The 3 Best Biotech Stocks of 2017

Biotech stocks rocked in 2017. At least a lot of them did. The SPDR S&P Biotech ETF has chalked up a gain of 40% with only a couple of weeks left in the year -- twice the return of the S&P 500 index.

But which biotech stocks performed best of all? Excluding biotechs with tiny market caps below $200 million, three stocks take the top honors for the year: Sangamo Therapeutics (NASDAQ: SGMO), XOMA Corporation (NASDAQ: XOMA), and Marinus Pharmaceuticals (NASDAQ: MRNS). Here's what made 2017 such a fantastic year for these biotech stocks.

Gold, silver, and bronz winners podiums
Gold, silver, and bronz winners podiums

Image source: Getty Images.

Sangamo Therapeutics

Sangamo Therapeutics ranks as the third best biotech stock of 2017, with a sizzling gain of more than 440%. The company began the year with a market cap of a little over $200 million and is on track to finish with a valuation topping $1.4 billion.

While Sangamo made solid progress from the outset of the year, an update in May lit a fire beneath the stock. When the biotech provided its first-quarter results on May 10, it also announced a partnership with Pfizer in developing gene therapy programs for hemophilia A. This endorsement by one of the world's largest drugmakers provided a big boost for Sangamo, whose gene therapy program uses zinc finger nuclease genome-editing technology, an approach that has been eclipsed over the past few years by newer technologies such as CRISPR.

There was plenty of other good news for Sangamo this year as well. The biotech received orphan-drug and fast-track designations for several of its pipeline candidates. The first patients received treatment in a couple of phase 1/2 clinical studies evaluating gene therapies SB225 and SB913. Probably the only factor holding Sangamo stock back somewhat was the company's public stock offering, which generated gross proceeds of $83.4 million.

XOMA Corporation

XOMA Corporation claimed the second-highest performance in 2017 among biotech stocks, with its share price soaring close to 700%. Earlier this year, XOMA was a nano-cap stock valued around $25 million. It will probably end 2017 with a market cap of $275 million or more.

Nearly all of XOMA's gains have come since late August. The company announced on Aug. 25 that it was licensing anti-IL-1 beta antibody gevokizumab to Novartis. Under the terms of this deal, XOMA received $31 million in upfront payments (including a $5 million equity investment) plus potential milestone payments and tiered royalties on future sales of gevokizumab.

That proved to be just the beginning of good news for XOMA related to product licensing deals. A few weeks after the Novartis announcement, XOMA earned a $3 million milestone payment from a 2015 licensing arrangement with Nanotherapeutics for an experimental anti-botulism drug. In October, XOMA announced three additional licensing deals for its phage display libraries for antibody discovery. And on Dec. 7, the biotech reported that it had licensed XOMA 358, an experimental drug targeting treatment of hypoglycemia, to small drugmaker Rezolute.