Infliximab versus Cyclophosphamide for Severe Behçet's Syndrome.

Background: Cyclophosphamide and infliximab are recommended as induction therapies for severe Behçet's syndrome. Whether infliximab is safer and more effective than cyclophosphamide in treating severe Behçet's syndrome is not known.

Methods: In this phase 2, Bayesian, multicenter randomized controlled trial, we assigned patients fulfilling the International Study Group's criteria for Behçet's syndrome who had major vascular or central nervous system involvement to receive either intravenous infliximab (5 mg/kg at weeks 0, 2, 6, 12, and 18) or cyclophosphamide (0.7 g/m² intravenously at weeks 0, 4, 8, 12, 16, and 20, with a maximal dose of 1.2 g/infusion). All patients received the same glucocorticoid regimen. The primary outcome was complete response (clinical, biological, and radiological remission with a daily prednisone dose ≤0.1 mg/kg) at week 22.

Results: Between May 2018 and April 2021, 52 patients with severe Behçet's syndrome (n=37 [71%] with vascular Behçet's syndrome and n=15 [29%] with neuro-Behçet's syndrome) were randomly assigned to receive either infliximab or cyclophosphamide. Complete response was achieved by 22 out of 27 (81%) and 14 out of 25 (56%) patients in the infliximab and cyclophosphamide treatment groups, respectively (estimated difference, 29.8 percentage points; 95% credible interval, 6.6 to 51.7). The posterior probability that at least 70% of treated individuals achieved complete response by week 22 was 97.4% for infliximab and 6.0% for cyclophosphamide. Overall, adverse events were recorded in 8 out of 27 (29.6%) patients receiving infliximab and 16 out of 25 (64%) patients receiving cyclophosphamide (estimated difference, -32.3 percentage points; 95% credible interval, -55.2 to -6.6). Serious adverse events were reported in 15% and 12% of patients receiving infliximab and cyclophosphamide, respectively.

Conclusions: Among patients with severe Behçet's syndrome, induction therapy with infliximab had a superior complete response rate at 22 weeks and fewer adverse events than induction with cyclophosphamide. (Funded by the French Ministry of Health.).