Efficacy and Safety of Denosumab Biosimilar QL1206 Versus Denosumab in Patients with Bone Metastases from Solid Tumors: A Randomized Phase III Trial

BACKGROUND: Denosumab has been approved for the treatment of bone metastases from solid tumors. QL1206 is the first denosumab biosimilar and needs to be compared with denosumab in a phase III trial. OBJECTIVE: This phase III trial aims to compare the efficacy, safety, and pharmacokinetics between QL1206 and denosumab in patients with bone metastases from solid tumors. METHODS: This randomized, double-blind, phase III trial was conducted in 51 centers in China. Patients aged 18–80 years, with solid tumors and bone metastases, and an Eastern Cooperative Oncology Group performance status of 0–2 were eligible. This study was divided into a 13-week double-blind period, a 40-week open-label period, and a 20-week safety follow-up period. In the double-blind period, patients were randomly assigned (1:1) to receive three doses of QL1206 or denosumab (120 mg subcutaneously every 4 weeks, each). Randomization was stratified by tumor types, previous skeletal-related events, and current systemic anti-tumor therapy. In the open-label period, up to ten doses of QL1206 could be given in both groups. The primary endpoint was percentage change in urinary N-telopeptide/creatinine ratio (uNTX/uCr) from baseline to Week 13. Equivalence margins were ± 0.135. Secondary endpoints included percentage change in uNTX/uCr at Week 25 and 53, percentage change in serum bone-specific alkaline phosphatase at Week 13, 25, and 53, and time to on-study skeletal-related events. The safety profile was evaluated based on adverse events and immunogenicity. RESULTS: From September 2019 to January 2021, in the full analysis set, 717 patients were randomly assigned to receive QL1206 (n = 357) or denosumab (n = 360). Median percentage changes in uNTX/uCr at Week 13 in two groups were − 75.2% and − 75.8%, respectively. Least-squares mean difference in the natural log-transformed ratio of uNTX/uCr at Week 13 to baseline between the two groups was 0.012 (90% confidence interval − 0.078 to 0.103), within the equivalence margins. There were no differences in the secondary endpoints between the two groups (all p > 0.05). Adverse events, immunogenicity, and pharmacokinetics were similar in the two groups. CONCLUSIONS: Denosumab biosimilar QL1206 had promising efficacy, tolerable safety, and pharmacokinetics equivalent to denosumab and could benefit patients with bone metastases from solid tumors. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04550949, retrospectively registered on 16 September, 2020 SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40259-023-00579-5.