Biogen is one of the stocks that I have been tracking lately since Zacks seems so bullish on its prospects. The Fool had selected it as one of its official Stock Advisor Recommendations as early as June 12 according to this published article on their site.
However, this article published on June 23 discloses that Biogen is a "former Stock Advisor Recommendation." A second article published on June 24 confirms this. I don't subscribe to any official Motley Fool publications, so I cannot say why the stock has been dropped. It may be due to the amount of debt that the company carries, but I cannot say for sure.