Long-term effectiveness and acceptability of switching from intravenous to subcutaneous infliximab in patients with inflammatory bowel disease treated with intensified doses: The REMSWITCH-LT study.

Background: The long-term risk of relapse after switching from intravenous (IV) to subcutaneous (SC) infliximab remains unknown in inflammatory bowel disease (IBD).

Aims: To assess the long-term effectiveness and acceptability of switching from IV to SC infliximab in patients with IBD treated with or without an intensified IV regimen.

Methods: We extended the follow-up of the REMSWITCH study including patients with IBD in clinical remission who were switched from IV to SC infliximab (120 mg/2 weeks). Relapse was defined as clinical relapse or faecal calprotectin increase ≥150 μg/g compared to baseline.

Results: After median follow-up of 18 [15-20] months, among 128 patients, rates of relapse were 13.8% (8/58), 18.4% (7/38), 35.3% (6/17) and 86.7% (13/15) at last follow-up (p < 0.001), in those receiving 5 mg/kg/8 weeks, 10 mg/kg/8 weeks, 10 mg/kg/6 weeks and 10 mg/kg/4 weeks at baseline, respectively. Among relapsing patients, dose escalation led to clinical remission in 82.1% (23/28). In multivariable analyses, factors associated with higher risk of relapse were IV infliximab 10 mg/kg/4 weeks (OR = 61.0 [6.1-607.0], p < 0.001) or 10 mg/kg/6 weeks (OR = 4.7 [1.1-20.2], p = 0.017), and decreased (OR = 5.6 [1.5-20.3], p = 0.004) or stable (OR = 5.0 [1.6-15.0], p = 0.009) serum levels of infliximab between baseline and first post-switch visit. Acceptability was improved at 6 months and did not decrease over time (6.9 ± 1.6 before the switch vs. 8.8 ± 1.3 at 6 months and 8.8 ± 1.3 at last follow-up; p < 0.001). No severe adverse events were reported.

Conclusions: Switching from IV to SC infliximab 120 mg every other week is safe and well accepted leading to low long-term risk of relapse. Tight monitoring and dose escalation should be recommended for patients receiving 10 mg/kg/6 weeks and 4 weeks, respectively.