MM-121: Phase II data

A double-blind, placebo-controlled, international Phase II trial in 118 patients who have failed anti-estrogen therapy showed that IV MM-121 plus oral Aromasin exemestane missed the primary endpoint of improving PFS with an HR of <=0.5 vs. Aromasin alone (HR=0.75, 95% CI: 0.48, 1.15). Merrimack said overall survival (OS) data are immature, but trend in favor of MM-121 plus Aromasin vs. Aromasin alone (HR=0.41, 95% CI: 0.19, 0.9).

The frequency of adverse events was similar between treatment arms. Adverse events more commonly reported in the MM-121 arm were diarrhea, mucosal inflammation and decreased appetite. No cases of pulmonary embolism (PE) or other venous thromboembolic events were reported in either arm. Patients received a loading dose of 40 mg/kg MM-121 followed by 20 mg/kg MM-121 once weekly plus Aromasin or Aromasin alone. Merrimack said it will work with Sanofi to determine a path forward for MM-121, but declined to disclose details. ...