Shares of Ariad Pharmaceuticals (NASDAQ:ARIA) fell today, but on Friday after a tremendous week filled with buyout speculation, Motley Fool health-care analyst David Williamson answered viewer questions about the biotech. Shares rose 12% on Thursday and 25% on Friday, on news of a rumor that Eli Lilly and GlaxoSmithKline have an interest in buying the biotech now that its leukemia drug Iclusig is back on the market, with shares 50% lower than where they were before its safety issues were known.

In this video from Friday's Market Checkup, David looks at two questions about the stock, and the biotech business as a whole. He discusses, why even when battling a very serious disease such as leukemia, some drugs should be reserved as a last resort, and he tells investors how giant companies can mitigate risk by licensing drugs from much smaller companies, such as Ariad.