How do you maximize the profits of a drug that treats a very rare disease?

Kerry Owens, a doctor in Oklahoma City who specializes in kidney disorders, was stunned by the call to her mobile phone in September 2015. She and a team of specialists were treating a new mother from nearby Enid, whose health had begun to deteriorate after giving birth. The doctors ran countless tests but couldn't pinpoint what was wrong. Briefly they worried it might be an extremely rare and potentially fatal blood disorder called atypical hemolytic-uremic syndrome, or aHUS, which afflicts about 1 in 500,000 people each year. They put the patient on a drug called Soliris, which had recently been approved to treat the condition. But her health continued to decline, so they stopped the Soliris infusions. Now a sales rep was on the other end of Owens's phone from Alexion Pharmaceuticals Inc, the New Haven-based maker of Soliris -- one of the world's most expensive drugs, typically priced from $500,000 to $700,000 a year.