Long-term (52-week) efficacy and safety of ipragliflozin add-on therapy to insulin in Japanese patients with type 1 diabetes mellitus: An uncontrolled, open-label extension of a phase III study

Introduction: The aim of the present study was to assess the long-term (52-week) efficacy and safety of ipragliflozin in insulin-treated Japanese patients with type 1 diabetes mellitus and inadequate glycemic control.

Materials and methods: In this 28-week, open-label extension of a multicenter, randomized, placebo-controlled, 24-week phase III study, ipragliflozin recipients continued treatment (50 mg, once daily), and placebo recipients were switched to once-daily 50 mg ipragliflozin at the start of the extension period. The ipragliflozin dose could be increased to 100 mg if warranted. The primary end-point was change in glycated hemoglobin; secondary end-points were change in insulin dose and bodyweight. Safety outcomes were monitored as treatment-emergent adverse events.

Results: A total of 53 (placebo switched to ipragliflozin) and 108 (ipragliflozin) patients completed the open-label extension (treatment period 2), with 24 and 44 patients, respectively, receiving dose increases. From baseline to end of treatment, the overall mean change (standard deviation [SD]) in glycated hemoglobin was -0.33% (0.72; -3.7 mmol/mol [7.9]), with changes in basal, bolus and total insulin doses of -3.76 IU (SD 3.85 IU), -2.51 IU (SD 7.08 IU) and -6.27 IU (SD 8.16 IU), respectively. No serious drug-related treatment-emergent adverse events or deaths were reported. Treatment-emergent adverse events leading to study discontinuation occurred in zero and three (2.6%) patients in the placebo switched to ipragliflozin and ipragliflozin groups, respectively; all were considered drug-related. There were no cases of severe hypoglycemia or diabetic ketoacidosis, and no safety concerns related to dose increase.

Conclusions: The efficacy and safety of 50 mg, once-daily ipragliflozin in insulin-treated type 1 diabetes mellitus patients were confirmed in this long-term, open-label extension study. No safety concerns were attributed to a dose increase to 100 mg.