Pfizer (NYSE:PFE) investors have cheered the stock's remarkable gains this year, but the company's performance in the shadow of major patent expirations has been remarkable. New drugs have risen to supplant the firm's old blockbusters, and rheumatoid arthritis drug Xeljanz, approved by the Food and Drug Administration last year, has led the charge as one of tomorrow's most promising therapies.

Unfortunately, European regulators didn't feel the same way. Late last week, Europe's Committee for Medicinal Products for Human Use, or CHMP, recommended that Xeljanz not be approved to treat rheumatoid arthritis across the Atlantic. Should you be worried about Xeljanz's failure in Europe? Motley Fool contributor Dan Carroll and health care analyst Max Macaluso tell you what you need to know in the video below.