Postmenopausal women with locally advanced or metastatic estrogen receptor positive (ER+) and/or progesterone receptor positive (PR+), HER2-negative breast cancer are participating in the randomized, double blind trial.
Merrimack senior medical director Akos Czibere said, "We are hopeful that by combining MM-121 with exemestane, we can block the ErbB3 pathway, which we believe promotes this resistance and, ultimately, prevent the patient’s cancer from progressing."
The study has enrolled 118 patients, which is being conducted in the US, Canada, Russia and Europe with results expected in the latter half of 2013.
A fully human monoclonal antibody targeting ErbB3, MM-121 is being developed in collaboration with Sanofi.