The first triple negative breast cancer immunotherapy trial to date has yielded some hopeful results for metastatic TNBC, according to results presented at the 2017 American Society of Clinical Oncology Annual Meeting.
The checkpoint-blocking drug Keytruda shrank pre-treated tumors by more than 30 percent in 5 percent and stabilized disease in 21 percent of women in the group. All patients who saw their tumors shrink lived for at least another year. In comparison, the patients who did not experience tumor regression had lower survival rates. (Remember: This is metastatic TNBC, or stage 4, not earlier, or more treatable, forms, such as stages 1-3.)
The trial included two groups of patients with metastatic TNBC. The first consisted of 170 patients who had received earlier chemotherapy. The second group was previously untreated and had tumors expressing the checkpoint molecule PD-L1.
Both groups tolerated the treatment well, with 12 percent of patients in the first group, and 8 percent in the second group reporting side effects such as fatigue and nausea. Four percent of patients in the first group, but none in the second, stopped the treatment because of these effects.