UPDATE 2-Pfizer's Spiriva may raise risk of stroke-US FDA

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By Susan Heavey

WASHINGTON, March 18 (Reuters) - The lung drug Spiriva, marketed by Pfizer Inc (PFE.N) and Boehringer Ingelheim Pharmaceutical Inc, may increase the risk of stroke, the U.S. Food and Drug Administration said on Tuesday.

The FDA said the risk assessment was not yet conclusive, but it was issuing a statement as part of an effort to tell doctors and patients about potential problems as soon as possible. The agency said it was working with Boehringer to evaluate the possible risk.

Spiriva HandiHaler is used to treat chronic obstructive pulmonary disease, or COPD, and is co-promoted worldwide by Pfizer and Boehringer Ingelheim, a privately held German company.

A preliminary company analysis of about 13,500 patients from 29 clinical studies found that risk of stroke was 8 in 1,000 patients taking the once-daily inhaled drug, compared with 6 in 1,000 who took a placebo, the FDA said. The agency has not confirmed the results, it added.

Four of the studies involved a version of Spiriva approved in Europe called Spiriva Respimat.

In a statement, Boehringer said the companies were "continuing to evaluate information from a variety of sources." It did not say when its final analysis of the data would be completed. Representatives for Pfizer referred calls to Boehringer.

The FDA has come under fire in recent years for its failure to quickly notify the public about safety problems with drugs and devices.

Agency officials have defended their actions, but also agreed to make public any potential problems sooner before fully reviewing the concerns. Critics have said this new approach could scare patients and doctors away from needed treatment.

"It is important to interpret these preliminary results with caution. FDA has not confirmed these analyses," the FDA said in a statement posted on its Web site here

The FDA said patients should not stop taking Spiriva, but should continue to report problems to the agency.

Known chemically as tiotropium, Spiriva has replaced Boehringer's older drugs -- Atrovent and Combivent -- that are used several times a day. The company declined to release Spiriva's sales figures.

Pfizer shares closed up 43 cents, or 2 percent, to $21 on the New York Stock Exchange. (Editing by Andre Grenon)