Use of EuroLupus Cyclophosphamide Dosing for the Treatment of Lupus Nephritis in Childhood-onset Systemic Lupus Erythematosus in North America

Objective. Childhood-onset systemic lupus erythematosus (cSLE) has higher rates of lupus nephritis (LN) than adult-onset SLE, often requiring intensive immunosuppression. This study examined North American practices and preferences for the low-dose EuroLupus cyclophosphamide (CYC) protocol, as compared to the high-dose National Institutes of Health (NIH) CYC protocol, to treat LN in cSLE. Methods. A 35-item Web-based survey was distributed to Childhood Arthritis and Rheumatology Research Alliance (CARRA) and Pediatric Nephrology Research Consortium (PNRC) providers. The survey assessed participant demographics, CYC prescribing practices, perceptions of EuroLupus protocol, and LN vignette treatment decisions; 1 vignette was taken from a 2009 CARRA survey and responses were compared. Multivariable logistic regression analyzed provider factors associated with use of low- vs high-dose CYC. Results. Responses were provided by 185/421 (44%) pediatric rheumatologists (CARRA) and 40/354 (11%) pediatric nephrologists (PNRC). Among respondents who prescribed CYC for pediatric LN over the past year (n = 135), half reported using EuroLupus. When presented with the same vignette about an adolescent with class IV LN, 32% of pediatric rheumatologists chose EuroLupus dosing in 2020, vs 6% in 2009. Provider factors associated with choosing the low-dose regimen were familiarity with the protocol (OR 4.2, P = 0.006) and greater perceived benefit (OR 1.6, P < 0.0001). Pediatric nephrologists had similar responses to the pediatric rheumatology providers. Overall, 78% of respondents perceived EuroLupus protocol efficacy to be equivalent to the high-dose protocol in cSLE LN. Conclusion. Pediatric specialists are currently more likely to use low-dose CYC to treat cSLE LN than they were a decade ago. Nevertheless, familiarity with EuroLupus dosing remains low.