The addition of a standard anti-diabetic dose of metformin does not improve outcome in patients with advanced pancreatic cancer treated with gemcitabine and erlotinib, a new study published online ahead of print in the journal The Lancet Oncology has shown.
For the multicenter, double-blind, placebo-controlled, phase II trial, researchers enrolled 121 patients with advanced pancreatic cancer. Patients were randomly assigned 1:1 to receive gemcitabine 1,000 mg/m2 IV on days 1, 8, and 15 every 4 weeks plus erlotinib 100 mg once daily with either oral metformin 500 – 1,000 mg twice daily or placebo twice daily.
Results showed that the 6-month overall survival rate was 63.9% (95% CI: 51.9, 75.9) in the placebo arm versus 56.7% (44.1, 69.2) in the meformin arm (P=0.41).
Researchers found that median overall survival was 7.6 months (95% CI: 6.1, 9.1) in the placebo group compared with 6.8 months (95% CI: 5.1, 8.5) in the metformin group (HR = 1.056; 95% CI: 0.72, 1.55; P=0.78).
In regard to safety, 25% of patients in each group experienced grade 3-4 neutropenia. Grade 3-4 diarrhea and fatigue were more common in the metformin arm, while skin rash occurred more frequently in the placebo arm.
The researchers note that “future research should include studies of more potent biguanide, and should focus on patients with hyperinsulinemia and patients with tumors showing markers of sensitivity to energetic stress…”