Sitagliptin (Januvia) has long been used to reduce blood sugar in people with type 2 diabetes, but a new study indicates that it can do the same for those with type 1 diabetes. Sitagliptin is a DPP-4 inhibitor; that is, it inhibits, or temporarily prevents, the enzyme DPP-4 from destroying a helpful hormone called GLP-1. GLP-1, which is released by the gut when food arrives there from the stomach, lowers blood sugar by causing the release of insulin, reducing the secretion of glucagon, and slowing stomach emptying and nutrient absorption.
Unfortunately, GLP-1 is broken down by DPP-4 after only about a minute of beneficial action. Because GLP-1 could lower blood sugar a lot more if DPP-4 weren’t so efficient at destroying it, a DPP-4 inhibitor such as sitagliptin comes in very handy for people with type 2 diabetes. Until now, however, it has not been tested in people with type 1 diabetes.
Now, a small pilot study conducted by Satish Garg, MD, of the University of Colorado, has found that sitagliptin lowers blood sugar in inadequately controlled type 1s as well. The 20 type 1 subjects were given 100 mg of sitagliptin daily or a placebo for four weeks, then switched to the alternate treatment for four more weeks. The sitagliptin lowered their mean blood glucose by about 12 mg/dL and their A1Cs by 0.27%, and they were able to cut their insulin dose by nearly 10 percent during the treatment period.
Dr. Garg plans to firm up his findings with a four-month multicenter study of sitagliptin in 120 type 1 patients.