Efficacy and safety of the dipeptidyl peptidase-4 inhibitor, sitagliptin, in patients with type 2 diabetes mellitus inadequately controlled on glimepiride alone or on glimepiride and metformin.
OBJECTIVE
To assess the efficacy and safety of a 24-week treatment with sitagliptin, a highly selective once-daily oral dipeptidyl peptidase-4 (DPP-4) inhibitor, in patients with type 2 diabetes who had inadequate glycaemic control [glycosylated haemoglobin (HbA(1c)) >or=7.5% and <or=10.5%] while on glimepiride alone or in combination with metformin.


METHODS
After a screening, diet/exercise run-in and drug wash-off period, a glimepiride +/- metformin dose titration/stabilization period and a 2-week, single-blind placebo run-in, 441 patients (of ages 18-75 years) were randomized to receive the addition of sitagliptin 100 mg once daily or placebo in a 1 : 1 ratio for 24 weeks. Of these patients, 212 were on glimepiride (>or=4 mg/day) monotherapy and 229 were on glimepiride (>or=4 mg/day) plus metformin (>or=1,500 mg/day) combination therapy. Patients exceeding pre-specified glycaemic thresholds during the double-blind treatment period were provided open-label rescue therapy (pioglitazone) until study end. The primary efficacy analysis evaluated the change in HbA(1c) from baseline to Week 24. Secondary efficacy endpoints included fasting plasma glucose (FPG), 2-h post-meal glucose and lipid measurements.


RESULTS
Mean baseline HbA(1c) was 8.34% in the sitagliptin and placebo groups. After 24 weeks, sitagliptin reduced HbA(1c) by 0.74% (p < 0.001) relative to placebo. In the subset of patients on glimepiride plus metformin, sitagliptin reduced HbA(1c) by 0.89% relative to placebo, compared with a reduction of 0.57% in the subset of patients on glimepiride alone. The addition of sitagliptin reduced FPG by 20.1 mg/dl (p < 0.001) and increased homeostasis model assessment-beta, a marker of beta-cell function, by 12% (p < 0.05) relative to placebo. In patients who underwent a meal tolerance test (n = 134), sitagliptin decreased 2-h post-prandial glucose (PPG) by 36.1 mg/dl (p < 0.001) relative to placebo. The addition of sitagliptin was generally well tolerated, although there was a higher incidence of overall (60 vs. 47%) and drug-related adverse experiences (AEs) (15 vs. 7%) in the sitagliptin group than in the placebo group. This was largely because of a higher incidence of hypoglycaemia AEs (12 vs. 2%, respectively) in the sitagliptin group compared with the placebo group. Body weight modestly increased with sitagliptin relative to placebo (+0.8 vs. -0.4 kg; p < 0.001).


CONCLUSIONS
Sitagliptin 100 mg once daily significantly improved glycaemic control and beta-cell function in patients with type 2 diabetes who had inadequate glycaemic control with glimepiride or glimepiride plus metformin therapy. The addition of sitagliptin was generally well tolerated, with a modest increase in hypoglycaemia and body weight, consistent with glimepiride therapy and the observed degree of glycaemic improvement.
Hermansen
K
K
Aarhus University Hospital, Aarhus, Denmark.
Kipnes
M
M
Luo
E
E
Fanurik
D
D
Khatami
H
H
Stein
P
P
D000293:Adolescent; D000328:Adult; D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D054873:Dipeptidyl-Peptidase IV Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007003:Hypoglycemia / Q000517:prevention & control*; D007004:Hypoglycemic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D008297:Male; D008687:Metformin / Q000494:pharmacology / Q000627:therapeutic use*; D008875:Middle Aged; D011719:Pyrazines / Q000494:pharmacology / Q000627:therapeutic use*; D016037:Single-Blind Method; D000068900:Sitagliptin Phosphate; D013453:Sulfonylurea Compounds / Q000494:pharmacology / Q000627:therapeutic use*; D016896:Treatment Outcome; D014230:Triazoles / Q000494:pharmacology / Q000627:therapeutic use*
D054873:Dipeptidyl-Peptidase IV Inhibitors; D007004:Hypoglycemic Agents; D011719:Pyrazines; D013453:Sulfonylurea Compounds; D014230:Triazoles; C057619:glimepiride; D008687:Metformin; D000068900:Sitagliptin Phosphate