SAN RAFAEL, Calif., June 3, 2013 (GLOBE NEWSWIRE) -- BioMarin Pharmaceutical Inc. (Nasdaq:BMRN) today announced an update on the ongoing Phase 1/2 study for its poly ADP-ribose polymerase (PARP) inhibitor BMN 673 for the treatment of solid tumors. BMN 673 has exhibited substantial single-agent anti-tumor activity in deleterious germline BRCA ovarian and breast cancers in the trial. The data were presented during a poster presentation at the 2013 American Society of Clinical Oncology Annual Meeting. In the 28 gBRCA ovarian cancer patients, the RECIST response rate was 44% or 11 of 25 evaluable patients, the CA-125 response rate was 70% or 19 of 27 evaluable patients and the clinical benefit response rate was 82% or 23 of 28 patients. In the 18 gBRCA breast cancer patients, the RECIST response rate was 39% or 7 of 18 patients and the clinical benefit rate was 67% or 12 of 18 patients. Of the 18 gBRCA breast cancer patients, there were six partial responses (three yet to be confirmed) and one complete response. Four ongoing patients have had stable disease for less than 12 weeks. Treatment is ongoing in 12 of the 18 breast cancer patients in the study. "Patients with germline BRCA-associated tumors have no targeted treatment options. There is a need for therapies that target specific molecular defects in tumors, and PARP inhibitors offer that potential in BRCA-related cancers. We have seen excellent anti-tumor activity in some of our patients treated with BMN 673. Continued study of this molecule will be meaningful for advancing the care for patients suffering from these cancers," said Professor Johann de Bono, Professor of Experimental Cancer Medicine at The Institute of Cancer Research, London, and Honorary Consultant in Medical Oncology at The Royal Marsden NHS Foundation Trust. BMN 673 was generally well-tolerated. The dose-limiting toxicity was Grade 3 thrombocytopenia. Myelosuppression, most of which was moderate in severity, occurred in 10-20% of patients with chronic dosing. Fatigue, nausea and alopecia were observed in 20-30% of patients. Signs of activity were seen as low as 100 µg/day, and the maximum tolerated dose was 1.0 mg/day, which is the expected dose for further development. BMN 673 also has good bioavailability and a long half-life which supports once daily dosing.