The combination of Imfinzi (durvalumab) with standard chemotherapy leads to high treatment effectiveness in patients with triple-negative breast cancer (TNBC), a Phase 2 trial shows.

The research, “Randomized phase II neoadjuvant study (GeparNuevo) to investigate the addition of durvalumab to a taxane-anthracycline containing chemotherapy in triple negative breast cancer (TNBC),” was recently presented at the 2018 ASCO Annual Meeting in Chicago.

Imfinzi is a type of immunotherapy called an immune checkpoint inhibitor, which binds to the PD-L1 molecule and blocks its interaction with the PD-1 receptor in immune cells. This mechanism is used by cancer cells to evade immune attacks.

The combination of immune checkpoint inhibitors with chemotherapy has led to high response rates in patients with TNBC. This breast cancer type gets its name from the absence of the three most common types of receptors responsible for breast cancer growth: hormone epidermal growth factor receptor 2, estrogen receptors, and progesterone receptors.

Researchers conducted the GeparNuevo Phase 2 trial (NCT02685059) to assess the addition of Imfinzi to standard chemotherapy in primary TNBC patients who had not yet received surgery. 

A total of 174 patients received either Imfinzi or placebo every four weeks, along with chemotherapy. This included weekly Abraxane (nab-paclitaxel) for weeks 2-14, followed by epirubicin or cyclophosphamide once every two weeks for four cycles.

Patients were stratified based on the amount of white blood cells in their tumor. Those with 10 percent or less immune cells were included in the “low” group, while those with 60 percent or more immune cells in their tumors were deemed “high.” An intermediate group included patients with 11-59 percent of infiltrating immune cells.

The study’s primary goal was to measure the rate of patients without any signs of cancer in their breast or axillary lymph nodes, which is called the pathologic complete response (pCR) rate.

Scientists also assessed pCR rates in stratified subgroups and according to other factors, including response rates, breast conservation rate, toxicity, compliance, and survival.

All patients completed treatment by September 2017. Among them, 37.9 percent were in the low subgroup, 47.7 percent were in the intermediate subgroup, and 14.4 percent were in the high subgroup. Median Ki67, a proliferation marker in breast cancer, was 49.0 percent.

Researchers reported 86 serious adverse events and 65 immune-related adverse events. However, 84 of 174 patients (48.3 percent) showed a pCR.

“Combination of chemotherapy with durvalumab/placebo yielded a high pCR rate in TNBC. Treatment was feasible,” the scientists wrote.