Exposure–efficacy relationship of vedolizumab subcutaneous and intravenous formulations in Crohn’s disease and ulcerative colitis

Background and aims: This posthoc analysis of the GEMINI and VISIBLE studies in ulcerative colitis (UC) and Crohn's Disease (CD) assessed exposure−efficacy of vedolizumab intravenous (IV) and subcutaneous (SC). Methods: A previously described population pharmacokinetic model was used to predict average serum and trough concentrations at steady state (Cav,ss, Ctrough,ss) and simulate the transition from vedolizumab IV to SC. Efficacy was defined as clinical remission at week 52: complete Mayo score ≤ 2 points and no individual subscore > 1 point (UC), and CD activity index score ≤ 150 points (CD). Results: Data were from 1968 patients (GEMINI 1 [n = 334], VISIBLE 1 [n = 216], GEMINI 2 [n = 1009], VISIBLE 2 [n = 409]) who received maintenance treatment with vedolizumab IV-Q8W, IV-Q4W, SC-Q2W, or placebo. Model-predicted Cav,ss for IV-Q8W and SC-Q2W was similar in UC and CD. Cav,ss was higher for IV-Q4W than IV-Q8W and SC-Q2W. Ctrough,ss values from IV and SC aligned well with pooled observed Ctrough by treatment group in UC and CD. Cav,ss was equivalent for SC and IV. For UC and CD, efficacy rates were greater in patients in the highest quartiles of vedolizumab exposure for both formulations. Conclusion: Exposure−efficacy relationships for IV and SC vedolizumab administration were comparable, confirming that both are equally effective during maintenance treatment.