Health care analyst Max Macaluso recently sat down with Fool contributor Keith Speights to talk about some of the best speculative biotech plays on the market. Max and Keith discussed three companies that investors should consider: Keryx Pharmaceuticals (NASDAQ:KERX), Sarepta Therapeutics (NASDAQ:SRPT), and MannKind (NASDAQ:MNKD).

Both Keryx and Sarepta have soared over the last year. Keryx is up a whopping 190% so far in 2013. Meanwhile, Sarepta's shares jumped nearly 50% year-to-date after an amazing run last year.

The nice run by Keryx was powered by high expectations for its kidney disease drug Zerenex. Sarepta's success has stemmed from excitement over its Duchenne muscular dystrophy drug eteplirsen.

MannKind also has enjoyed a great year so far. Shares are up nearly 80% in the first three and a half months of 2013. Investors are eagerly awaiting results from what they hope to be the final study for inhalable insulin product Afrezza.

In this video, Max and Keith talk about the prospects for each of these three speculative biotech stocks.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.