A panel of outside expert advisers to the Food and Drug Administration voted 12-2 to recommend approval of the twice-daily drug, known generically as aclidinium bromide.

The drug treats chronic obstructive pulmonary disease (COPD), commonly called smoker's cough as it is often caused by cigarette smoking. It is the fourth-leading killer of Americans from disease.

Panelists said the lung helped patients breathe, but called for the company to do post-approval studies to test safety because some patients died from heart problems during clinical trials.

"I think the efficacy is modest, but with COPD treatments, the efficacy tends to be modest," said panel member Dr. William Calhoun, professor at the University of Texas Medical Branch.

"It seems to me that the critical question here is the safety issue."

The FDA usually follows panel recommendations, although it is not required to, and a final decision is expected by April 23.

Shares of Forest, which has a licensing agreement with Almirall to market the drug in the United States, closed up 1.2 percent at $32.21 on the New York Stock Exchange.

Forest is counting on new treatments such as aclidinium to help prop up profits after its blockbuster antidepressant Lexapro is expected to lose U.S. patent protection this year.

Up to 24 million people in the United States, and more than 100 million worldwide, suffer from COPD, which gets worse with age and can persist even if patients stop smoking.

Wall Street expects global sales of COPD treatments to exceed $5 billion in 2014.

COMPETING FOR SMOKERS

FDA staff reviewers earlier this week raised concerns about potential heart problems linked to drugs in the same class.

In the clinical trials for Forest and Almirall's lung drug, four patients taking the drug died from cardiac arrest and one from heart failure, out of a total of about 1,500 people who took the 400 microgram dose of the inhaled powder.

FDA staff said clinical trials may not have been big enough to show whether the problems came from the drug, or because patients with the disease may also have heart problems.

If approved, Forest's drug, which the company plans to sell under the name Tudorza Pressair, would compete with Boehringer Ingelheim and Pfizer Inc's Spiriva, which is also an inhaled drug that opens airways.

Other treatments for chronic lung disease are inhaled steroids such as AstraZeneca Plc's Symbicor and GlaxoSmithKline Plc's Advair.

Forest gained U.S. approval last year for Daliresp, a tablet that treats exacerbations caused by chronic lung disease.

"Today shows our commitment to the COPD community with a second product to treat a very common disease," said Dr. Marco Taglietti, senior vice president for research and development at Forest Laboratories.

"Certainly we're very pleased the committee has agreed the product is effective and has adequate safety to be approved."

(Reporting by Anna Yukhananov; editing by Gary Hill and Andre Grenon)

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