Serious infection risk after 1 year between patients with rheumatoid arthritis treated with rituximab or with a second TNFi after initial TNFi failure: results from The British Society for Rheumatology Biologics Register for Rheumatoid Arthritis

BACKGROUND: Both tumour necrosis factor inhibitors (TNFi) and rituximab (RTX), a B-cell depleting biologic, can disrupt the immune system in rheumatoid arthritis (RA). RTX is licensed in Europe for use following TNFi failure. However, safety data on serious infections are scarce for RTX in daily practice. This analysis aims to compare the risk of serious infections in the first year after a switch to either TNFi or RTX in patients who have failed a first TNFi
METHODS: This study included patients with RA registered with the British Society for Rheumatology Biologics Register (BSRBR-RA) who switched to either a second TNFi or RTX after failing a first TNFi. Patients were followed until first serious infection (SI), treatment discontinuation, last recorded follow-up or the end of the first year after the switch, which ever came first. SI was defined as requiring hospitalisation, intravenous antibiotics, or resulting in death. The risk of first serious infection was compared between TNFi and RTX using Cox proportional hazard models adjusted using propensity scores using inverse probability of treatment weighting.
RESULTS: This analysis included 3,419 TNFi and 1,396 RTX patients contributing 2,765 and 1,224 person-years (pyrs) respectively. SI occurred in 164 (4.8%) TNFi and 81 (5.8%) RTX patients giving a crude rate of 59 SI/1,000pyrs and 66 SI/1000pyrs respectively. The adjusted hazard ratio for SI was 1.0(95%CI 0.7-1.4).
CONCLUSION: The risk of serious infections was comparable over the first year of treatment between TNFi and RTX treatment in patients who had failed a single prior TNFi.