Figure 2. Mean (±1 SEM) Maximum Effect Visual Analog Scale Scores for the Primary Outcome Measure of Drug Liking by Challenge Session for CAM2038 at 24 and 32 mg.
The dotted line denotes that this was a bipolar scale. Each hydromorphone dose response challenge (0, 6, and 18 mg; intramuscular) was conducted over a 3-day period, with the randomized dose order fixed within patient. Significant interaction effects for dose by session were found for drug liking (F8,308 = 74; P < .001 and F8,338 = 56.5; P < .001 for CAM2038, 24 mg and 32 mg, respectively). The filled symbols indicate a significant difference between that specific active hydromorphone dose (either 6 or 18 mg) during the qualification phase vs postrandomization challenges (Tukey t test; P < .05). CAM2038, 24 mg: n = 22; 32 mg: n = 24.