Repare Therapeutics announces data from Phase 1 MYTHIC clinical trial

Repare Therapeutics reported initial data from Modules 1 and 2 of its ongoing Phase 1 MYTHIC clinical trial evaluating lunresertib alone and in combination with camonsertib, an ATR inhibitor. The data are being presented in a plenary session titled, “New Drugs on the Horizon” at the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics, being held October 11-15, 2023 in Boston, Mass. “The data presented today, although early, are highly promising as lunresertib in combination with camonsertib results in clear clinical activity across several tumor types and genotypes along with a favorable safety and tolerability profile,” said Dr. Timothy A. Yap, MBBS, PhD, FRCP, Professor in the Department of Investigational Cancer Therapies and Vice President, Head of Clinical Development in the Therapeutics Discovery Division at The University of Texas MD Anderson Cancer Center and Principal Investigator on the MYTHIC trial. MYTHIC, a first-in-human, global, open-label Phase 1 dose-escalation clinical trial to evaluate safety, pharmacokinetics, pharmacodynamics and preliminary anti-tumor activity of lunresertib as a monotherapy or in combination with camonsertib in patients with advanced solid tumors harboring CCNE1 amplification or FBXW7 or PPP2R1A deleterious alterations achieved clinical proof of concept. As of September 5, 2023, the cutoff date for the data presented at the AACR-NCI-EORTC conference, 67 patients were enrolled in Module 1 and 59 patients in Module 2. Protocol-defined overall response at the combination preliminary recommended phase 2 dose was 33.3%; CBR at the combination preliminary RP2D was 50.0%. In all evaluable patients, across all doses, OR was 23.6% and CBR was 41.8%. In patients with gynecologic tumors at the combination preliminary RP2D, the RECIST response was 50%, OR 60%, and CBR 70%. Patients in this cohort had a median of 3 and up to 9 prior lines of therapy. Patient enrollment in MYTHIC continues both to optimize the schedule for the combination and to further investigate the promising antitumor signals seen to date in a larger number of patients with selected tumors and genomic alterations.