Hypocalcemia in patients with metastatic bone disease receiving denosumab.

9628 Background: Patients (pts) with metastatic bone disease (MBD) are at risk of skeletal-related events (SREs). Potent antiresorptives reduce the risk of SREs, by inhibiting cancer-induced bone destruction, which also reduces release of skeletal calcium (Ca) into the bloodstream. Hypocalcemia (hypoCa) may occur if Ca and vit D intake is inadequate while taking antiresorptive agents. A combined analysis of 3 phase III trials in pts with MBD showed denosumab (DMAb) was superior to zoledronic acid (ZA) in preventing SREs. The overall safety profiles were similar; hypoCa was more common with DMAb (9.6%) than ZA (5.0%). Characteristics of hypoCa events in DMAb pts in these clinical trials and from post marketing adverse event (AE) reports are presented. Methods: Pts with solid tumors or multiple myeloma and MBD were randomized (1:1) to DMAb 120 mg SC or ZA 4 mg IV (adjusted for renal function) every 4 weeks (Q4W). Pts were advised to take daily Ca (≥ 500 mg) and vit D (≥ 400 IU); intake was collected by pt r...