Comparing the efficacy of vedolizumab between males and females: a post-hoc analysis of GEMINI-1 and VARSITY.

Vedolizumab is a first-line treatment option for ulcerative colitis. There are differences in incidence of ulcerative colitis between males and females, but whether sex affects treatment outcomes is less clear. We examined sex-based differences in patients with ulcerative colitis initiated on vedolizumab from two major randomized controlled trials (RCTs). We conducted a post-hoc analysis on participants with ulcerative colitis from the VARSITY and GEMINI-1 RCTs who received vedolizumab. Outcomes of interest were rates of clinical improvement, clinical remission, and endoscopic improvement at weeks 6, 14, and 52 in male and female participants, as were differences in concentrations of trough vedolizumab and C-reactive protein; 1009 persons in GEMINI-1 and VARSITY trials were included. Male and female patients had similar disease characteristics aside from males being more likely to have Mayo 3 grade endoscopic severity at baseline (62.8 vs. 48.9%, P < 0.001). At week 6, females were more likely to have endoscopic improvement (47.4 vs. 35.2%, P = 0.001) and increased vedolizumab trough levels [34.0 (23.0-44.5) vs. 28.9 (19.0-34.6), P < 0.001]. The probability of achieving clinical remission (28.9 vs. 34.5%, P = 0.057) or endoscopic improvement (35.5 vs. 39.3%, P = 0.212) at week 52 was not different between males and females. Females with ulcerative colitis treated with vedolizumab appear more likely to achieve early endoscopic improvement than males, though longer-term outcomes demonstrated no difference. Further studies are required to better understand mechanisms through which sex or sex-associated factors could influence response to therapy in ulcerative colitis.