MM-121: Additional Phase II data

Data from 99 patients with triple-negative breast cancer (TNBC) in the second cohort of an open-label, U.S. Phase II trial showed that once-weekly IV MM-121 plus paclitaxel followed by standard treatment with doxorubicin and cyclophosphamide until surgical resection led to a pCR rate of 42.9% vs. 51.7% for paclitaxel alone followed by standard treatment until surgical resection. Merrimack said there was no formal quantitative endpoint specified for the trial. Rates of serious adverse events were 28.1% for the MM-121 arm vs. 15.6% for the control arm and rates of grade >=3 adverse events were 50% for the MM-121 arm vs. 31.3% for the control arm. The company previously reported data from the first cohort of 101 patients with estrogen receptor-positive and/or progesterone receptor-positive, HER2-negative breast cancer showing that MM-121 plus paclitaxel followed by standard treatment until surgical resection led to a pCR rate of 10.6% vs. 3.3% for the control arm (see BioCentury, Dec. 9, 2013). ...