Does Regeneron Pharmaceuticals’ Winning Streak Signal Irrational Exuberance?

Does Regeneron Pharmaceuticals’ Winning Streak Signal Irrational Exuberance?

Source: 
Motley Fool
snippet: 

Year to date, shares of Regeneron Pharmaceuticals (NASDAQ: REGN) have gained nearly 50% despite significant declines in the overall market. Arguably, strong growth from its core pipeline consisting of Eylea (eye injection used to treat various forms of retinal disorders) and Dupixent (biological therapy used to treat allergies) have been fueling the rally.