Bioequivalence of 240 mg Apalutamide Tablets and Preparation in Aqueous Food Vehicles for Alternative Administration.

A 240-mg single tablet has been developed with the focus of reducing the pill burden of the apalutamide daily dose of 240 mg (4 × 60-mg tablets). An open-label, randomized, single-dose phase 1 study with a 2-sequence and 2-period crossover design in healthy men determined the bioequivalence of a 240-mg single tablet versus the currently available 4 × 60-mg tablets (Part 1, N = 74) and assessed effect of a high-fat meal (Part 2, N = 21) on apalutamide maximum plasma concentration (Cmax) and the area under the plasma concentration-time curve (AUC0-72 h). The 90% confidence interval of geometric mean ratios for Cmax and AUC0-72 h fell between 80% and 125% for both Part 1 and Part 2. No new safety concerns with the 240-mg single tablet were observed. To support the use of different food vehicles as well as nasogastric (NG) tubes for alternative administration, we conducted in vitro compatibility studies to evaluate the purity, dose, and stability of 240-mg tablets dispersed in applesauce/yogurt/orange juice/green tea as well as in NG tubes (polyurethane/silicone/polyvinyl chloride). The studies confirmed the alternative administrations do not affect the purity, dose-accuracy, or stability of apalutamide. The apalutamide 240-mg tablet is bioequivalent to 4 × 60-mg tablets and compatible with the tested food vehicles and NG tubes.

Pharmacokinetics, Safety, and Antitumor Effect of Apalutamide with Abiraterone Acetate plus Prednisone in Metastatic Castration-Resistant Prostate Cancer: Phase Ib Study.

PURPOSE: Apalutamide is a next-generation androgen receptor (AR) inhibitor approved for patients with nonmetastatic castration-resistant prostate cancer (CRPC) and metastatic castration-sensitive prostate cancer. We evaluated the pharmacokinetics, safety, and antitumor activity of apalutamide combined with abiraterone acetate plus prednisone (AA-P) in patients with metastatic CRPC (mCRPC). PATIENTS AND METHODS: Multicenter, open-label, phase Ib drug-drug interaction study conducted in 57 patients with mCRPC treated with 1,000 mg abiraterone acetate plus 10 mg prednisone daily beginning on cycle 1 day 1 (C1D1) and 240 mg apalutamide daily starting on C1D8 in 28-day cycles. Serial blood samples for pharmacokinetic analysis were collected on C1D7 and C2D8. RESULTS: Systemic exposure to abiraterone, prednisone, and prednisolone decreased 14%, 61%, and 42%, respectively, when apalutamide was coadministered with AA-P. No increase in mineralocorticoid excess-related adverse events was observed. Patients without prior exposure to AR signaling inhibitors had longer median treatment duration and greater mean decrease in prostate-specific antigen (PSA) from baseline compared with those who had received prior therapy. Confirmed PSA reductions of ≥50% from baseline at any time were observed in 80% (12/15) of AR signaling inhibitor-naïve patients and 14% (6/42) of AR signaling inhibitor-treated patients. CONCLUSIONS: Treatment with apalutamide plus AA-P was well tolerated and showed evidence of antitumor activity in patients with mCRPC, including those with disease progression on AR signaling inhibitors. No clinically significant pharmacokinetic interaction was observed between abiraterone and apalutamide; however, apalutamide decreased exposure to prednisone. These data support development of 1,000 mg abiraterone acetate plus 10 mg prednisone daily with 240 mg apalutamide daily in patients with mCRPC.