Read it again:
In addition to patients in the first cohort now receiving their second cycle of dosing, the Institutional Review Board (“IRB”) and Safety Committee have approved escalated dosing levels for the second cohort. The Company has been advised that the second cohort will begin dosing during the week beginning December 16.
The first cohort is "now receiving", the second cohort "will begin" next week. Like I said, I don't know how far to interpret this. If the two cohorts will dose together, it would have been stated in that way IMO.