US FDA declines to approve Scholar Rock’s muscle weakness drug; shares fall

Scholar Rock's shares dropped 14% premarket after the FDA issued a Complete Response Letter for its promising drug apitegromab, citing manufacturing deficiencies at a third-party Catalent facility rather than drug-specific concerns. While Scholar Rock plans to resubmit once the facility issues are resolved, this delay impacts a drug with projected revenues of nearly $2 billion by the early 2030s, particularly in the growing muscle preservation market alongside GLP-1s, and underscores broader manufacturing site risks, as Catalent's Indiana plant has affected other developers like Regeneron.

Analysis

Scholar Rock (SRRK) has experienced a significant regulatory setback, with its shares falling 14% in premarket trading after the U.S. FDA issued a Complete Response Letter (CRL) for its key drug candidate, apitegromab. Crucially, the rejection is not based on the drug's clinical data but on manufacturing deficiencies identified at a third-party Catalent facility in Indiana. This same facility, recently acquired by Novo Nordisk, has also caused regulatory delays for other firms like Regeneron, highlighting a concentrated supply chain risk. The delay clouds the outlook for apitegromab, a drug analysts forecast could achieve nearly $2 billion in revenue by the early 2030s by targeting spinal muscular atrophy and the growing market for muscle preservation alongside GLP-1 obesity treatments. While Scholar Rock plans to resubmit its application following remediation by Catalent, the unspecified timeline for resolving the manufacturing issues introduces significant uncertainty for SRRK's primary growth driver.

Key Decisions for Investors

• Investors should closely monitor communications from Catalent and its new owner, Novo Nordisk, regarding the remediation timeline for the Indiana facility, as this is the primary gating item for apitegromab's approval and a key catalyst for SRRK's stock.
• The 14% drop in SRRK's stock may present a speculative opportunity for high-risk tolerance investors, contingent on a swift resolution, as the FDA did not cite issues with the drug's intrinsic safety or efficacy.
• Consider reviewing exposure to other biotech firms, such as Regeneron, that rely on Catalent's Indiana plant, as they face a similar, demonstrated risk of regulatory and production delays.