Orphan drugs are an exciting potential market for investors -- due to the rarity of diseases treated by these therapies, the drugs are afforded extra patent protection, high prices for drugs. But the rules of biotech still apply -- it's important to be careful with any stock whose success is tied to a single drug. And Aegerion (NASDAQ:AEGR), with its HoFH drug Juxtapid, is a classic example. Sales haven't been impressive, and the pipeline looks pretty bare. That's not to say Juxtapid won't deliver -- It just hasn't impressed so far.

In the video below, health care analysts Michael Douglass and David Williamson give more thoughts on the stock.