WASHINGTON (Reuters) - Regulators will ask outside experts if the higher of two proposed doses of a Novartis AG drug is needed to treat chronic obstructive pulmonary disease, documents released on Friday said.

A key question for outside advisers who meet next week is "whether the second higher dose of 150 (micrograms) is necessary and supported by submitted efficacy data and balancing safety data," Food and Drug Administration staff wrote in a preliminary analysis of the drug, indacaterol.

Novartis studies showed lung function was better after 12 weeks of treatment with either of the two doses compared with a placebo, FDA reviewers said. The two doses were not compared directly.

Analysts say it is important for Novartis to win approval for both doses. The company is aiming to make indacaterol part of a combination drug that could generate blockbuster sales.

Selecting the proper dose also is the "major safety issue," the FDA's summary said. For asthma patients, high doses of medicines similar to indacaterol have been linked to worsening of asthma that can be fatal.

"Although such a risk of worsening disease has not been shown in COPD, it is nevertheless important to select the appropriate and safe dose," Dr. Badrul Chowdhury, head of the agency's pulmonary division, wrote in the agency's summary.

The FDA panel is set to decide on Tuesday afternoon on whether to recommend approval of one or both doses of indacaterol, which already is sold in Europe. The agency usually follows panel recommendations.

A final FDA ruling is due by April 1. Vontobel analyst Andrew Weiss said potential risks could become the main issue at the panel meeting. The FDA could delay a final decision and ask Novartis for more study of the drug's risks, he said.

"This could mean that the approval is delayed by another one to two years, which would mean the combination therapy would also be delayed for another one to two years," Weiss said.

The FDA rejected indacaterol in October 2009 and asked for more research.

Analysts have forecast modest sales for the drug as a stand-alone treatment, but some expect as much as $5 billion a year from the combination treatment.

In a separate summary released by the FDA, Novartis said indacaterol was safe and effective at opening airways, and the higher dose provided "better symptom control."

Novartis and GlaxoSmithKline Plc are battling to dominate the market for next-generation respiratory drugs for conditions such as COPD. The disease, sometimes called "smoker's lung," causes potentially fatal breathing trouble and chronic coughing.

Indacaterol is already on sale under the brand name Onbrez Breezhaler in Europe, where it had revenue of $33 million in 2010. The U.S. name will be Arcapta Neohaler.

The FDA posted the staff and Novartis summaries at http://bit.ly/fg5BhH.

Novartis shares fell 0.6 percent in Swiss trading.

(Reporting by Lisa Richwine in Washington and Katie Reid in Zurich)

Source: Reuters US Online Report Health News

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