April 1 (Bloomberg) -- Merck & Co. won U.S. approval to sell Janumet, the first pill to treat type-2 diabetes by targeting all causes of the disease.

Janumet combines Merck's Januvia, approved in the U.S. last year, with the older drug metformin for treating type-2 diabetes. The new pill was cleared for sale by the Food and Drug Administration and will be available this month, Merck spokeswoman Amy Rose said in an e-mailed statement yesterday.

The medicine will help Merck compete for a bigger share of the $17 billion market for diabetes treatments, with Januvia and Janumet expected to have more than $2 billion in combined annual sales by 2010, analysts said. Diabetes is caused when the body doesn't produce or effectively use insulin needed to regulate sugar in the blood. Januvia increases the body's creation of insulin while metformin, the most commonly prescribed diabetes pill, helps process it.

``It is important mostly as a convenience and from a co-pay perspective,'' said Deutsche Bank analyst Barbara Ryan in a March 29 telephone interview. ``The data would suggest that Januvia is being used above and beyond anything else on the market as an add-on therapy, and it is being added on to metformin.''

About 37 percent of diabetes drug prescriptions are for metforim, said Merck vice president for clinical research John Amatruda.

The type-2 form of the disease accounts for 90 percent to 95 percent of the 230 million people with diabetes worldwide, according to the International Diabetes Foundation.

People with type-1 diabetes, which often occurs early in life, must take insulin every day because their bodies don't produce the hormone at all. Insulin is needed to convert sugar, starches and other food into energy.

The shares of Whitehouse Station, New Jersey-based Merck rose 22 cents to $44.17 as of 4 p.m. March 30 in New York Stock Exchange composite trading.

Januvia's Marketing

Januvia, which costs about $5 a pill, is one of the most important new drugs developed by Merck, the third-largest U.S. maker of prescription drugs, and has accounted for about 30 percent of its spending on marketing to doctors since its approval, said Ryan.

It is being prescribed as an addition or substitution for other diabetes treatments, including metformin, which is made by more than a dozen generic drugmakers; Eli Lilly & Co.'s Byetta; Takeda Pharmaceutical Co.'s Actos; and GlaxoSmithKline Plc's Avandia.

To contact the reporter on this story: Shannon Pettypiece in New York at spettypiece@bloomberg.net

Last Updated: April 1, 2007 11:41 EDT