Merck's Injectable Keytruda Shows Promise in Pivotal Trial, Paving Way for Potential FDA Approval

Merck's efforts to extend the patent life of its blockbuster cancer drug Keytruda have taken a significant step forward with positive results from a pivotal Phase III trial. The study, which evaluated a new subcutaneous formulation of Keytruda, demonstrated non-inferiority to the current intravenous (IV) version and even showed superiority in some key measures.

Trial Results and Clinical Implications

The Phase III study, known as 3475A-D77, focused on patients with metastatic non-small cell lung cancer (NSCLC). The subcutaneous formulation of Keytruda met its primary endpoint of non-inferiority to the IV version, with some notable advantages:

• Higher overall response rate when combined with chemotherapy (45.4% for subcutaneous vs. 42.1% for IV)
• Improved progression-free survival (8.1 months for subcutaneous vs. 7.8 months for IV)
• Faster administration time, with patients spending about half the time in the clinic compared to the IV version

The safety profile of the subcutaneous formulation was comparable to the IV version, with adverse effects occurring in 47% of patients for both formulations. The treatment-related death rate was 3.6% for the subcutaneous drug and 2.4% for the IV version.

Regulatory Progress and Market Implications

Based on these promising results, the U.S. Food and Drug Administration (FDA) has accepted a Biologics License Application (BLA) for the new subcutaneous formulation. The agency has set a decision date of September 23, 2025, for potential approval across all of Keytruda's previously approved solid tumor indications.

This development is crucial for Merck as it seeks to maintain Keytruda's market dominance beyond its current patent expiration date in 2028. Keytruda generated $29 billion in revenue for Merck last year, underscoring its importance to the company's portfolio.

Collaborative Efforts and Future Outlook

The new formulation of Keytruda is the result of a collaboration between Merck and Alteogen. It combines Keytruda with berahyaluronidase alfa, a human protein that enables subcutaneous administration. This partnership highlights the importance of collaborative innovation in addressing challenges in drug delivery and patent protection.

Merck is also conducting a Phase II patient preference study, called 3475A-F11, to evaluate whether patients show a preference between the IV and subcutaneous versions of Keytruda. The results of this study could further strengthen the case for the new formulation and potentially influence its adoption in clinical practice.

As the pharmaceutical industry continues to evolve, innovations like Merck's subcutaneous Keytruda demonstrate the ongoing efforts to improve patient care while navigating complex market dynamics and patent considerations.