The U.S. Food and Drug Administration approved Januvia (sitagliptin), the first in a new class of drugs known as DPP-IV inhibitors, as a treatment for type 2 diabetes.

The drug, which assists the body in controling high blood sugar, can be used alone or with other oral diabetes drugs in combination with diet and exercise.

Januvia and a rival drug called Galvus, which is awaiting FDA approval, both work to enhance the body's own ability to lower blood sugar. In clinical trials of this new class of drugs, patients did not gain weight.

Merck said the price of the once-a-day tablet would be $4.86.

"For millions of Americans with type 2 diabetes, who continue to have inadequate blood sugar control, the approval of Januvia marks an important advance in the fight against diabetes," said Dr. Steven Galson, director of the FDA's Center for Drug Evaluation and Research.

"We now have another option that treats the disease in an entirely new way that can be added to existing treatment regimens to help patients gain more control over their blood sugar levels," he said in a statement.

Januvia and Galvus will compete with older diabetes medications known as thiazolidinediones, or TZDs, used to make patients less resistant to insulin. These drugs have been linked to water retention and weight gain.