Medivation, Astellas to Present Enzalutamid Data at ASCO GU Symposium

Medivation, Inc.

and Astellas Pharma Inc. (Tokyo: 4503) announced that data for enzalutamide, an oral androgen receptor inhibitor, will be presented at the American Society of Clinical Oncology (ASCO) 2013 Genitourinary (GU) Cancers Symposium in Orlando, Florida. Title: Enzalutamide monotherapy: Phase 2 study results in hormone-naive prostate cancer patients (Abstract #18) This phase 2 study assessed the efficacy and safety of enzalutamide monotherapy (160 mg) in 67 patients who had never received hormone therapy and presented with normal testosterone levels (e230 ng/dL). The analysis showed: Ninety-three percent of study participants experienced a e80% PSA decrease at week 25. -- Median change in PSA was -99.6% (range -100% to -86.5%). -- Serum testosterone increased by a mean of 114% at week 25 compared with baseline. -- Frequent treatment-emergent adverse events (AEs) were mostly Grade 1 or 2 and included gynecomastia (36%), fatigue (34%), nipple pain (19%), and hot flush (18%). -- Endocrine level changes and the most common drug-related AEs were consistent with potent AR signaling inhibition. Title: Enzalutamide in combination with docetaxel in men with metastatic castration-resistant prostate cancer (mCRPC): preliminary results from a phase 1 study (Abstract #63) -- A phase I study of enzalutamide given in combination with docetaxel in men with metastatic castration-resistant prostate cancer (mCRPC) who are on androgen deprivation therapy is currently ongoing. Preliminary data suggest that enzalutamide does not affect tolerability of docetaxel or have a clinically meaningful impact on docetaxel pharmacokinetics in this patient population. -- Overall, enzalutamide was well tolerated with no patients discontinuing because of an enzalutamide-related adverse event. Title: Impact of on-study corticosteroid use on efficacy and safety in the phase 3 AFFIRM study of enzalutamide, an androgen receptor inhibitor (Abstract #6) -- A post-hoc analysis of AFFIRM, a randomized, multinational, placebo-controlled phase 3 study among patients with mCRPC who had previously received docetaxel, showed that concomitant corticosteroid (CS) use was associated with reduced overall survival (median of 12.8 months in the CS group vs. median not met in the no CS group) and higher rates of grade 3-4 adverse events (63.3% in the CS group vs. 34.4% in the no CS group) in this population. Title: Improved outcomes in elderly patients with metastatic castration-resistant prostate cancer (mCRPC) treated with the androgen receptor inhibitor enzalutamide: results from the Phase 3 AFFIRM trial (Abstract #16) -- A post-hoc analysis of the phase 3 AFFIRM study showed that outcomes in elderly (e75 years) and younger ( Safety and tolerability findings were comparable between the two age groups. Title: Enzalutamide improves health-related quality of life (HRQoL) in men with metastatic castration-resistant prostate cancer (mCRPC) following docetaxel-based therapy: results from the AFFIRM study (Abstract #17) -- An analysis of patients enrolled in the enzalutamide phase 3 AFFIRM study showed that a greater percentage of patients on enzalutamide reported health-related quality of life (HRQoL) improvement compared to placebo (42.2% vs. 14.5%; p Both enzalutamide and placebo groups reported deterioration at some point during the study. However, compared with patients receiving placebo, patients receiving enzalutamide had a significantly prolonged time to HRQoL deterioration. Title: Long-term responders to enzalutamide (ENZA) during the phase 3 AFFIRM trial: baseline characteristics and efficacy outcomes (Abstract #20) -- In this post hoc analysis of AFFIRM data, 35% of patients remained on enzalutamide for e12 months and 22% for e18 months. Compared with the all-enzalutamide group and the placebo group, patients in the long-term exposure subgroup had somewhat less disease burden at baseline, lower concomitant steroid use, and improved efficacy outcomes consistently across multiple endpoints.