Background and Aims: Methionine aminopeptidase 2 inhibitors (MetAP2i) are a promising new therapeutic approach for the treatment of diabetes. Beloranib is a prototype MetAP2i which, when tested in obese type 2 diabetes subjects, resulted in 2.0% reduction in HbA1c and 13% body weight loss from baseline following 26 weeks of treatment. A novel MetAP2i, ZGN-1061, is in Phase 1 clinical testing. ZGN-1061 is a potent and selective inhibitor of MetAP2 enzyme activity and shows similar effects on obesity as beloranib in animal models, but has an improved safety profile in model systems of thrombotic risk. The aim of this study was to evaluate the anti-diabetic potential of ZGN1061 in diet-induced obese (DIO) mice and relate these changes to weight loss and change of body composition. Materials and methods: Male C57BL/6J mice were placed on a high fat diet (45% kcal as fat) for 34 weeks then were treated with ZGN-1061 at doses of 0.03, 0.1 and 0.3 mg/kg (SC, QD) or beloranib at 0.1 mg/kg (SC, QD) for 4 weeks (n=10/group). Body weight, food intake, DEXA body composition and oral glucose tolerance test (OGTT) were assessed. Results: ZGN-1061 dose dependently reduced body weight by 4.4%, 17.0%, and 29.5% after 29 days of treatment. In comparison, beloranib achieved 31.5% weight loss. Mice in the 0.3 mg/kg 1061 and 0.1 mg/kg beloranib dose groups were still losing weight over the final week of the study suggesting dosing longer than one month could show greater weight loss. Energy intake (kJ/gram lean mass) was transiently reduced in the two higher ZGN-1061 dose groups as well as the beloranib group by 23%, 28% and 31% at day 16, respectively. However, by the end of the study, energy intake was no different from vehicle in all drug treated groups. At day 27 body composition as measured by DEXA show ZGN-1061 reduced the % fat and increased the % lean mass at both the mid and high dose groups with no change in the low dose group. On day 30 an OGTT was performed. Baseline fasted glucose was reduced relative to vehicle by 12.3%, 16.4% and 27.1% in the ZGN-1061 dose response. Beloranib had a 23.7% reduction of fasted glucose. Oral glucose tolerance was improved with treatment as shown by 12.0%, 27.2% and 33.2% reductions of the glucose AUC 0-120 and 25.4%, 44.4% and 60.1% reductions of insulin AUC 0-120 across the ZGN-1061 doses. Calculation of HOMA-IR reveal a marked drug effect to reduce the insulin resistance index at all dose levels of ZGN-1061, where the lowest dose improved HOMA-IR by 40.3% and the highest dose by 81.2%. Conclusions: The MetAP2i ZGN-1061 dose-dependently improves glycemic control and insulin sensitivity in DIO mice. Weight loss at the higher doses likely contributes to the improvement of glucose control, however, glucose was reduced even at the lowest dose which was weight neutral and had no effect on fat mass after one month of dosing.