Scholar Rock's Spinal Muscular Atrophy Drug Faces FDA Delay Over Catalent Indiana Inspection

The FDA has issued a Complete Response Letter (CRL) for Scholar Rock's apitegromab Biologics License Application (BLA) for spinal muscular atrophy, attributing the decision to observations from a routine general site inspection of Catalent Indiana LLC, a third-party fill-finish facility acquired by Novo Nordisk. Crucially, the CRL did not cite concerns regarding apitegromab's efficacy or safety data, but rather manufacturing site issues that are also impacting regulatory approvals for Regeneron's EYLEA HD. Scholar Rock plans to resubmit its BLA once Catalent Indiana remediates the FDA's observations, while a European marketing authorization decision is anticipated by mid-2026.

Analysis

Scholar Rock (SRRK) has received a Complete Response Letter (CRL) from the U.S. FDA for its apitegromab Biologics License Application, representing a delay in the U.S. approval timeline. Crucially, the CRL is not based on the drug's clinical profile; the FDA cited no concerns regarding apitegromab's efficacy or safety data. The rejection is attributed solely to unresolved observations at a third-party fill-finish facility, Catalent Indiana, which was acquired by Novo Nordisk (NVS). The systemic nature of this manufacturing issue is underscored by its concurrent impact on Regeneron (REGN), which is also facing regulatory delays for its EYLEA HD applications due to problems at the same facility. Scholar Rock's path forward involves resubmitting its application following Catalent's remediation of the FDA's findings. The market has interpreted this news as a manageable, external setback rather than a fundamental flaw, as evidenced by SRRK's stock increasing 1.24% to $32.99. Furthermore, the company maintains a parallel regulatory pathway in Europe, where a decision on its marketing authorization application is anticipated by mid-2026, providing an alternative route to commercialization.

Key Decisions for Investors

• The FDA's CRL for SRRK's apitegromab should be viewed as a delay in the revenue timeline rather than a threat to the drug's ultimate approvability, given the issue is isolated to a third-party manufacturer and not the drug's clinical data.
• Investors should monitor disclosures from Catalent Indiana and parent company Novo Nordisk regarding the timeline for remediating the FDA's site observations, as this is now the critical gating factor for both SRRK's and REGN's U.S. applications.
• Consider the ongoing European review of apitegromab, with a decision expected by mid-2026, as a key de-risking event and a separate commercialization catalyst that mitigates some of the uncertainty associated with the U.S. regulatory delay.