Risk of fall and clinical fracture associated with androgen receptor inhibitors: A systematic review and meta-analysis.

Abstract

71 Background: Patients treated with androgen receptor inhibitors (ARIs) report a higher incidence of falls; although a potential mechanism of action is unknown. This systematic review evaluates the relative risk (RR) of fall and fracture in prostate cancer (PCa) patients that receive ARIs. Methods: We conducted a comprehensive literature search using Cochrane, Scopus and MedlinePlus databases from inception through August 2019, and evaluated all published prospective phase II, III and IV randomized controlled trials that treated PCa patients with ARIs. Reported fall and fractures as adverse events (AEs) were extracted for analysis. Retrospective, phase I, non-randomized phase II, and studies with control arms that used one of the ARIs were excluded. A mixed effects model was used to estimate effects of ARI on the RR, with the included studies treated as random effects and study arms treated as fixed effects in the pooled analysis. Sample size for each study was used to weight the mixed model. Results: Eleven studies met our inclusion criteria. The total population was 11,382; 6536 were in the ARI arm and 4846 in the control (CTL) arm. Study types were: 8 phase III; 2 phase II; 1 phase IV. Subjects in the ARI arm received enzalutamide, apalutamide or darolutamide in combination with androgen deprivation therapy or other enzalutamide combinations while in the CTL arm received placebo, bicalutamide or abiraterone. Treatment duration ranged from 5.4 to 20.5 mo for ARI vs. 5.4 to 18.3 mo for CTL. The reported incidence of fall was 481 (7.4%) in ARI and 201 (4.1%) for CTL. The incidence of fracture was 204 (3.1%) in ARI and 93 (1.9%) in control. The use of ARI was associated with an increased risk: all fall grades (RR 1.83; 95% CI 1.56-2.15; p <0.01); high grade fall (RR 1.69; 95% CI 1.09 – 2.62; p=0.019); all grade fracture (RR 1.56; 95% CI 1.23-1.97; p <0.01) and likely high grade fracture (RR 1.62; 95% CI 0.97 – 2.69; p=0.063). Conclusions: The use of ARI significantly increases falls and fractures in PCa patients as assessed by this meta-analysis study. Further studies would be warranted to identify and understand potential mechanisms and develop strategies to decrease falls and fractures associated with ARI use.