Comparison of the efficacy and safety of a proposed biosimilar QL1206 with reference denosumab in patients with bone metastasis from breast cancer: a subgroup analysis of a randomized, double-blinded phase III study

Abstract

Purpose: This study presents a subgroup analysis of the efficacy and safety of QL1206, a biosimilar of the reference denosumab (Xgeva®, Amgen Inc.), in patients with bone metastasis from breast cancer enrolled in a randomized, double-blinded, phase III trial (NCT04550949). Methods: In this subgroup analysis, patients with bone metastasis from breast cancer of the phase Ⅲ trial were included. Patients had been randomly assigned in a 1:1 ratio to receive either 3 cycles treatment of QL1206 or denosumab (120 mg, every 4 weeks), subsequently received 10 cycles treatment of QL1206 (120 mg) over a 40-week period, followed by a 20-week safety follow-up. The primary endpoint was the percentage changes from baseline to Week 13 in urinary N-telopeptide corrected for creatinine (uNTx/Cr). Results: Three hundreds and eleven patients were included in the breast cancer subgroup. The most common site of bone metastasis was vertebrae (66.4%) when enrolled; 27.7% patients had more than 3 bone metastatic sites. At Week 13, the median percentage change in uNTx/Cr from baseline was -69.9% (range, -98.1%–568.0%) and -74.3% (range, -97.7%–386.3%) in the QL1206 and references denosumab groups, respectively. After a 53-week treatment period, most patients demonstrated increased bone density or stable disease. The time to first on-study skeletal-related events (SREs) was not evaluable in the two groups. Safety profiles were similar between the two groups. Conclusions: QL1206 demonstrated similar efficacy and safety to the reference denosumab in breast cancer patients with bone metastases, supporting QL1206 as an option for supportive care in this population.