One-Year Clinical Outcomes of Subcutaneous Infliximab Maintenance Therapy Compared With Intravenous Infliximab Maintenance Therapy in Patients With Inflammatory Bowel Disease: A Prospective Cohort Study

Background Although the pharmacokinetic profile of subcutaneous (SC) infliximab (IFX) is superior to conventional intravenous (IV) IFX, long-term efficacy and safety of SC IFX in patients with inflammatory bowel disease (IBD) have not been reported yet. This study aimed to evaluate long-term clinical outcomes of IBD patients treated with SC IFX compared with those of IBD patients treated with IV IFX during maintenance therapy. Methods This prospective cohort study enrolled 61 IBD patients in clinical remission who received scheduled IFX maintenance therapy. Of them, 38 patients were switched to SC IFX, while 23 patients continued IV IFX with dose optimization. Enrolled patients were followed up for 1 year. The primary outcome was durable remission defined as clinical remission (Crohn's disease, Harvey-Bradshaw index <5; ulcerative colitis, partial Mayo score <2) and biochemical remission (C-reactive protein <0.5 mg/dL) with IFX trough level >= 3 mu g/mL throughout the follow-up period. Results One-year clinical remission, 1-year biochemical remission, and mucosal healing did not differ between the IV and SC IFX groups (n = 20 of 23 vs 33 of 38; P = 1.000; n = 22 of 23 vs 34 of 38; P = .641; and n = 10 of 18 vs 17 of 25; P = .414, respectively). During follow-up, the number of patients with IFX trough level <3 mu g/mL was significantly lower in the SC IFX group (n = 0 of 38, 0%) than in the IV IFX group (n = 10 of 23, 43%) (P < .001). The SC IFX group showed higher 1-year durable remission than the IV IFX group (n = 31 of 38, 82% vs n = 11 of 23, 48%; P = .013). The incidence of IFX-related adverse events did not differ significantly between both groups (26% vs 39%; P = .446). Conclusion The SC IFX switch induced a higher 1-year durable remission rate than continuing IV IFX in patients with IBD during scheduled maintenance therapy, showing similar safety. Lay Summary Long-term efficacy and safety of subcutaneous infliximab in patients with inflammatory bowel diseases have not been reported yet. Switching from intravenous to subcutaneous infliximab showed higher 1-year durable remission than continuing intravenous infliximab during scheduled maintenance therapy, with similar safety.