Efficacy of metformin in combination with immune checkpoint inhibitors (anti-PD-1/anti-CTLA-4) in metastatic malignant melanoma.

Background: Metformin is one of the biguanides commonly used in patients with type II Diabetes Mellitus. Apart from its hypoglycemic properties, metformin also inhibits the cell cycle by restricting protein synthesis and cell proliferation via regulating the LKB1/AMPL pathway. Furthermore, it also enhances the PD-1 blockade through a reduction of tumor hypoxia.