Phase III TRITON3 trial of Rubraca meets primary endpoint in prostate cancer

Benefit was observed in both primary efficacy analyses of patients with chemotherapy-naïve metastatic castration-resistant prostate cancer (mCRPC): first, those who had mutations in BRCA, as well as all patients randomized in the trial, inclusive of mutations in BRCA or ATM (the overall intent-to-treat population (ITT)). The Rubraca arm (n=201) achieved statistical significance over the control arm (n=101) for the primary endpoint of rPFS with a hazard ratio of 0.50 (95% CI: 0.36-0.69). The median PFS for the population of patients with BRCA mutations treated with Rubraca was 11.2 months vs 6.4 months among those who received physician’s choice.

There was a significant Improvement in rPFS in the ITT population, inclusive of those with BRCA or ATM mutations. Rubraca also showed statistical significance in all 405 patients randomized in TRITON3. The Rubraca arm (n=270) successfully achieved statistical significance over the control arm (n=135) for the primary endpoint of rPFS with a hazard ratio of 0.61 (95% CI: 0.47-0.80). The median PFS for all patients enrolled in TRITON3 and treated with Rubraca was 10.2 months vs 6.4 months among those who received physician’s choice (p=0.0003).

The safety profile of Rubraca observed in the TRITON3 study was consistent with Rubraca labelling. During the first quarter of 2023, the Company plans to submit a supplemental New Drug Application (sNDA) to the FDA for the BRCA subgroup of patients and intends to discuss with the FDA submitting for the broader ITT population. Clovis Oncology will submit an expanded description of the TRITON3 results for presentation in a scientific session at the Prostate Cancer Foundation Annual Scientific Retreat later this month and plans to submit additional data to a medical meeting in early 2023.