PFK-158 is a potent and selective inhibitor of PFKFB3 that is currently being investigated in a phase I study in patients with advanced solid malignancies. Target: PFKFB3in vitro: PFK-158 is the first 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) inhibitor to undergo clinical trial testing in cancer patients. PFK-158, a small molecule therapeutic candidate that inactivates a novel cancer metabolism target never before examined in human clinical trials. PFK-158 is not only a first-in-class cancer drug but also the first to target glucose metabolism by inhibiting PFKFB3. PFK-158 is a nanomolar inhibitor of recombinant PFKFB3. PFK-158 inhibits PFKFB3 activity and glycolysis in cancer cells.in vivo: PFK158 is well tolerated in rats and dogs resulting in an acceptable pre-clinical therapeutic index. PFK158 is very effective in multiple preclinical mouse models of human-derived tumors and syngeneic murine models. IND-enabling safety and toxicity studies demonstrated that PFK158 is well tolerated in rats and dogs and supported the initiation of a phase I trial that is now underway.