A phase 2B randomised trial of hyperbaric oxygen therapy for ulcerative colitis patients hospitalised for moderate to severe flares.

Abstract

Hyperbaric oxygen has been reported to improve disease activity in hospitalised ulcerative colitis (UC) patients. To evaluate dosing strategies with hyperbaric oxygen for hospitalised UC patients. We enrolled UC patients hospitalised for acute flares (Mayo score 6-12). Initially, all patients received 3days of hyperbaric oxygen at 2.4 atmospheres (90minutes with two air breaks) in addition to intravenous steroids. Day 3 responders (reduction of partial Mayo score≥2 points and rectal bleeding score≥1 point) were randomised to receive a total of 5days vs 3days of hyperbaric oxygen. We treated 20 patients with hyperbaric oxygen (75% prior biologic failure). Day 3 response was achieved in 55% (n=11/20), with significant reductions in stool frequency, rectal bleeding and CRP (P<0.01). A more significant reduction in disease activity was observed with 5days vs 3days of hyperbaric oxygen (P=0.03). Infliximab or colectomy was required in only three patients (15%) despite a predicted probability of 80% for second-line therapy. Day 3 hyperbaric oxygen responders were less likely to require re-hospitalisation or colectomy by 3months vs non-responders (0% vs 66%, P=0.002). No treatment-related adverse events were observed. Hyperbaric oxygen appears to be effective for optimising response to intravenous steroids in UC patients hospitalised for acute flares, with low rates of re-hospitalisation or colectomy at 3months. An optimal clinical response is achieved with 5days of hyperbaric oxygen. Larger phase 3 trials are needed to confirm efficacy and obtain labelled approval.