What's Behind REPL's Impressive 131% Surge Over Three Months?

Replimune Group’s stock has climbed substantially by 131.1% in the three-month period, marking a significant turnaround driven by encouraging regulatory developments. The catalyst centers on the FDA’s recent acceptance of a resubmitted biologics license application (BLA) for the company’s lead candidate RP1, designed to work in combination with Bristol Myers’ Opdivo (nivolumab), targeting advanced melanoma treatment. Regulatory authorities have designated April 10, 2026, as the decision timeline, providing investors with clear visibility on the approval pathway.

The Journey From Setback to Progress

The current momentum follows an earlier regulatory obstacle. In July 2025, the FDA issued a complete response letter (CRL) that raised specific concerns about data consistency across the IGNYTE study population. The regulatory body questioned whether the study design met standards for demonstrating therapeutic efficacy and requested clarification on how individual treatment components contributed to the results. Notably, the agency did not flag any safety issues with the RP1/Opdivo combination.

Rather than accept this outcome, Replimune engaged in comprehensive discussions with FDA reviewers to address the identified gaps. The company restructured its clinical data presentation and refined the trial design documentation. The FDA subsequently confirmed that the resubmitted materials adequately resolved the prior concerns, paving the way for the application’s formal acceptance.

Clinical Evidence Supporting Market Confidence

The renewed investor optimism reflects tangible clinical progress. At the ESMO Congress in October, Replimune presented additional IGNYTE phase II findings highlighting performance in acral melanoma patients. Within this subgroup, the RP1/Opdivo combination demonstrated a 44% objective response rate with a median response duration extending to 11.9 months—metrics that suggest meaningful clinical benefit.

Beyond melanoma, the investigational drug pairing has shown encouraging safety and efficacy signals in non-melanoma skin cancer patients. The company is simultaneously progressing a larger phase III study comparing RP1/Opdivo versus standard treatment options in melanoma patients who have progressed following anti-PD1 and anti-CTLA-4 therapies.

Replimune’s pipeline extends beyond RP1, with a second oncolytic immunotherapy candidate, RP2, advancing through mid-to-late stage development for metastatic uveal melanoma and hepatocellular carcinoma indications.

What the Approval Timeline Means

For shareholders, the April 2026 decision date removes uncertainty that had previously weighed on valuations. This clarity—combined with FDA confirmation that resubmitted data adequately addresses prior objections—has restored confidence in the program’s viability. The stock’s three-month appreciation reflects this shift from regulatory risk to visible pathway forward, with the potential for a meaningful approval decision within 12 months.