The article suggests compromised immunity as one negative consequence from interfering with the complement cascade, but I am sure you got that too. The article did bring me back to this comment from GSK regarding the competitive prospects of their HIF stabilizer:
Now to be clear I don't think there is a large risk here, and Peter makes a good point regarding dosing. But after a run up I personally decided to play it safe and take profits (which of course means the stock is destined to go up ;)