Reliable and practical outcome measures for clinical trials in systemic lupus erythematosus (SLE) remain limited. Currently used primary endpoints, including the SLE Responder Index (SRI) and BILAG-based Composite Lupus Assessment (BICLA), comprise more than 120 items, making them cumbersome to score and difficult to implement in routine clinical practice. The Systemic Lupus Erythematosus Disease Activity Score (SLE-DAS) is a recently validated 17-item tool with high accuracy and sensitivity for detecting changes in SLE disease activity. The newly developed SLE-DAS Responder Index (SLE-DAS RI) may offer a more practical and high-performing outcome measure. It defines treatment response as a reduction in SLE-DAS of ≥1.72 together with the absence of moderate-to-severe disease activity, indicated by an SLE-DAS score of ≤7.64.
A recent study published in Rheumatology (Oxford) found that the SLE-DAS RI was a robust efficacy endpoint in SLE clinical trials, associated with sustained disease control, reduced glucocorticoid exposure, and meaningful improvements in patient-reported outcomes.
The post-hoc analysis pooled data from the placebo arms of three randomized controlled trials of anifrolumab, MUSE, TULIP-1, and TULIP-2, involving 438 patients. The SLE-DAS RI was defined as a reduction in SLE-DAS of ≥1.72 alongside a score of ≤7.64 at week 52.
Of the 438 patients, 34.0% achieved SLE-DAS RI response at week 52. Responders showed greater reductions in disease activity and lower cumulative glucocorticoid exposure compared with non-responders. In multiple linear regression analyses, SLE-DAS RI response was the most significant predictor of health-related quality of life (HR-QoL) improvements across multiple domains, showing stronger predictive performance than both BICLA and SRI-4. SLE-DAS RI responders also had a 41.9% lower risk of flare, as assessed using the SLE-DAS flare tool and Cox regression.
The study further evaluated the ability of SLE-DAS to identify moderate-to-severe disease activity (MSDA). At screening, the SLE-DAS MSDA threshold identified 96.1% of patients with MSDA and more accurately reflected HR-QoL burden at week 12 compared with BILAG-2004 and SLEDAI-2K.
The findings supported the SLE-DAS RI as a clinically meaningful and sensitive efficacy measure and highlighted the broader utility of SLE-DAS in identifying moderate-to-severe disease activity and supporting future SLE trial design.
References
- Jesus D, Henriques C, Matos A, Doria A, Inês LS. SLE-DAS responder index: a novel outcome measure with high performance for physician and patient outcomes in anifrolumab phase 2-3 trials. Rheumatology (Oxford). 2026 May 5;65(5):keag177.
- Jesus D, Henriques C, Matos A, Doria A, Inês L. POS0733 Validation of the SLE-DAS Responder Index as an accurate and feasible endpoint for SLE clinical trials: a post-hoc study in the phase 2 and 3 anifrolumab clinical trials. Ann Rheum Dis. 2024;83(Suppl 1):1004. https://doi.org/10.1136/annrheumdis-2024-eular.4639