Long-term safety, tolerability, and efficacy of the dipeptidyl peptidase-4 inhibitor sitagliptin in Japanese patients with type 2 diabetes

The long-term safety, tolerability, and efficacy of sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, were evaluated in a multicenter, open-label, single-arm, 52-week study in Japanese patients with type 2 diabetes mellitus who had inadequate glycemic control (HbA1c 6. 9-10. 4%) on diet and exercise therapy. A total of 177 patients entered the study and 139 (78. 5%) completed the 52-week treatment period. Through 52 weeks of treatment, sitagliptin (50 or 100 mg once daily) was well tolerated. The most commonly reported adverse experiences were nasopharyngitis (35. 0%), constipation (8. 5%), back pain (5. 1%) and upper respiratory tract inflammation (5. 1%). The incidences of hypoglycemia and pre-specified pooled gastrointestinal adverse experiences were low (each 1. 7%). No significant changes in body weight were observed with sitagliptin treatment over the 52-week treatment period. In general, there was no change in the type, severity or incidence of adverse experiences with long-term treatment (52 weeks) compared with shorter-term treatment (28 weeks). The safety and tolerability profile of sitagliptin in this study was consistent with that previously reported for Japanese and non-Japanese patients. After 52 weeks of sitagliptin treatment, HbA1c was significantly (p < 0. 001) reduced from baseline (-0. 7% ± 0. 6). Consistent with this observation, mean changes from baseline in 2 h post-meal glucose and fasting plasma glucose were also significantly reduced from baseline at week 52 (both p < 0. 001). In summary, in this study of Japanese patients with type 2 diabetes who had inadequate glycemic control on diet and exercise, sitagliptin was well tolerated and provided an effective improvement in glycemic parameters over 52 weeks. © 2011 The Japan Diabetes Society.