An approved therapy for advanced ovarian cancer — Rubraca (rucaparib) by Clovis Oncology — has been designated a breakthrough therapy by the U.S. Food and Drug Administration as a potential treatment for metastatic castration-resistant prostate cancer (mCRPC) patients with BRCA mutations.
This FDA designation is given to speed the development of medications that might treat serious conditions and potentially provide an improvement on available therapies.
“We hope the decision by the FDA to grant this Breakthrough Therapy designation for Rubraca offers encouragement to the prostate cancer community, and we will do our best to make Rubraca available to eligible prostate cancer patients as quickly as possible,” Patrick J. Mahaffy, president and CEO of Clovis Oncology, said in a press release.
About a quarter of advanced prostate cancers show mutations in BRCA1, BRCA2 or other genes encoding proteins that repair damaged DNA. These tumors are more sensitive to further DNA damage, and often respond well to treatments that block other proteins involved in DNA repair.
Rubraca is an oral medicine that inhibits PARP1, PARP2, and PARP3 enzymes, which play a key role in DNA repair when the BRCA proteins are not functioning properly.
The FDA based its decision on preliminary results from TRITON 2 study, which will be presented for the first time at the European Society for Medical Oncology (ESMO) 2018 Congress in Munich, and at the 25th Annual Scientific Retreat of the Prostate Cancer Foundation in Carlsbad, California, later this month.
The Phase 2 trial (NCT02952534) is testing the efficacy and safety of Rubraca (600 mg twice a day) in mCRPC patients who have inherited or acquired BRCA mutations, and who were already treated with androgen receptor-directed therapy and taxane-based chemotherapy.
Its primary goal is to determine the proportion of patients who respond to Rubraca, and those who achieve a significant lowering of their PSA levels. Secondary measures include duration of response, time to disease progression or death, and overall survival.
“We are pleased the FDA has granted Breakthrough Therapy designation to Rubraca in mCRPC,” said Howard R. Soule, PhD, executive vice president and chief scientific officer of the Prostate Cancer Foundation.
“There is tremendous need for new therapeutic options in advanced prostate cancer. In particular, we are enthusiastic about the potential for targeted therapies that may provide more meaningful benefits to patients with specific genetic mutations,” Soule added.
Enrollment in TRITON2 is ongoing. The trial expects to evaluate about 160 patients from at least 100 worldwide locations, and to study other mutations besides BRCA1/2.
Rubraca was approved by the FDA in April as a maintenance treatment for people with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in a complete or partial response to platinum-based chemotherapy.