BACKGROUND: Metaplastic breast cancer (MPBC) is a rare subtype of breast cancer that is difficult to manage and is resistant to therapy. Immunotherapy is becoming a promising option for care of several types of cancers including triple negative breast cancer.

CASE REPORT: We present a case of a patient with chemo-refractory metastatic metaplastic-type of breast cancer with failures to 3 active lines of chemotherapy. The patient achieved a complete and sustained response to chemo-immunotherapy combination with acceptable tolerability and minimal adverse events. The treatment was a combination of anti-PD-L1 antibody (durvalumab) immunotherapy in combination with the chemotherapeutic agent, paclitaxel.

CONCLUSIONS: This is the first case reporting the successful use of durvalumab and paclitaxel combination for treatment of triple negative breast cancer in general, and in metastatic MPBC in specific.

Keywords: Antigens, CD274, paclitaxel, Triple Negative Breast Neoplasms, Antibodies, Monoclonal, Antineoplastic Agents, Immunological, Antineoplastic Agents, Phytogenic, Carcinoma, Squamous Cell, Immunotherapy, Therapies, Investigational