Comparing the Effects of Ipragliflozin versus Metformin Added to Sitagliptin on Visceral Fat Reduction in Asian Patients with Type 2 Diabetes: A Prospective, Multicenter, Blinded-Endpoint Randomized Controlled Study (PRIME-V Study)

Background: Visceral fat accumulation is associated with insulin resistance and various metabolic complications. We aimed to determine the effect of ipragliflozin (sodium-dependent glucose transporter-2 inhibitor) versus metformin with a dipeptidyl peptidase-4 (DPP-4) inhibitor (sitagliptin) in reducing visceral fat in Asian patients with insufficiently controlled type 2 diabetes. Methods: A prospective, multicenter, blinded-endpoint, randomized controlled study was conducted to evaluate the efficacy of treatment with either ipragliflozin or metformin combined with sitagliptin on visceral fat reduction and glycemic control among Japanese patients with type 2 diabetes, HbA1c 7-10%, and BMI ≥22 kg/m2. Patients who met the eligibility criteria were randomly assigned (1:1) to receive ipragliflozin 50 mg (n=51) or metformin 1000-1500 mg daily (n=52). The primary outcome was rate change in visceral fat area measured by computed tomography at 24 weeks of therapy. Two radiologists, blinded to patients' clinical information and randomized treatment assignment, analyzed the images. Secondary outcomes included effects on blood glucose, fasting insulin level, and lipids. The full analysis set was used for analysis. Findings: Mean percent reduction in visceral fat area was significantly greater in the ipragliflozin group than in the metformin group (-12·06% vs. -3·65%, group difference [95% CI] -8·40%; [-16·4 to -3·38], P=0·040). The ipragliflozin group also showed significant lowering of fasting insulin (-20·73% vs. 0·85%, group difference [95% CI] -21·58%, [2·80 to 34·20], P=0·018), while HbA1c decreased in the metformin group compared with ipragliflozin group. Interpretation: Ipragliflozin significantly reduced the visceral fat area compared with metformin, as the secondary agent used in combination with DPP-4 inhibitor. Since the fasting insulin level decreased, the reduction in visceral fat associated with ipragliflozin administration might have contributed to the improvement in insulin resistance. Trial Registration Number: Trial registration: UMIN 000015170. Funding Statement: To conduct this study, an agreement was signed between Chiba University and Astellas Pharma Inc. (Tokyo, Japan). Astellas Pharma Inc. funded this work. Declaration of Interests: KY received research grants from Astellas Pharma Inc. and MSD K.K. (Tokyo, Japan), and received a lecture fee from Astellas Pharma Inc. and Sumitomo Dainippon Pharma (Tokyo, Japan). No conflicts of interest are declared for other authors. Ethics Approval Statement: The study protocol was approved by the Institutional Review Boards (IRBs), Ethics Review Committees, or Ethics Committees of the following institutions: Chiba University Hospital (ID number: G26009), Asahi General Hospital (ID number: 2014091602), National Hospital Organization Chiba Medical Center, Seirei Sakura Citizen Hospital, Chiba Rosai Hospital (ID number: 26-21), Toho University Sakura Medical Center (ID number: 2014-077), Tokyo Women’s Medical University Yachiyo Medical Center (ID number: 150303), Chiba Aoba Municipal Hospital, Kimitsu Chuo Hospital, Funabashi Central Hospital (ID number: H27-1), and Chiba Kaihin Municipal Hospital. In other facilities, approval was provided at Chiba University Hospital (which had the centralized IRB).