NEW YORK – Clovis Oncology on Monday said it plans to submit a supplemental new drug application to the US Food and Drug Administration for its PARP inhibitor Rubraca (rucaparib) as a treatment for patients with BRCA1/2-mutant metastatic castration-resistant prostate cancer based on positive results from a Phase III TRITON3 study.
The firm expects to submit the sNDA for this indication in the first quarter of 2023, and also discuss with the agency data on the entire prostate cancer patient population in the TRITON3 trial, which included those with either BRCA1/2 or ATM mutations.
In TRITON3, Rubraca was evaluated as a monotherapy against physician's choice of chemotherapy or androgen deprivation therapy. The trial enrolled 405 patients with chemotherapy-naïve metastatic castration-resistant prostate cancer harboring a mutation in BRCA1/2 or ATM. In the BRCA1/2-mutant group, the median progression-free survival on Rubraca was 11.2 months versus 6.4 months for those in the comparator arm.
In the whole study population, including patients with BRCA1/2 and ATM mutations, treatment with Rubraca also significantly improved median progression-free survival compared to physician's choice of chemo or androgen deprivation therapy, 10.2 months versus 6.4 months, respectively. However, when researchers analyzed outcomes just for patients with ATM mutations, the improvement was less pronounced, with a median progression-free survival of 8.1 months on Rubraca versus 6.8 months in the control arm.
"Men with this type of metastatic prostate cancer want to get their genetically targeted therapy as early as possible, and this trial clearly shows the value of rucaparib as a treatment for these men," Alan Bryce, principal investigator of the TRITON3 trial and chair of the division of hematology and medical oncology at the Mayo Clinic and principal investigator of the TRITON3 trial, said in a statement. "A key point is that rucaparib can replace chemotherapy in this setting. The current standard of care for these men is chemotherapy with docetaxel, and rucaparib is the only PARP inhibitor which has beaten a docetaxel-containing control arm in a clinical trial."
Rubraca is currently approved in the US as a treatment for recurrent ovarian cancer and BRCA1/2-mutant prostate cancer patients who have been previously treated with an androgen receptor-directed therapy and a taxane-based chemotherapy. If the drug is approved based on the latest data, it would also be available for a subset of chemotherapy-naïve prostate cancer patients.
Clovis plans to present results from TRITON3 at the Prostate Cancer Foundation Annual Scientific Retreat and at a medical meeting in 2023.