Scholar Rock corrects statement on FDA conditions for ISEMBYLD approval

Scholar Rock Holding Corporation disclosed in a Form 8-K dated September 15, 2026 that it had made an error during a live investor webcast held on September 14, 2026. The call had been called to announce FDA approval of ISEMBYLD (apitegromab-mstn) for treating spinal muscular atrophy in patients age 2 and older who are already on an SMN2-targeted therapy.¹

During the question and answer portion of that call, company management incorrectly said the FDA had not imposed any post-marketing safety commitments related to bone or reproductive safety for ISEMBYLD.¹

The filing clarifies that this was not accurate. As part of the approval, the FDA required Scholar Rock to conduct a post-marketing study tracking pregnancy outcomes, including complications and birth results, in patients exposed to the drug during pregnancy.¹ In addition, the FDA asked the company to report all serious and non-serious fracture cases, domestic or foreign, as 15-day alert reports.¹

Scholar Rock said it plans to carry out the pregnancy study and submit the fracture reports as the FDA has requested.¹

The disclosure was filed under Item 7.01 (Regulation FD Disclosure) and is not considered "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, nor incorporated by reference into other filings unless specifically stated.¹ The report was signed by Junlin Ho, General Counsel and Corporate Secretary, on September 15, 2026.