Core Insights - Replimune Group, Inc. presented biomarker data and updated clinical data from the IGNYTE clinical trial of RP1 plus nivolumab at the SITC 2025 meeting, indicating potential to reverse resistance mechanisms to PD-1 blockade in advanced melanoma patients who previously failed anti-PD-1 therapy [1][2] Company Overview - Replimune Group, Inc. is a clinical stage biotechnology company focused on developing novel oncolytic immunotherapies, with its lead product candidate RP1 based on a proprietary strain of herpes simplex virus [4][6] - The company aims to transform cancer treatment by maximizing tumor killing potency and activating systemic anti-tumor immune responses through its RPx platform [6] Clinical Trial Insights - The IGNYTE phase 2 cohort included 140 patients with stage IIIB-IV cutaneous melanoma who had confirmed progression on anti-PD-1 therapy for over 8 weeks [3] - RP1 was administered intratumorally every two weeks for up to 8 doses, combined with intravenous nivolumab, which was then given alone for up to 2 years [3] Efficacy and Response Rates - The combination of RP1 and nivolumab demonstrated a clinically meaningful overall response rate (ORR) of 33.6% and a median duration of response of 24.8 months, with consistent results across different tumor types [5] - The treatment showed comparable efficacy in BRAF-mutant and BRAF-wild-type advanced melanoma, with greater activity observed in BRAF-naïve patients [5] Mechanism of Action - RP1 plus nivolumab was shown to upregulate gene signatures associated with responsiveness to PD-1 blockade, reversing multiple resistance mechanisms that were not addressed during prior anti-PD-1 therapy [5]