December saw shares of Rigel Pharmaceuticals (NASDAQ:RIGL) drop more than 20%. The tumble happened after Rigel's partner AstraZeneca (NYSE:AZN) released phase 2b data concerning their experimental rheumatoid arthritis drug fostamatinib. While the drug outperformed the placebo, it failed to beat AbbVie's (NYSE:ABBV) Humira. (AbbVie, formerly the branded pharmaceutical division of health care powerhouse Abbott Labs (NYSE:ABT), is now listed on the NYSE). In this video, Motley Fool health care analysts Max Macaluso and Brenton Flynn break down this story for investors.

Brenton Flynn has no positions in the stocks mentioned above. Max Macaluso, Ph.D. has no positions in the stocks mentioned above. The Motley Fool has no positions in the stocks mentioned above. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.