MM-151

MM-151 is an oligoclonal mixture of three fully human monoclonal IgG1 antibodies that target non-overlapping epitopes on the epidermal growth factor receptor (EGFR). Developed by Merrimack Pharmaceuticals, it was designed to inhibit ligand-mediated EGFR signaling, downregulate EGFR expression, and enhance immune effector functions such as antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). The drug aimed to overcome resistance mechanisms seen with other anti-EGFR therapies in solid tumors, particularly metastatic colorectal cancer. Preclinical studies demonstrated enhanced activity compared to cetuximab through multiple mechanisms including ligand antagonism and receptor downregulation. Clinical trials showed objective responses in patients with refractory solid tumors, but development has been discontinued[1][5][6][7][10].