Efficacy and safety of biosimilar trastuzumab (HLX02) in patients with HER2-positive advanced breast cancer: a retrospective real-world analysis.

BACKGROUND

HLX02 is the first China-manufactured trastuzumab biosimilar. Few data are currently available about HLX02 in clinical practice. This study was designed to evaluate the real-world safety and efficacy of HLX02 in patients with HER2-positive metastatic breast cancer (MBC), as well as assessed the effectiveness of switching from trastuzumab originator (Herceptin) to HLX02 during treatment.

METHODS

Between April 2021 and October 2022, all patients with HER-2-positive MBC who received at least one cycle of HLX02 at Fudan University Shanghai Cancer Center were included in a retrospective analysis. Patients were divided into two groups: the naïve group (patients treated with HLX02 from the beginning) and the switched group (patients who switched from Herceptin to HLX02). Efficacy evaluation and adverse events were compared between the two groups.

RESULTS

A total of 124 eligible patients were finally included, with 80 patients (64.5%) in the naïve group, 44 patients (35.5%) in the switched group. The follow-up ranged from 0.7 to 40.2 months, the effectiveness rates were 57.5% in the naïve group and 54.5% in the switched group, respectively (P=0.751). The estimated median progression-free survival (PFS) were 13.70 (95% CI: 8.634-18.766) months and 14.70 (95% CI: 6.684-22.716) months in the naive and switched groups, respectively (P=0.192). Multivariate cox regression analysis suggested that brain metastasis and the current number of treatment lines were independent predictors of MBC PFS. Compared with first-line treatment, second-line treatment and third- or later-line treatment increased the disease risk by 2.095 times (95% CI: 1.043-4.210, P=0.038) and 3.035 times (95% CI:1.751-5.262, P<0.001), respectively. The incidence and distribution of treatment-emergent adverse events (TEAEs) occurrence between the two groups were relatively similar, with no significant statistical difference.

CONCLUSIONS

HLX02 demonstrated favorable efficacy and safety in real-world practice comparable to those observed in previous HLX02 studies. Switching between trastuzumab originator and biosimilar for MBC treatment had no impact on efficacy and did not increase safety risks.