Researchers aimed to identify clinical predictors of long-term response to Abiraterone [ Zytiga ] ( defined as more than 12 months drug exposure ) in a retrospective cohort of metastatic castration-resistant prostate cancer patients treated in post-Docetaxel setting at 24 Italian centers.
A total of 143 patients met the inclusion criteria. Their median age was 73 years, median Gleason score 8 and median Abiraterone exposure 20 months.
At the univariate analysis, a significant correlation with the duration of Abiraterone exposure was found for Gleason score ( hazard ratio, HR=0.82, 95% CI 0.71-0.96; p=0.012 ), PSA ( HR=1.10, 95% CI 1.03-1.18; p=0.08 ) and lactic dehydrogenase levels ( HR=1.22, 95% CI 1.02-1.46; p=0.027 ), while the association between lower alkaline phosphatase levels and treatment duration was marginally significant ( HR=1.07, 95% CI 0.99-1.16; p=0.074 ).
Only PSA and Gleason score were predictive of long-term treatment duration in the multivariate analysis. No other clinical factors resulted to be predictive of sustained response to Abiraterone, including metastatic disease at diagnosis and visceral disease, suggesting that all subgroups of patients may derive a substantial clinical benefit from Abiraterone treatment.
These findings need to be validated in prospective, larger studies. ( Xagena )
Verzoni E et al, Oncotarget 2016; Epub ahead of print