Medivation Inc. ( MDVN ) and partner Astellas Pharma Inc. ( ALPMY ) reported top-line results from a phase II study (TERRAIN), comparing Xtandi (enzalutamide) to AstraZeneca's ( AZN ) Casodex (bicalutamide) in metastatic prostate cancer patients whose disease has progressed following treatment with a luteinizing hormone-releasing hormone analogue therapy or after surgical castration.
The phase II study was conducted to evaluate Xtandi 160 mg once daily against Casodex 50 mg once daily. Results revealed a statistically significant increase in progression-free survival (PFS) in the Xtandi group compared to patients in the Casodex arm (15.7 months versus 5.8 months), thereby successfully meeting the primary endpoint of the study. Median time on treatment was longer for Xtandi (11.7 months) compared to Casodex (5.8 months).
However, patients reported more serious adverse events in the Xtandi arm (31.1%) as compared to patients in the Casodex arm (23.3%). The company intends to present additional data from the study at an upcoming medical conference.
We note that Xtandi is already approved for the treatment of metastatic castration-resistant prostate cancer (CRPC) in patients who have previously received Taxotere (docetaxel). In Sep 2014, Xtandi's label was expanded to treat chemotherapy-naive metastatic CRPC patients.
We are pleased with the company's label expansion efforts. Medivation and Astellas are currently conducting multiple studies on Xtandi in additional indications including breast cancer among others.
Xtandi has been performing well ever since its launch. The drug delivered U.S. net sales of $449.6 million, as reported by Astellas in the first nine months of 2014, up 68.9% from the year-ago period.
Currently, both Medivation and Astellas carry a Zacks Rank #3 (Hold). A better-ranked stock in the biotech sector is Amgen ( AMGN ) carrying a Zacks Rank #1 (Strong Buy).