Atezolizumab (Tecentriq) is an immunotherapy approved by the Food and Drug Administration to treat metastatic triple-negative breast cancer that expresses the PD-L1 protein. Immunotherapies push the body's own immune system to attack cancer cells. Atezolizumab is the first immunotherapy to show positive results in in phase III trial for triple-negative breast cancer.
Atezolizumab works in people who have tumors that express the PD-L1 protein. This protein has a role in telling the immune system that a given cell is part of your body. In tumors that express PD-L1, the protein tricks the immune system into believing cancer cells are healthy cells, which prevents these cells from attacking the cancer.
Atezolizumab blocks PD-L1, allowing the immune system to attack breast cancer cells.
An immunotherapy is a medicine that works to engage your immune system, your body's natural defense against diseases. Since cancer cells are mutated versions of your own cells, the immune system treats them as a natural part of your body. Immunotherapies block certain communications between immune cells and cancer cells. This causes the immune system to treat the cancer cells as a threat and to destroy them.
Atezolizumab targets the PD-L1 protein, stopping a reaction that tells immune cells not to attack breast cancer cells. With that reaction blocked, the immune system sees breast cancer cells as a disease and destroys them.
The PD-L1 protein is not found in all tumors. Doctors will test the immune cells in and around the breast cancer to see if they express PD-L1 and are likely to respond to atezolizumab.
People taking atezolizumab and nab-paclitaxel experienced side effects including nausea, cough, low white blood cell counts and hypothyroidism, a condition where your body does not produce enough thyroid hormones. People taking atezolizumab are also more likely to experience grade 3 or 4 neuropathy than people taking nab-paclitaxel alone. Side effects that are grade 3 or 4 interfere with daily life and require medical attention.
Atezolizumab, like other immunotherapies, is linked to immune-related side effects that can take different forms, including problems in the lungs, liver or intestines or reactions to the infusion of the medicine. Your healthcare providers will talk to you about watching for these problems and what symptoms you should report right away.