Bispecific antibodies for the treatment of breast cancer.

INTRODUCTION: There are more than two dozen bispecific antibodies (BsAbs) in development with a variety of designs which are relevant to breast cancer. The field of BsAbs for breast cancer includes agents that co-direct immune recognition of the cancer cell, target unique cancer antigens, and target the microenvironment. BsAbs are being developed for use as antibody-drug conjugates and as homing signals for engineered T-cells. AREAS COVERED: This review covers potential targets for bispecific antibodies, agents in pre-clinical development, agents in clinical trials, combinatorial therapies, and future directions. EXPERT OPINION: There is no BsAb approval expected for breast cancer in the near term, but late-stage trials are underway. Future BsAb roles in breast cancer are possible given unmet needs in estrogen receptor+ disease, residual disease, and de-escalating chemotherapy use. The HER2+ space shows hints of success for BsAbs, but is already crowded. Areas of unmet need still exist.