In the biotech space today, three stocks made absolutely massive moves, with each popping or dropping by more than 20% in a single day. First up is Peregrine (NASDAQ:PPHM), the day's biggest winner by far, up nearly 50% today on the announcement that it would be announcing results for its preclinical immuno-oncology drugs at an upcoming conference next week. Motley Fool health-care analyst David Williamson notes here that despite the remarkably strong interest in this space, this feels as if the market is overbuying the rumor. With the company's phase 3 drug Bavituximab having had some troubles with its phase 2 testing, this is a stock he recommends staying away from for the moment.

Today's other winner, Arrowhead Research Corp. (NASDAQ:ARWR), saw shares soar upward 25% after two Wall Street analysts showed the small-cap company some love. Deutsche Bank initiated coverage on the stock with a "buy" rating and a $45 price target. RBC also initiated coverage with a buy and a $35 price target but saw its bull case to be potentially over $60. The market is excited over the company's hepatitis B drug. David discusses what to watch with this company, and why he'll be keeping a close eye on this one.

And finally, Xoma (NASDAQ:XOMA) is today's big loser, down 25% after pausing the development of its osteoarthritis drug Gevokizumab. While this isn't completely the end for Gevokizumab, this was a very big indication for the drug. However, since the drug is being tested in a whopping 11 indications, losing just one probably doesn't warrant having the company lose a fourth of its value.

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David Williamson and The Motley Fool have no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.

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