Real-world outcomes of first-line treatment with HLX02 versus reference trastuzumab plus pertuzumab in HER2-positive metastatic breast cancer

Abstract Background HLX02 (Zercepac®) is the first trastuzumab biosimilar manufactured in China. This study presents the first real-world comparison of HLX02 with reference trastuzumab (RTZ) plus pertuzumab and chemotherapy as the first-line treatment for HER2-positive metastatic breast cancer (MBC) patients. Methods Medical data of patients with HER2-positive MBC who received HLX02 or RTZ, both combined with pertuzumab and various chemotherapies as the first-line therapy at Beijing Cancer Hospital from January 2019 to August 2023 were reviewed retrospectively. The survival outcomes, efficacy, and adverse events were analyzed. Results In total, 118 patients were included in this study retrospectively, among whom 66 patients received RTZ and 52 received HLX02. No significant difference was observed in progression-free survival (PFS) between the groups (median PFS: 22.0 months for RTZ vs. 19.0 months for HLX02, P = .832). Additionally, the objective response rate, disease control rate, and safety profiles were similar across both groups. Of all 118 patients, 20 (16.9%) patients experienced progression in the central nervous system (CNS), with a median time to CNS progression of 15.0 months (95% confidence interval, CI, 12.8–17.2). Conclusion The real-world data suggested that both HLX02 and RTZ, when combined with pertuzumab and various chemotherapy regimens, offer comparable efficacy and safety as first-line treatments for HER2-positive advanced breast cancer patients in China.