A+C, The spike coincided with RSPI being added to the long portfolio on the $heff I-Hub board (links below). The heaviest day of volume was approx 10 mil shares, and with a .02-.03 cent stock that's only $200-300 K traded and only half of that was on the buy side. So at least some of the recent activity and volume was from $heff and his followers.
Clinical data is due soon from the CX-1739 RD Phase 2 and also from the Dronabinol Sleep Apnea Phase 2, and the shareholder vote for the R/S reverse split will be Aug 16, so there's bound to be at least a few entities out there positioning themselves in the stock.
These reverse splits often are accompanied by a financing to recapitalize the company, so that adds the potential for even more intrigue vis-a-vis the share price. Despite the drop off in volume the stock has been holding above .03 without much of a retracement -