Triple negative breast cancer: Emerging light on the horizon-a narrative review

Abstract

Triple negative breast cancer (TNBC) continues to be an aggressive disease entity associated with poor survival outcomes. The mainstay of treatment has historically been cytotoxic chemotherapy treatment. However, promising novel therapies including immunotherapy agents, antibody-drug conjugates, poly (ADP-ribose) polymerase (PARP) inhibitors and targeted therapies are emerging. In recent clinical trials, these various treatment modalities have demonstrated improvements in progression-free and overall survival in select patient populations. Specifically, the IMpassion130 and KEYNOTE-355 clinical trials observed a significant survival advantage among TNBC patients treated with immune checkpoint inhibitors and chemotherapy who were program death receptor ligand-1 (PD-L1) positive. Sacituzumab govitecan, a novel antibody drug conjugate, also has demonstrated an impressive overall survival result in previously heavily pre-treated TNBC patients. Targeted therapies such as PARP inhibitors, AKT inhibitors and androgen receptor antagonists may also have modest clinical activity and benefit for select patients. Future studies combining promising targeted therapies, cytotoxic agents and immunotherapy drugs are currently underway. Despite recent clinical trial successes, disease heterogeneity and limited access to molecular testing and novel therapies continue to be barriers in routine clinical practice. Nonetheless, we are optimistic that recent advances in clinical trial research will soon lead to significant improvement in the quality of care and survival for patients diagnosed with TNBC.