government agency as a consequence of misconduct of any kind, and that Mr. Mills is not, to his knowledge, presently the subject of any ongoing debarment, suspension, exclusion, disqualification, or restriction proceeding before any government agency.

IN NO EVENT SHALL MR. MILLS BE LIABLE TO REGENXBIO OR TO ANY OTHER PARTY FOR ANY INDIRECT, INCIDENTAL, SPECIAL, PUNITIVE, DELAY OR CONSEQUENTIAL DAMAGES, OR DAMAGES FOR LOST PROFITS OR LOSS OF BUSINESS RESULTING FROM, ARISING OUT OF, OR IN CONNECTION WITH THE SERVICES, HOWEVER CAUSED AND UNDER ANY THEORY OF LIABILITY, WHETHER BASED IN CONTRACT, TORT (INCLUDING NEGLIGENCE) OR OTHER THEORY OF LIABILITY, REGARDLESS OF WHETHER MR. MILLS WAS ADVISED OF THE POSSIBILITY OF SUCH DAMAGES AND NOTWITHSTANDING THE FAILURE OF ESSENTIAL PURPOSE OF ANY LIMITED REMEDY. IN NO EVENT SHALL MR. MILLS’ CUMULATIVE LIABILITY FOR DAMAGES OF ANY TYPE TO REGENXBIO UNDER THIS AGREEMENT EXCEED FIFTY THOUSAND DOLLARS. MR. MILLS DISCLAIMS ALL WARRANTIES WITH RESPECT TO ITS SERVICES, INCLUDING THE IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, WARRANTIES ARISING FROM COURSE OF DEALING OR USAGE OF TRADE, QUALITY OF INFORMATION, SECURITY, RELIABILITY, TIMELINESS, AND AVAILABILITY OF BACKED-UP DATA. REGENXBIO IS SOLELY RESPONSIBLE FOR THE SECURITY AND INTEGRITY OF ITS DATA AND SYSTEMS.

In exchange for certain payments and other consideration under this Agreement, the parties agree to enter into REGENXBIO’s standard form employment release agreement.

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IN WITNESS WHEREOF, and intending to be legally bound, each Party hereby executes this Agreement effective as of the Effective Date.

Exhibit A

Scope of Work

Mr. Mills will provide services in connection with serving as an advisor to the President and Chief Executive Officer of RGENXBIO, as reasonably requested by REGENXBIO from time to time.

Schedule 1

Equity Awards Outstanding as of June 12, 2024

Incentive Stock Options*

*Incentive stock options which are not vested and exercised within three months of the Effective Date will be treated for tax purposes as non-qualified stock options.

Non-Qualified Stock Options

Restricted Stock Units