With the release of ASCO abstracts, essentially a huge clinical trial data release ahead of the annual cancer conference, we witnessed a few pops and drops among biotech stocks. 

In this video, healthcare analyst David Williamson takes a closer look at two stocks seeing 20% moves -- Oncothyreon (NASDAQ:ONTY.DL) and Halozyme (NASDAQ:HALO) -- and discusses what these events mean for investors.

David Williamson has no position in any stocks mentioned. Follow David on Twitter: @MotleyDavid.

The Motley Fool has no position in any of the stocks mentioned. 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.