Regeneron Pharmaceuticals (NASDAQ:REGN) reported fourth-quarter results that beat expectations, and investors -- who have been snapping up the stock this week based on news that it's working on a treatment for the 2019n-CoV coronavirus -- bid up the shares another 5%. Revenue rose 13% in the quarter to $2.17 billion, topping analysts' consensus estimate of $2.11 billion. Non-GAAP earnings per share rose 10% to $7.50, beating expectations of $6.92.

Regeneron's growth was driven by its eye drug Eylea, sales of which were up 11% in the quarter, and inflammation-reducer Dupixent, which had global sales growth of 136%. The company partners with Bayer for Eylea sales outside the U.S., and with Sanofi for worldwide sales of Dupixent.

Pipepette dropping sample into a test tube.

Image source: Getty Images.

Management declined to provide guidance for 2020, saying it was restructuring its collaboration agreement with Sanofi for two of its drugs, but said on the conference call that it was "comfortable" with the current analyst consensus, which is for non-GAAP EPS growth of 6% to $26.14.

Regeneron announced on Tuesday that it's collaborating with the U.S. Department of Health and Human Services to develop an antiviral treatment for the 2019n-CoV coronavirus, and said on the conference call that it will have the first iteration within a few months. The large-cap biotech company has a rapid-response infectious disease platform that produced a three-antibody cocktail for Ebola that proved superior to the existing standard antiviral treatment in a trial last year. Regeneron's stock has risen 15% since that announcement.