Two independent studies have added new evidence to the benefits of combined therapies with Merck‘s PD-1 inhibitor Keytruda (pembrolizumab) for the treatment of aggressive triple-negative breast cancer (TNBC).
Adding Keytruda to standard therapies for breast cancer improved the number of patients achieving a complete response to therapy.
The findings will be featured in a poster, “Efficacy/safety of epacadostat plus pembrolizumab in triple-negative breast cancer and ovarian cancer: Phase I/II ECHO-202 study,” to be presented at the American Society of Clinical Oncology (ASCO) 2017 Annual Meeting, set for June 2-6 in Chicago.
Designed to target the PD-1 receptor, Keytruda is meant to improve the activity of immune T-cells capable of fighting cancer cells. Originally approved by the U.S. Food and Drug Administration (FDA) to treat melanoma, Keytruda has since won FDA approval for several other cancers, such as non-small cell lung cancer, head and neck squamous cell carcinoma, classical Hodgkin lymphoma (cHL), and bladder cancer.
Researchers at the University of Pennsylvania’s Abramson Cancer Center are currently studying the benefits of Keytruda for other cancer types, including TNBC. Their Phase 1/2 ECHO-202 trial (NCT02178722) involved 39 patients with TNBC who received a combination of Keytruda and an investigational checkpoint inhibitor known as epacadostat, developed by Incyte.
Undergoing dose escalating evaluations, the combined therapy was found to be generally well-tolerated with no major adverse events being reported.
“In each patient group, the combination did not add any significant increase in side effects compared to what patients experience with the PD-1 inhibitor alone,” Dr. Tara Gangadhar, who led five of the new analyses from the ECHO-202 trial, said in a press release. Gangadhar is an assistant professor of hematology oncology at the university’s Perelman School of Medicine.
A second study, “Pembrolizumab plus standard neoadjuvant therapy for high-risk breast cancer (BC): Results from I-SPY 2,” evaluated the clinical benefits of Keytruda plus standard of care, given before surgery, to HER2-negative metastatic breast cancer.
The multicenter Phase 2 I-SPY 2 trial (NCT01042379) included 69 women who received Keytruda plus Taxol (paclitaxel) or standard therapy with Taxol alone. The Keytruda-Taxol combo more than tripled TNBC patients’ complete response rate compared to Taxol alone.
Patients with hormone receptor positive breast cancer had a 28 percent complete response rate, compared to the 14.8 percent response rate among the control group.
“This is incredibly exciting news for patients with aggressive cancers and the beginning of generating new and better curative options at diagnosis,” said Angela DeMichele, chair of trial operations for the study. “These findings reflect a growing body of knowledge about how these drugs interact with the immune system that will lead to safer use of PD-1 inhibitors in future studies.”