From: Chitrabhanu Ballav and Stephen C.L. Gough, Safety and Efficacy of Sitagliptin-Metformin in Fixed Combination for the Treatment of Type 2 Diabetes Mellitus (review), Clinical Medicine Insights: Endocrinology and Diabetes 2013:6 25-37, doi: 10.4137/CMED.S7314
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Trials Assessing Efficacy and Safety of Metformin and Sitagliptin
In the study by Reasner et al, FDC of sitagliptin/metformin (sita/met) 50/1000 mg twice daily was compared with metformin 1000 mg twice daily as the initial treatment in patients aged 18 to 78 years with type 2 diabetes for more than 3 years and a mean HbA1c of 9.8%. The primary end point was the effect of 18 weeks of treatment on mean HbA1c, safety, and tolerability. In the study, 484 subjects in the sita/met FDC group and 482 patients in the metformin group completed the protocol. Reduction in HbA1c was 2.4% (95% confidence interval [CI], −2.5 to −2.2) from baseline of 9.9% with sita/met FDC, which was significantly greater than the 1.8% (95% CI, −0.8 to −0.4) from baseline HbA1c of 9.8% with metformin alone. This difference was consistent across all subgroups defined by age, gender, baseline body mass index (BMI), and duration of type 2 diabetes. Around 49% of patients on combination treatment achieved a target HbA1c of ,7% compared with 34% on metformin alone. Improvement in HbA1c was greater in patients with a higher HbA1c at baseline. There was also a greater reduction in fasting plasma glucose with the combination treatment (−3.8 mmol/L with combination and −3.0 mmol/L with metformin monotherapy). There was also a significant improvement in β-cell function, as measured by the homeostatic model assessment β (HOMA-β), a surrogate marker of insulin secretion derived from simultaneous blood glucose and insulin levels, with sita/met FDC compared with metformin monotherapy. At week 18, body weight was reduced by 1.6 kg in both groups. Weight loss was progressive until 12 weeks with a plateau between 12 and 18 weeks. Both sita/met FDC and metformin resulted in small improvement in total cholesterol, HDL cholesterol, triglyceride, and non-HDL cholesterol, and the changes were comparable between groups.
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