pembrolizumab + nab-paclitaxel + doxorubicin + cyclophosphamide

This is a **combination regimen** including four anticancer agents: pembrolizumab, nab-paclitaxel, doxorubicin, and cyclophosphamide, used primarily in the treatment of high-risk, early-stage or locally advanced triple-negative breast cancer (TNBC) and in investigational settings for other HER2-negative breast cancers. **Pembrolizumab** is a monoclonal antibody targeting PD-1, enabling T-cell mediated anti-tumor immunity (an immune checkpoint inhibitor). **Nab-paclitaxel** is an albumin-bound formulation of paclitaxel, a mitotic inhibitor targeting tubulin. **Doxorubicin** is an anthracycline antineoplastic agent acting primarily via DNA intercalation and topoisomerase II inhibition. **Cyclophosphamide** is an an alkylating agent that promotes cell death via DNA crosslinking. The combination leverages the immune-stimulating properties of pembrolizumab with the cytotoxic effects of chemotherapy to increase pathological complete response rates in the neoadjuvant or metastatic setting[1][5]. Clinical trials use this regimen or close variants to maximize responses in TNBC (notably NCT03289819[1]), although some studies substitute epirubicin for doxorubicin in the anthracycline component. The principal mechanism of benefit is synergistic immunotherapy and cytotoxic chemotherapy.