FDA Cancer Regulator Rejects Replimmune's Melanoma Drug, Impacting Stock

What's Happening?

Replimmune's advanced melanoma drug, RP1, faced a surprise rejection from the FDA, with the agency's top cancer regulator, Richard Pazdur, directly intervening to issue the complete response letter. The rejection was reportedly due to concerns about the trial design, where the drug's tumor-killing effect could not be separated from the effect of the immunotherapy Opdivo. This decision led to a significant drop in Replimmune's stock, which fell 75% after the rejection and continued to decline. The rejection followed a debate at a conference attended by Pazdur and Vinay Prasad, the then-CBER director, who ultimately deferred to Pazdur's judgment.

Why It's Important?

The FDA's rejection of RP1 highlights the complexities and challenges in drug approval processes, particularly for innovative treatments like immunotherapies. This decision impacts Replimmune financially, as evidenced by the sharp decline in its stock value, and raises questions about the regulatory hurdles faced by biotech companies. The intervention by a high-ranking FDA official underscores the importance of trial design and data integrity in drug approvals, which can have significant implications for the biotech industry and investors.

What's Next?

Replimmune plans to request a follow-up meeting with the FDA to understand the reasons behind the rejection and explore potential paths forward. This could involve revisiting the trial design or providing additional data to address the FDA's concerns. The outcome of these discussions will be crucial for Replimmune's future strategy and its ability to bring RP1 to market.