Advisers vote 10-3 for Replimune's melanoma virus

After two FDA rejections, an advisory panel backed RP1's effectiveness in advanced melanoma; the agency's own decision was due Aug. 2.

An FDA advisory committee voted 10 to 3 that Replimune's RP1 — an oncolytic virus also called vusolimogene oderparepvec, or Tudriqev — produced clinically meaningful data in advanced melanoma when combined with Bristol Myers Squibb's Opdivo. The agency had rejected it twice: last July, deeming the phase 1/2 Ignyte trial neither adequate nor well-controlled, and again in April, calling the resubmitted data insufficient. That second rejection cost the company 60% of its workforce. The FDA is not bound by the vote; a decision was slated for Aug. 2.

The dispute is about measurement. Ignyte enrolled 140 patients whose disease had progressed on an anti-PD-1 drug, and Replimune puts the overall response rate at 33.6%. The FDA counters that the trial departed from RECIST v1.1 — investigators could re-inject tumours after progression and still count later shrinkage as response — and that limiting the analysis to patients with uninjected target lesions, the ones that test for a systemic effect, drops the rate to 15.7%. The three no votes came from advisers who could not get past those methodology problems.

For patients whose melanoma has outrun PD-1 drugs, re-treatment yields a 5% to 10% response and the standard alternative is TIL therapy — months long, hard to access, with serious side effects. An injected virus with a simpler safety profile would widen who can actually receive treatment, not just lengthen the list of options.

Watch the FDA's own decision and the ongoing phase 3 Ignyte-3 trial, which most advisers said the real answer depends on.

Source: Fierce Biotech