Replimune Shares Positive RP1 and RP2 Data at 2024 ASCO Meeting

Replimune Group, Inc., a biotech company focusing on oncolytic immunotherapies, presented promising clinical data for its RP1 and RP2 programs at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting held from May 31 to June 4 in Chicago. The presentations highlighted key results from the IGNYTE clinical trial and other studies involving RP1 and RP2, emphasizing their potential in treating difficult tumor types.

The IGNYTE trial, involving RP1 combined with nivolumab in patients with anti-PD-1-resistant melanoma, reported a 12-month overall response rate (ORR) of 32.7%. The responses were durable and consistent with previously reported six-month data. The combination therapy exhibited a favorable safety profile, primarily involving transient grade 1/2 adverse events, indicating systemic immune activation. Notably, the trial showed that in 94 patients who had primary resistance to prior anti-PD-1 therapy, the ORR was 34%. For the 66 patients who had progressed on prior anti-PD-1 combined with anti-CTLA-4 therapy, the ORR was 27.3%. All responses lasted more than six months, with a median duration of response exceeding 36 months. Moreover, over half of the patients experienced either a complete response (CR), partial response (PR), or stable disease (SD).

The company is on track to submit a biologics license application (BLA) for RP1 to the U.S. Food and Drug Administration (FDA) in the second half of 2024. A Phase 3 confirmatory study (IGNYTE-3) is planned, expected to commence before the BLA submission.

Michael Wong, M.D., Ph.D., from The University of Texas MD Anderson Cancer Center, highlighted the promising effects of RP1 in anti-PD-1 failed melanoma, noting its attractive risk-benefit profile compared to other treatments. The unmet need for effective treatments in this patient population is significant, as only about half of melanoma patients respond to first-line treatments.

RP2, another product candidate from Replimune, was also discussed in an oral presentation. In a study involving patients with metastatic uveal melanoma, including those with liver and extra-hepatic metastases, RP2 demonstrated an ORR of 29.4% and a disease control rate (DCR) of 58.8%. RP2, either as a monotherapy or combined with nivolumab, showed a favorable safety profile and durable anti-tumor activity. Biomarker data indicated immune cell infiltration and increased PD-L1 expression in tumors, along with changes in the systemic T cell repertoire following the combination treatment. Replimune is finalizing the protocol for a registration-directed study for RP2 based on FDA feedback.

Replimune's RP1 is a lead product candidate based on a proprietary strain of herpes simplex virus engineered to maximize tumor-killing potency and induce a systemic anti-tumor immune response. RP2, also engineered from the herpes simplex virus, is designed to express an anti-CTLA-4 antibody-like molecule, further enhancing its tumor-targeting capabilities.

The promising data from the RP1 and RP2 programs presented at ASCO 2024 underscores the potential of Replimune's RPx platform in providing new treatment options for patients with hard-to-treat cancers. The company's focus on developing a novel portfolio of oncolytic immunotherapies aims to transform cancer treatment by maximizing the immunogenicity of tumor cell death and activating systemic anti-tumor immune responses.