The U.S. Food and Drug Administration on Tuesday approved Alexion Pharmaceutical Inc's (ALXN) treatment for an ultra-rare and potentially fatal genetic disorder. Alexion's enzyme-replacement therapy, Kanuma, which received European approval in September, was approved to treat patients, including infants, with lysosomal acid lipase deficiency (LAL-D), that can lead to liver failure, heart disease and early death. Alexion shares closed up $9.57, or 5.34%, at $188.72. There are only a few thousand patients with LAL-D in the United States, Alexion said. It estimates four to eight babies per year will be born with the infantile form of LAL-D. But life-saving treatments for ultra-rare diseases can command extremely high prices. The company believes Kanuma will eventually generate annual sales in excess of $1 billion. "But given the extremely low awareness of this disease, the high mortality and low incidence in prevalence, we would expect the dynamics of this launch to be slow and steady," Alexion Chief Executive David Hallal said in a telephone interview. "It takes many years in ultra-rare diseases to reach a $1 billion threshold." Onset of LAL-D tends to happen around the age of 5. Infants born with the disease usually die before their first birthday. In a clinical trial, six of nine babies who received Kanuma survived beyond 12 months. Kanuma, which the company acquired with its $8.4 billion purchase of Synageva BioPharma in June, could be priced at $300,000 to $400,000 annually, Morningstar analyst Stefan Quenneville forecast. Alexion's flagship drug Soliris, which treats two rare diseases and is in late-stage testing for three more, costs around $500,000 a year. The company plans to discuss pricing for Kanuma later on Tuesday. Unlike most drugmakers that charge much higher prices for medicines sold in the United States, Alexion plans similar pricing globally. I think with such pricing they will not sell much even in US. Anyone knows whether medical insurance covers such treatments? If not I will short the stock. $ALXN, Alexion Pharmaceuticals, Inc. / 10080