There is no standard treatment for giant-cell tumour of bone (GCTB), a rare but very aggressive osteolytic tumour. In a phase II open-label trial in adults or adolescents with histologically confirmed GCBT, 282 patients were divided into three cohorts based on whether tumours were surgically salvageable or based on prior treatment with denosumab. Denosumab reduced the need for morbid surgery, representing a new therapy option for these patients with GCTB.