According to a phase 3 equivalence study, the pertuzumab biosimilar QL1209 was comparable to reference pertuzumab in efficacy, safety, and immunogenicity among patients with early or locally advanced HER2-positive breast cancer.

These results were first presented at the 2023 European Society for Medical Oncology Annual Congress in Madrid, Spain.

Dual HER2-blockade with trastuzumab and pertuzumab plus docetaxel in the neoadjuvant setting has been approved by the FDA for the treatment of early HER2-positive breast cancer. QL1209 is a biosimilar of the reference product pertuzumab.

In this phase 3 trial, 516 patients with HER2-positive, early or locally advanced, ER-negative, PR-negative breast cancer with a primary tumor larger than 2cm in diameter, who had not previously received any anticancer therapy were enrolled. Patients were randomized on a 1-to-1 basis, stratified by disease stage, to receive neoadjuvant treatment with either QL1209 or originator pertuzumab (cycle 1 loading dose: 840mg, cycles 2 to 4: 420mg), plus trastuzumab and docetaxel once every 3 weeks for 4 cycles. There were 257 patients randomized to the QL 1209 arm and 259 to the pertuzumab arm.

The primary end point of the study was total pathologic complete response as determined by independent review committee (IRC). Secondary end points included total pathologic complete response as determined by investigator, pathological complete response of the breast tumor by both IRC and investigator, objective response rate (ORR), safety, and immunogenicity.

Of the 516 patients who received neoadjuvant treatment, 482 underwent surgery (QL1209 arm, n = 238; pertuzumab arm, n = 244). The total pathologic complete response rate by IRC of the QL1209 arm was 42.7% compared with 45.2% in the pertuzumab arm (ratio of QL1209 to pertuzumab: 0.946; 90% confidence interval [CI]; 0.8 to 1.11; P = .014). The ORR of the QL1209 arm was 82.1% vs 81.9% in the pertuzumab arm. The incidence of grade ≥3 treatment-related adverse events 31.9% vs 34.7%, respectively.

 Study authors concluded, “QL1209 demonstrated equivalence to [pertuzumab] in efficacy and showed comparable safety profile and immunogenicity in patients with early or locally advanced HER2-positive breast cancer.”

Source:

Shao Z, Zhang J, Qian J, et al. Neoadjuvant QL1209 (a pertuzumab biosimilar) compared with pertuzumab plus trastuzumab and docetaxel in early or locally advanced, HER2-positive, ER(-)/PR(-) breast cancer: A multicenter, randomized, double-blind, equivalence, phase III study. Presented at 2023 ESMO Annual Congress; October 20-24, 2023; Madrid, Spain. Abstract 245P