Shares of Rigel Pharmaceuticals (NASDAQ:RIGL) were down big yesterday on news that AstraZeneca's (NASDAQ:AZN) oral rheumatoid arthritis drug was less effective than Abbott Labs' (NYSE:ABT) RA drug in clinical trials. But what does all this have to do with Rigel? In this video, Motley Fool health care analyst Brenton Flynn tells us what the connection is and why it may be a blow that will prove very difficult for Rigel to recover from.

However, what's bad for Rigel and AstraZeneca might be good news for Abbott Labs. Abbott's spinning off its pharma business early next year, and arthritis drug Humira will account for the lion's share of that company's profits. To help investors better understand the upcoming event, the Fool has created a brand new premium report outlining both Abbott Labs and its spinoff, AbbVie. Inside, we outline all of the must-know opportunities and risks facing both companies, so make sure to claim this 2-for-1 report by clicking here now

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