Januvia - sitagliptina

What is Januvia?

Januvia is a medicine that contains the active substance sitagliptin. It is available as round tablets (pink: 25 mg; beige: 50 and 100 mg).

What is Januvia used for?

Januvia is used in patients with type 2 diabetes to improve the control of glucose (sugar) levels in the blood. It is used as follows, in addition to diet and exercise:

• in monotherapy, in patients who are not satisfactorily controlled with diet and exercise and in whom metformin (an antidiabetic medicine) is not suitable;

• in combination with metformin or a PPAR gamma agonist (a type of antidiabetic medicine), such as a thiazolidinedione, in patients who are not satisfactorily controlled on metformin or the PPAR gamma agonist used alone;

• in combination with a sulphonylurea (another type of antidiabetic medicine) in patients who are not satisfactorily controlled with the sulphonylurea alone and in whom metformin is not suitable;

• in combination with both metformin and a sulphonylurea or a PPAR gamma agonist, in patients who are not satisfactorily controlled with these two medicines;

• in combination with insulin, with or without metformin, in patients who are not satisfactorily controlled with a stable dose of insulin.

The medicine can only be obtained with a prescription.

How is Januvia used?

Januvia is taken at a dose of 100 mg once a day, with or without food. If Januvia is taken in combination with a sulphonylurea or with insulin, it may be necessary to reduce the dose of the sulphonylurea or insulin to reduce the risk of hypoglycaemia (low blood sugar levels).

How does Januvia work?

Type 2 diabetes is a disease in which the pancreas does not produce enough insulin to control the level of glucose in the blood or where the body is unable to use insulin effectively. The active substance in Januvia, sitagliptin, is a dipeptidyl-peptidase-4 inhibitor (DPP-4). It works by inhibiting the degradation of "incretin" hormones in the body. These hormones, which are released after a meal, stimulate the pancreas to produce insulin. By increasing the level of incretin in the blood, sitagliptin stimulates the pancreas to produce more insulin when the glycemic rate is high, while it is ineffective when the concentration of glucose in the blood is low. Sitagliptin also reduces the amount of glucose produced by the liver by increasing insulin levels and decreasing the levels of the glucagon hormone. Together, these processes reduce blood glucose and contribute to the control of type 2 diabetes.

What studies have been carried out on Januvia?

Januvia has been studied in nine studies involving nearly 6, 000 patients with type 2 diabetes whose blood glucose levels were not adequately controlled:

• in four of these studies Januvia was compared with placebo (a dummy treatment). Januvia or placebo were used alone in two studies involving 1 262 patients, in addition to metformin in a study involving 701 patients and in addition to pioglitazone (a PPAR gamma agonist) in a study of 353 patients;

• in two studies Januvia was compared with other antidiabetic medicines. In the first study, Januvia was compared to glipizide (a sulphonylurea), when they were used in addition to metformin in 1, 172 patients. In the second study Januvia was compared with metformin, used alone, in 1 058 patients;

• in three further studies Januvia was compared with placebo when they were added to other antidiabetic medicines: a glimepiride (another sulphonylurea), with or without metformin, in 441 patients; to the combination of metformin and rosiglitazone (a PPAR gamma agonist) in 278 patients; and a stable dose of insulin, with or without metformin, in 641 patients.

In all the studies the main measure of effectiveness was the change in the blood concentration of a substance called glycosylated hemoglobin (HbA1c), which gives an indication of the effectiveness of blood glucose control.

What benefit has Januvia shown during the studies?

Januvia was more effective than placebo both as a single agent and in combination with other antidiabetic medicines. In patients who took Januvia alone, HbA1c levels decreased by 0.48% (from about 8.0% at the start of the studies) after 18 weeks and by 0.61% after 24 weeks. On the other hand, they increased by 0.12% and 0.18% respectively in patients taking placebo. The addition of Januvia to metformin reduced HbA1c levels by 0.67% after 24 weeks, compared to a reduction of 0.02% in placebo-added patients. The addition of Januvia to pioglitazone reduced HbA1c levels by 0.85% after 24 weeks, compared with a 0.15% reduction in placebo-added patients.

In studies in which Januvia was compared to other medicines, the efficacy of adding Januvia to metformin was similar to that of the addition of glipizide. When taken alone, Januvia and metformin achieved similar reductions in HbA1c levels, but the effectiveness of Januvia seemed to be slightly lower than that of metformin.

In the other studies, when Januvia was added to glimepiride (with or without metformin), HbA1c levels decreased by 0.45% after 24 weeks, compared with a 0.28% increase in placebo-added patients. HbA1c levels decreased by 1.03% after 18 weeks in patients adding Januvia to metformin and rosiglitazone, against a decrease of 0.31% in those adding placebo; finally, they decreased by 0.59% in patients who added Januvia to insulin (with or without metformin), compared to a 0.03% decrease in those adding placebo.

What is the risk associated with Januvia?

Among the most common side effects reported with Januvia (generally observed in more than 5% of patients) are upper respiratory tract infections (colds) and nasopharyngitis (inflammation of the nose and throat). For the full list of all side effects reported with Januvia, see the Package Leaflet. Januvia should not be used in people who may be hypersensitive (allergic) to sitagliptin or any of the other ingredients.

Why has Januvia been approved?

The Committee for Medicinal Products for Human Use (CHMP) decided that Januvia's benefits are greater than its risks and recommended that it be given marketing authorization.