P733 Long-term effectiveness and acceptability of switching from intravenous to subcutaneous infliximab in patients with inflammatory bowel diseases treated with intensified doses: the REMSWITCH-LT study

Abstract

Abstract Background We recently demonstrated that switching from intravenous to subcutaneous infliximab is safe and well-accepted at short-term in IBD patients including those with intensified IV regimen. However, the long-term risk of relapse in these patients remains unknown. We assessed the long-term effectiveness and acceptability of switching from intravenous to subcutaneous infliximab in patients with inflammatory bowel diseases (IBDs) treated with or without intensified intravenous regimen. Methods In this prospective multicenter observational study, IBD patients in clinical remission (partial Mayo score ≤ 2 or Harvey-Bradshaw index ≤ 4) were switched to a unique dose of subcutaneous infliximab (120 mg every other week). Pharmacological and biological data were collected at baseline, 6 months and at last follow-up (median follow-up : 18 [15-20] months). Relapse was defined as clinical relapse or fecal calprotectin increase ≥ 150 mg/g compared with baseline. Results Among 184 eligible patients, 72.3% (n = 133/184) agreed to switch. At M6, a relapse occurred in 10.2% (n = 6/59), 7.3% (n = 3/41), 16.7% (n=3/18), and 66.7% (n=10/15) (P < .001) of patients receiving 5 mg/kg every 8 wks, 10 mg/kg every 8 wks, 10 mg/kg every 6 wks, and 10 mg/kg every 4 wks, respectively. At 18 months, the rate of relapse was 13.6% (n=8/59), 17.7% (n=7/41), 33.3% (n=6/18), and 86.7% (n=13/15) (P < .001) of patients receiving 5 mg/kg every 8 wks, 10 mg/kg every 8 wks, 10 mg/kg every 6 wks, and 10 mg/kg every 4 wks, respectively. Dose escalation led to recapture clinical remission in 82.1% (23/28) of the patients, including 83.3% (15/18) and 80.0% (8/10) in those receiving 240 mg every other week or 120 mg every week, respectively. Infliximab serum levels increased after the switch (P < .0001) except for patients receiving 10 mg/kg every 4 wks. In multivariable analysis, 10 mg/kg every 4 wks regimen (OR= 61.0; [6.0-600.1], p <0.001) and 10 mg/kg every 6 wks regimen (OR=4.7; [1.1-20.2], p = 0.039) had a higher risk of relapse at 18 months as well as reduced (58.3%) or stable (52.6%) infliximab serum levels between baseline and visit 1 compared with increased serum levels (19.7%) (P = 0.006 and P = 0.008, respectively). Patients’ acceptability (10-point scale) was improved by the switch (6.9 ± 1.6 for IV vs 8.6 ± 1.4 at V1 after the switch; P < .0001) and did not decrease over time during SC maintenance regimen 8.8 ± 1.3 at 6 months and 8.8 ± 1.3 at 18 months. No severe adverse event was reported. Conclusion Switching from IV to SC infliximab 120mg eow is safe and well-accepted leading to a low long-term risk of relapse in IBD patients. Tight monitoring and escalated dose should be recommended for patients receiving 10mg/kg/6 weeks and 4 weeks, respectively.