Multiplex serum protein analysis reveals potential mechanisms and markers of response to hyperimmune caprine serum in systemic sclerosis

Cellular and Molecular Diversity in Scleroderma

With the increasing armamentarium of high-throughput tools available at manageable cost, it is attractive and informative to determine the molecular underpinnings of patient heterogeneity in systemic sclerosis (SSc). Given the highly variable clinical outcomes of patients labelled with the same diagnosis, unravelling the cellular and molecular basis of disease heterogeneity will be crucial to predicting disease risk, stratifying management and ultimately informing a patient-centered precision medicine approach. Herein, we summarise the findings of the past several years in the fields of genomics, transcriptomics, and proteomics that contribute to unraveling the cellular and molecular heterogeneity of SSc. Expansion of these findings and their routine integration with quantitative analysis of histopathology and imaging studies into clinical care promise to inform a scientifically driven patient-centred personalized medicine approach to SSc in the near future.

Scope and Consistency of Outcomes Reported in Trials of Patients With Systemic Sclerosis

OBJECTIVE

The core outcome set for trials in systemic sclerosis (SSc) was developed in 2008 and comprises 11 domains and 31 measures, leading to the development of the Combined Response Index in Diffuse Cutaneous Systemic Sclerosis (CRISS). We aimed to assess the scope and consistency of outcomes reported in trials of SSc and the uptake of this core set and the CRISS.

METHODS

Medline, the Cochrane Central Register of Controlled Trials, Embase, and ClinicalTrials.gov were searched to identify randomized trials published from January 1, 2000 to April 29, 2018 in adults with limited or diffuse SSc. Outcomes and measures were recorded for each trial, classified into domains and the frequency of outcomes before after publication of the publication of the core set calculated.

RESULTS

From 152 trials, 4,193 outcomes were classified into 84 domains. The 3 most common domains were health-related quality of life (HRQoL) and function (59%, 130 measures), skin (47%, 59 measures), and pulmonary (45%, 168 measures). After the publication of the core outcome set, no trial reported the complete core set with adherence to each of the 11 domains, ranging from 6.1% to 54.4% and adherence to each of the 31 measures ranging from 0% to 48.1%. The 5 measures required for the CRISS were reported completely in 11% of trials.

CONCLUSION

Despite recognition that uniform acquisition and reporting of outcomes would enable a better evaluation of proposed SSc therapeutics, the outcome domains and measures reported in randomized trials in SSc remain very inconsistent, with little impact of the core outcome set.

News and failures from recent treatment trials in systemic sclerosis

There have been many recent trials in systemic sclerosis (SSc) that have explored treatment for skin or lung. Some have been encouraging, but there has also been disappointment reflecting potential limitations of treatment effect of study design. These trials are discussed and reviewed. Studies conducted in SSc are described and discussed with a focus on endpoint selection and trial design as well as potential mechanism of action and treatment effect. Studies have included very encouraging trials of interleukin 6 blockade, immunosuppression, and broad-spectrum tyrosine kinase inhibition. Other trials including recent studies of peroxisome proliferator-activated receptor agonists and specific intracellular signaling inhibitors such as imatinib or anti-transforming growth factor beta blocking strategies have been more disappointing. Trial design is improving, and overall, there are now almost positive trials using agents with great promise, and studies are also providing important biological insight into SSc. It is hoped that ongoing studies will further progress the field and move it toward better treatments for SSc that still represent a major unmet medical need.

Interleukin-6 and Related Proteins as Biomarkers in Systemic Sclerosis

The search for biomarkers in systemic sclerosis (SSc) is driven by a goal to stratify patients, identify potential subgroups for treatment, and help assess response to therapy. Emerging evidence indicates that interleukin-6 (IL-6) and some family members are key biomarkers involved in SSc pathogenesis and therefore suitable targets for therapy. Recent studies evaluating IL-6 and its canonical Janus kinase/signal transducers and activators of transcription downstream pathways in modulating fibrotic response and immune cell function suggest a pivotal role for IL-6 in SSc pathogenesis. Although the significance and effect of local tissue expression of IL-6 and its family members are less well established, high levels of circulating IL-6 may identify subgroups of patients with early-stage disease, particularly those at risk for progressive lung fibrosis. In addition, higher disease activity may portend poor prognostic outcome in terms of survival and skin disease. Longitudinal assessment of serum levels of IL-6 and its signaling associates may prove valuable in monitoring response to treatment. As an IL-6–dependent surrogate marker, C-reactive protein may assist cohort enrichment if targeted treatment for IL-6 demonstrates efficacy, especially in subgroups with high IL-6 levels. Although IL-6 appears to be a key factor in the hierarchy of the complex network of disease-associated molecules, the systemic or autocrine/paracrine manner in which IL-6 asserts its profibrotic effects—particularly its interaction with other key pathogenic factors in SSc—is unknown. Ongoing clinical trials will help to delineate the mechanisms of IL-6 in SSc pathogenesis and inform on the role of these biomarkers.