A pharma company's growth can skyrocket once the FDA approves its leading drug. That's exactly what happened to Alexion in 2007 when it launched Soliris, a treatment that eases the symptoms of paroxysmal nocturnal hemoglobinuria, a rare terminal illness that destroys blood cells in the body. While only a few thousand in the U.S. suffer from PNH, Soliris is the only FDA-approved treatment.

Unlike big pharma companies that target widespread diseases such as diabetes and heart disease, Alexion wants to continue to carve out its niche by developing treatments for uncommon diseases. Moreover, the company wants to make game-changers -- drugs that don't just reduce symptoms but drastically improve patients' quality of life.

For now, that involves winning approval for Soliris to treat other diseases that harm people through the same basic mechanism as PNH. Alexion is trying to get FDA approval to treat a rare kidney disease by the fourth quarter of 2011.

Last updated September 13 2011: 8:10 AM ET
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