When to Switch to Subcutaneous Infliximab? The RE-WATCH Multicenter Study

Background: The infliximab (IFX) biosimilar, CT-P13, is available as an intravenous (IV) and subcutaneous (SC) formulation. Although current indications allow the transition from IV CT-P13 to SC CT-P13 after two IV administrations, some clinicians prefer to postpone switching until stable clinical remission has been achieved. Methods: We evaluate the endoscopic response, treatment persistence, clinical remission, endoscopic remission, and safety profile after one year of treatment with IFX in patients switched from IV to SC after 6 weeks (early switch group) or after 6 months (late switch group). Results: There were no statistical differences between the two groups after one year in terms of endoscopic response (71.4% vs 70.8%, P = .95), steroid-free clinical remission (62.5% vs 68.7%, P = .51), or IFX retention rate (75.0% vs 66.7%, P = .35). We observed higher endoscopic remission rates in early switch patients as compared to late switch patients; however, this trend was not significant (69.6% vs 52.1%, P = .07). A return to IV-IFX was required in 1 of 43 early switch patients and in 3 of 44 late switch patients (2.3% vs 6.8%, P = .31). Clinical indexes, fecal calprotectin and C-reactive protein (CRP) levels significantly decreased after one year regardless of group. Adverse events were also comparable between groups (4.5% vs 8.3%, P = .46). Conclusions: Our study has shown that early switch from IV-IFX to SC-IFX at 6 weeks is effective in terms of clinical and endoscopic remission at one year yielding similar results to late switch at 6 months.