Replimune Stock Awaits FDA Decision After Panel Backing

Replimune said in a press release on July 30, 2026, that the FDA’s Cellular, Tissue, and Gene Therapies Advisory Committee voted 10–3 that efficacy data from the IGNYTE trial for RP1 plus nivolumab were evaluable, drawing renewed focus on Replimune stock ahead of the Aug. 2, 2026 action date.

FDA Panel Supports RP1 Efficacy Data Amid Ongoing Review

The advisory committee’s 10–3 vote on July 30, 2026, found the IGNYTE trial efficacy results for RP1 plus nivolumab “evaluable and clinically meaningful,” according to the company’s press release. The vote is non-binding but adds momentum to Replimune’s Biologics License Application (BLA) resubmission seeking accelerated approval. The FDA’s target action date is Aug. 2, 2026, and no approval has been granted as of July 31.

The RP1 BLA has undergone three review cycles, including two Complete Response Letters (CRLs). The first, issued in July 2025, cited the pivotal study’s heterogeneous population and the inability to isolate RP1’s contribution in the combination. The second CRL in April 2026 reiterated concerns about relying on a single-arm study without a control group. FDA staff briefing documents released on July 28, 2026, maintained skepticism about the evidence, highlighting issues with response assessment, duration of response, and survival analyses. Several committee members who voted in favor described the data as “messy” or borderline, reflecting ongoing reservations despite their support.

Trial Data and Confirmatory Study Timeline

The IGNYTE trial (RPL-001-16) is a single-arm, multicenter Phase 1/2 study enrolling about 140 patients with anti-PD-1–refractory advanced cutaneous melanoma. All participants received RP1, a locally injected oncolytic immunotherapy, combined with nivolumab, an anti-PD-1 agent. There was no concurrent control arm. Tumor responses were evaluated using RECIST v1.1 criteria at the FDA’s request. Reviewers noted that local injection can cause shrinkage confined to injected lesions, raising questions about systemic antitumor activity in this population with limited treatment options.

Replimune reported an objective response rate (ORR) of 33.6% (95% confidence interval [CI] 25.8–42.0%) in the key cohort, with a median duration of response (DOR) of 24.8 months and about a 15% complete remission rate. FDA staff reanalyzed the data, excluding responders whose target lesions were all injected or who had no target lesions at baseline. This adjusted assessment yielded an ORR of 15.7% (95% CI 10.1–22.8%) and a median DOR of 14.1 months. Reviewers noted that more than 53% of company-reported responders lacked non-injected target lesions, limiting interpretation of systemic benefit.

Replimune presented an overall survival analysis showing responders lived significantly longer than non-responders, but FDA scientists said this analysis is not interpretable in a single-arm context. The agency has indicated that randomized, controlled evidence is necessary to isolate RP1’s contribution. The ongoing randomized confirmatory trial, IGNYTE-03, was about 10% enrolled at the time of the first resubmission, suggesting a multi-year horizon for definitive results. External analyses estimate confirmatory data may not be available until late 2027 if approval is deferred.

The company presented updated clinical data and three-year survival analyses at major oncology meetings in late May 2026 as part of its resubmission.

Regulatory Outlook and Next Steps

The FDA must issue a decision by the Aug. 2, 2026 action date. While the advisory vote is non-binding, it is likely to influence the agency’s deliberations. The FDA will either grant accelerated approval based on tumor response data or require additional randomized evidence, determining the timeline for when confirmatory results from the ongoing trial will become decisive for RP1’s future.