Liraglutide outperforms sitagliptin in HbA1c reductions

Liraglutide appears to be more effective in reducing HbA1c, fasting plasma glucose and weight compared with sitagliptin, according to the results of a head-to-head comparison study.

“These findings support the use of liraglutide (Victoza, Novo Nordisk) as an effective glucagon-like peptide 1 agent to add to metformin,” the researchers said.

The parallel-group, open-label trial included patients aged 18 to 80 years with type 2 diabetes who had poor glycemic control (HbA1c >7.5%) and were currently taking metformin. The researchers randomly assigned patients to 26 weeks of treatment with daily 1.2 mg liraglutide (n=225), 1.8 mg liraglutide (n=221) or 100 mg sitagliptin (n=219; Januvia, Merck).

After 26 weeks of treatment, patients assigned 1.8 mg liraglutide experienced the greatest decrease in HbA1c (–1.5%; 95% CI, –1.63 to –1.37), followed by those assigned to 1.2 mg liraglutide (–1.24%; 95% CI, –1.37 to –1.11) and 100 mg sitagliptin (–0.9%; 95% CI, –1.03 to –0.77).

Mean decreases in fasting plasma glucose were significantly greater with liraglutide. Patients assigned to the 1.8-mg dose experienced a 38.5 mg/dL decrease and patients assigned to the 1.2-mg dose experienced a 33.7 mg/dL decrease compared with 15 mg/dL with sitagliptin.

Overall, the estimated mean treatment difference between liraglutide and sitagliptin was –0.6% for patients assigned to the 1.8-mg group and –0.34% for the 1.2-mg group.

Weight loss also differed between the three treatment groups. The 1.8-mg liraglutide was associated with the greatest weight loss (–7.44 lb), followed by 1.2-mg liraglutide (–6.29 lb) and sitagliptin (–2.11 lb).

Adverse events with both drugs were mild or moderate, according to the researchers. Nausea was the most commonly reported event and occurred more in patients assigned to lirglutide (1.8 mg, 27%; 1.2 mg, 21%) compared with sitaglitpin (5%). About 5% of patients in each treatment group experienced minor hypoglycemia. –by Matthew Brannon

The results are not surprising, both in terms of efficacy as well as side effects. I had conducted some clinical trials with liraglutide and the dropout rate because of nausea and vomiting was significant. These results are consistent with the American Association of Clinical Endocrinologists algorithm — the GLP-1 are slightly more effective, but the downside is that they are associated with a higher incidence of side effects, in addition to being injectable vs. oral.

– Helena W. Rodbard, MD
Medical Director, Endocrine and Metabolic Consultants, Rockville, Md.

Pratley RE. Lancet. 2010;375:1447–1456.