Orphan drugs are a fascinating area for potential investment -- they command premium pricing, treat niche diseases, and often have extended patent protection since they're so specialized.

And while this area of the market is speculative, the opportunities are enormous. And there are ways to mitigate your risk, particularly by investing in companies with broad pipelines (or a single drug that has already proven commercially successful).

In the video below, health care analysts Michael Douglass and David Williamson lay out why investors should be watching Alexion (NASDAQ:ALXN), Shire (NASDAQ:SHPG), and ISIS (NASDAQ:IONS) in this exciting and innovative corner of the market.