Sitagliptin is a once-daily oral medication in the depeptidyl-peptidase-4 (DPP-4) inhibitor class of medications. Data from a phase 3 non-inferiority trial of sitagliptin vs. glipizide was presented. This was a double-blind randomized multicenter trial conducted in 1172 patients with type 2 diabetes. Patients who were not controlled on metformin monotherapy were randomized to either sitagliptin 100 mg/day or glipizide up to 20 mg/day. After 52 weeks of treatment, 63% of the sitagliptin group and 59% of the glipizide group had HbA1c values <7%; sitagliptin thus met the criteria for non-inferiority. The glipizide group, however, had a significantly higher occurrence of hypoglycemia (32.0% vs. 4.9%, respectively; p<0.001). Patients taking sitagliptin lost significantly more weight over the 52 weeks when compared to those taking glipizide (−1.5 kg vs. + 1.1 kg respectively; p<0.001). Although the primary endpoint was measured at 52 weeks, the study will continue for a total of 104 weeks.

The safety profile of sitagliptin was determined by combining data from four different clinical trials. No clinically significant differences were observed between sitagliptin and placebo in adverse events, incidence of hypoglycemia, body weight, or laboratory values in these studies. The most frequently reported (≥3% and greater than placebo) adverse events with sitagliptin were stuffy or runny nose and sore throat, headache, diarrhea, upper respiratory tract infection, joint pain, and urinary tract infection. Although not considered clinically significant, small rises in uric acid and neutrophil count and slight reductions in alkaline phosphatase values were observed in comparison to placebo-treated patients.

Sitagliptin is currently under review by the US Food and Drug Administration; regulatory filings in other countries are pending.