Januvia, the first in a new class of diabetes treatments, is set for approval in the European Union.

Marketed by Merck Sharp & Dohme, the drug has been given the green light by the EMEA's medicines committee, with final clearance expected within three months.

Januvia (sitagliptin) looks set to beat a rival drug, Novartis Galvus (vildagliptin) to the market in Europe as it has in the US, where it was launched in November.

The drugs are expected to be major successes, with analysts predicting global peak sales in excess of $1.5 billion for Januvia and Galvus.

Both are oral, once-daily, selective DPP-4 inhibitors. The drugs are proven to be as effective as existing treatments at lowering blood sugar levels, but have fewer side-effects, such as weight gain.

Other side-effects seen in older treatments include hypoglycaemia (where the blood sugar is lowered too far) and oedema (fluid retention).

Analysts expect many doctors to be persuaded to switch away from older drugs such as sulphonyureas to the DPP-4 inhibitors.

Both MSD and Novartis hope that further studies will show their drugs to be clearly superior in lowering blood glucose safely. Novartis have begun a head-to-head trial between Galvus and GSKs Avandia (rosiglitazone), the current top-selling oral diabetes treatment.

How the new drugs work

DPP-4 inhibitors work by enhancing a natural body process, the incretin system, that lowers blood sugar. When blood sugar is elevated, incretins work in two ways to help the body regulate high blood sugar levels: they trigger the pancreas to increase the release of insulin and signal the liver to reduce its production of glucose.

DPP-4 inhibitors enhance the body's own ability to control blood sugar levels by increasing the active levels of these incretin hormones in the body, helping to lower blood sugar levels in patients with type II diabetes.

pharmafocus@wiley.co.uk