CHICAGO — The addition of pembrolizumab to eribulin demonstrated no significant improvements in terms of PFS, OS or objective response rate among patients with hormone receptor-positive, HER2-negative metastatic breast cancer, Sara M. Tolaney, MD, MPH, breast medical oncologist at Dana-Farber Cancer Institute, told HemOnc Today at the ASCO Annual Meeting.
“To date, we’ve had very little data for the activity of checkpoint inhibitors in estrogen receptor-positive breast cancer, with some data suggesting very modest activity of checkpoint inhibition as monotherapy,” Tolaney said.
Tolaney and colleagues conducted a randomized phase 2 study to compare the efficacy of eribulin (Halaven, Eisai) plus pembrolizumab (Keytruda, Merck) and eribulin alone among patients with HR-positive metastatic breast cancer.
There was no statistically significant difference in PFS, the primary endpoint, between the two groups, Tolaney said. PFS also did not improve in the subset of patients with PD-L1 positivity.
Furthermore, adding pembrolizumab to eribulin did not benefit OS or the objective response rate, according to Tolaney.
“There certainly does need to be further work to better understand why it was that there was no benefit seen,” Tolaney said.
“There is work that is ongoing in ER-positive breast cancer, specifically a large preoperative trial exploring the benefits of adding pembrolizumab to chemotherapy in the preoperative setting,” she added. “There will be more to come and hopefully we’ll be able to understand these findings better.” – by Alaina Tedesco
Tolaney SM, et al. Abstract 1004. Presented at: ASCO Annual Meeting; May 31-June 4, 2019; Chicago.
Disclosure: Tolaney reports consulting or advising for AstraZeneca, Celldex, Eisai, Genentech, Immunomedics, Lilly, Merck, NanoString Technologies, Nektar, Novartis, Pfizer, Puma Biotechnology, Sanofi and Tesaro; receiving research funding from AstraZeneca, Bristol-Myers Squibb, Cyclacel, Eisai, Exelixis, Genentech/Roche, Lilly, Merck, NanoString Technologies, Nektar, Novartis and Pfizer; and travel, accommodations and expenses from AstraZeneca, Celldex, Eisai, Genentech/Roche, Immunomedics, Lilly, Merck, NanoString Technologies, Nektar, Novartis, Pfizer and Puma Biotechnology.