ORLANDO, FL, USA (UroToday.com) - The S9346 trial demonstrated that PSA recurrence after initial ADT carried a poor prognosis, as 25% of patients had PSA > 4 after 7 months ADT and had a median OS of 13 months. Thomas Flaig and colleagues presented their work in an abstract session on S1014 that examined the efficacy of abiraterone acetate (AA) in these patients. Patients were chemo-naïve and had PSA > 4 and had been on ADT for 6-12 months. Eligible patients were then treated with 1000mg AA daily and 5mg prednisone twice daily. The primary outcome of interest was PSA < 0.2 within 12 months of initiating AA therapy.
Forty-one patients were enrolled in the study, of which 13% (5 patients) had an undetectable PSA. 23% had PSA between 0.2 and 4, while 53% had no response. Median PFS was 17.4 months and median OS was 23.9 months. Twelve patients had grade 3 adverse events while 2 patients had grade 4 events (elevated LFTs and rectal bleeding).
The study did not reach its pre-specified level of 6 responses, although the finding of 5 patients with undetectable PSA was encouraging. Additionally, the OS of 23.9 months compared favorably to that of S9346, which is notable in this poor prognosis setting.
Presented by Thomas W. Flaig, MD at the 2015 Genitourinary Cancers Symposium - "Integrating Biology Into Patient-Centric Care" - February 26 - 28, 2015 - Rosen Shingle Creek - Orlando, Florida USA
University of Colorado Denver
Reported by Nikhil Waingankar, MD, medical writer for UroToday.com