Abstract Background In the REMSWITCH-VLT (Very-Long Term), we assessed the very long-term effectiveness (including endoscopic and transmural data), safety, acceptability, and progression of bowel damage after switching from IV to SC infliximab in IBD patients initially treated with standard or intensified IV regimens. Methods This multicenter prospective study enrolled consecutive IBD patients in clinical remission (partial Mayo score ≤ 2 or Harvey–Bradshaw Index ≤ 4) on IV infliximab. Patient follow-up was standardized, with data collected on the day of the switch to SC infliximab (corresponding to the theoretical date of the next IV infusion) (= V0), and for long-term follow-up visits at 6, 18, and 42 months (±3 months). Relapse was defined as a partial Mayo score 2 or Harvey–Bradshaw Index 4, or an increase in fecal calprotectin ≥ 150 mg/g from baseline (V0). Acceptability was assessed using a numerical scale from 0 to 10. Results A total of 133 patients were included (Table 1). Risk of relapse according to initial IV dose and interval is illustrated in Figure 1. Dose escalation to 240 mg every two weeks or 120 mg weekly recaptured clinical remission in 83.8% (31/37). No significant difference existed between the two intensification strategies (84.2% 16/19 vs 83.3% 15/18, p = ns). Serum infliximab levels increased after switching (p 0.0001), except in patients previously receiving 10 mg/kg every 4 weeks. At last follow-up, only 3/133 patients (2.2%) had developed anti-infliximab antibodies ( 10 ng/mL). In multivariate analysis, patients previously treated with 10 mg/kg every 4 weeks (OR = 28.4 5.5–144.2, p 0.001) and 10 mg/kg every 6 weeks (OR = 5.4 1.7–17.0, p = 0.003) had an increased risk of relapse at 42 months after switching to standard-dose SC infliximab (120 mg every 2 weeks). Overall, only 22/133 patients (16.5%) discontinued infliximab due to loss of response or intolerance at 42 months. No significant differences were observed according to prior IV dosing regimen. Rates of endoscopic remission and transmural healing under SC infliximab at 42 months were 72.9% (97/133) and 65.4% (87/133), respectively, and 92.4% (97/105) and 82.8% (87/105) among those still receiving SC infliximab at month 42. Only 3/133 patients (2.2%) showed progression of bowel damage, and none required surgery. Acceptability improved significantly after switching to SC infliximab (6.9 ± 1.6 for IV vs 8.6 ± 1.4 at 6 months; p 0.0001) and remained stable over time (9.0 ± 1.5 at 42 months). No serious adverse events were reported. Conclusion Switching from IV to SC infliximab is safe and well accepted in the very long term, resulting in low rates of clinical, endoscopic, and transmural relapse in IBD patients. Conflict of interest: Prof. Dr. Buisson, Anthony: Consulting fees from: Abbvie, AlfaSigma, Amgen, Arena, Biogen, Celltrion, CTMA, Ferring, Galapagos, Guty Care, Janssen, Hikma, Lilly, Mylan, Nexbiome, Pfizer, Roche, Takeda, Tillotts Lecture fees from: Abbvie, Alfa Sigma, Amgen, Biogen, Celltrion, Ferring, Galapagos, Hikma, Janssen, Lilly, Mayoli-Spindler, MSD, Pfizer, Roche, Sanofi-Aventis, Takeda, Tillotts, Vifor-Pharma Research fundings from: Abbvie, Alfa Sigma, Celltrion, Janssen, Lessaffre, Lilly, Pfizer, Takeda Nachury, Maria: Abbvie, Alfa Sigma, Biosynex, Celltrion, Galapagos, Janssen, Lilly, MSD, Pfizer, Takeda Bazoge, Maëva: No conflict of interest Yzet, Clara: No conflict of interest Wils, Pauline: No conflict of interest Dodel, Marie: No conflict of interest Banana Hamadidi, Amira: No conflict of interest Pereira, Bruno: No conflict of interest Fumery, Mathurin: Grant: Pfizer Personal Fees: Abbvie, Janssen, Takeda, MSD, Biogen, Amgen, Sandoz, Fresenius, Gilead, Celgene, Galapagos, Mylan, Tillots, Ferring, Pfizer, Hospira, CTMA, Boehringer, Lilly, Arena Non-financial Support: Abbvie, Janssen, Takeda, MSD, Galapagos, Ferring, Pfizer
Buisson et al. (2026) studied this question.