Once-Versus Twice-daily Mesalazine to Induce Remission in Paediatric Ulcerative Colitis: A Randomised Controlled Trial

Background: Trials in adults suggested that, in ulcerative colitis [UC], once-daily [OD] dosing of 5-ASA [5-amino salicylic acid] may be as or more effective than twice-daily [BD] dosing. In this induction of remission, investigator-blinded, randomised controlled-trial, we aimed to compare effectiveness and safety of once-versus twice-daily mesalazine in paediatric UC. Methods: Children, aged 4-18 years with a PUCAI [Paediatric Ulcerative Colitis Activity Index] of 10-55 points at inclusion, were randomised in blocks of six with blinded allocation to OD or BD mesalazine, using a weight-based dosing table. The primary outcome was mean PUCAI score at Week 6. Results: A total of 83/86 randomised children were eligible and analysed: 43 in the OD group and 40 in the BD group (mean age 14 +/- 2.7 years, 43 [52%] males, 51 [62%] extensive colitis). The groups did not differ with regard to disease activity or any other parameter at baseline. There was no difference in median PUCAI score between the OD group and BD group at Week 6: 15 (interquartile range [IQR] 5-40) versus 10 [0-40]; p = 0.48]. Response was seen in 25 [60%] OD versus 25 [63%] BD dosing [p = 0.78]. Proportion of children in remission [PUCAI < 10] at Week 6 was 13 [30%] OD versus 16 [40%] BD; p = 0.35]. Most adverse events were related to disease aggravation; the rates of serious adverse events were similar [p > 0.2]. Conclusions: In this first randomised controlled trial in children, no differences were found between OD and BD dosing for any clinical outcome. Remission was achieved in 35% of children treated with mesalazine for active UC.