SGLT2 inhibitors as potentially helpful drugs in PI3K inhibitor-induced diabetes: a case report

Background Hyperglycemia is the most common side-effect of phosphatidylinositol 3-kinase (PI3K) inhibitors that are approved for the treatment of some advanced or metastatic breast cancers. This side-effect is likely due to the central role of PI3K in insulin signalling. Here we report the use of a sodium-glucose cotransporter 2 (SGLT2) inhibitor to manage severe hyperglycemia. Case presentation We describe a 74-year-old woman who developed severe uncontrolled hyperglycemia after commencing alpelisib, a new oral PI3K inhibitor indicated for a metastatic breast cancer, despite taking oral anti-diabetic drugs, metformin and vildagliptin, combined with intravenous insulin infusion of up to 250 units/day. The introduction of the SGLT2 inhibitor dapagliflozin rapidly improved blood glucose with a drastic reduction in insulin dosage, from 250 to 12 units/day, and without significant side-effects. Conclusions We report the successful management of hyperglycemia induced by alpelisib using a SGLT2 inhibitor without the need to discontinue effective cancer treatment.