FDA Actions in September: Keytruda Advances, Rare Disease Wins, and SMA Setbacks

September proved to be a pivotal month for the pharmaceutical industry, with the U.S. Food and Drug Administration (FDA) issuing a series of significant decisions that will shape the landscape of drug development and patient care. From bolstering the future of blockbuster immunotherapies to addressing ultra-rare diseases, the agency's actions have far-reaching implications for patients, healthcare providers, and pharmaceutical companies alike.

Merck's Keytruda Secures Critical Approval

In a move that could significantly impact the future of cancer immunotherapy, the FDA approved a subcutaneous version of Merck's blockbuster drug Keytruda on September 19. The new formulation, branded as Keytruda Qlex, is approved for 38 cancer indications, mirroring most of the solid tumor indications of its intravenous counterpart.

This approval comes at a crucial time for Merck, as Keytruda faces patent expiration in 2028. The subcutaneous version is expected to play a key role in Merck's strategy to maintain its market position beyond the loss of exclusivity. In clinical trials, Keytruda Qlex demonstrated comparable efficacy to the intravenous formulation, with a 45% overall response rate in non-small cell lung cancer patients versus 42% for the original Keytruda.

Merck has indicated that Keytruda Qlex will be priced "at parity" with the intravenous version, which currently costs approximately $11,800 for a three-week course. The pharmaceutical giant aims to make the new formulation available by late September, potentially revolutionizing the administration of this critical cancer therapy.

Rare Disease Treatments Make Strides

The rare disease community saw significant advancements in September, with notable approvals for ultra-rare conditions. Stealth BioTherapeutics achieved a major milestone with the FDA's approval of elamipretide (Forzinity) for Barth syndrome, an ultra-rare mitochondrial disease affecting around 150 patients in the United States. This approval marks the culmination of over a decade of research and regulatory discussions.

Forzinity targets a crucial molecule in the mitochondria, aiming to boost cellular energy production and maintain healthy organ function. The drug's approval covers patients weighing at least 30 kg, though it notably excludes children under the age of 5, who often experience the most severe effects of Barth syndrome.

In another rare disease win, Takeda's Vonvendi received FDA approval for routine prophylaxis in adults with von Willebrand Disease (VWD) and for perioperative management of bleeding in pediatric VWD patients. This expansion makes Vonvendi the only recombinant von Willebrand Factor replacement therapy indicated for both adults and children with VWD, a bleeding disorder affecting over 3 million people in the U.S.

Setbacks in Spinal Muscular Atrophy Treatments

The spinal muscular atrophy (SMA) treatment landscape faced challenges as the FDA issued rejections for two promising therapies on September 23. Scholar Rock's apitegromab and Biogen's high-dose formulation of Spinraza both received complete response letters, primarily due to manufacturing concerns.

Scholar Rock's rejection stemmed from issues at a third-party manufacturer, Catalent Indiana LLC, recently acquired by Novo Nordisk. The company emphasized that the FDA did not cite concerns with apitegromab's efficacy or safety data, and is working to address the observations for a prompt resubmission.

Similarly, Biogen's high-dose Spinraza faced setbacks related to manufacturing, with the FDA requesting updated technical information in the chemistry manufacturing and controls portion of the application. Biogen plans to address these concerns and refile "promptly," maintaining optimism about the treatment's potential approval.

These rejections represent a temporary setback for the SMA community, delaying access to potentially more effective treatment options. However, both companies remain committed to addressing the FDA's concerns and bringing these therapies to market.