Merrimack's MM-111 Gets Orphan Drug Status For Gastric & Esophageal Cancers

(RTTNews) - The U.S. Food and Drug Administration's Office of Orphan Products Development has granted two separate orphan drug designations for Merrimack Pharmaceuticals, Inc.'s (MACK) bispecific antibody, MM-111, indicated for the treatment of esophageal cancer and for the treatment of gastric as well as gastroesophageal junction cancers.

MM-111 is designed to inhibit ErbB3 (HER3) receptor signaling in cancers that overexpress ErbB2 (HER2). Overexpression of the ErbB2 cell surface receptor has been reported in 7-34 percent of gastric cancers according to various scientific articles. Research has indicated that ErbB3 expression is associated with poor prognosis in gastric cancer and may contribute to resistance to some current standard treatments. MM-111 is currently being tested in a Phase 2 trial in advanced gastric, esophageal and gastroesophageal junction cancers.

Merrimack Pharmaceuticals added that these two orphan drug designations would potentially provide it with 7-year marketing exclusivity for MM-111 and other benefits if the drug is approved by the FDA.