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

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. 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). 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). 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.