Replimune to resubmit RP1 BLA for advanced melanoma after FDA alignment; agency prioritizes review following April 2026 CRL, citing urgent patient need.
By: Regulatory Desk
Replimune Group has reached agreement with the U.S. Food and Drug Administration (FDA) on a path forward for reconsideration of its Biologics License Application (BLA) for RP1 (vusolimogene oderparepvec) in combination with nivolumab in advanced melanoma. The company said it will resubmit the application within days. The FDA indicated it will treat the filing as an urgent matter and prioritize review, underscoring the significant unmet need among patients whose disease has progressed after anti‑PD‑1‑based treatment.
Background: April 2026 CRL
The resubmission follows the FDA’s issuance of a Complete Response Letter (CRL) on April 10, 2026, in which the agency requested additional evidence to support efficacy. Importantly, the FDA did not raise concerns regarding RP1’s safety profile or identify manufacturing issues.
Therapy Profile
RP1 is based on a proprietary herpes simplex virus strain engineered with the fusogenic protein GALV‑GP R⁻ and granulocyte‑macrophage colony‑stimulating factor (GM‑CSF). The therapy promotes direct tumor cell destruction while stimulating a broader anti‑tumor immune response that may enhance the activity of checkpoint inhibitors such as nivolumab.
Clinical Evidence: IGNYTE Trial
Supporting evidence comes from the Phase 2 IGNYTE trial (NCT03767348), which evaluated RP1 plus nivolumab in patients with advanced melanoma progressing after anti‑PD‑1 therapy. The study demonstrated durable anti‑tumor activity in this particularly challenging population, where many patients derive limited benefit from existing options.
Disease Burden
Melanoma is the fifth most commonly diagnosed cancer in the United States, with an estimated 112,000 new cases expected in 2026. Approximately 8,500 Americans die from advanced melanoma each year. While immune checkpoint inhibitors have transformed treatment, nearly half of patients either fail to respond or eventually develop disease progression.
Regulatory Path Ahead
“We are grateful to the FDA leadership for their willingness to engage in a collaborative dialogue towards finding a meaningful path forward for RP1,” said Sushil Patel, Ph.D., Chief Executive Officer of Replimune. “We are encouraged by the agency’s commitment to supporting patients and U.S. innovation and look forward to working closely with the FDA to bring this important therapy to the advanced melanoma community as swiftly as possible.”
The FDA’s decision to prioritize review may accelerate the regulatory timeline for RP1. If approved, the therapy could provide a new treatment option for patients with advanced melanoma who have progressed after anti‑PD‑1 treatment and currently face few effective alternatives.
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