Denosumab safety and efficacy in giant cell tumor of bone (GCTB): Interim results from a phase II study.

Abstract

10034 Background: GCTB, an osteolytic tumor causing skeletal morbidity, contains osteoclast-like giant cells and mononuclear cells expressing RANKL, a mediator of osteoclast activation. Denosumab binds RANKL, inhibiting osteoclast activity. In an initial phase 2 study, 86% of subjects with GCTB responded to denosumab. We report data from a prespecified 12‐month interim analysis in a second open-label phase 2 study of denosumab in GCTB. Methods: Subjects with surgically unsalvageable GCTB (cohort 1) or salvageable GCTB with planned surgery (cohort 2) received subcutaneous denosumab 120 mg every 4 weeks, with a 120 mg loading dose on days 8 and 15. The primary objective was to evaluate the safety of denosumab. The analysis also included subjective assessments of disease progression and the proportion of cohort-2 subjects for whom surgery was delayed, reduced in scope, or not required. Safety analyses included all subjects who received denosumab; efficacy analyses included subjects who received denosumab for...