The nosology of systemic sclerosis: how lessons from the past offer new challenges in reframing an idiopathic rheumatological disorder

Emerging cellular and immunotherapies for systemic sclerosis: from mesenchymal stromal cells to CAR-T cells and vaccine-based approaches

PURPOSE OF REVIEW

Although two targeted therapies have received recent approval for systemic sclerosis (SSc)-associated interstitial lung disease, they do not show major disease-modifying activity, highlighting the need for novel therapies and innovative paradigms. To that end, cellular therapies may represent a new opportunity for the treatment of SSc. The purpose of this review is to provide an up-to-date overview of emerging cell-based disease-modifying therapies in SSc.

RECENT FINDINGS

Initial small studies in patients with severe refractory systemic lupus erythematosus (SLE) using engineered regulatory cells show promising results. CD19-directed CAR-T have shown promising results in one case report of refractory diffuse cutaneous SSc patients. T cells engineered to express a chimeric autoantibody receptor (CAAR-T cells) may be even more relevant via the specific elimination of auto-reactive B cells. Targeting pro-fibrotic or senescence-related pathways may also constitute promising approaches in SSc.

SUMMARY

Building on the classification of the clinical phenotype and prediction of clinical trajectory based on individual patients' autoantigen and/or autoantibody profile, cellular therapies targeting the same autoantigen or related autoreactive cells may represent an unprecedented opportunity to implement personalized medicine in SSc.

Beyond very early systemic sclerosis: deciphering pre‑scleroderma and its trajectories to open new avenues for preventive medicine

The identification of individuals with systemic sclerosis in an oligosymptomatic phase preceding the very early manifestations of the disease represents a challenge in the search for a new window of opportunity in systemic sclerosis. This phase could be identified in a clinical scenario as the pre-scleroderma phase, in which the disease would still be far from systemic sclerosis-related fibrotic or irreversible manifestations in skin or organs. In this Personal View, we discuss parameters and candidate definitions for a conceptual framework of pre-scleroderma, from the identification of populations at risk to autoantibodies and their potential functional activities. We discuss how this new paradigm of pre-scleroderma could represent a game-changing approach in the management of systemic sclerosis, allowing the treatment of patients at high risk of organ involvement or skin fibrosis before such events occur.

Cutaneous Manifestations, Clinical Characteristics, and Prognosis of Patients With Systemic Sclerosis Sine Scleroderma: Data From the International EUSTAR Database

Importance

Systemic sclerosis (SSc) sine scleroderma (ssSSc) is a subset of SSc defined by the absence of skin fibrosis. Little is known about the natural history and skin manifestations among patients with ssSSc.

Objective

To characterize the clinical phenotype of patients with ssSSc compared with patients with limited cutaneous SSc (lcSSc) and diffuse cutaneous SSc (dcSSc) within the EUSTAR database.

Design, Setting, and Participants

This longitudinal observational cohort study based on the international EUSTAR database included all patients fulfilling the classification criteria for SSc assessed by the modified Rodnan Skin score (mRSS) at inclusion and with at least 1 follow-up visit; ssSSc was defined by the absence of skin fibrosis (mRSS = 0 and no sclerodactyly) at all available visits. Data extraction was performed in November 2020, and data analysis was performed from April 2021 to April 2023.

Main Outcomes and Measures

Main outcomes were survival and skin manifestations (onset of skin fibrosis, digital ulcers, telangiectasias, puffy fingers).

Results

Among the 4263 patients fulfilling the inclusion criteria, 376 (8.8%) were classified as having ssSSc (mean [SD] age, 55.3 [13.9] years; 345 [91.8%] were female). At last available visit, in comparison with 708 patients with lcSSc and 708 patients with dcSSc with the same disease duration, patients with ssSSc had a lower prevalence of previous or current digital ulcers (28.2% vs 53.1% in lcSSc; P < .001; and 68.3% in dcSSc; P < .001) and puffy fingers (63.8% vs 82.4% in lcSSc; P < .001; and 87.6% in dcSSc; P < .001). By contrast, the prevalence of interstitial lung disease was similar in ssSSc and lcSSc (49.8% and 57.1%; P = .03) but significantly higher in dcSSc (75.0%; P < .001). Skin telangiectasias were associated with diastolic dysfunction in patients with ssSSc (odds ratio, 4.778; 95% CI, 2.060-11.081; P < .001). The only independent factor for the onset of skin fibrosis in ssSSc was the positivity for anti-Scl-70 antibodies (odds ratio, 3.078; 95% CI, 1.227-7.725; P = .02). Survival rate was higher in patients with ssSSc (92.4%) compared with lcSSc (69.4%; P = .06) and dcSSc (55.5%; P < .001) after up to 15 years of follow-up.

Conclusions and Relevance

Systemic sclerosis sine scleroderma should not be neglected considering the high prevalence of interstitial lung disease (>40%) and SSc renal crisis (almost 3%). Patients with ssSSc had a higher survival than other subsets. Dermatologists should be aware that cutaneous findings in this subgroup may be associated with internal organ dysfunction. In particular, skin telangiectasias in ssSSc were associated with diastolic heart dysfunction.

Differentially expressed genes in systemic sclerosis: Towards predictive medicine with new molecular tools for clinicians

Systemic sclerosis (SSc) is a rare and chronic autoimmune disease characterized by a pathogenic triad of immune dysregulation, vasculopathy, and progressive fibrosis. Clinical tools commonly used to assess patients, such as the modified Rodnan skin score, difference between limited or diffuse forms of skin involvement, presence of lung, heart or kidney involvement, or of various autoantibodies, are important prognostic factors, but still fail to reflect the large heterogeneity of the disease. SSc treatment options are diverse, ranging from conventional drugs to autologous hematopoietic stem cell transplantation, and predicting response is challenging. Genome-wide technologies, such as high throughput microarray analyses and RNA sequencing, allow accurate, unbiased, and broad assessment of alterations in expression levels of multiple genes. In recent years, many studies have shown robust changes in the gene expression profiles of SSc patients compared to healthy controls, mainly in skin tissues and peripheral blood cells. The objective analysis of molecular patterns in SSc is a powerful tool that can further classify SSc patients with similar clinical phenotypes and help predict response to therapy. In this review, we describe the journey from the first discovery of differentially expressed genes to the identification of enriched pathways and intrinsic subsets identified in SSc, using machine learning algorithms. Finally, we discuss the use of these new tools to predict the efficacy of various treatments, including stem cell transplantation. We suggest that the use of RNA gene expression-based classifications according to molecular subsets may bring us one step closer to precision medicine in Systemic Sclerosis.

Domains and outcome measures for the assessment of limited cutaneous systemic sclerosis: an international collaborative scoping review

OBJECTIVES

The aim of this study was to comprehensively identify instruments within relevant domains employed to assess lcSSc since the endorsement of its consensus definition in 1988. The overall objective is to inform the creation of a Combined Response Index for Scleroderma Trials Assessing lcSSc (CRISTAL).

METHODS

MEDLINE and Embase were searched using terms selected to comprehensively retrieve titles and abstracts mentioning both lcSSc and dcSSc, along with those only mentioning lcSSc, SSc sine scleroderma, limited SSc and/or CREST/CRST. Because our initial assessment of the literature revealed that very few studies included only lcSSc subjects, we also assessed literature that included both cutaneous subsets. A total of 3964 titles and abstracts were screened by two reviewers, and 270 articles were selected for data extraction.

RESULTS

We identified 27 domains encompassing 459 instruments. Instruments from 'Skin involvement', 'Pulmonary involvement' and 'Health-related quality of life and general functioning' were the most frequently retrieved. Among the 15 most represented instruments announced as primary end points in efficacy or effectiveness studies, 7 were clinician-reported outcomes (ROs), 7 were patient ROs, and one was a performance outcome (6 min-walk test). The mean proportion of lcSSc patients in studies of lcSSc, including studies that mention both lcSSc and dcSSc, was 56.4%, demonstrating that this subset is underrepresented in the literature, given that the prevalence of lcSSc ranges from 60% to 80% in national registries and international cohorts.

CONCLUSION

This scoping literature review provides a comprehensive identification of domains and outcomes used to assess lcSSc. Our results also highlight that lcSSc is underrepresented in the literature.

Current global perspectives on silicosis-Convergence of old and newly emergent hazards

Silicosis not a disease of the past. It is an irreversible, fibrotic lung disease specifically caused by exposure to respirable crystalline silica (RCS) dust. Over 20,000 incident cases of silicosis were identified in 2017 and millions of workers continue to be exposed to RCS. Identified case numbers are however a substantial underestimation due to deficiencies in reporting systems and occupational respiratory health surveillance programmes in many countries. Insecure workers, immigrants and workers in small businesses are at particular risk of more intense RCS exposure. Much of the focus of research and prevention activities has been on the mining sector. Hazardous RCS exposure however occurs in a wide range of occupational setting which receive less attention, in particular the construction industry. Recent outbreaks of silicosis associated with the fabrication of domestic kitchen benchtops from high‐silica content artificial stone have been particularly notable because of the young age of affected workers, short duration of RCS exposure and often rapid disease progression. Developments in nanotechnology and hydraulic fracking provide further examples of how rapid changes in technology and industrial processes require governments to maintain constant vigilance to identify and control potential sources of RCS exposure. Despite countries around the world dealing with similar issues related to RCS exposure, there is an absence of sustained global public health response including lack of consensus of an occupational exposure limit that would provide protection to workers. Although there are complex challenges, global elimination of silicosis must remain the goal.

See relatedEditorial

[Systemic sclerosis-related interstitial lung disease: Diagnostic and therapeutic strategy in the light of recent clinical trials]

Systemic sclerosis (SSc) is an autoimmune disease associated to fibrotic manifestations. Interstitial lung disease (SSc-ILD), one of the main fibrotic features of SSc, is the first cause of SSc-related death. The management of SSc-ILD has recently benefited from the results of key randomised controlled trials. French authorities have approved Nintedanib for the treatment of SSc-ILD, and tocilizumab has recently been approved by the Food and Drug Administration (FDA) in the United-States (US). These recent approvals challenge the management of this fibrotic manifestation of SSc. This narrative literature review, at the crossroad of internal medicine and pulmonology, discusses what could be an up-to date approach, in terms of diagnostic and therapeutic strategies for SSc-ILD, in the light of the results from recent clinical trials.

Symptom experience of limited cutaneous systemic sclerosis from the Patients' perspective: A qualitative study✰,✰✰,★,★★

OBJECTIVES

Limited cutaneous systemic sclerosis (lcSSc) is the largest subgroup of people with SSc, but little is known about symptom experience from the patients' perspective. This study aimed to comprehensively identify domains and symptoms reported as bothersome by patients with lcSSc and to analyze themes and sub-themes capturing symptom experience in this population.

METHODS

Focus groups of patients with lcSSc were conducted using a structured guide. Patients were recruited based on an a priori purposive framework to include men and women with SSc. Focus groups were recorded, transcribed, anonymized, and analyzed using the RADaR technique (rigorous and accelerated data reduction) combined with iterative, deductive and inductive approaches.

RESULTS

Four 2-hour Focus groups comprising participants with lcSSc were conducted (N = 26). Ninety-four symptoms were identified with 22 domains. Symptoms from the following domains were mentioned in all Focus groups: skin, musculoskeletal (MSK), cardiac, pulmonary, gastro-intestinal (GI) manifestations, fatigue, sleep, Raynaud's phenomenon (RP), pain, and digital ulcers. The three most cited domains in a pre-meeting survey were GI, RP and MSK. Seven themes defining symptom experience were identified: difficulty attributing symptoms to this complex systemic disease, influence of symptom temporality, impairment of emotional well-being, limitations in functioning (including several sub-themes of functioning), survival, symptoms management and uncertainty.

CONCLUSION

This study comprehensively identified domains and symptoms considered bothersome from the perspective of patients with lcSSc and summarized patient experience of lcSSc-related symptoms. This study is the first step in the design of a future combined response index dedicated to lcSSc that could foster specific research on this subpopulation of patients.

Therapeutic Approaches to Systemic Sclerosis: Recent Approvals and Future Candidate Therapies

Systemic sclerosis is the rheumatic disease with the highest individual mortality. The severity of the disease is determined by the extent of fibrotic changes to cutaneous and internal organ tissues, the most life-threatening visceral manifestations being interstitial lung disease, SSc-associated-pulmonary arterial hypertension and myocardial involvement. The heterogeneity of the disease has initially hindered the design of successful clinical trials, but considerations on classification criteria have improved patient selection in trials, allowing the identification of more homogeneous groups of patients based on progressive visceral manifestations or the extent of skin involvement with a focus of patients with early disease. Two major subsets of systemic sclerosis are classically described: limited cutaneous systemic sclerosis characterized by distal skin fibrosis and the diffuse subset with distal and proximal skin thickening. Beyond this dichotomic subgrouping of systemic sclerosis, new phenotypic considerations based on antibody subtypes have provided a better understanding of the heterogeneity of the disease, anti-Scl70 antibodies being associated with progressive interstitial lung disease regardless of cutaneous involvement. Two targeted therapies, tocilizumab (a monoclonal antibody targeting interleukin-6 receptors (IL-6R)) and nintedanib (a tyrosine kinase inhibitor), have recently been approved by the American Food & Drug Administration to limit the decline of lung function in patients with SSc-associated interstitial lung disease, demonstrating that such better understanding of the disease pathogenesis with the identification of key targets can lead to therapeutic advances in the management of some visceral manifestations of the disease. This review will provide a brief overview of the pathogenesis of SSc and will present a selection of therapies recently approved or evaluated in this context. Therapies evaluated and approved in SSc-ILD will be emphasized and a review of recent phase II trials in diffuse cutaneous systemic sclerosis will be proposed. We will also discuss selected therapeutic pathways currently under investigation in systemic sclerosis that still lack clinical data in this context but that may show promising results in the future based on preclinical data.

Clinical characteristics, visceral involvement, and mortality in at-risk or early diffuse systemic sclerosis: a longitudinal analysis of an observational prospective multicenter US cohort

BACKGROUND

Early diffuse cutaneous systemic sclerosis (dcSSc) has the highest case fatality among rheumatic diseases. We report baseline characteristics, current immunosuppressive therapies, progression of skin and internal organ involvement, and mortality in a multicenter prospective cohort from the United States (US) of America.

METHODS

We performed a longitudinal analysis of participants from 12 US centers, from April 2012 to July 2020. All participants had early dcSSc or were at-risk for dcSSc, with ≤2 years since the first non-Raynaud's phenomenon (RP) symptom.

RESULTS

Three hundred one patients were included with a baseline median disease duration of 1.2 years since RP and a mean modified skin score of 21.1 units. At baseline, 263 (87.3%) had definite dcSSc and 38 (12.7%) were classified as at-risk; 112 (49.6%) patients were positive for anti-RNA polymerase III antibodies. The median follow-up duration was 24.5 months (IQR = 10.3-40.7 months). One hundred ninety (63.1%) participants were treated with an immunosuppressive therapy, of which mycophenolate mofetil was most used at baseline and follow-up. Of 38 who were classified as at-risk at baseline, 27 (71%) went on to develop dcSSc; these patients were characterized by higher baseline mean HAQ-DI (0.8 versus 0.4, p = 0.05) and higher baseline mRSS (8.8 versus 4.4, p < 0.01) in comparison with those who remained as limited cutaneous SSc. In the overall cohort, 48 participants (21.1%) had clinically significant worsening of skin fibrosis, mainly occurring in the first year of follow-up; 41 (23.3%) had an absolute forced vital capacity decline of ≥10%. Twenty participants (6.6%) died, of which 18 died in the first 3 years of follow-up. Cardiac involvement (33.3%), gastrointestinal dysmotility (22.2%), and progressive interstitial lung disease (ILD) (16.7%) were the main causes of death.

CONCLUSION

This US cohort highlights the management of early SSc in the current era, demonstrating progression of skin and lung involvement despite immunosuppressive therapy and high mortality due to cardiac involvement.

Novel classifications for systemic sclerosis: challenging historical subsets to unlock new doors

PURPOSE OF REVIEW

Systemic sclerosis (SSc) is a severe rheumatic disease characterized by a considerable heterogeneity in clinical presentations and pathophysiological mechanisms. This variability has a substantial impact on morbidity and mortality and limits the generalizability of clinical trial results. This review aims to highlight recent studies that have proposed new innovative approaches to decipher this heterogeneity, in particular, by attempting to optimize disease classification.

RECENT FINDINGS

The historical dichotomy limited/diffuse subsets based on cutaneous involvement has been challenged by studies highlighting an underestimated heterogeneity between these two subtypes and showing that presence of organ damage and autoantibody profiles markedly influenced survival beyond skin extension. Advanced computational methods using unsupervised machine learning analyses of clinical variables and/or high-throughput omics technologies, clinical variables trajectories modelling overtime or radiomics have provided significant insights on key pathogenic processes that could help defining new subgroups beyond the diffuse/limited subsets.

SUMMARY

We can anticipate that a future classification of SSc patients will integrate innovative approaches encompassing clinical phenotypes, variables trajectories, serological features and innovative omics molecular signatures. It nevertheless seems crucial to also pursue the implementation and standardization of readily available and easy to use tools that can be used in clinical practice.

Domains and outcome measures for the assessment of limited cutaneous systemic sclerosis: a scoping review protocol

INTRODUCTION

Limited cutaneous systemic sclerosis (lcSSc) is the most frequent subset of systemic sclerosis. Despite this, lcSSc is not the major focus of clinical studies. The lack of interventional studies in lcSSc is due, in part, to a paucity of relevant outcome measures to effectively evaluate this subset. A combined response index dedicated to lcSSc would facilitate development of well-designed trials and approval of new drugs. The objective of this scoping review is to perform a broad and comprehensive identification of the outcome measures (core set items) within relevant domains, which have been used so far to assess lcSSc.

METHODS AND ANALYSIS

The planned scoping review will be based on the approach proposed by Arksey et al and further developed by Levac et al. Development and reporting will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-Extension for Scoping Reviews checklist and guidelines. The development of the search strategy was guided by the concepts of domains and outcomes based on the Outcome Measures in Rheumatology approach and by the different names and definitions of SSc, with a specific emphasis on their occurrence in clinical trial studies. Two databases will be searched: MEDLINE and Embase. Studies in English, published from the year 1988 onwards, will be included, since 1988 corresponds to the publication of LeRoy's first consensus definition of lcSSc. Data will be extracted and analysed using a standardised charting tool.

ETHICS AND DISSEMINATION

No ethical approval is required for this study. The results will be submitted to an international peer-reviewed journal and scientific conferences, informing the discussion on which items should be included in a combined response index dedicated to lcSSc (the CRISTAL project: Combined Response Index for Scleroderma Trial Assessing lcSSc).

Considerations for a combined index for limited cutaneous systemic sclerosis to support drug development and improve outcomes

Systemic sclerosis (SSc; systemic scleroderma) is characterized by a heterogeneous range of clinical manifestations. SSc is classified into limited cutaneous SSc (lcSSc) and diffuse cutaneous subgroups (dcSSc) based on the extent of skin involvement. Randomized controlled trials in scleroderma have mainly focused on dcSSc partly because the measurement of skin involvement, critical for evaluating a therapeutic intervention is more dynamic in this subset. Nonetheless, lcSSc, the most common cutaneous subset (about 2/3), is also associated with significant morbidity and detrimental impact on health-related quality of life. The lack of interventional studies in lcSSc is partly due to a lack of relevant outcome measures to evaluate this subgroup. Combining several clinically meaningful outcomes selected specifically for lcSSc may improve representativeness in clinical trials and responsiveness of outcomes measured in randomized controlled trials. A composite index dedicated to lcSSc combining such relevant outcomes could advance clinical trial development for lcSSc by providing the opportunity to test and select among candidate drugs that could act as disease-modifying treatments for this neglected subgroup of SSc. This proposed index would include items selected by expert physicians and patients with lcSSc across domains grounded in the lived experience of lcSSc. This article reviews the reasons behind the relative neglect of lcSSc, discusses the current state of outcome measures for lcSSc, identifies challenges, and proposes a roadmap for a combined lcSSc-specific treatment response index.