Merrimack's experimental pancreatic cancer drug MM-398 meets main goal of Phase III study

Merrimack Pharmaceuticals announced Thursday that a late-stage trial of its experimental drug MM-398 in patients with metastatic pancreatic cancer met its main goal of overall survival (OS), sending the company's shares up more than 70 percent. CEO Robert Mulroy said "we are excited by the results... Given that there have only been a handful of successful Phase III trials in pancreatic cancer in the past 25 years."

The NAPOLI-1 study included 417 patients with metastatic pancreatic cancer who received prior gemcitabine-based therapy. Subjects were randomised to receive MM-398 in combination with 5-fluorouracil (5-FU) and leucovorin every two weeks, a higher dose of MM-398 alone every three weeks or a control arm of 5-FU and leucovorin. Merrimack's MM-398 is a nanoliposomal encapsulation of the chemotherapeutic irinotecan.

Results of the study showed that patients who received MM-398 in combination with 5-FU and leucovorin achieved OS of 6.1 months, which was a significant improvement over the 4.2 month survival seen in the control arm. In addition, Merrimack noted that a "significant advantage" was observed for progression-free survival in the MM-398 arm.

The company indicated that the most common serious adverse events in patients given MM-398 were neutropenia, fatigue, diarrhea and vomiting. Merrimack said that sepsis was the only serious life threatening event that occurred with a more than 2 percent difference between the combination arm and the control arm. "The top-line safety data we were very pleased with, particularly relative to this cancer patient population," Mulroy remarked.

Merrimack added that patients who received MM-398 alone had median OS of 4.9 months, which the drugmaker noted was not significantly higher than that of 4.2 months in the control arm.

The drugmaker said it plans to submit a filing to the FDA for the MM-398 combination regimen this year. In addition, the company is investigating the drug in a mid-stage trial of patients with metastatic colorectal cancer and Phase I studies in Ewing's sarcoma and glioma. Merrimack is also assessing a potential companion diagnostic for MM-398 in patients with multiple cancer types to determine those most likely to benefit from the drug.

To read more Top Story articles, click here.