TQB2440 compared with reference pertuzumab for HER2-positive, ER/PgR-negative, early or locally advanced breast cancer: a multicenter, randomized, double-blind, parallel-controlled, phase III equivalence trial

Background: This randomized, double-blind study aimed to establish the equivalence of TQB2440 (a pertuzumab biosimilar) versus the reference pertuzumab, in the combination of trastuzumab and docetaxel, for patients with human epidermal growth factor receptor 2 (HER2)-positive early or locally advanced breast cancer. Materials and methods: Patients were randomly assigned (1 : 1) to receive four cycles of neoadjuvant therapy, either TQB2440 or the reference pertuzumab each plus trastuzumab and docetaxel, followed by surgery and adjuvant treatment. The primary endpoint was total pathological complete response (tpCR) by an independent review committee (IRC), with equivalence margins of 0.76-1.32. Secondary endpoints included breast pathological complete response (bpCR) by IRC, tpCR/bpCR by the investigator, breast-conserving surgery (BCS) rate, objective response rate (ORR), event-free survival (EFS), disease-free survival (DFS), and safety. Results: From 21 October 2020 to 14 August 2022, 412 patients were assigned to TQB2440 (207 patients) or reference pertuzumab (205 patients). The IRC-assessed tpCR was 58.9% with TQB2440 and 58.1% with the reference pertuzumab. The relative risk was 1.02 (90% confidence interval 0.89-1.16), which was entirely within the predefined equivalence margins. The IRC-assessed bpCR (67.6% versus 63.9%), investigator-assessed tpCR (60.4% versus 58.1%), bpCR (65.7% versus 62.0%), BCS rate (13.0% versus 13.2%), and ORR (73.9% versus 67.3%) were comparable in the two groups. At the data cut-off, the median EFS and DFS were not reached. Safety, pharmacokinetics (PK), and immunogenicity profiles were similar between the two groups. Conclusion: TQB2440 showed equivalent efficacy, comparable safety, PK, and immunogenicity profiles to reference pertuzumab in the neoadjuvant treatment of patients with HER2-positive early or locally advanced breast cancer.