Denosumab versus zoledronic acid in cases of surgically unsalvageable giant cell tumor of bone: A randomized clinical trial.

Although denosumab has been approved as an antiresorptive agent for giant cell tumor of bone, its efficacy has not been proven.To compare the efficacy and safety of denosumab and zoledronic acid treatment in patients with surgically unsalvageable giant cell tumor of bone.

A total of 250 patients with surgically unsalvageable giant cell tumor of bone were included in this randomized clinical trial. Patients received either subcutaneous denosumab (DB group; 120 mg per 4 weeks plus an additional 120 mg on days 8 and 15; n = 125) or intravenous zoledronic acid (ZA group; 4 mg per 4 weeks; n = 125) for six cycles. Disease status, clinical benefits, treatment-emergent adverse effects, overall survival, and cost of treatment were evaluated during the follow-up period. Statistical significance was determined using 95% confidence intervals.

Denosumab and zoledronic acid had similar tumor responses (p = 0.18) and clinical benefits (p = 0.476). Disease progression was observed in fewer patients in the DB group (1%) than ZA group (2%). Denosumab caused fatigue (p = 0.0004) and back pain (p < 0.0001), while zoledronic acid caused hypocalcemia (p < 0.0001), flu-like symptoms (p = 0.021), hypotension (p = 0.021), and hypokalemia (p = 0.021). Denosumab treatment was markedly more expensive than zoledronic acid treatment (p < 0.0001). The cost to manage treatment-emergent adverse effects was higher for the ZA group than the DB group (p = 0.0425). Overall survival was the same for both treatments (p = 0.066).

Denosumab is a safe but costly alternative to zoledronic acid for treatment of surgically unsalvageable giant cell tumor of bone.