The U.S. arm of Tokyo-based Astellas Pharma and U.S.-listed Medivation ($MDVN) said enzalutamide met its primary endpoint in a Phase II study to treat metastatic castration-resistant prostate cancer (mCRPC).
The data, published in the Lancet medical journal, of the Terrain trial showed a "statistically significant increase in progression-free survival for enzalutamide compared to bicalutamide" in treating mCRPC, according to a press release.
In March of last year, Astellas and Medivation announced tentative promising data from the Phase II trial of enzalutamide, an androgen receptor inhibitor, compared to bicalutamide in mCRPC at the European Association of Urology Congress in Spain. The publication in the Lancet confirmed the earlier initial assessments.
The Lancet article, the release said, noted that the Terrain trial of 375 patients in the United States and Europe was the first direct comparison study for efficacy and safety of the two treatments for mCRPC, though adverse reactions were seen in almost a third of the patients treated with enzalutamide.
"The median time on treatment in TERRAIN was 11.7 months in the enzalutamide group versus 5.8 months in the bicalutamide group," the press release stated. "Serious adverse events were reported in 31.1% of enzalutamide-treated patients and 23% of bicalutamide-treated patients."
Astellas co-markets enzalutamide as Xtandi as part of a 2009 development and commercialization global agreement with Medivation. Both companies sell the treatment in the U.S., while Astellas manufactures and handles regulatory work globally outside the United States.
- here's the release