Concordance and discordance in SLE clinical trial outcome measures: Analysis of three anifrolumab phase 2/3 trials

Ian N. Bruce, Richard A. Furie, Eric F. Morand, Susan Manzi, Yoshiya Tanaka, Kenneth C. Kalunian, Joan T. Merrill, Patricia Puzio, Emmanuelle Maho, Christi Kleoudis, Marius Albulescu, Micki Hultquist, Raj Tummala

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Abstract

Objectives In the anifrolumab systemic lupus erythematosus (SLE) trial programme, there was one trial (TULIP-1) in which BILAG-based Composite Lupus Assessment (BICLA) responses favoured anifrolumab over placebo, but the SLE Responder Index (SRI(4)) treatment difference was not significant. We investigated the degree of concordance between BICLA and SRI(4) across anifrolumab trials in order to better understand drivers of discrepant SLE trial results. 

Methods TULIP-1, TULIP-2 (both phase 3) and MUSE (phase 2b) were randomised, 52-week trials of intravenous anifrolumab (300 mg every 4 weeks, 48 weeks; TULIP-1/TULIP-2: n=180; MUSE: n=99) or placebo (TULIP-1: n=184, TULIP-2: n=182; MUSE: n=102). Week 52 BICLA and SRI(4) outcomes were assessed for each patient. 

Results Most patients (78%-85%) had concordant BICLA and SRI(4) outcomes (Cohen's Kappa 0.6-0.7, nominal p<0.001). Dual BICLA/SRI(4) response rates favoured anifrolumab over placebo in TULIP-1, TULIP-2 and MUSE (all nominal p≤0.004). A discordant TULIP-1 BICLA non-responder/SRI(4) responder subgroup was identified (40/364, 11% of TULIP-1 population), comprising more patients receiving placebo (n=28) than anifrolumab (n=12). In this subgroup, placebo-treated patients had lower baseline disease activity, joint counts and glucocorticoid tapering rates, and more placebo-treated patients had arthritis response than anifrolumab-treated patients. 

Conclusions Across trials, most patients had concordant BICLA/SRI(4) outcomes and dual BICLA/SRI(4) responses favoured anifrolumab. A BICLA non-responder/SRI(4) responder subgroup was identified where imbalances of key factors driving the BICLA/SRI(4) discordance (disease activity, glucocorticoid taper) disproportionately favoured the TULIP-1 placebo group. Careful attention to baseline disease activity and monitoring glucocorticoid taper variation will be essential in future SLE trials. 

Trial registration numbers NCT02446912 and NCT02446899.

Original languageEnglish
Pages (from-to)962-969
Number of pages8
JournalAnnals of the Rheumatic Diseases
Volume81
Issue number7
DOIs
Publication statusPublished - Jul 2022

Keywords

  • Autoimmune Diseases
  • Biological Therapy
  • Lupus Erythematosus, Systemic

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