Rucaparib in BRCA-Mutant Metastatic Prostate Cancer: TRITON2 Trial
Posted: Tuesday, September 8, 2020
The phase II TRITON2 study reported that the PARP inhibitor rucaparib appears to have antitumor activity in patients with metastatic castration-resistant prostate cancer with a BRCA1 or BRCA2 gene alteration. “Based on these results, rucaparib was granted accelerated approval by the U.S. Food and Drug Administration for the treatment of men with a deleterious BRCA mutation associated metastatic castration-resistant prostate cancer,” stated Simon Chowdhury, MD PhD, of Guy’s Hospital, London, and colleagues in the Journal of Clinical Oncology.
A total of 115 patients with a deleterious BRCA alteration in their prostate cancer were enrolled in the study. At baseline testing, the disease was assessed by independent radiology review (62 patients) or investigator assessment (65 patients), with 57 patients being assessed via both methods. Patients were treated with 600 mg of rucaparib twice daily, for a median duration of 8.1 months, with follow-up of 17.1 months.
The authors reported an overall response rate for the population that underwent an independent radiology review of 43.5%, compared with 50.8% for the investigator-evaluable population. The best response of stable disease or better occurred in 88.7% of patients in the population that underwent independent radiology review and 89.2% of the investigator-evaluable population, with 8 patients having a confirmed complete response between the two groups. The prostate-specific antigen response rate was reported to be 54.8% for the whole cohort.
The safety profile of rucaparib consistent with prior studies in which rucaparib was used to treat ovarian cancer. Treatment-emergent adverse events occurred in 99.1% of patients, with 60% of patients experiencing events of grade 3 or greater. The most frequently encountered adverse events included asthenia/fatigue, nausea, and anemia/decreased hemoglobin. A total of 73 patients had treatment interruption or dose reduction.
Disclosure: For full disclosures of the study authors, visit ascopubs.org.