As of my understanding of ET/PV/MF - I did read some new materials in the field the past weekend - I don't see this as either works or doesn't work in MF. These patients have different abnormal parameters, a drug doesn't have to work in ALL parameters in ET/PV/MF. To me at least the normalization of platelet count part would carry over. So it won't be complete failure IMO. The key is to find right dosing schedule and in what parameters it works, in what it doesn't, thus define a path forward.
As of price target, I have no idea. I set a limit buy order when I feel risk/reward is good, if it hits fine, if it doesn't fine too. I sell when I feel risk/reward isn't good anymore. I never sell at the top (like so many other people do) unless it is buyout situation when I don't have a choice.