Failure of a systemic lupus erythematosus response index developed from clinical trial data: lessons examined and learned

Use of Physician Global Assessment in systemic lupus erythematosus: a systematic review of its psychometric properties

OBJECTIVE

The Physician Global Assessment (PGA) is a visual analogue score that reflects the clinician's judgement of overall SLE disease activity. The aim of this systematic literature review is to describe and analyse the psychometric properties of the PGA.

METHODS

This systematic literature review was conducted by two independent reviewers in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. All articles published through 1 July 2019 in PubMed were screened, with no limitation on year of publication, language or patients' age. Psychometric properties data were analysed according to the OMERACT Filter methodology version 2.1.

RESULTS

The literature search identified 91 studies. Face validity was reported in all the articles retrieved in which the PGA was used alone or as part of composite indices (Systemic Responder Index, Safety of Estrogen in Lupus Erythematosus National Assessment Flare Index, Lupus Low Disease Activity State, Definitions of Remission in Systemic Lupus Erythematosus criteria). Content validity was reported in 89 studies. Construct validity was demonstrated by a good correlation (r ≥ 0.50) between the PGA with the SLEDAI (12 studies), SLAM (4 studies), LAI, BILAG and ECLAM (2 studies each). Criterion validity was assessed exploring the PGA correlation with quality of life measurements, biomarker levels and treatment changes in 28 studies, while no study has evaluated correlation with damage. A good responsiveness for PGA was shown in eight studies. A high variability in scales was found, causing a wide range of reliability (intraclass correlation coefficient 0.67-0.98).

CONCLUSION

PGA is a valid, responsive and feasible instrument, though its reliability was impacted by the scale adopted, suggesting the major need for standardization of its scoring.

Interferon-directed therapies for the treatment of systemic lupus erythematosus: a critical update

The interferon (IFN) pathway, especially type I IFN, plays a critical role in the immunopathogenesis of systemic lupus erythematosus (SLE). We have gained significant insights into this pathway over the past two decades, including a better understanding of the key mediators of inflammation upstream and downstream of type I IFN. This has led to the identification of multiple potential targets for the treatment of SLE, for which a significant unmet need remains due to the failure of many patients to adequately respond to standard-of-care medications. Unfortunately, most new therapies in SLE have disappointed in preclinical or clinical trials to date, including a number that target type I IFN. Nevertheless, several IFN-directed therapies aimed at specific steps within this immunologic pathway have recently shown promise, and additional agents are in the treatment pipeline. In this review, we focus on the results of key therapeutic studies targeting the type I IFN pathway and discuss the future state of IFN-blockade in SLE.

A promising approach to targeting type 1 IFN in systemic lupus erythematosus

Despite advances in understanding systemic lupus erythematosus (SLE) pathogenesis, most clinical trials of new targeted therapies have been met with disappointment. The type I IFN pathway is believed to play an important role in SLE, and the proposed involvement of this pathway helps explain the frustration behind the failure at targeting either IFN-α or the type 1 IFN receptor itself. In this issue of the JCI, Furie et al. report on an intriguing phase 1b study that demonstrates an approach for inhibiting this pathway in the skin using an mAB (BIIB059) that targets the blood DC antigen 2 (BDCA-2) receptor on plasmacytoid DCs (pDCs). BIIB059 decreased IFN expression and improved cutaneous lupus disease activity, with a favorable safety profile. Whether or not this strategy will be effective in managing SLE in other organs remains unanswered. However, these results suggest that closing the door on targeting the type 1 IFN pathway in SLE may be premature and highlight the emerging question of whether an organ-specific approach toward lupus trials and treatment should be the wave of the future.

Current challenges in the development of new treatments for lupus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with a considerable impact on patients' quality of life. Despite the plethora of clinical trials for SLE since the turn of the millennium, only one new treatment has been approved for the condition, and the overall pace of successful drug development remains slow. Nevertheless, the myriad of clinical studies has yielded insights that have informed and refined our understanding of eligibility criteria, outcome measures and trial design in SLE. In this review, we highlight the achievements of clinical trials as well as the major pitfalls that have been identified in drug development for SLE and, in doing so, identify areas where collaboration and consensus will be important to facilitate progress.

Development and Validation of a Novel Evidence-Based Lupus Multivariable Outcome Score for Clinical Trials

OBJECTIVE

Trials of new systemic lupus erythematosus (SLE) treatments are hampered by the lack of effective outcome measures. To address this, we developed a novel Lupus Multivariable Outcome Score (LuMOS) and assessed its performance using data from 2 randomized controlled trials of belimumab in patients with SLE.

METHODS

The LuMOS formula was developed by analyzing raw data from 2 pivotal trials, the Study of Belimumab in Subjects with SLE 52-week (BLISS-52) and 76-week (BLISS-76) trials, which are the basis for approval of belimumab. Using the BLISS-76 trial data as the learning data set, we carried out multivariable logistic regression analyses to optimize discrimination of outcomes between patients treated with 10 mg/kg belimumab and patients receiving placebo over the first 52 weeks of follow-up. In addition, the performance of LuMOS was assessed using an independent validation data set from the BLISS-52 trial.

RESULTS

The LuMOS model incorporated the following response criteria: a ≥4-point reduction on the Safety of Estrogens in Lupus Erythematosus National Assessment version of the SLE Disease Activity Index, an increase in C4 levels, a decrease in anti-double-stranded DNA titers, and changes in the British Isles Lupus Assessment Group scores for organ system manifestations (no worsening in renal components, and improvements in mucocutaneous components). A decrease in the prednisone dose and increase in C3 levels had very minor impacts on the total LuMOS score. In all analyses of the BLISS-76 and BLISS-52 trial data sets, the mean LuMOS scores were significantly higher (P < 0.0001) in patients treated with 1 mg or 10 mg belimumab compared to placebo. In contrast to the performance of the SLE Responder Index 4 (SRI-4), the LuMOS revealed significant differences between the active treatment group (1 mg belimumab in the BLISS-76 cohort) and placebo group. The effect sizes were significantly much higher with the LuMOS than with the SRI-4.

CONCLUSION

The evidenced-based LuMOS outcome scoring system, developed with data from the BLISS-76 trial of belimumab in patients with SLE and validated with data from the BLISS-52 trial, exhibits a superior capacity to discriminate responders from nonresponders when compared to the SRI-4. Use of the LuMOS may improve the efficiency and power of analyses in future lupus trials.