Ji L, et al. - The researchers compared the effectiveness of once-daily metformin extended release (XR) in terms of gastrointestinal (GI) tolerability, with non-inferior efficacy, vs thrice-daily metformin immediate release (IR) in treatment-naïve Chinese patients with type 2 diabetes (T2DM). From baseline to week 16, metformin XR was non-inferior to metformin IR for the least squares mean (LSM) change in glycated hemoglobin (HBA1c). For overall GI adverse event (AE) incidence, metformin XR was not superior to metformin IR during treatment of Chinese T2DM patients.

Methods

• The researchers performed this prospective, open-label, randomized, multicenter, phase IV interventional study.
• They recruited Chinese T2DM patients to receive either metformin XR or metformin IR with a 2-week screening period, 16-week treatment period, and 2-week follow-up period without treatment.
• A non-inferiority assessment of XR metformin vs IR metformin in glycated hemoglobin (HBA1c) least squares mean (LSM) change from baseline to week 16 and the superiority of GI tolerability for metformin XR vs metformin IR were the co-primary endpoints.

Results

• The researchers randomized 532 patients to metformin IR (n=267) or metformin XR (n=265).
• In each group, the HbA1c LSM change was -1.61% and -1.58%, respectively (LSM difference, 0.03; 95% confidence interval [CI], -0.10, 0.17).
• In the metformin IR-only group, the incidences of drug-related AEs were 26.5% (n=66) and 32.2% (n=85) in the metformin XR-only group.
• In the metformin IR-only group and in the metformin XR-only group, GI AEs were 23.8% and 22.3%, respectively (difference, -1.52; 95% CI, -8.60, 5.56).
• Findings revealed that the treatment difference met the predefined non-inferiority upper CI margin of 0.4% in HbA1c.