A new Phase 3 trial suggests that administering immunotherapy to patients with a common form of early-stage breast cancer before surgery may improve outcomes. The study, published in Nature Medicine, focused on individuals diagnosed with estrogen receptor positive (ER+)/human epidermal growth factor receptor 2-negative (HER2-) breast cancers, a subtype that accounts for 70% of all breast cancers.
The trial involved 510 patients who were all good candidates for surgery. Half of the patients received nivolumab (Opdivo), an immunotherapy drug that disables a protein called PD-1 on the surface of cancer cells, before surgery, along with standard chemotherapy. The other half received pre-operative chemotherapy plus a placebo, followed by surgery. All patients then received endocrine therapy after surgery.
The results showed that 25% of patients who received nivolumab before surgery had a "pathological complete response" - no sign of cancer at the time of surgery - compared to 14% of those who did not receive pre-operative nivolumab. The study also found that patients with tumors that produced larger amounts of PD-1 were more likely to benefit from the pre-operative immunotherapy.
"We hope that these results inform treatment decisions and, in turn, improve outcomes for patients with breast cancer, ultimately improving cure rates," said study co-lead author Dr. Heather McArthur, professor of internal medicine in the Division of Hematology and Oncology at UT Southwestern Medical Center in Dallas.