Ariad's chronic myeloid leukemia drug ponatinib (marketed under the brand name Iclusig) had excellent clinical trial results, and was approved by the Food and Drug Administration ahead of schedule in mid-December. Why, then, did shares of Ariad drop around 14% last month despite this good news? Isn't an FDA approval usually good news for biotech stocks?

Our analysts Max Macaluso and Brenton Flynn break down this story in the following video and also discuss what to watch at Ariad in 2013.

Brenton FlynnMax Macaluso, Ph.D., and The Motley Fool have 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.