Regeneron's macular degeneration drug Eylea is a great success, said Schleifer. The product launched in early 2012 and Schleifer noted that analysts first thought the company would sell $100 million worth of the drug. Later the estimates were raised to a few hundred million dollars, then $500 million. Regeneron is now expected to sell $750 million of Eylea this year and the company only has 14% market share. Schleifer said that unlike Eylea's chief rival, his company's drug only needs to be given half as often. Since macular degeneration drugs must be given as a direct injection in the eye, it's easy to see why patients prefer Eylea over the competition. Cramer said the story remains strong at Regeneron, and even after the company's huge move higher "it's not done yet."