FDA orders new asthma drug warnings to take effect

WASHINGTON (Reuters) - U.S. health regulators have finalized new warnings for controversial inhaled asthma drugs, but exercised new powers to order the changes on products made by GlaxoSmithKline PLC and AstraZeneca PLC.

The warnings, expected since February, say medicines known as long-acting beta-agonists, or LABAs, should never be used on their own to treat asthma, Food and Drug Administration officials said on Wednesday. While some of the companies accepted the changes, others resisted, agency officials said.

Glaxo's Serevent and Novartis AG's Foradil, which Merck & Co Inc markets in the United States, are all LABAs. Two more widely used blockbuster medicines -- Glaxo's Advair and AstraZeneca's Symbicort -- are combination drugs that include LABAs.

Letters announcing the final label warning were also sent to Sepracor Inc, now part of Dainippon Sumitomo Pharma Co and the maker of Brovana, and Dey Pharma, a subsidiary of Mylan Inc that makes Perforomist, the FDA said.

"FDA is ordering the involved companies to make labeling changes capturing these new recommendations," Dr. Badrul Chowdhury, head of the FDA's pulmonary drugs division, told Reuters. "Not all of the companies have accepted all the changes ... so that's where the ordering comes in."

FDA officials initially called on doctors to halt use of LABAs in patients also using a steroid once their asthma was under control, but on Wednesday amended that warning to instruct doctors to wean patients off the LABAs over time in a "step down" approach.

Earlier draft warnings, including a call for children with asthma who need additional LABAs therapy to be prescribed a combination product to ensure that the drug is not used alone, remain, the FDA said.

(Reporting by Susan Heavey, editing by Leslie Gevirtz)