...and dumped their position now before it really gets ugly. If Z160 fails this could easily drop back below $1. Failure seems to be the trend in biotech the last few weeks so nobody is going to take a chance here. Smart traders are getting out now with whatever profit or loss they currently hold in their position and moving on.
People are giving you thumbs down, but last time this tanked on no news (last year sometime, not the R/S), a day or two later the bad news was released. Like many biotech stocks it is clear that major trades either direction are made before news is public.