LAUSR

BACKGROUND Budesonide-MMX is a topically active corticosteroid degraded by cytochrome-P450 enzymes, resulting in favourable side-effect profile. We aimed to assess effect of CYP genotypes on safety and efficacy, and make a direct comparison with systemic corticosteroids. RESEARCH DESIGN AND METHODS We enrolled UC patients receiving budesonide-MMX and IBD patients on methylprednisolone in our prospective, observational-cohort study. Before and after treatment regimen clinical activity indexes, laboratory parameters (electrolytes, CRP, cholesterol, triglyceride, dehydroepiandrosterone, cortisol, beta-crosslaps, osteocalcin), and body composition measurements were assessed. CYP3A4 and CYP3A5 genotypes were determined in the budesonide-MMX group. RESULTS 71 participants were enrolled (budesonide-MMX: 52; methylprednisolone: 19). CAI decreased (p<0.05) in both groups. Cortisol decreased (p<0.001), and the level of cholesterol was elevated in both groups (p<0.001). Body composition altered only following methylprednisolone. Bone homeostasis (osteocalcin; p<0.05) and DHEA (p<0.001) changed more prominently after methylprednisolone. Glucocorticoid-related adverse events were more common following methylprednisolone treatment (9 patients [47.4 %]) compared to 1 patient (1.9 %). CYP3A5(*1/*3) genotype positively influenced efficacy, but not safety. Only one patient's CYP3A4 genotype differed. CONCLUSIONS CYP genotypes can affect the efficacy of budesonide-MMX; however, further studies would be needed with analyses of gene expression. Although budesonide-MMX is safer than methylprednisolone, due to glucocorticoid-related side effects, admission should require greater precaution.