Intensive drug therapy versus standard drug therapy for symptomatic intestinal Crohn's disease strictures (STRIDENT): an open-label, single-centre, randomised controlled trial.

Background: Strictures are the most common structural complication of Crohn's disease. Surgery and endoscopic balloon dilation are the main treatments; drug therapy has been considered contraindicated. Given that most strictures have an inflammatory component, we aimed to find out whether strictures are responsive to drug treatment and whether intensive drug therapy is more effective than standard drug therapy.

Methods: This open-label, single-centre, randomised controlled trial was performed in one specialist inflammatory bowel disease centre in Australia. Patients aged 18 years or older with Crohn's disease were included. Eligible patients had a de novo or postoperative anastomotic intestinal stricture on MRI or ileocolonoscopy, symptoms consistent with chronic or subacute intestinal obstruction (postprandial abdominal pain in the presence of a confirmed stricture), and evidence of active intestinal inflammation. Patients were randomly assigned (2:1) to receive intensive high-dose adalimumab (160 mg adalimumab once per week for 4 weeks followed by 40 mg every 2 weeks, with escalation of dose at 4 months and 8 months if assessment of disease activity indicated active inflammation) plus thiopurine (initial dose of azathioprine 2·5 mg/kg or mercaptopurine 1·5 mg/kg, with dose adjustment based on thiopurine metabolite testing) or standard adalimumab monotherapy (160 mg at week 0, 80 mg at week 2, then 40 mg every 2 weeks) using stratified fixed block randomisation. Stratification factors were stricture dilation at study baseline colonoscopy and current biologic drug use. The primary endpoint was improvement (decrease) in the 14-day obstructive symptom score at 12 months by one or more points compared with baseline. This trial is registered with ClinicalTrials.gov, NCT03220841, and is completed.

Findings: Between Sept 10, 2017, and Sept 6, 2019, 123 patients were screened and 77 randomly assigned to intensive adalimumab plus thiopurine treatment (n=52) or standard adalimumab treatment (n=25). At 12 months, improvement in obstructive symptom score was noted in 41 (79%) of 52 patients in the intensive treatment group and 16 (64%) of 25 in the standard treatment group (odds ratio [OR] 2·10 [95% CI 0·73-6·01]; p=0·17). Treatment failure occurred in five (10%) patients in the intensive treatment group versus seven (28%) in the standard treatment group (OR 0·27 [95% CI 0·08-0·97]; p=0·045); four patients in each group required stricture surgery (0·44 [0·10-1·92]; p=0·27). Crohn's Disease Activity Index was less than 150 in 36 (69%) patients in the intensive treatment group versus 15 (60%) in the standard treatment group (1·50 [0·56-4·05]; p=0·42). MRI at 12 months showed improvement using the stricture MaRIA score (≥25%) in 31 (61%) of 51 versus seven (28%) of 25 patients (3·99 [1·41-11·26]; p=0·0091). MRI complete stricture resolution was seen in ten (20%) versus four (16%) patients (1·28 [0·36 to 4·57]; p=0·70). Intestinal ultrasound at 12 months showed improvement (>25%) in bowel wall thickness in 22 (51%) of 43 versus seven (33%) of 21 patients (2·10 [0·71 to 6·21]; p=0·18). Faecal calprotectin normalised in 32 (62%) versus 11 (44%) patients (2·04 [0·77-5·36]; p=0·15). Normalisation of CRP was seen in 32 (62%) versus 11 (44%) patients (2·04 [0·77-5·36]; p=0·15). Eight (15%) patients in the intensive treatment group and four (16%) in the standard treatment group reported serious adverse events. No deaths occurred during the study.

Interpretation: Crohn's disease strictures are responsive to drug treatment. Most patients had improved symptoms and stricture morphology. Treat-to-target therapy intensification resulted in less treatment failure, a reduction in stricture-associated inflammation, and greater improvement in stricture morphology, although these differences were not significantly different from standard therapy.

Funding: Australian National Health and Medical Research Council, Gastroenterological Society of Australia Ferring IBD Clinician Establishment Award, Australasian Gastro Intestinal Research Foundation, AbbVie, and the Spotlight Foundation.