In a Phase 3 clinical trial Merrimack Pharmaceuticals' (MACK) cancer drug MM-398 (irinotecan encapsulation injection) achieved its primary endpoint of a statistically significant improvement in overall survival (OS) in pancreatic cancer patients when given in combination with 5-fluorouracil (5-FU) and leucovorin. The combo regimen achieved an overall survival of 6.1 months, a 1.9 month improvement over the control arm.
When administered as a monotherapy, however, MM-398 failed to meet its primary endpoint. Patients receiving the drug achieved an OS of 4.9 months versus 4.2 months in the control arm. The modest improvement was not statistically significant.
There was a higher level of adverse events in patients receiving the monotherapy compared to the combination regimen.
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