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 a blockbuster cancer drug to addressing ultra-rare diseases, the agency's actions have far-reaching implications for patients, healthcare providers, and pharmaceutical companies alike.
Keytruda's Subcutaneous Formulation Secures Approval
In a major win for Merck, the FDA approved a subcutaneous version of its flagship cancer immunotherapy, Keytruda (pembrolizumab), 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 is a strategic move for Merck as it prepares for Keytruda's patent expiration in 2028. The subcutaneous version could help maintain the drug's market position in the face of potential biosimilar competition. Keytruda has been a powerhouse for Merck, generating $29.5 billion in sales in 2024.
The FDA's decision was based on data demonstrating comparable efficacy and safety between the subcutaneous and intravenous formulations. In non-small cell lung cancer patients, Keytruda Qlex showed a 45% overall response rate compared to 42% for the original Keytruda, with similar progression-free and overall survival rates.
Rare Disease Treatments See Mixed Results
Stealth BioTherapeutics' Decade-Long Journey Ends in Success
After more than ten years of development and regulatory discussions, Stealth BioTherapeutics finally secured FDA approval for elamipretide (Forzinity) on September 19. The drug is indicated for Barth syndrome, an ultra-rare mitochondrial disease affecting approximately 150 patients in the U.S.
Forzinity targets a key molecule in the mitochondria to boost cellular energy production and maintain organ function. The approval covers patients weighing at least 30 kg but excludes children under 5 years old, who often experience the most severe symptoms of Barth syndrome.
The path to approval was challenging, with an initial rejection in May due to insufficient efficacy data. However, the FDA proposed using the accelerated approval pathway, leading to Stealth's successful resubmission based on an intermediate endpoint.
Setbacks for Spinal Muscular Atrophy Treatments
September 23 marked a difficult day for the spinal muscular atrophy (SMA) community, with the FDA rejecting two potential treatments due to manufacturing concerns.
Scholar Rock's apitegromab, a myostatin blocker, was denied approval due to issues at a third-party manufacturer, Catalent Indiana LLC. The FDA did not raise concerns about the drug's efficacy or safety, and Scholar Rock is working to address the observations and resubmit "as soon as possible."
On the same day, Biogen faced a setback for its high-dose formulation of Spinraza (nusinersen). The FDA requested updated technical information in the chemistry manufacturing and controls portion of the application. Biogen plans to address these issues promptly and refile the application.
Both companies emphasized that the rejections were not related to clinical data concerns, maintaining optimism about the eventual approval of their respective SMA treatments.
Advancements in Other Therapeutic Areas
The FDA's September actions also included approvals and expanded indications for treatments across various conditions:
- Takeda's Vonvendi received approval for routine prophylaxis in adults with von Willebrand Disease (VWD) and perioperative management of bleeding in pediatric VWD patients.
- Johnson & Johnson's Inlexzo, a drug-device combination for non-muscle invasive bladder cancer, was approved on September 9.
- Corstasis Therapeutics' Enbumyst, the first intranasal loop diuretic for edema in heart failure, hepatic, and renal disease patients, received FDA approval on September 16.
These developments reflect the ongoing efforts of pharmaceutical companies to address unmet medical needs and improve patient care across a spectrum of diseases, from rare genetic disorders to more common conditions affecting millions of Americans.
References
- September's FDA Action Bolsters Keytruda, Ultra-Rare Disease but Deals Two SMA Defeats
The FDA in September issued two rejections for spinal muscular atrophy therapies—both linked to manufacturing problems—and granted approvals in Barth syndrome and for a subcutaneous version of Merck’s Keytruda that could be key to the blockbuster’s future earnings.
Explore Further
What is the projected impact of Keytruda Qlex's approval on Merck's market position as it approaches patent expiration in 2028?
How does elamipretide's (Forzinity) approval for Barth syndrome compare to other treatments available for ultra-rare mitochondrial diseases?
What are the next steps Scholar Rock and Biogen are planning to address manufacturing concerns related to their SMA treatments?
What is the competitive landscape for intranasal loop diuretics following the FDA approval of Enbumyst for edema management?
What are the main factors contributing to the accelerated approval pathway used for Forzinity, and how might this framework influence future rare disease drug approvals?