CAMBRIDGE, Mass., July 22, 2013 (GLOBE NEWSWIRE) — Merrimack Pharmaceuticals, Inc. (Nasdaq:MACK) today announced the enrollment of its first patient in a Phase 2 clinical trial of its bispecific antibody, MM-111, for the treatment of advanced gastric, esophageal and gastroesophageal junction (GEJ) cancers.
Overexpression of the HER2 (ErbB2) cell surface receptor has been reported in 7-34 percent of stomach and esophageal cancers. The HER2 receptor triggers tumor growth and survival when it binds together with an additional receptor known as HER3 (ErbB3) and another protein called heregulin. HER3 expression has been associated with poor prognosis in gastric cancer. MM-111 is designed to anchor to both receptors, HER2 and HER3, on the cell surface and block heregulin’s ability to transmit tumor growth signals, thus inhibiting the tumor cell’s ability to thrive.