FDA Panel Votes 10-3 to Back Replimune's RP1 in Melanoma, Sending Shares Soaring After Hours

An FDA advisory committee voted 10-3 on July 30, 2026 that the benefit-risk profile of Replimune’s (REPL) RP1 plus nivolumab is favorable for adults with advanced melanoma who have progressed on anti-PD-1 therapy, delivering a surprising rebuke to the agency’s own review staff and sending the stock soaring 39% in after-hours trading.

REPL closed at $5.41 on July 29 and was trading at $8.41 after hours on July 30, up $2.37 (39.2%), according to Public.com. The stock had been crushed 32% two days earlier when FDA briefing documents called the IGNYTE trial data “not interpretable.” The after-hours rebound retraced most of that crash.

The Cellular, Tissue, and Gene Therapies Advisory Committee (CTGTAC) voted on whether the Phase 1/2 IGNYTE single-arm trial demonstrated substantial evidence of effectiveness for RP1 (vusolimogene oderparepvec) in combination with Bristol Myers Squibb’s Opdivo (nivolumab) in patients with unresectable advanced cutaneous melanoma who progressed after anti-PD-1 therapy. Ten panelists voted yes; three voted no.

What the panel said

“I voted yes for various reasons, but I also share some hesitation that other people have explained. The FDA did a wonderful job in pointing out some deficits of this trial design,” said Melinda L. Yushak, MD, MPH, assistant professor at Emory University School of Medicine and co-chair of the Melanoma Working Group at Winship Cancer Institute. “Ninety-six percent of patients had 12 weeks or more of PD-1-based therapy, and they had confirmatory scans confirming they had progression. This is a very hard-to-treat patient population. The only thing that changed was these patients received RP1 and had some complete responses and some partial responses.”

Yushak added: “We do need the phase 3 data to fully answer this question. Also as a community, we need to figure out how to better design trials for intratumoral therapies.”

The dissenting votes focused on the statistical uncertainty. “I did vote no because it’s my profession to have the level of evidence and evaluation. I’m not in the clinically meaningful side of things, so my vote is driven by that. There is so much uncertainty to what that overall response rate is,” said Karla Ballman, PhD, chair of the Division of Clinical Trials and Biostatistics at the Mayo Clinic.

The data behind the vote

The IGNYTE trial enrolled 140 patients with advanced melanoma who had confirmed disease progression on an anti-PD-1 regimen. By independent central review, the confirmed objective response rate was 33.6% by modified RECIST v1.1 criteria, including a 15.0% complete response rate. Median duration of response exceeded 35 months in an earlier analysis.

A 3-year landmark overall survival analysis presented at the 2026 ASCO Annual Meeting showed a median OS of 32.9 months, with 1-year, 2-year, and 3-year OS rates of 75.3%, 61.5%, and 47.8%. Median OS was not reached among responders, compared with 18.5 months among non-responders.

The FDA’s briefing documents, released July 28, had argued the response assessment methods were “unreliable,” that responses could be due to direct tumor injection rather than a systemic effect, and that the contribution of RP1 to the combination “cannot be established.” The panel largely rejected that argument, weighing the unmet need in a population with no approved options after anti-PD-1 failure.

Third try after two rejections

RP1 has been rejected by the FDA twice. The first Complete Response Letter in July 2025 said IGNYTE was not “an adequate and well-controlled clinical investigation.” A second CRL in April 2026 maintained the same objection. The June 2026 resubmission was classified as a Class 1 response, the most expedited review type, setting the August 2 PDUFA date and triggering today’s AdComm.

The vote comes under new FDA leadership at CBER. STAT News reported that earlier resistance to RP1 was driven by former top oncology regulator Rick Pazdur and former CBER director Vinay Prasad, both of whom have since departed. The panel’s endorsement suggests the agency’s posture has shifted.

What to watch next

The August 2 PDUFA date falls on a Sunday, meaning the FDA may act Friday July 31 or Monday August 3. The FDA typically follows its advisory committees but is not bound by them. A positive vote does not guarantee approval, but it shifts the odds. REPL closed at $11.20 on July 31 (Polygon), more than doubling from the $5.41 July 29 close. Cantor Fitzgerald upgraded the stock to Overweight with a $12 price target. The confirmatory Phase 3 IGNYTE-3 trial (NCT06264180) is ongoing, randomly assigning patients to RP1 plus nivolumab against a physician’s choice comparator, and would serve as the basis for any post-marketing confirmatory requirement.

Replimune has no approved products and no revenue. At the July 31 close of $11.20, the company’s market cap sits near $1.0 billion. A third CRL would be catastrophic. An approval would mark the first oncolytic virus immunotherapy for melanoma and validate a platform that Replimune has spent years building.

For the full background on RP1’s regulatory history and the briefing documents that crashed the stock, see our earlier coverage and our PDUFA preview.

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