Alexion Pharmaceuticals ( ALXN): Cramer explained that Alexion has so-called orphan drugs to treat rare blood disorders. The "orphan" status means the government helps in any way possible to bring these drugs to market. Alexion's primary drug, Soliris, is one of the most expensive drugs available, costing $500,000 a year. The company is now seeking to expand Soliris to treat rare kidney diseases, which could add another $900 million to Soliris already $2 billion in revenues. Tack on other possible uses for Soliris and, Cramer said, Alexion could have $5.4 billion in revenue over the next few years. That's part of the reason why shares of Alexion are up 321% since Cramer first recommended it in Oct 2010.