Repare Therapeutics Presents Phase 1 Data on Camonsertib with Radiotherapy at ASTRO Meeting

CAMBRIDGE, Mass. & MONTREAL—Repare Therapeutics Inc. (Nasdaq: RPTX), a clinical-stage precision oncology company, has recently showcased data demonstrating the clinical advantages of camonsertib. This oral small molecule ATR inhibitor, when used in combination with palliative radiation, has shown promising results in treating metastatic tumors with ataxia-telangiectasia-mutated (ATM) mutations. The data, gathered from a clinical trial conducted in partnership with Memorial-Sloan Kettering Cancer Center, were presented at the American Society for Radiation Oncology (ASTRO) annual meeting in Washington, DC by Dr. Nancy Lee, a specialist in radiation oncology and early drug development.

Dr. Maria Koehler, Executive Vice President and Chief Medical Officer of Repare, expressed optimism regarding the early Phase 1 data. She emphasized that this study is the first to combine camonsertib, an ATR inhibitor, with palliative radiation, and the preliminary results indicate potential for significant clinical benefits, especially for patients with pathogenic ATM mutations. According to Dr. Koehler, the response rate and safety profile observed in this Phase 1 trial are highly encouraging.

The study enrolled 17 patients with metastatic tumors characterized by ATM mutations. Among these, 12 had pathogenic ATM mutations, while the remaining 5 had variants of unknown significance (VUS). The primary cancer types included gastrointestinal (5 patients), pancreas (5 patients), breast (2 patients), lung (2 patients), bladder (2 patients), and thyroid (1 patient).

Key findings from the study revealed that the recommended Phase 2 dose for camonsertib is 160 mg, administered once daily before radiation therapy (4Gy) on days 1-5. Interim response data were available for 16 patients at the time of submission. At the 2-month mark, the pathogenic ATM mutation group exhibited 2 complete responses (CR), 5 partial responses (PR), and 4 cases of stable disease (SD). In contrast, the VUS group showed 1 PR and 4 SD. By the 6-month mark, among 9 evaluable patients, the pathogenic group experienced 2 CR, 4 PR, and 1 SD, while the VUS group had 1 SD and 1 case of progressive disease (PD).

Repare Therapeutics Inc. is a precision oncology company that leverages its proprietary synthetic lethality approach to develop novel cancer treatments. Utilizing its genome-wide, CRISPR-enabled SNIPRx® platform, the company focuses on discovering and developing highly targeted therapies addressing genomic instability and DNA damage repair. Repare's pipeline includes lunresertib (RP-6306), a PKMYT1 inhibitor in Phase 1/2 clinical development, and camonsertib (RP-3500), an ATR inhibitor also in Phase 1/2 clinical development. Additionally, the pipeline features RP-1664, a Phase 1 PLK4 inhibitor, and RP-3467, a preclinical Polθ ATPase inhibitor program, alongside other undisclosed preclinical projects.