UPDATE 2-Merck's Januvia wins new uses but risks outlined

(Adds FDA comment, closing stock price)

NEW YORK, Oct 17 (Reuters) - Merck & Co MRK.N said on Wednesday U.S. regulators have approved use of its Januvia diabetes drug in new combinations with other treatments, but noted reports of serious conditions among some patients taking the medicine since its approval a year ago.

Januvia was approved in October 2006 for use by itself, or with the widely used drug metformin, or with members of another class of diabetes drugs called thiazolidinediones, such as Takeda Pharmaceutical's 4502.T Actos and GlaxoSmithKline's GSK.L.

It has racked up surprisingly strong sales, which have been a linchpin of sizzling growth in Merck’s recent earnings and share price.

The company said on Wednesday the U.S. Food and Drug Administration has approved its follow-up application to use Januvia in combination with another leading class of diabetes drugs called sulfonylureas when sulfonylureas alone do not adequately control blood sugar.

Merck said Januvia can now also be used in combination with both a sulfonylurea and metformin when those two types of drugs provide inadequate control. It can also now be used as an initial therapy in combination with metformin.

The company said it had received reports that some patients taking Januvia developed serious complications, including a potentially fatal skin condition called Stevens-Johnson Syndrome and serious allergic reactions. But it said no “causal” link between the drug and the conditions has been established.

John Amatruda, Merck’s vice president for clinical development, said no cases of Stevens-Johnson Syndrome were seen in any of Januvia’s clinical trials although a “a few” cases have been reported since the drug’s approval. He said Merck is continuing to monitor any possible patient risk.

“It’s not possible to establish a causal relationship,” Amatruda said in an interview. “We don’t know what other medications these patients were on.”

Merck said on Wednesday reports of serious allergic reactions, such as anaphylaxis and angioedema, had already been included in Januvia’s package insert label.

The label will be updated to caution patients to stop taking Januvia if they develop an allergic reaction, Amatruda said.

An FDA spokeswoman said the labeling changes were warranted, but that the level of concern was not high.

Shares of the Whitehouse Station, New Jersey-based drugmaker edged up 39 cents to close at $53.42 on the New York Stock Exchange, amid a slight decline for the drug sector. (Reporting by Ransdell Pierson, Lewis Krauskopf, Bill Berkrot and Kim Dixon)