Assessment of corticosteroid (CS)-associated adverse events (AEs) with long-term (LT) exposure to low-dose prednisone (P) given with abiraterone acetate (AA) to metastatic castration-resistant prostate cancer (mCRPC) patients (Pts).

Abstract

169 Background: AA is the prodrug of abiraterone, which inhibits CYP17A1 and testosterone synthesis and prolongs survival of mCRPC pts. A low dose of P is given when AA is administered to mCRPC pts. LT use of moderate-/high-dose CS has an established AE profile. We investigated whether LT use of low-dose P with or without AA led to CS-associated AEs. Methods: 2,267 mCRPC pts in COU-AA-301 and COU-AA-302 received 5 mg bid P, representing 2,006 pt-yrs of P exposure. 1,333 pts received AA + P. We utilized an inclusive Standardized MedDRA Queries–oriented approach to identify 112 preferred terms for known CS-associated AEs from both databases. CS-associated AEs during 3-mo exposure intervals and across all exposure to P were assessed. Results: The overall incidence of CS-associated AEs for any P exposure was 25%, 26%, and 23% for all pts, AA + P, and P alone, respectively. The incidence of grade ≥ 3 CS-associated AEs with any P exposure was 5%, 5%, and 4% for all pts, AA + P, and P alone, respectively. The most common grade ≥ 3 CS-associated AEs occurring in ≥ 0.1% of all pts were hyperglycemia (2%), cataract (0.4%), diabetes mellitus (0.4%), gastrointestinal hemorrhage (0.3%), adrenal insufficiency (0.1%), hip fracture (0.1%), melena (0.1%), and spinal osteoporotic compression fracture (0.1%). The overall incidence of weight increase (grade 1/2 only) was 4%, 4%, and 5% for all pts, AA + P, and P alone, respectively. Most were grade 1 (3.4%).When assessed by duration of exposure (3-mo intervals up to ≥30 mo), grade ≥ 3 CS-associated AEs fluctuated between 1% and 2%, but no discernable trend was observed. The observed change in weight from baseline showed no apparent increase over time. Conclusions: With over 2,000 pt-yrs of exposure, low-dose P given with or without AA is associated with an overall low incidence of CS-associated AEs. The frequencies of CS-associated AEs were low with increased duration of exposure to P. Clinical trial information: NCT00638690 , NCT00887198 .