Petersson, J

Abstract Background Adalimumab (ADA) is efficacious and well tolerated in adult patients with ulcerative colitis (UC).1,2 SERENE-UC (NCT02065622) is a study evaluating higher ADA dosing regimens from which induction study results have previously been reported3; here, we report data from the maintenance study. Methods This Phase 3, double-blind, randomised, multicentre study evaluated higher vs. standard ADA dosing regimens for induction and maintenance therapy in adult patients with moderately to severely active UC. Following completion of the induction study at Week 8, all patients were re-randomised 2:2:1 to ADA 40 mg every week (40 EW), ADA 40 mg every other week (40 EOW), or exploratory ADA 40 mg with therapeutic drug monitoring (TDM) regimens, stratified by induction treatment regimen, clinical response status at Week 8, and clinical remission (CRem) status at Week 8 among Week 8 responders. Efficacy endpoints were evaluated in Week 8 responders (ITT-RP) unless indicated differently. The primary efficacy endpoint was proportion of patients achieving CRem (full Mayo Score ≤2 with no subscore >1) at Week 52. The endoscopic component of the Mayo Score was scored via central reading. Non-responder imputation was used for missing values. Comparisons between 40 EW and 40 EOW dosing regimens used the Cochran–Mantel–Haenszel test adjusted for stratification. Safety assessment included a collection of adverse events (AEs), vital signs, and laboratory data. Results Of 852 patients in the Global (ex-Japan) induction study, 757 were re-randomised at Week 8 and 371 were included in the ITT-RP. In the ITT-RP, induction baseline demographics and disease characteristics were generally balanced across the 3 treatment arms; range across arms for mean UC disease duration was 6.2–7.8 years, 6.8–11.7% had prior infliximab use, and 62.5–63.5% were receiving corticosteroids. The overall mean ADA exposure was 252.2 days. The table displays results for efficacy endpoints. The observed safety profile was similar between maintenance treatment arms, including AEs of special interest (generally <1% across arms). Conclusion In the Global (ex-Japan) study of SERENE-UC, CRem at Week 52 was numerically higher among Week 8 responders in patients receiving ADA 40 EW compared with 40 EOW maintenance regimens (∆ = 10.5%), but not statistically significant. Higher maintenance treatment with 40 EW was generally safe and well tolerated with a similar safety profile to 40 EOW. No new long-term safety concerns were observed. References

The colonic mucus layer serves as an important barrier and prevents colonic bacteria from invading the mucosa and cause inflammation. The regulation of colonic mucus secretion is poorly understood. The aim of this study was to investigate the role of the mucus barrier in induction of colitis. Furthermore, regulation of mucus secretion by luminal bacterial products was studied. The colon of anesthetized Muc2 −/− , Muc1 −/− , wild-type (wt), and germ-free mice was exteriorized, the mucosal surface was visualized, and mucus thickness was measured with micropipettes. Colitis was induced by DSS (dextran sodium sulfate, 3%, in drinking water), and disease activity index (DAI) was assessed daily. The colonic mucosa of germ-free and conventionally housed mice was exposed to the bacterial products LPS (lipopolysaccharide) and PGN (peptidoglycan). After DSS induction of colitis, the thickness of the firmly adherent mucus layer was significantly thinner after 5 days and onward, which paralleled the increment of DAI. Muc2 −/− mice, which lacked firmly adherent mucus, were predisposed to colitis, whereas Muc1 −/− mice were protected with significantly lower DAI by DSS compared with wt mice. The mucus barrier increased in Muc1 −/− mice in response to DSS, whereas significantly fewer T cells were recruited to the inflamed colon. Mice housed under germ-free conditions had an extremely thin adherent colonic mucus layer, but when exposed to bacterial products (PGN or LPS) the thickness of the adherent mucus layer was quickly restored to levels observed in conventionally housed mice. This study demonstrates a correlation between decreasing mucus barrier and increasing clinical symptoms during onset of colitis. Mice lacking colonic mucus (Muc2 −/− ) were hypersensitive to DSS-induced colitis, whereas Muc1 −/− were protected, probably through the ability to increase the mucus barrier but also by decreased T cell recruitment to the afflicted site. Furthermore, the ability of bacteria to regulate the thickness of the colonic mucus was demonstrated.