Sitagliptin, Merck & Co Inc’s investigational oral treatment for type 2 diabetes, controls blood sugar with a low risk of hypoglycaemia and a neutral effect on body weight, according to results of two 12-week Phase II studies announced on 14 September at the European Association for the Study of Diabetes (EASD) in Athens. This is positive news for sitagliptin (also known as MK-431) since many current type 2 diabetes treatments are limited by these side effects. If current Phase III studies are positive, approval of sitagliptin is expected in 2006-2007.

Sitagliptin is a DPP-4 inhibitor, a novel drug class that also includes Novartis’ investigational vildagliptin (LAF 237). These drugs act by extending the action of incretins, gut hormones that regulate insulin and glucose production after a meal. Research into the role of incretins has also resulted in the development of Amylin and Eli Lilly’s Byetta (exenatide), which was approved in the USA last May. This injected type 2 diabetes treatment acts by mimicking the action of incretins within the body.

Type 2 diabetes is the most frequent form of the disease and is becoming more common. New treatments are urgently needed and DPP-4 inhibitors represent a promising approach, since their novel action means that they could potentially be used either as initial monotherapy or in combination with other drugs. Animal studies also suggest that, unlike current type 2 diabetes treatments, the DPP-4 inhibitors may potentially delay disease progression, but this remains to be confirmed in long-term studies in human patients.

By Sue Lyon in Athens.