Merrimack Pharmaceuticals Inc. is moving forward without MM-141 (istiratumab) after top-line data from the phase II CARRIE study in front-line metastatic pancreatic cancer showed that adding the bispecific, tetravalent monoclonal antibody (MAb) to standard-of-care (SOC) nab-paclitaxel/gemcitabine failed to beat the SOC regimen plus placebo in the primary efficacy endpoint of progression-free survival (PFS). The study also missed secondary efficacy endpoints: objective response rate, disease control rate, duration of response and overall survival.