Replimune Presents Late-Breaking Abstract and Additional Posters on RP1 at 40th Annual Meeting of the Society for the Immunotherapy of Cancer (SITC 2025)
Oral presentation of biomarker data shows RP1 plus nivolumab reverses multiple resistance mechanisms to PD-1 blockade in advanced melanoma following definitive anti-PD-1 failure
WOBURN, Mass., Nov. 07, 2025 (GLOBE NEWSWIRE) -- Replimune Group, Inc. (NASDAQ: REPL), a clinical stage biotechnology company pioneering the development of novel oncolytic immunotherapies, today announced that biomarker data and updated clinical data from the IGNYTE clinical trial of RP1 plus nivolumab was presented as a late-breaking abstract during an oral session at the 40th Annual Meeting of the Society for the Immunotherapy of Cancer (SITC 2025) in National Harbor, Maryland. Two additional posters on RP1 are also being presented.
“These data are important because they demonstrate that RP1 plus nivolumab can potentially reprogram the tumor microenvironment and reverse mechanisms of resistance to immune checkpoint blockade,” said Kostas Xynos, M.D., Ph.D., Chief Medical Officer of Replimune. “Low T cell levels in tumors, tumor PD-L1 expression, T-cell activation and IFNy gene signature expression, as well as the loss of antigen presentation machinery are well known mechanisms of resistance to immune checkpoint blockade.”
Data from the late-breaking abstract (#1327) presented by Trisha Wise-Draper, M.D., Ph.D., show:
- Pharmacodynamic changes that were not achieved during prolonged prior anti–PD-1 therapy demonstrate that the addition of RP1 reverses multiple resistance mechanisms to PD-1 blockade and highlights the contribution of RP1 in melanoma patients who previously failed such treatment.
- Treatment with RP1 plus nivolumab led to upregulation of gene signatures associated with responsiveness to PD-1 blockade.
- With additional follow-up (7 months), RP1 combined with nivolumab continues to demonstrate a clinically meaningful response rate (ORR: 33.6%) and durability (median duration of response: 24.8 months).
- Consistent duration of response was observed across PD-L1–positive and negative tumors, as well as in both primary and secondary resistance settings. Median duration of response for PD-L1-negative patients was 24.8 months and for patients with primary resistance was 22.6 months.
Additional posters being presented at the meeting include:
- Abstract 611: RP1 plus nivolumab in patients with and without prior BRAF-directed therapy: A subgroup analysis of patients with anti-PD-1 failed BRAF-mutant melanoma from the IGNYTE clinical trial (Katy Tsai, M.D.)
- RP1 plus nivolumab demonstrated comparable efficacy in BRAF-mutant and BRAF–wild-type advanced melanoma.
- Greater activity was observed in BRAF-naïve patients – similar to findings from the SECOMBIT and DREAMseq trials.
- Abstract 600: Retreatment with RP1 in combination with nivolumab in patients with advanced anti-PD-1- failed melanoma (Gino K. In, M.D.)
- Extended RP1 treatment beyond 8 doses was well tolerated providing clinical benefit in a majority of patients.
About IGNYTE
The IGNYTE phase 2 cohort enrolled 140 patients with stage IIIB-IV cutaneous melanoma and confirmed progression on anti-PD1- based therapy for > 8 weeks as the last prior treatment. RP1 was administered intratumorally into superficial and/or deep/visceral tumors once every 2 weeks for up to 8 doses (≤10 mL per cycle) with intravenous nivolumab (240 mg); nivolumab was then given alone (240 mg every 2 weeks or 480 mg every 4 weeks) for up to 2 years, with further RP1 allowed if indicated.
About RP1
RP1 (vusolimogene oderparepvec) is Replimune’s lead product candidate and is based on a proprietary strain of herpes simplex virus engineered and genetically armed with a fusogenic protein (GALV-GP R-) and GM-CSF, intended to maximize tumor killing potency, the immunogenicity of tumor cell death, and the activation of a systemic anti-tumor immune response.
About Replimune
Replimune Group, Inc., headquartered in Woburn, MA, was founded in 2015 with the mission to transform cancer treatment by pioneering the development of novel oncolytic immunotherapies. Replimune’s proprietary RPx platform is based on a potent HSV-1 backbone intended to maximize immunogenic cell death and the induction of a systemic anti-tumor immune response. The RPx platform is intended to ignite local activity consisting of direct selective virus-mediated killing of the tumor resulting in the release of tumor derived antigens and altering of the tumor microenvironment to then activate a strong and durable systemic response. The RPx product candidates are expected to be synergistic with most established and experimental cancer treatment modalities, leading to the versatility to be developed alone or combined with a variety of other treatment options. For more information, please visit .
Forward Looking Statements
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