Hopefully you have had an opportunity to ready through the 9-13-2013 SEC 14D-9 filing. It looks to me like a CYA document fot ASTX. Note this was developed after all the potential litigation investigation. The section on the 12 public traded development stage , oncology-focused biotechnology companies allegedly reviewed by Jefferies is very interesting. Not sure how a number of these companies justified the low tender offer for ASTX. Many of the companies have signifcant debt, lower revenues and not as good a pipeline as ASTX.
The only actual lawsuit filed was one by a professional lead plantiff. The person is the lead plantiff in over 100 lawsuits. The game is be THE class action lawsuit and then settle for a trial amount for every other member of the class but a significant amount for the lead plantiff and, of course, legal fees. This stops all other attempts at class action lawsuits.