RecruitingPhase 2Drug trialNeoadjuvant Trastuzumab Deruxtecan (SHR-A1811) + Pertuzumab in HER2+ Breast CancerPatients with Stage II-III HER2-positive breast cancer will receive three cycles of treatment with Trastuzumab Deruxtecan (SHR-A1811) + Pertuzumab, followed by imaging assessment. If clinical complete response (cCR) or radiological complete response/near radiological complete response (rCR/near rCR) is achieved, they will continue to receive an additional three cycles of treatment with Trastuzumab Deruxtecan (SHR-A1811) + Pertuzumab, followed by surgery. If cCR/rCR or near rCR is not achieved, the treatment will be switched to the THPy regimen (paclitaxel-based regimen + Trastuzumab + Pyrotinib) for three cycles.