MDV3100 is an oral, once-daily investigational drug that acts by inhibiting androgen receptor signaling.
The study reported that men taking MDV3100 lived for a median of 18.4 months, compared with 13.6 months for men taking placebo and also met all secondary endpoints, including radiographic progression-free survival, soft tissue response rate and time to prostate-specific antigen (PSA) progression.
Co-principal investigator of the AFFIRM study chief Howard Scher said: "MDV3100 outperformed our expectations in the AFFIRM trial by meeting the primary and secondary endpoints with strong statistical significance and demonstrating a favorable safety profile."
"These results, together with its convenient once-daily oral dosing regimen, should make MDV3100 a promising option for men with prostate cancer who have received prior hormones and chemotherapy," Scher added.
MDV3100 is also being evaluated in the Phase 3 PREVAIL trial and the Phase 2 TERRAIN trial in men with prostate cancer who have failed hormonal therapy but have not yet received chemotherapy, and in a Phase 2 study in men with prostate cancer who have not yet received hormonal therapy.
Experimental cancer medicine professor Johann de Bono commented: "The almost five-month overall survival benefit MDV3100 showed over placebo in this trial is noteworthy, as is the fact that men with post-chemotherapy prostate cancer taking MDV3100 lived for a median of a year and a half."
Medivation president and CEO David Hung said: "The robust overall survival data produced in the AFFIRM trial by MDV3100, the first androgen receptor signaling inhibitor, clinically validate this novel mechanism of action in treating men with prostate cancer who have received prior chemotherapy."
The drug related side effects included fatigue, diarrhea and hot flush as well as cardiac disorders such as myocardial infarction, seizure and liver function test abnormalities.
Medivation is a biopharmaceutical company focused on the rapid development of novel small molecule drugs to treat serious diseases and Astellas Pharma is dedicated to improving the health of people around the world through provision of innovative and reliable pharmaceuticals.