Hercessi, Biosimilar to Herceptin, Shows Favorable Efficacy, Safety in Treating HER2+ MBC in Real-World Setting

Trastuzumab-strf (Hercessi, HLX02; Accord BioPharma Inc), a biosimilar to trastuzumab (Herceptin; Genentech), demonstrated favorable efficacy and safety in a real-world setting when treating patients with HER2-positive (HER2+) metastatic breast cancer (MBC). The study results, which were recently published in Frontiers in Oncology, also showed that a switch from the reference product to its biosimilar had no impact on efficacy, nor did the switch increase safety risks in patients.¹

Approved in 2024 for the treatment of HER2–over-expressing breast and gastric cancers and gastroesophageal junction adenocarcinomas, Hercessi binds to and inactivates the HER2 receptor to slow down cell replication, like its reference product.²

Reference trastuzumab is an FDA-approved antineoplastic biologic that targets HER2+ breast and gastric cancer. It was approved in 1998, making it one of the first available “targeted” chemotherapies for patients. Trastuzumab deruxtecan is a trastuzumab conjugate that releases its cytotoxic components after binding and entering HER2-expressing cells, treating HER2+ gastric, lung, colorectal, and metastatic breast cancers.^2,3

Herzuma is indicated in adult patients as a monotherapy or as part of a combination therapy in adjuvant breast cancer and metastatic breast cancer. As a biosimilar, Hercessi is a large, complex molecule that is highly similar to and has no clinically meaningful differences in safety, purity, and potency from its reference product, Herceptin.^1,2

Despite its biosimilarity to its reference product, the investigators stated that there were few data available about Hercessi’s use within clinical practice. This study was designed to evaluate the real-world safety and efficacy of Hercessi in patients with HER2+ MBC, and the effectiveness of switching from the original product, Herceptin, to the biosimilar during treatment.¹

Patients with HER2+ MBC were enrolled in the retrospective analysis between April 2021 and October 2022, all of whom received at least 1 cycle of Hercessi at Fudan University Shanghai Cancer Center. Patients were divided into 2 groups: the naïve group (patients treated with Hercessi from the beginning) and the switched group (patients who switched from Herceptin to Hercessi). Efficacy evaluation and adverse events (AEs) were compared between the 2 groups.¹

A total of 124 eligible patients were included in the analysis. Approximately 64.5% (n = 80) of patients were assigned to the naïve group and the remaining 35.5% (n = 44) to the switched group. The follow-up ranged from about 0.7 to 40.2 months. The findings indicated that effectiveness rates were about 57.5% and 54.5% in the naïve and switched groups, respectively (P = .751). Estimated median progression-free survival (PFS) was about 13.70 (95% CI 8.634–18.766) months and 14.70 (95% CI 6.684–22.716) months in the naïve and switched groups, respectively (P = .192).¹

A multivariate cox regression analysis suggested that brain metastasis and the current number of treatment lines were independent predictors of PFS in MBC, wrote the investigators. Compared with first-line treatment, second-line treatment and third- or later-line treatment was shown to increase the disease risk by about 2.095 (95% CI 1.043–4.210; P = .038) and 3.035 times (95% CI 1.751–5.262; P < .001), respectively. Significantly, the incidence and distribution of treatment-emergent AEs occurrence between the 2 groups were relatively similar, with no significant statistical difference.¹

“This study has several limitations. Firstly, as it utilizes retrospective real-world data with limited sample of patients using [Hercessi]. Limited sample may lead to low statistical power of the association analysis, so it is necessary to expand the sample size and conduct a large-scale clinical trial with multicenter cooperation. Future studies with larger sample sizes also could validate stratified analysis based on the coadministered drugs, such as adjunctive medications, target therapy, or combined with different chemotherapy,” wrote the study authors. “…These findings offered valuable information for implementation of switching from trastuzumab originator to a biosimilar.”¹

REFERENCES

1. Ye X, Wang L, Liu W, et al. Efficacy and safety of biosimilar trastuzumab (HLX02) in patients with HER2-positive advanced breast cancer: a retrospective real-world analysis. Front Oncol. 2025;15:1622854. Published 2025 Aug 1. doi:10.3389/fonc.2025.1622854

2. Ferruggia K. FDA Approves Trastuzumab Biosimilar to Treat Forms of HER2-Overexpressing Cancer. Pharmacy Times. April 29, 2024. Accessed September 24, 2025. https://www.pharmacytimes.com/view/fda-approves-trastuzumab-biosimilar-to-treat-forms-of-her2-overexpressing-cancer

3. McGovern G. Trastuzumab Biosimilar Demonstrates Sufficient Efficacy in HER2+ Advanced Gastric Cancer. Pharmacy Times. August 5, 2025. Accessed September 24, 2025. https://www.pharmacytimes.com/view/trastuzumab-biosimilar-demonstrates-sufficient-efficacy-in-her2-advanced-gastric-cancer