Denosumab and zoledronic acid treatment in patients with genitourinary cancers and bone metastases.

5079 Background: Phase III trial results showed that denosumab is superior to zoledronic acid (ZA) in preventing skeletal-related events (SREs) in patients with cancer and metastatic bone disease (Lipton et al; 2012, Eur J Cancer). Genitourinary (GU) cancers are some of the most commonly diagnosed cancers worldwide. We now compare the efficacy and safety of denosumab (DMAb) or ZA in a subgroup analysis of patients with GU cancers enrolled in the pivotal phase III trials. Methods: Patients were randomized 1:1 to receive DMAb (120 mg, SC) or ZA (4 mg, IV, adjusted for renal function) every 4 weeks. Daily calcium and vitamin D supplements were strongly recommended. Time to 1st on-study SRE, using a Cox proportional hazards model, time to 1st and subsequent on-study SRE, using the Anderson-Gill model, and safety were evaluated for the GU subgroup in an ad hoc analysis. Results: 2,128 patients (1,052 DMAb; 1,076 ZA) had GU cancers (prostate = 1,901, renal = 155, bladder = 63, and transitional cell = 9). DMAb s...