Chances are you've never heard of Regeneron (REGN), but you will definitely wish you bought its stock years ago.

This trailblazer in the biotech industry is led by founder Leonard Schleifer, a former doctor turned billionaire who has climbed to the top through savvy deal making and a laser-like focus on development.

After two decades of struggles and mounting losses, Regeneron hit the jackpot in 2011 with a blockbuster treatment that restores vision in older adults called Eylea.

"This is what we were spending our lives trying to accomplish. It's not just preventing vision loss, which it does, it's actually returning vision. That's the holy grail in vision," Schleifer told CNNMoney during a tour of the company's Tarrytown, N.Y. headquarters.

Eylea's launch exceeded even the most wildly optimistic projections, raking in $840 million in sales during the first year alone.

Owners of Regeneron stock have celebrated a 398% surge during the three years that ended June 30. That's easily the best performance among any stock currently in the S&P 500.

"Regeneron has been a great success, but it's been 25 years in the making," said Citigroup analyst Yaron Werber, who has a "buy" rating on the stock.