BioMarin Pharmaceutical Inc. received the backing of U.S. advisers for a drug to treat a rare metabolic disease that can affect growth.

The drug, Vimizim, should be approved for Moriquio A syndrome, which can cause joint deformities and contractures, a panel of advisers to the Food and Drug Administration voted today. The FDA is scheduled to decide whether to clear the drug for sale by the end of February, though it isn’t required to follow the advisers’ recommendations.

BioMarin, which drew $501 million in 2012 revenue, has a slate of experimental treatments for rare diseases and cancer that analysts estimate will boost company revenue by at least 20 percent in 2014 and 2015. Vimizim may generate $278 million in sales in 2016 and surpass $500 million in annual revenue in 2018, according to the average of analysts’ estimates compiled by Bloomberg.

Shares of Novato, California-based BioMarin, which gained 36 percent this year through yesterday, were halted today for the advisory panel meeting.

The panel voted 20-1 the drug should be approved though at least one person only supported approval in some who may respond best to the treatment.

While most panelists seemed comfortable using a six-minute walk test to evaluate whether the drug works, the FDA was hesitant about whether patients’ ability to walk further indicated the drug has a meaningful effect on quality of life.

Orphan Drugs

The panel voted 20-1 that the clinical trial data BioMarin submitted for Vimizim proved the medicine works, though at least seven panelists said the data showed the drug is effective only for some patients.

BioMarin is among companies developing drugs for diseases that affect as few as 5,000 to 10,000 patients worldwide and are priced at as much as $400,000 a year per patient.

Medicines for such small patient populations, known as orphan drugs, get exclusive marketing rights as an incentive for their development in the U.S. and Europe, while the small patient populations mean fewer participants are needed for clinical trials. They’ve drawn the interest of large pharmaceutical companies looking to fend off a drop in sales as patents on blockbuster drugs expire.

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