Insulin more effective add-on than sitagliptin in glucose control

By Sally Robertson, B.Sc.Jun 15 2012

Insulin seems to be a more effective add-on regimen than sitagliptin in patients with diabetes inadequately controlled by metformin monotherapy, show study findings.

Insulin glargine lowered patients' glycated hemoglobin (HbA1c) levels 0.59% more than sitagliptin during the 24-week study, report Pablo Aschner (Hospital Universitario San Ignacio, Bogotà, Columbia) and colleagues in The Lancet.

In addition, patients who received the insulin regimen were 1.6 times more likely than those given sitagliptin to achieve an HbA1c of less than 7%, and 2.5 times more likely to achieve an HbA1c of less than 6.5%.

Aschner and team say that, until now, no studies have compared the use of dipeptidyl peptidase-4 (DPP-4) inhibitors with that of basal insulin in diabetics who have not responded to metformin.

The Evaluation of Insulin Glargine versus Sitagliptin in Insulin-naïve Patients (EASIE) trial was a multicenter, randomized, open-label study conducted across 17 countries and including 513 Type 2 diabetes patients who had an HbA1c of 7% or more despite having taken metformin for at least 6 months.

Throughout the study, patients in the insulin group self-monitored their blood glucose and injected insulin doses that were titrated to attain a fasting plasma glucose between 4.0 mmol/L and 5.5 mmol/L. Those taking sitagliptin took their medication (100 mg) orally once a day.

After 24 weeks, the mean HbA1c level among the insulin glargine patients was reduced significantly further than in the sitagliptin patients, by 1.72% compared with 1.13%.

In addition, more insulin patients achieved an HbA1c of less than 7% than did sitagliptin patients, at 68% versus 42%. The corresponding rates for attainment of an HbA1c value lower than 6.5% were 40% versus 17%.

Furthermore, significantly more of the insulin versus sitagliptin patients reached the HbA1c goal of less than 7% by week 12, only half-way through the treatment period.

However, symptomatic hypoglycemic events were more frequent with insulin versus sitagliptin use, at 4.21 versus 0.50 events per patient-year, although severe hypoglycemia was seen in only three (1%) patients on insulin and one (<1%) on sitagliptin. And six percent of patients in the insulin group had at least one serious treatment-emergent adverse event, compared with 3% of those in the sitagliptin group.

The authors say that, given the potential long-term benefits and improved efficacy of insulin, "strong arguments could be made" to use insulin early in the course of disease, when a fairly low dose can be used and the risk for hypoglycemia reduced.

"The results of this comparative effectiveness trial might help physicians to choose between two drugs for patients whose diabetes is uncontrolled on metformin and provide clinical experience to guide the design of future studies needed to assess the long-term efficacy of these two therapeutic strategies," write Ascher et al.

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