Background: Statins compete with DHEAS for influx through the SLCO2B1 transporter, which may prolong time to progression (TTP) on androgen deprivation therapy. Abiraterone acetate (AA) may also undergo SLCO-mediated transport. Based on preclinical findings showing antagonism, we hypothesized that statins may compete with AA for influx via SLCO2B1 and could negatively impact drug efficacy.
Methods: We queried two institutional clinical databases (Dana-Farber Cancer Institute [DFCI], Johns Hopkins University [JHU]) for CRPC patients treated with AA. Treatment duration was a surrogate for TTP. Associations between statin use and AA duration were estimated using the Kaplan-Meier method. Multivariable Cox regression modeling adjusted for known prognostic factors.
Results: Of the 224 DFCI and 270 JHU patients included, the majority (96%) had metastatic disease. Nearly half (41% and 45%) were statin users. In the DFCI cohort, there was a trend toward longer AA duration in statin users: 14.2 versus 9.2 months (HR 0.79, 95%CI: 0.57-1.09, P = 0.14). There was no association between statin use and AA duration in the JHU cohort: 8.3 versus 8.0 months (HR 0.89, 95%CI: 0.69-1.16, P = 0.38) in the statin users versus non-users, except for a trend in patients that had not previously received docetaxel or enzalutamide (HR 0.79; 95%CI: 0.57-1.10).
Conclusions: Contrary to our initial hypothesis, there was a trend toward longer (rather than shorter) AA duration in statin users in the entire DFCI cohort and in the enzalutamide- and docetaxel-naïve JHU patients. Together, these results do not support the hypothesis that statins interfere with AA efficacy.
Keywords: SLCO transport; abiraterone acetate; duration; prostate cancer; statins.
© 2017 Wiley Periodicals, Inc.