ORIC Advances Rinzimetostat To Phase 3 After Strong Phase 1b Data In Prostate Cancer

ORIC Pharmaceuticals, Inc. provided an update on its rinzimetostat (ORIC-944) program, highlighting promising Phase 1b data in combination with darolutamide in patients with metastatic castration-resistant prostate cancer (mCRPC) who had previously received abiraterone. The study evaluated two dose levels, with findings supporting strong efficacy signals and a favourable safety profile.

Based on dose optimisation and exposure-response analysis, the 400 mg once-daily dose of rinzimetostat combined with darolutamide was selected as the recommended Phase 3 dose (RP3D). This dose demonstrated comparable efficacy to the higher 600 mg dose but with fewer adverse events and minimal need for dose modifications, making it more suitable for long-term treatment.

“The combination dose optimisation data announced today provide confirmatory evidence that support rinzimetostat’s potential best-in-disease clinical profile, reinforcing its path towards becoming a practice-changing therapy for patients with prostate cancer,” said Jacob M. Chacko, M.D., president and chief executive officer. “The durability observed to date is consistent with the competitor PRC2 inhibitor currently in Phase 3 in mCRPC and appears meaningfully improved relative to other approved standard of care therapies. Notably, rinzimetostat demonstrated this impressive durability with a markedly cleaner safety profile than competitor regimens.”

Preliminary efficacy results at the selected dose showed encouraging outcomes across multiple endpoints. Patients experienced high radiographic progression-free survival (rPFS) rates, with 84% maintained at five months, along with meaningful PSA reductions and strong circulating tumor DNA (ctDNA) responses. These results suggest potential advantages over existing therapies such as Xtandi®, Jevtana®, Taxotere®, and Pluvicto®.

“These data provide compelling validation for advancing rinzimetostat in combination with darolutamide into Phase 3 registrational trials in patients with prostate cancer,” said Pratik S. Multani, M.D., chief medical officer. “We expect our first Phase 3 trial, Himalayas-1, in patients with mCRPC previously treated with abiraterone, to initiate in the first half of 2026 while we continue to evaluate rinzimetostat in additional indications in prostate cancer and beyond.”

Building on these findings, ORIC plans to initiate the global Phase 3 Himalayas-1 trial in the first half of 2026, enrolling approximately 600 patients. The study will compare rinzimetostat plus darolutamide against standard-of-care treatments, targeting a large and underserved market where effective, well-tolerated oral therapies remain limited.