Phase-1 study of abiraterone acetate in chemotherapy-naïve Japanese patients with castration-resistant prostate cancer.
Bottom Line: At each dose level, mean serum corticosterone concentrations increased, while testosterone and dehydroepiandrosterone sulfate concentrations rapidly decreased following a single AA dose and were further reduced to near the quantification limit on day 8 regardless of the dose.At least 3 patients from each dose-group experienced ≥50% prostate-specific antigen reduction, suggesting clinical benefit from AA in Japanese CRPC patients.AA was generally well-tolerated, and, therefore, the recommended AA dosage regimen in Japanese CRPC patients is 1000 mg oral dose under modified fasting conditions (at least 1 h premeal or 2 h postmeal).
Affiliation: Division of Oncology and Hematology, National Cancer Center Hospital East, Chiba, Japan.Show MeSH
Related in: MedlinePlus
Mentions: As shown in a waterfall plot (Fig.3), 20/27 patients achieved ≥50% PSA decline from baseline at one or more evaluation time points during the entire treatment period ([n = 7] 250 mg, [n = 3] 500 mg, [n = 5 each] in 1000 [−1 h] and [+2 h] mg cohorts). Among these patients, ≥50% declines in PSA levels were confirmed to have been maintained for at least 4 weeks in 18/27 (67%) patients. The PSA response rate was highest (83%) in the 1000 (+2 h) mg cohort, followed by 67% in the 1000 (−1 h) mg and the 250-mg cohorts, and 50% in the 500 mg cohort. The mean percentage change from baseline in PSA levels at week 12 was −51.2% for 250 mg; −29.1% for 500 mg; −60.4% for 1000 mg (−1 h); and −37.6% for 1000 mg (+2 h) cohorts.
Affiliation: Division of Oncology and Hematology, National Cancer Center Hospital East, Chiba, Japan.