SC TO-I/A

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE TO

(Amendment No. 1)

(Rule 13a-4)

Tender Offer Statement Under Section 14(d)(1) or 13(e)(1)

of the Securities Exchange Act of 1934

REGENXBIO Inc.

(Name of Subject Company (Issuer) and Filing Person (Offeror))

Options to Purchase Common Stock, Par Value $0.0001 per share

(Title of Class of Securities)

75901B107

(CUSIP Number of Class of Securities)

Curran Simpson

President and Chief Executive Officer

REGENXBIO Inc.

9804 Medical Center Drive

Rockville, Maryland 20850

(240) 552-8181

(Name, Address, and Telephone Number of Person Authorized to Receive Notices and Communications on Behalf of Filing Person)

With Copies to:

     Patrick J. Christmas
Executive Vice President, Chief Strategy and Legal Officer
REGENXBIO Inc.
9804 Medical Center Drive
Rockville, Maryland 20850
(240) 552-8181

     Kerry Shannon Burke
Matthew C. Franker
Covington & Burling LLP
One CityCenter
850 Tenth Street N.W.
Washington, D.C. 20001
(202) 662-6000

    


☐	Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

Check the appropriate boxes below to designate any transactions to which the statement relates:


☐	third party tender offer subject to Rule 14d-1.
☒	Issuer tender offer subject to Rule 13e-4.
☐	going-private transaction subject to Rule 13e-3.
☐	amendment to Schedule 13D under Rule 13d-2.

Check the following box if the filing is a final amendment reporting the results of the tender offer: ☐

If applicable, check the appropriate box(es) below to designate the appropriate rule provision(s) relied upon:


☐	Rule 13e-4(i) (Cross-Border Issuer Tender Offer)
☐	Rule 14d-1(d) (Cross-Border Third-Party Tender Offer)

This Amendment No. 1 to Schedule TO (together with any exhibits and annexes attached hereto, this “Amendment No. 1”), is filed by REGENXBIO Inc., a Delaware corporation (the “Company”), and amends and supplements the Tender Offer Statement on Schedule TO filed by the Company with the Securities and Exchange Commission on June 3, 2026 (the “Schedule TO”). The Schedule TO relates to an offer by the Company (the “Exchange Offer”) to certain non-executive employees to exchange some or all of their eligible outstanding options to purchase shares of the Company’s common stock for replacement options to purchase shares of the Company’s common stock, upon the terms and subject to the conditions set forth in the Offer to Exchange Eligible Options for Replacement Options dated June 3, 2026 (the “Offer to Exchange”), included as Exhibit (a)(1)(A) to the Schedule TO and incorporated herein by reference.

This Amendment No. 1 is being made to reflect certain updates as described below. Except as otherwise set forth in this Amendment No. 1, the information set forth in the Schedule TO and the exhibits filed therewith remains unchanged and is incorporated herein by reference to the extent relevant to the items in this Amendment No. 1. Capitalized terms used but not defined herein have the meanings ascribed to them in the Schedule TO. You should read this Amendment No. 1 together with the Schedule TO and the Offer to Exchange.

Item 12. Exhibits.


Exhibit Number		Description
(a)(1)(A)*		Offer to Exchange Eligible Options for Replacement Options, dated June 3, 2026

(a)(1)(B)*		Communication to Employees from Chief People Officer, sent on June 3, 2026

(a)(1)(C)*		Form of Announcement Email

(a)(1)(D)*		Terms of Election

(a)(1)(E)*		Form of Confirmation Email

(a)(1)(F)*		Form of Reminder Email

(a)(1)(G)*		Screenshots of Option Exchange Website

(a)(1)(H)*		Option Exchange Frequently Asked Questions

(a)(1)(I)*		Employee Presentation

(a)(1)(J)		Communication to Eligible Employees from Chief People Officer, sent on July 1, 2026

(b)		Not applicable

(d)(1)*		2015 Equity Incentive Plan (incorporated by reference to Exhibit 10.3 of the Registration Statement on Form S-1/A (File No. 333-206430) filed with the SEC on September 15, 2015)

(d)(2)*		Form of Restricted Stock Unit Award Agreement for the 2015 Equity Incentive Plan (incorporated by reference to Exhibit 10.4 of the Annual Report on Form 10-K (File No. 001-37553) filed with the SEC on March 1, 2021)

(d)(3)*		Form of Stock Option Award Agreement for the 2015 Equity Incentive Plan (incorporated by reference to Exhibit 10.5 of the Annual Report on Form 10-K (File No. 001-37553) filed with the SEC on March 1, 2021)

(d)(4)*		REGENXBIO Inc. 2025 Equity Incentive Plan (incorporated by reference to Exhibit 99.1 of the Registration Statement on Form S-8 (File No. 333-288040) filed with the SEC on June 13, 2025)

(d)(5)*		Form of Restricted Stock Unit Award Agreement for the 2025 Equity Incentive Plan (incorporated by reference to Exhibit 10.2 of the Quarterly Report on Form 10-Q (File No. 001-37553) filed with the SEC on August 7, 2025)

(d)(6)*		Form of Stock Option Award Agreement for the 2025 Equity Incentive Plan (incorporated by reference to Exhibit 10.3 of the Quarterly Report on Form 10-Q (File No. 001-37553) filed with the SEC on August 7, 2025)

(d)(7)*		2015 Employee Stock Purchase Plan (incorporated by reference to Exhibit 10.4 of the Registration Statement on Form S-1/A (File No. 333-206430) filed with the SEC on September 8, 2015)

(g)		Not applicable

(h)		Not applicable

107*		Filing Fee Table

* Previously filed.


			REGENXBIO INC.

Date:	July 1, 2026	By:	/s/ Curran Simpson
			President and Chief Executive Officer