Prostate specific antigen (PSA) declines were seen in a dose-dependent manner in these patients. In the lowest dose group, after two months of treatment PSA levels declined 45% to 66%. PSA levels in the second lowest dose group declined 75% to 89% after the first month of treatment. MDV3100 has been well tolerated to date in both dose groups.
The ongoing Phase I-II trial is an open-label US study enrolling prostate cancer patients who have failed standard hormonal therapies. The study is enrolling patients in up to seven dose groups of three patients each at escalating doses, with each group continuing treatment for at least three months barring any safety issues. The six patients enrolled to date comprise the two lowest dose groups, which to date have completed one and two months of treatment. The study endpoints include safety, tolerability, pharmacokinetics, effects on serum PSA levels and disease progression.
Medivation expects to complete the study, and report final top-line study results, in 2008. If these results are positive, Medivation expects to seek FDA agreement in 2008 to enter pivotal Phase III registration studies in hormone refractory prostate cancer.
David Hung, president and CEO of Medivation, said: “The significant, rapid onset PSA declines experienced to date by our first six hormone refractory prostate cancer patients treated with MDV3100 mark an auspicious beginning to this trial. These declines occurred in a clearly dose-dependent manner at the lowest doses of MDV3100 tested, which suggests that higher doses may produce even greater PSA declines.”