NEW ORLEANS, LA USA (UroToday.com) - Abiraterone acetate (AA) inhibits CYP17A1 in the steroid synthesis pathway and also decreases testosterone production. It is shown to prolong survival in metastatic castrate-resistant prostate cancer (mCRPC) patients. However, a low dose prednisone is administered along with AA. The study evaluated whether the long-term use of corticosteroids with and without AA led to corticosteroid (CS) associated adverse events (AE).
2 267 mCRPC patients in COU-AA-301 and COU-AA-302 studies received 5mg twice daily prednisone and represented 2006-patient-years of prednisone exposure. 1 333 patients received AA + prednisone while the rest received prednisone only. The primary end-point was corticosteroid-associated AE (endocrine disorders, eye disorders, GI disorders, infection, metabolism and nutrition disorders, among others).
The overall incidence of steroid-associated AEs for any prednisone exposure was 24.6% (all patients), 25.5% (AA+prednisone), and 23.3% (prednisone only). The incidence of grade ≥ 3 AEs with any prednisone was 4.5% (all patients), 5.1% (AA+prednisone), and 3.7% (prednisone only). The most common grade ≥ 3 AEs were hyperglycemia (2%), cataract (0.4%), diabetes mellitus (0.4%), gastrointestinal hemorrhage (0.3%), adrenal insufficiency (0.1%), hip fracture (0.1%), mela (0.1%), and osteoporotic spinal fracture (0.1%). The overall incidence of hyperglycemia (all grades) was 7.4% (all patients), 7.8% (AA +prednisone) and 6.9% (prednisone only). The overall incidence of weight gain (grade1/2 only) was 4% (all patients), 4% (AA+predinosone), and 5% (prednisone only).
When assessed by duration of exposure by every 3-month interval up to 30 months for both hyperglycemia and weight gain, grade ≥ 3 fluctuated between 1% and 2%, but no trend was observed. All-grade AE fluctuated up to 12% but, again, without any trends.
The group concludes that with over 2000-year-patient exposure, low dose prednisone, with or without AA, is associated with an overall low incidence of adverse events and these do not appear to be cumulative over time.
Presented by Leonard G. Gomella at the American Urological Association (AUA) Annual Meeting - May 15 - 19, 2015 - New Orleans, LA USA
Thomas Jefferson University Hospitals, Philadelphia, PA USA
Reported by Mohammed Haseebuddin, MD, medical writer for UroToday.com