A Pilot Study of Ketogenic Diet and Metformin in Glioblastoma: Feasibility and Metabolic Imaging

Ketogenic diet is high-fat, low carbohydrate diet. Ketogenic diet will be maintained on a continuous basis. The diet will begin at an approximately 3:1 fat to carbohydrate + protein ratio for 5 days. If the patient does not show urine ketosis (1.5 mmol/L or 27.0 mg/dL), the ketosis diet will be advanced to approximately 4:1 ratio for 5 days. If the patient still does not attain ketosis a 24 hour fast will be done to promote ketosis. The diet will encourage at least 30 ml per day of Medium Chain Triglycerides (MCT) oil to enhance ketosis.

Metformin will be administered as a single 850 mg dose P.O. at Week 8, then titrated up to 850 mg P.O. BID at Week 10, and then 850 mg T.I.D. at Week 12, as tolerated.