RARE: Other company developments

Item 8.01 Other Events. On October 19, 2026, Ultragenyx Pharmaceutical Inc. (the “Company”) and Baylor Research Institute (“BRI”) entered into a settlement agreement with Navinta LLC (“Navinta”) resolving patent litigation related to patents covering the Company’s DOJOLVI® (triheptanoin) oral liquid. The litigation, which was filed in the United States District Court for the District of New Jersey, resulted from the submission by Navinta of an Abbreviated New Drug Application (“ANDA”) to the U.S. Food and Drug Administration seeking approval to market a generic version of DOJOLVI in the United States. Under the terms of the settlement agreement, the Company will grant Navinta a non-exclusive, royalty-free license to market its generic version of DOJOLVI beginning January 1, 2033, which would be extended to July 1, 2033 if pediatric exclusivity is granted for DOJOLVI, subject to certain conditions and exceptions customary for agreements of this type. Similar patent litigation brought by the Company against other ANDA filers related to DOJOLVI remains pending in the U.S. District Court for the District of New Jersey. As required by law, the settlement agreement will be submitted to the U.S. Federal Trade Commission and the U.S. Department of Justice. The description of the settlement agreement contained herein does not purport to be complete. 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. Ultragenyx Pharmaceutical Inc. Date: October 19, 2026 By: /s/ Howard Horn Howard Horn Executive Vice President, Chief Financial Officer, Corporate Strategy