Following Portola Pharmaceuticals' Q4 results, William Blair analyst John Sonnier says he's "cautiously optimistic" on the potential for regulatory approval of betrixaban on June 24. The analyst believes approval would be worth $60 per share. Since the initial disclosure of the failed Phase III primary endpoint, the "evolution of the betrixaban story has been highly supportive," Sonnier tells investors in a research note. He believes the full data presentation at the International Society on Thrombosis and Haemostasis annual meeting in May and further sub-study results presented at the American Heart Association Scientific Sessions in November were "highly supportive of the overall benefit from betrixaban therapy." The analyst keeps an Outperform rating on Portola.