Replimune's Third Attempt Succeeds: FDA Grants Accelerated Review for RP1 in Advanced Melanoma

Replimune secures FDA priority review for RP1 plus Nivolumab in advanced melanoma, buoyed by updated 32.9% response rate and durable 33.7-month median response.

Just months after a second rejection appeared to seal the fate of its lead immunotherapy, Replimune has pulled off an unexpected regulatory reversal. The US Food and Drug Administration has agreed to a prioritised review of RP1—a combination therapy with Nivolumab for advanced melanoma patients who have exhausted standard checkpoint inhibitors. The breakthrough follows the departure of FDA Commissioner Marty Makary in May 2026, a change that industry observers say may have opened the door for a fresh assessment of stalled applications.

The company's previous attempt in April 2026 was rebuffed over concerns about the IGNYTE study design and the difficulty of isolating RP1's individual contribution to the treatment effect. That setback triggered a severe cost-cutting programme, including lay-offs and a sharp scale-back of US manufacturing. With this new agreement, Replimune has effectively resuscitated a programme that was teetering on the edge.

The renewed optimism rests on updated data from IGNYTE, a 140-patient trial. The objective response rate stands at 32.9%, with complete remissions observed in 15% of patients—a notable figure in a population where around half do not derive lasting benefit from existing checkpoint inhibitors. Crucially, no treatment-related deaths occurred, and the median duration of response stretched to 33.7 months, pointing to durable disease control. The FDA's decision to grant priority review reflects the high unmet need: around 8,500 Americans die from skin cancer each year, and effective second-line options remain scarce.

The timing of the regulatory thaw coincides with the start of the ASCO 2026 annual meeting in Chicago, where Replimune is scheduled to present long-term overall survival data from the study. Investors will be watching closely for three-year survival figures that could reinforce the case for a full approval.

At the stock level, the news has already triggered sharp pre-market gains, though analysts remain split. Some have raised their price targets on the back of the FDA agreement, while others caution that the drug's history of regulatory turbulence warrants a measured outlook. Replimune operates in a fiercely contested field—more than 2,500 immunotherapy programmes are currently in development worldwide—and a single green light does not eliminate the competitive risk.

Replimune now faces the task of quickly resubmitting its dossier. If approval follows, RP1 would become a critical option for a patient group that has long been underserved by existing therapies. For a company that was forced into survival mode just weeks ago, the pendulum has swung decisively back in its favour.