Is adding dulaglutide to insulin safe and effective?

This study investigated the effectiveness and safety of dulaglutide (Trulicity) in combination with insulin in people with type 2 diabetes (T2D). It was determined that adding dulaglutide reduced HbA1c (measures average blood glucose over the last 3 months), reduced body weight, and did not increase the risk of hypoglycemia (dangerously low blood glucose).

Dulaglutide is a glucagon-like peptide 1 receptor agonist (GLP1RA). Glucagon-like peptide 1 (GLP1) is made in the intestines and released after a meal. GLP1 stimulates the release of insulin (the hormone that lowers blood glucose) and inhibits the release of glucagon (hormone that raises blood glucose). These hormonal changes control blood glucose levels. GLP1RAs are drugs that mimic the effects of GLP1.

Research suggests that combining dulaglutide with insulin may be more effective in controlling blood glucose levels, and may also reduce the risk of some of the side effects of insulin, like weight gain and hypoglycemia. However, little research is available.

This study examined data from two different studies. 891 people with T2D participated in total. 445 received insulin and dulaglutide. 150 received insulin and a placebo (drug with no active effect). 296 received 2 different types of insulin. The participants were followed up for 6 months.

HbA1c was reduced more in those who received dulaglutide and insulin, than in those who received insulin only, or insulin and placebo. The largest reductions were seen in those whose HbA1c was greater than 9% at the start of the study, falling an average of 2.5%. Duration of diabetes and the age of participants did not affect HbA1c levels.

Weight was reduced in all people who received dulaglutide, except for those with an HbA1c more than 9% at the start of the study, and those who had had diabetes for less than 10 years. Those who had an HbA1c greater than 9% at the start of the study gained weight, but were also receiving a higher dose of insulin. Those who received insulin, but not dulaglutide, gained weight.

Hypoglycemia occurred at similar rates in all groups.

The study concluded that combining dulaglutide with insulin reduces HbA1c and reduces weight, without increasing the risk of hypoglycemia. The greatest reductions in HbA1c occurred in people who started with higher HbA1c levels. 

This study was funded by Eli Lilly, the manufacturers of dulaglutide. There were differences between the studies, such as the kind of insulin used, that may have limited comparisons. Additionally, 6 months may not be long enough to investigate the long-term effects of dulaglutide.

Discuss the use of dulaglutide, in combination with insulin, with your physician.