Manufacturing Issues Derail Scholar Rock's Spinal Muscular Atrophy Drug Approval

Scholar Rock's investigational myostatin blocker apitegromab for spinal muscular atrophy (SMA) has hit a roadblock in its path to approval. The U.S. Food and Drug Administration (FDA) declined to approve the drug, citing manufacturing issues at a third-party facility. This setback highlights the critical importance of manufacturing processes in drug development and approval.

FDA Cites Third-Party Manufacturing Concerns

The FDA's rejection letter for apitegromab pointed to problems at a third-party fill-finish site owned by Novo Nordisk. This facility, formerly Catalent Indiana LLC, was acquired by Novo Nordisk in December 2024. Scholar Rock emphasized that the FDA's observations were not specific to apitegromab and did not raise concerns about the drug's efficacy or safety.

David Hallal, CEO of Scholar Rock, stated that the company is working closely with Catalent Indiana to address the FDA's observations. The biotech aims to resubmit its application "as soon as possible," although specific timing has not been provided.

Broader Implications for the Pharmaceutical Industry

The manufacturing issues at the Catalent facility have implications beyond Scholar Rock's apitegromab. A recent FDA investigation report, made public by STAT News, revealed significant quality control problems at the same facility. These issues included the presence of "atypical extrinsic particles" such as cat hair, bacterial contaminations, and pest infestations. Some of these problems reportedly date back to June 2022.

The impact of these manufacturing concerns extends to other pharmaceutical companies. Regeneron, for instance, announced last month that two decisions for its high-dose formulation of Eylea have been delayed to the fourth quarter due to problems at the same Catalent facility.

Market Response and Future Outlook

The news of the FDA's rejection had an immediate impact on Scholar Rock's stock, with shares dropping 12.5% in pre-market trading on Tuesday. However, analysts from BMO Capital Markets noted that the FDA's decision was "in line with expectations" and that the absence of additional efficacy or safety concerns could be seen as a "mild positive" for the company.

Scholar Rock remains optimistic about apitegromab's potential, citing positive data from the Phase III SAPPHIRE study. The trial, completed in October 2024, demonstrated significant improvement in motor function for SMA patients, with benefits apparent as early as 8 weeks and further improvements through 52 weeks of follow-up.

As the pharmaceutical industry continues to grapple with manufacturing challenges, the outcome of Scholar Rock's efforts to address the FDA's concerns will be closely watched by industry observers and investors alike.