Neoadjuvant Study of DV in Combination Toripalimab or Sequence Chemotherapy in HR-negative, HER2 Low-expressing Breast Cancer

Required: ESR1 negative (ER <1% by IHC) (<1% ER nuclear staining by IHC)

Tumour hormone receptor (HR)-negative, defined as IHC-stained invasive carcinoma with a proportion of cells positive for both ER and PgR nuclear staining of <1% according to ASCO/CAP guideline 2020

Required: PR (PGR) negative (PgR <1% by IHC) (<1% PgR nuclear staining by IHC)

Tumour hormone receptor (HR)-negative, defined as IHC-stained invasive carcinoma with a proportion of cells positive for both ER and PgR nuclear staining of <1% according to ASCO/CAP guideline 2020

Required: HER2 (ERBB2) low expression (IHC 1+ or IHC 2+ with no amplification by ISH) (IHC 1+ or IHC 2+ with no amplification by ISH)

low HER2 expression confirmed by the central laboratory, defined as HER2 protein expression of IHC 1+ or IHC 2+ with no amplification by in situ hybridisation (ISH)

Cannot have received: anti-tumour systemic therapy

have not received any prior anti-tumour systemic therapy for breast cancer

Cannot have received: PD-(L)1, PD-L2, CTLA4 inhibitors and other antibody-coupled drugs

Prior treatment with PD-(L)1, PD-L2, CTLA4 inhibitors and other antibody-coupled drugs

Cannot have received: investigational drugs

Use of investigational drugs or major surgery within 4 weeks prior to start of study drug administration

Cannot have received: adjuvant endocrine therapy

Previous carcinoma in situ of the breast with adjuvant endocrine therapy within 5 years of surgery