Tefferi is obviously a very smart doctor, but I think he went out on a limb criticizing Jakafi - he pretty much said it wouldn't show any survival benefit and then had to backtrack a little when it did. But he still basically considers Jakafi to be virtually useless, and continues to say so.
I have no horse in the GERN race - just pointing out that Tefferi seems to me to be a bit unbalanced in this area.