Merrimack regains MM-121 rights from Sanofi

Merrimack Pharmaceuticals Inc. (NASDAQ:MACK) will regain worldwide development and commercialization rights to MM-121 from Sanofi (Euronext:SAN; NYSE:SNY), effective Dec. 17. Sanofi had rights to the human mAb against epidermal growth factor receptor 3 ( EGFR3; HER3; ErbB3) under a 2009 deal. MM-121 is in Phase II testing for ovarian cancer, breast cancer and non-small cell lung cancer (NSCLC). Merrimack said the deal termination was a mutual decision and that Sanofi will cover costs for the Phase II program for the next six months.

Merrimack also reported data from a second cohort of patients in a Phase II trial evaluating MM-121 plus paclitaxel followed by doxorubicin and cyclophosphamide in neoadjuvant breast cancer. In patients with triple-negative breast cancer (TNBC) (n=99), MM-121 plus paclitaxel led to a pathological complete response rate of 42.9% vs. 51.7% for paclitaxel alone. Merrimack reported data from a cohort of patients with estrogen receptor-positive and/or progesterone receptor-positive breast cancer in November. ...