RP1 monotherapy showed clear anti-tumor activity with an overall response rate of nearly 35 percent and complete response rate of nearly 22 percent in evaluable patients

SAN DIEGO, CA, USA I April 07, 2024 I Replimune Group, Inc. (NASDAQ: REPL), a clinical stage biotechnology company pioneering the development of a novel portfolio of oncolytic immunotherapies, today announced the presentation of interim results from ARTACUS, a Phase 1/2 clinical trial evaluating RP1 monotherapy for the treatment of skin cancers in patients who have had solid organ or hematopoietic cell transplants, by Michael R. Midgen, M.D., of the University of Texas MD Anderson Cancer Center during an oral session at the AACR 2024 Annual Meeting in San Diego. The results were initially presented late last year at the 38th Annual Meeting of the Society for Immunotherapy of Cancer (SITC).

In the study, treatment with RP1 as monotherapy, for up to 25 doses, resulted in an overall response rate (ORR) of 34.8 percent (8 of 23 evaluable patients, including 5 complete responses and 3 partial responses) with most responses ongoing as of the data cutoff date of September 18, 2023. In the evaluable patient population (n=23), 20 had cutaneous squamous cell carcinoma (CSCC) and three had merkel cell carcinoma. Of note, a patient treated with RP1 for CSCC also had a complete response of a new primary basal cell carcinoma which appeared post baseline. There was no evidence of allograft rejection including of hepatic and lung allografts. RP1 monotherapy was well tolerated, and the safety profile was similar to the profile in non-immunocompromised patients with advanced skin cancers. Additional biomarker data collected showed an increase in CD+8 T, a type of immune cell, and an increase in the expression of PD-L1, after treatment suggesting immune activation. The slides are available on the Replimune website under presentations.

“Organ transplant recipients are at a higher risk for skin cancer when compared to the broader population and have access to a limited number of treatment options given that systemic immunotherapy is typically contra-indicated,” said Sushil Patel, Ph.D., CEO of Replimune. “These data show RP1 as monotherapy has clear anti-tumor activity and may be a safe and effective treatment option for these patients with an overall response rate of nearly 35 percent with good durability of benefit to date.”

ARTACUS is a multicenter, open-label, two-part Phase 1b/2 study evaluating RP1 as monotherapy for the treatment of locally advanced or metastatic cutaneous malignancies in patients who underwent a kidney, liver, heart, lung, or other solid organ transplant, or hematopoietic cell transplantation, who are on chronic immunosuppressive treatment, in whom systemic immunotherapy is typically contra-indicated. Researchers will assess the safety of RP1 and also evaluate its ability to shrink tumors. ARTACUS is currently recruiting patients. To learn more, contact clinicaltrials@replimune.com or +1-781-222-9570.

About RP1
RP1 is Replimune’s lead product candidate and is based on a proprietary new strain of herpes simplex virus engineered and genetically armed with a fusogenic protein (GALV-GP R-) and GM-CSF 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 a novel portfolio of 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 designed to have a unique dual local and systemic 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 ignite 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 www.replimune.com.

SOURCE: Replimune