MM-121: Additional Phase II data

Additional data from 132 NSCLC patients with EGFR wild-type tumors in Group A of a single-arm, open-label, international Phase II trial showed that MM-121 plus Tarceva erlotinib led to a median PFS, the primary endpoint, of 1.9 months vs. 1.8 months for Tarceva alone (HR=0.81, 95% CI: 0.55, 1.2, p=0.29). In 36 patients who were positive for the biomarker heregulin, MM-121 plus Tarceva significantly improved median PFS vs. Tarceva alone (1.9 vs. 1.7 months, HR=0.38, 95% CI: 0.18, 0.8, p=0.011). Data were presented at the American Society of Clinical Oncology meeting in Chicago. Merrimack said it is considering further confirmatory studies with MM-121 in NSCLC, although they would "likely not rely on erlotinib as the backbone therapy."

Last year, a DSMB said interim data from the overall population in Group A of the trial showed that MM-121 plus Tarceva would not meet the primary endpoint of improving PFS. Merrimack said interim data from patients in Group A showed that MM-121 plus Tarceva met undisclosed pre-specified criteria for continuing to full enrollment of 120 patients. Merrimack continued Group A to full enrollment based on "expectations of the potential for subgroup benefit" (see BioCentury, April 8, 2013 & Aug. 12, 2013). ...