Orphan Drug Designation Granted to MM-121 for the Treatment of Heregulin-Positive Non–Small-Cell Lung Cancer

MM-121 is a fully human monoclonal antibody designed to block tumor survival signals

The FDA has granted orphan drug designation to MM-121 (seribantumab, Merrimack Pharmaceuticals, Inc.), an investigational drug candidate, for the treatment of heregulin positive non-small-cell lung cancer. MM-121 is a fully human monoclonal antibody designed to block tumor survival signals and enhance the antitumor effect of combination therapies by targeting the cell surface receptor HER3 (ErbB3) in patients with high expression of the biomarker heregulin.

The FDA's orphan drug designation is granted to drugs and biologics intended to treat rare diseases or conditions with a prevalence of fewer than 200,000 people in the U.S. This designation includes eligibility for a seven-year period of marketing exclusivity for MM-121 upon approval, as well as other development assistance and financial incentives.

MM-121 is currently being evaluated in the SHERLOC study, a global randomized phase 2 study that will assess progression-free survival of MM-121 in combination with docetaxel versus docetaxel alone. The study is enrolling patients with heregulin-positive non-small-cell adenocarcinoma of the lung who have progressed after a platinum-containing regimen and may have received anti-programmed death-1 or anti-programmed death ligand-1 therapy. Top-line data for the SHERLOC study are expected in the second half of 2018.

In addition, MM-121 will be evaluated in the SHERBOC trial, a global randomized phase 2, double-blind, placebo-controlled clinical study of the agent added to standard of care in patients with heregulin-positive, hormone receptor-positive, HER2-negative metastatic breast cancer. The first patient is expected to be dosed in the SHERBOC study by the end of 2017.

MM-121 targets phenotypically distinct heregulin-positive cancer cells within solid tumors. Heregulin-positive cancer cells are characterized by their ability to escape the effects of targeted, cytotoxic, and antiendocrine therapies and potentially contribute to rapid clinical progression in patients whose tumor cells test positive for heregulin. When used in the combination setting, MM-121 is designed to block the heregulin/HER3 signaling axis to make tumor cells more sensitive to the effects of the combination therapy.

Source: Merrimack; October 30, 2017.