Agents For Triple Negative Breast Cancer
Triple negative breast cancer is clinically heterogeneous and more aggressive than other types of breast cancer.
For curable disease, chemotherapy is standard of care.
For metastatic disease, chemotherapy was the only option for many years. Last March atezolizumab (Tecentriq), which is an immune check point inhibitor was FDA-approved for patients with PDL1 positive disease. Atezolizumab was approved as first line therapy in metastatic disease in combination with NAB-Paclitaxel (Abraxane). Atezolizumab is a monoclonal antibody that binds to PDL1 and blocks its interactions with the PD1 receptor causing the activation of the antitumor response and therefore cancer cell death.
In clinical trials the atezolizumab-abraxane arm had a progression-free survival of 7.5 months compared to five months in the abraxane only arm. And the survival in the atezolizumab-abraxane arm was 10 months longer compared with abraxane alone. The most common side effects were hair loss, neuropathy, nausea, cough, fever and hypothyroidism.
Other novel therapies that are currently being investigated for triple negative breast cancer are the PARP inhibitors outside of patients with germline mutations since they were FDA approved for patients with BRCA mutations. The PARP inhibitors have been used alone or in combination with chemotherapy. Antibodies targeting novel antigen on the tumor are sacituzumab and ladiratuzumab are currently being explored.
Other agents currently being tested are AKT inhibitors (ipatasertib, pimasertib) and MEK inhibitors.
Numerous trials are currently in phase II and III; hopefully will improve our treatment selection and results.