This is A multi-center, randomized, double-blind, parallel control，comparative clinical trial.~The primary objective is to evaluate whether the clinical efficacy of QL1209 and pertuzumab are similar in patients with early-stage or locally advanced HER2-positive and estrogen receptor/progesterone receptor negative breast cancer.~The secondary objective are to evaluate whether the clinical safety and immunogenicity of QL1209 and pertuzumab are similar in patients with early-stage or locally advanced HER2-positive and estrogen receptor/progesterone receptor negative breast cancer.
This is a randomized, double-blind, multicenter trial，parallel control designed to evaluate treatment with trastuzumab + QL1209 + docetaxel compared with trastuzumab + pertuzumab + docetaxel in the participants with early-stage or locally advanced HER2-positive and estrogen receptor/progesterone receptor negative breast cancer. The anticipated treatment duration is approximately 140 days.