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March 19 (Reuters) - Novo Nordisk NOVOb.CO said on Thursday the U.S. Food and Drug Administration has approved a higher dose of its blockbuster obesity drug Wegovy to reduce excess body weight and maintain weight reduction long term.

The 7.2 milligram dose of Wegovy received a priority review voucher to speed up the review time, in a first approval of a GLP-1 treatment under the Commissioner's National Priority Voucher program.

The approval was based on results that showed patients who were given the 7.2 mg dose once weekly recorded 20.7% weight loss on average and about one in three people experienced 25% or greater weight loss.

Novo Nordisk expects to launch the higher dose of Wegovy in a single-dose pen in the U.S. in April.

The higher dose is already approved in the UK to be administered as three separate injections.