Background and aims: This GEMINI 1 post hoc analysis evaluated vedolizumab efficacy for inducing deep remission in patients with ulcerative colitis and correlation between vedolizumab trough concentrations and deep remission rates.
Methods: Week 6 vedolizumab responders were re-randomized to placebo or vedolizumab every 8 or 4 weeks. Deep remission at Week 52 was measured using four different definitions [from most to least stringent]:  Mayo Clinic endoscopic score = 0, rectal bleeding score = 0 and decrease or no change from baseline in stool frequency score;  endoscopic score ≤1, rectal bleeding score = 0 and stool frequency score = 0;  endoscopic score ≤1, rectal bleeding score = 0, decrease or no change from baseline stool frequency score, and total score [endoscopic score + rectal bleeding score + stool frequency score] ≤1; and  endoscopic score ≤1, rectal bleeding score = 0 and stool frequency score ≤1. Steady-state trough vedolizumab serum concentrations were evaluated.
Results: At Week 6, 373 vedolizumab responders were re-randomized to maintenance placebo [n = 126] or vedolizumab every 8 [n = 122] or 4 [n = 125] weeks. Significantly more vedolizumab patients achieved deep remission at Week 52 for the most (placebo 8.7%, every 8 weeks 27.0% [p = 0.0001], every 4 weeks 28.0% [p < 0.0001]) and least (placebo 15.9%, every 8 weeks 43.4% [p < 0.0001], every 4 weeks 43.2% [p < 0.0001]) stringent definitions. Patients with higher vedolizumab trough concentration quartiles had higher deep remission rates [all definitions] compared with those with the lowest quartile or who received placebo.
Conclusion: Vedolizumab was associated with significantly higher deep remission rates than placebo at Week 52, regardless of deep remission definition [NCT00783718].