Form 8-K Ultragenyx Pharmaceutica For: Oct 08

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Ultragenyx Pharmaceutical Inc.

(Exact name of Registrant as Specified in Its Charter)

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

On October 8, 2026, Ultragenyx Pharmaceutical Inc. (the “Company”) entered into an asset purchase agreement (the “PRV Asset Purchase Agreement”), pursuant to which the Company agreed to sell a Rare Pediatric Disease Priority Review Voucher (“PRV”) to the buyer. The Company was awarded the PRV by the U.S. Food and Drug Administration (“FDA”) on September 17, 2026 upon approval of FAYUVITM (rebisufligene etisparvovec-hopf) also known as UX111, for the treatment of pediatric patients with mucopolysaccharidosis type IIIA (MPS IIIA, Sanfilippo syndrome Type A). Pursuant to the PRV Asset Purchase Agreement, the buyer agreed to pay the Company $203 million, payable in cash, upon the closing of the transaction.

The PRV Asset Purchase Agreement contains customary representations, warranties, covenants, and indemnification provisions subject to certain limitations. The transaction remains subject to customary closing conditions, including the expiration or termination of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976.

The foregoing description of the PRV Asset Purchase Agreement does not purport to be complete and is qualified in its entirety by the full text of the PRV Asset Purchase Agreement, a copy of which will be filed with the Company’s Annual Report on Form 10-K for the year ended December 31, 2026.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.