Investors in Achillion Pharmaceuticals (NASDAQ:ACHN) got a double-whammy of good news over the last two days, with Merck's (NYSE:MRK) purchase of fellow hepatitis c biotech Idenix pumping shares up over 40%. And Achillion is up over 50% today on further good news -- the FDA removed an almost year-long clinical hold on its drug sovaprevir, allowing its phase 2 drug trial to continue.

Good news -- but good enough to buy Achillion? What about competitors, like Gilead's (NASDAQ:GILD) Sovaldi and incoming drugs from AbbVie (NYSE:ABBV), Merck, and Bristol-Myers Squibb? In the video below, health care analyst Michael Douglass lays out his thoughts on why investors would be better served staying on the sidelines.