Burlington, MA-based Flexion ($FLXN) says that the FDA has lifted its clinical hold on its lead pain drug candidate, FX006. The biotech reports that had completed the FDA's "requested testing and investigation related to what was originally reported as a single case of septic arthritis of the knee." The removal of the regulatory obstacle clears the way for investigators to resume a Phase IIb study and launch Phase III in early 2015. Flexion shares were up about 6% this morning. Release