New combination: Saxagliptin and metformin extended release (Kombiglyze XR) was approved to improve glycemic control in adults with type 2 diabetes mellitus.
The Centers for Disease Control and Prevention estimate that approximately 23.5 million or 10.7% of adults in the United States carries a diagnosis of diabetes, of which 90% to 95% have type 2 diabetes. On November 5, 2010, saxagliptin and metformin hydrochloride extended-release (XR) tablets were approved by FDA with an indication as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus when treatment with both saxagliptin (a dipeptidyl peptidase-4 inhibitor) and metformin (a biguanide) is appropriate.
Efficacy. There has been no clinical efficacy or safety studies conducted specifically with saxagliptin and metformin XR. FDA approved once-daily saxagliptin and metformin XR based upon 2 phase 3 clinical trials evaluating the efficacy and safety of saxagliptin and metformin immediate release as separate tablets compared to placebo added to metformin immediate-release tablets. In a clinical trial of type 2 diabetic patients with inadequate glycemic control on diet and exercise alone, combination therapy resulted in significant reductions in HbA1c of -2.5% compared to -2.0% with metformin immediate release plus placebo. In a separate clinical trial randomizing patients with type 2 diabetes inadequately controlled on metformin monotherapy, patients receiving the combination therapy experienced significant reductions in HbA1c of -0.7% compared to an increase of +0.1% in patients taking metformin immediate release plus placebo.
Safety. In the above-mentioned clinical trials, adverse reactions reported in ≥5% of patients treated with saxagliptin and more commonly than in patients treated with placebo included upper respiratory tract infection, urinary tract infection, and headache. Adverse reactions reported in >5% of patients treated with metformin extended-release and more commonly than in patients treated with placebo included diarrhea and nausea/vomiting. Adverse reactions reported in ≥5% of treatment-naive patients treated with coadministered saxagliptin and metformin and more commonly than in patients treated with metformin alone were headache and nasopharyngitis. As Kombiglyze XR contains metformin, it shares the same boxed warning for lactic acidosis, a rare, but serious metabolic complication. Consequently, patients should be warned against excessive alcohol intake and Kombiglyze XR should be used very cautiously in hepatic impairment and is contraindicated in renal impairment.