Shares of Portola Pharmaceuticals (NASDAQ: PTLA), a biotech company focused on the development of drugs designed to treat thrombosis, bleeding disorders, and inflammation, skyrocketed by as much as 51% following a trading halt after the company announced that the Food and Drug Administration (FDA) had approved Bevyxxa (previously, betrixaban) for the treatment of venous thromboembolism (VTE) in patients hospitalized for acute medical illness. Two factors, in particular, make today's FDA approval especially exciting for shareholders.