MM-111 Update

MM-111 is being investigated in a Phase 2 clinical trial in combination with trastuzumab and paclitaxel versus a control arm of trastuzumab and paclitaxel in patients with second-line HER2+ gastric/gastroesophageal cancer (Press release, Merrimack, FEB 26, 2015, View Source [SID:1234501985]). The trial was designed with two co-primary endpoints: progression free survival in the overall population and progression free survival in the heregulin high population.

The Data Safety Monitoring Board (DSMB) for the trial met recently and recommended closure of the trial to further patient enrollment due to shorter progression free survival on the experimental arm relative to the control arm in the overall patient population. Based on the DSMB’s recommendation, Merrimack decided to stop enrollment in this trial. A preliminary analysis shows that a vast majority of patients in the trial were below the threshold of heregulin levels necessary to benefit from MM-111. As a result, Merrimack does not believe that further development of MM-111 in second line HER2+ gastric cancer is warranted. In addition, Merrimack does not plan to invest in additional development of MM-111 at this time.