Despite a generally bleak year for Gilead, and for biotech stocks in general, shares of Exelixis, Inc. Can these biotechs continue climbing throughout the new year and beyond, or are they about to sputter and run out of fuel? Let’s look at what’s propelling them upward to see why they might be better picks than Gilead Sciences. A string of good news for Exelixis’ lead cancer drug made this one of the best-performing biotech stocks of 2016.