Merrimack Pharmaceuticals, Inc. and Sanofi-Aventis signed an exclusive worldwide licensing agreement for the development and commercialization of MM-121, a fully human monoclonal antibody designed to block signaling of the ErbB3 receptor. MM-121 is currently in Phase I testing as a potential treatment for cancer. SA will make an upfront payment of $60 million and will be responsible for all development costs. Merrimack is eligible for an additional $470 million in milestone payments as well a...