First-line treatment with the checkpoint inhibitor Tecentriq (atezolizumab) plus the chemotherapy drug Abraxane (nab-paclitaxel) delayed disease progression or death in women with metastatic triple-negative breast cancer, researchers reported at the European Society for Medical Oncology 2018 Congress in Munich.
Tecentriq blocks the interaction between the PD-1 checkpoint receptor on T cells, which suppresses immune cell activity, and its binding partner, PD-L1. Blocking this linkage restores T-cell activity. People with higher PD-L1 levels in their tumors tend to do better on these medications, but this isn’t a reliable predictor of individual response. So far, this type of immunotherapy hasn’t shown much activity against so-called cold tumors like those seen in breast cancer, but combining checkpoint blockers with chemotherapy holds greater promise.
The IMpassion130 trial enrolled 902 people with triple-negative breast cancer, meaning it lacks hormone and HER2 receptors that would make it susceptible to other medications.
Among people with PD-L1 positive tumors, the median progression-free survival time was 7.5 months for those assigned to Tecentriq versus 5.0 months for those who received a placebo—a 38 percent reduction in the risk of disease progression or death. A preliminary analysis found that the overall survival time was 25.0 versus 15.5 months, respectively.
“Immune therapy on top of standard chemotherapy prolonged survival by 10 months in patients with tumors expressing PD-L1. This combination should become a new treatment option for patients with metastatic triple-negative breast cancer,” says lead researcher Peter Schmid, MD, PhD, of Queen Mary University of London.