An uncontrolled trial is one in which there is no placebo-treated group. An open label trial is one in which the patients and doctors know that they are being given the active drug (i.e., they are not blinded).

So instead of there being two groups, one treated and the other given a placebo, with nobody (investigators or patients) knowing who is getting which, one group was given the drug and another group was given nothing, and the investigators knew who was in each group.