FDA Accepts Clovis Oncology's Supplemental Drug Application for Rubraca in Advanced Prostate Cancer

NEW YORK – Clovis Oncology said on Wednesday that the US Food and Drug Administration accepted its supplemental new drug application of rucaparib (Clovis' Rubraca) as a treatment for BRCA1/2-mutated metastatic castrate-resistant prostate cancer. 

Additionally, the FDA granted priority review status to rucaparib in this setting. 

The FDA submission is based on the results of the TRITON trials. The company announced during the JP Morgan Conference in San Francisco that their Phase III TRITON3 trial is now openly enrolling patients and will serve as the confirmation data if the application based on the Phase II TRITON2 trial is accepted for accelerated approval. The latest data from the trial reported a 43.9 percent confirmed objective response rate. In addition, a 52.0 percent confirmed prostate-specific antigen response rate was observed in 98 response-evaluable patients who had a BRCA1/2 mutation. Responses to the drug were durable with 60 percent lasting 24 weeks or longer.

"Recently presented data suggests that Rubraca may play a meaningful role in the treatment of patients with BRCA1/2-mutant recurrent, metastatic castrate-resistant prostate cancer, and this filing represents an important milestone for Clovis as it brings us one step closer to potentially making this valuable therapy available," Clovis CEO Patrick J. Mahaffy said in a statement.

Approximately 43,000 patients are expected to be diagnosed with metastatic castrate-resistant prostate cancer in 2020, and up to 12 percent are expected to have a germline and/or somatic mutation in BRCA1 or BRCA2.

Rucaparib is an oral, small molecule inhibitor of PARP1, PARP2, and PARP 3. It was granted accelerated approval in late 2016 for advanced ovarian cancer patients with germline or somatic BRCA mutations who have undergone two or more chemotherapies. With that approval, the agency concurrently approved Foundation Medicine's FoundationFocus CDx BRCA test to identify patients with BRCA mutations. 

In 2018, rucaparib received supplemental approval as a maintenance treatment for patients with epithelial ovarian, fallopian tube, or primary peritoneal cancer who have been treated with two or more chemotherapies. In this setting the drug was efficacious in all patients, regardless of biomarker status. However, the FDA approved Foundation Medicine's FoundationFocus CDx BRCA LOH as a complementary diagnostic to identify patients with homologous recombination deficiency who tended to derive a greater magnitude of benefit in studies.