It all depends on how you define "home run".
Isolated pops on binary events(which is why you would sell after one occurs), to my mind qualify as hits, rather than real home runs, (as in the case of a DNDN or HGSI), which, over time, kept on rising(out of the park)in response(with certain qualifications) to their binary events.
Obviously, you wouldn't want to sell it all in cases like that.
Since I think ariad(as an investment)is, ultimately, very likely to qualify as a homerun, you can understand my reluctance to sell too quickly.