Second interim analysis (IA2) results from a phase II trial of TAK-385, an oral GnRH antagonist, in prostate cancer patients (pts).

200 Background: Gonadotropin-releasing hormone (GnRH) antagonists achieve rapid decrease in testosterone (T) without transient T surge seen with GnRH agonists and thus may avoid clinical flare symptomatology. TAK-385 is an investigational, oral, non-peptide GnRH antagonist highly selective for the human GnRH receptor (IC50 0.12 nM). We report IA2 results from a phase 2, randomized, open label, parallel group study of TAK-385 in pts with advanced prostate cancer (NCT02083185). Methods: Pts aged ≥ 18 yrs with histologically confirmed prostate cancer, baseline T > 150 ng/dL and prostate-specific antigen (PSA) > 2 ng/mL, who were candidates for first-line androgen deprivation therapy, were randomized to receive oral TAK-385, 80 or 120 mg, once daily (QD) or leuprorelin (LEU) 22.5 mg subcutaneously every 12 wks, for 48 wks. The primary endpoint was effective castration rate of TAK-385 (T < 50 ng/dL) from wk 5–24. Secondary endpoints included: safety, pharmacokinetics (PK), and PSA. Results: At data cut-off, 75...