Merck & Co was celebrating yesterday after winning approval in Europe to market the potential star in its pipeline – the once-daily diabetes treatment Januvia (sitagliptin). The compound becomes the first in the class of so-called dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors) to be given the green light in Europe.

Januvia is used to treat type 2 diabetes and works by enhancing a natural body process that lowers blood sugar, the incretin system. 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 decrease blood sugar levels in patients with type 2 diabetes.

Specifically, Januvia has been approved in combination with the generically-available metformin – plus diet and exercise – when this combination alone does not result in lowered blood glucose. Similarly, it has also been cleared in patients who need to take a thiazolidinedione, such as Eli Lilly and Takeda’s Actos (pioglitazone) or GlaxoSmithKline’s Avandia (rosiglitazone), as an add-on therapy where one drug alone – plus diet and exercise - does not have the desired treatment effect.

42 approvals to date

This latest swathe of approvals – in all 27 members of the expanded European Union - means the medicine has now been given the thumbs up in 42 countries around the world, including the USA. This also puts it well ahead on the track ahead of its major competitor – Novartis’ Galvus (vildagliptin): last month the US Food and Drug Administration requested more data involving a new clinical study after preclinical studies in animal models pointed to an adverse skin reaction.

Merck clearly plans to make the most of this gain, but revealed little more, saying in a statement only that it will launch Januvia “shortly.” The medicine was first approved in October last year and, by the end of the fourth quarter, had already reeled in some $42 million. It is widely expected to become a $2 billion a year drug, and this target is potentially even nearer after Actos and Avandia were found to be linked to an increased risk of fracture in women.