Rucaparib is the first PARP inhibitor that has been approved in a prostate cancer setting.
The FDA has approved rucaparib (Rubraca, Clovis Oncology) for monotherapy treatment in adult patients with a deleterious BRCA mutation (germline and/or somatic)-associated metastatic castration-resistant prostate cancer (mCRPC) who have received androgen receptor-director therapy and a taxane-based chemotherapy, according to a press release.
Nearly 192,000 men in the United States will be diagnosed with prostate cancer in 2020, and of those, approximately 43,000 are expected to be diagnosed with mCRPC, according to the American Cancer Society. Castration-resistant prostate cancer has a high risk of developing metastases and is an incurable disease.
Rucaparib is an oral, small molecule inhibitor of poly (ADP-ribose) polymerase (PARP)1, PARP2, and PARP3 that is currently being considered as monotherapy and in combination with other anti-cancer agents for multiple tumor types, including ovarian and mCRPC. It is also being examined for other cancer types as well.
“The data from the TRITON2 clinical trial supporting the FDA approval of Rubraca in mCRPC have been highly consistent over time, and we are pleased that the FDA has granted an accelerated approval for Rubraca in this third indication,” said Patrick J. Mahaffy, president and chief executive officer of Clovis Oncology. “We are proud to offer Rubraca as a new treatment option to physicians and eligible prostate cancer patients with a deleterious BRCA mutation beginning today.”
Accelerated approval of rucaparib was based on the multi-site, single-arm TRITON2 clinical trial that aimed to assess objective response rate (ORR) and duration of response (DOR) through analysis of 62 RECIST-evaluable patients with a BRCA (germline and/or somatic) mutation and measure disease (IRR); 115 patients with a BRCA (germline and/or somatic) mutation and measurable or non-measurable disease; and 209 patients with HRD-positive mCRPC. Data was assessed by independent radiologic review (IRR).
The TRITON2 clinical trial showed favorable results, including a confirmed 44% ORR by blinded-IRR assessment. Median DOR by blinded-IRR was not able to be evaluated by the data cut-off date. In addition, the trial found that, of the 115 patients with a germline and/or somatic deleterious BRCA mutation and measurable or non-measurable disease, 55% demonstrated a confirmed prostate specific antigen (PSA) response rate.
The most common adverse events in the BRCA mutation population were asthenia/fatigue, nausea, anemia, ALT/AST increased, decreased appetite, constipation, rash, thrombocytopenia, vomiting, and diarrhea.
In the news release, Clovis Oncology noted that they expect to purse the confirmatory study for rucaparib in their TRITON3 clinical trial.
“Standard treatment options for men with mCRPC have been limited to androgen receptor-targeting therapies, taxane chemotherapy, Radium-223 and sipuleucel-T,” said Wassim Abida, MD, medical oncologist, Memorial Sloan Kettering Cancer Center, and principal investigator for the TRITON2 study. “Rubraca is the first in a class of drugs to become newly available to patients with mCRPC who harbor a deleterious BRCA mutation. Given the level and duration of responses observed with Rubraca in men with mCRPC and these mutations, it represents an important and timely new treatment option for this patient population.”
1. Rubraca (Rucaparib) Approved in the US as Monotherapy Treatment for Patients with BRCA1/2-Mutant, Metastatic Castration-Resistant Prostate Cancer (mCRPC) Who Have Been Treated with Androgen Receptor-Directed Therapy and a Taxane-Based Chemotherapy. News Release. Business Wire; May 15, 2020. Accessed May 18, 2020. https://www.businesswire.com/news/home/20200515005527/en/Rubraca®-Rucaparib-Approved-U.S.-Monotherapy-Treatment-Patients.