Emerging drugs for the treatment of scleroderma: a review of recent phase 2 and 3 trials

Critical Analysis of Cytoplasmic Progression of Inflammatory Signaling Suggests Potential Pharmacologic Targets for Wound Healing and Fibrotic Disorders

Successful skin wound healing is dependent on an interplay between epidermal keratinocytes and dermal fibroblasts as they react to local extracellular factors (DAMPs, PAMPs, cytokines, etc.) surveyed from that environment by numerous membrane receptors (e.g., TLRs, cytokine receptors, etc.). In turn, those receptors are the start of a cytoplasmic signaling pathway where balance is key to effective healing and, as needed, cell and matrix regeneration. When directed through NF-κB, these signaling routes lead to transient responses to the benefit of initiating immune cell recruitment, cell replication, local chemokine and cytokine production, and matrix protein synthesis. The converse can also occur, where ongoing canonical NF-κB activation leads to chronic, hyper-responsive states. Here, we assess three key players, TAK1, TNFAIP3, and TNIP1, in cytoplasmic regulation of NF-κB activation, which, because of their distinctive and yet inter-related functions, either promote or limit that activation. Their balanced function is integral to successful wound healing, given their significant control over the expression of inflammation-, fibrosis-, and matrix remodeling-associated genes. Intriguingly, these three proteins have also been emphasized in dysregulated NF-κB signaling central to systemic sclerosis (SSc). Notably, diffuse SSc shares some tissue features similar to an excessive inflammatory/fibrotic wound response without eventual resolution. Taking a cue from certain instances of aberrant wound healing and SSc having some shared aspects, e.g., chronic inflammation and fibrosis, this review looks for the first time, to our knowledge, at what those pathologies might have in common regarding the cytoplasmic progression of NF-κB-mediated signaling. Additionally, while TAK1, TNFAIP3, and TNIP1 are often investigated and reported on individually, we propose them here as three proteins whose consequences of function are very highly interconnected at the signaling focus of NF-κB. We thus highlight the emerging promise for the eventual clinical benefit derived from an improved understanding of these integral signal progression modulators. Depending on the protein, its indirect or direct pharmacological regulation has been reported. Current findings support further intensive studies of these points in NF-κB regulation both for their basic function in healthy cells as well as with the goal of targeting them for translational benefit in multiple cutaneous wound healing situations, whether stemming from acute injury or a dysregulated inflammatory/fibrotic response.

A Phase II study of avenciguat, a novel soluble guanylate cyclase activator, in patients with systemic sclerosis: Study design and rationale of the VITALISScE™ study

Introduction

Systemic sclerosis is a rare autoimmune connective tissue disease characterised by (1) microvasculopathy; (2) immune dysregulation; and (3) progressive fibrosis of the skin and internal organs. Soluble guanylate cyclase plays an important role in maintaining vascular and immunological homeostasis and preventing organ fibrosis. Pharmacological modulation of soluble guanylate cyclase with soluble guanylate cyclase stimulators has shown anti-inflammatory and antifibrotic effects in animal models of systemic sclerosis, with a trend towards clinical efficacy in a Phase II study (RISE-SSc). However, the efficacy of soluble guanylate cyclase stimulators may be reduced under conditions of hypoxia and oxidative stress. Soluble guanylate cyclase activators have the potential to overcome this limitation. This paper describes the study design of VITALISScE™, a Phase II clinical trial assessing the efficacy, safety and tolerability of avenciguat, a novel soluble guanylate cyclase activator in patients with active systemic sclerosis at risk of progression.

Methods

The VITALISScE™ study (NCT05559580) is evaluating the action of avenciguat on all three aspects of systemic sclerosis pathophysiology. The primary endpoint is the rate of decline in forced vital capacity (mL) over 48 weeks. Secondary endpoints include absolute change from baseline at Week 48 in modified Rodnan skin score, Health Assessment Questionnaire Disability Index score and the proportion of responders based on the revised Composite Response Index in Systemic Sclerosis. Additional endpoints include a composite assessment of Raynaud's phenomenon, digital ulcer burden, functional outcomes and quality of life, safety, pharmacokinetics, and biomarkers associated with systemic sclerosis and the mechanism of action of avenciguat.

Results

VITALISScE™ is an ongoing, multicentre (180 sites; 38 countries), placebo-controlled, double-blind, parallel-group, Phase II clinical study. Recruitment is currently ongoing.

Conclusions

The VITALISScE™ study is assessing the efficacy, safety and tolerability of avenciguat in patients with active systemic sclerosis at risk of progression. Results will inform further development of avenciguat.

Trial Registration

VITALISScE™; EU CT No. 2022-500332-11-00; Clinicaltrials.gov: NCT05559580 (https://www.clinicaltrials.gov/study/NCT05559580).

Design of CONQUEST, a novel, randomized, placebo-controlled, Phase 2b platform clinical trial to investigate new treatments for patients with early active systemic sclerosis with interstitial lung disease

Objective

Safe, effective therapies are urgently needed for patients with systemic sclerosis. However, clinical trial recruitment is challenging given the limited number of people with systemic sclerosis and further restrictions imposed by eligibility criteria. Innovative approaches are needed to accelerate development of new therapies. This article describes the rationale and trial design for CONQUEST (NCT06195072), a novel platform clinical trial sponsored by the Scleroderma Research Foundation, a not-for-profit organization.

Methods

CONQUEST is a multicentre, double-blind, randomized, placebo-controlled, Phase 2b platform trial evaluating the efficacy, safety and pharmacodynamics of multiple investigational products to treat early active systemic sclerosis with interstitial lung disease versus placebo. The primary objective is to evaluate change from baseline to Week 52 in forced vital capacity (mL). Secondary objectives include evaluating changes from baseline to Week 52 in high-resolution computed-tomography-assessed lung involvement and dyspnoea, and overall treatment response (measured using the revised composite response index in diffuse systemic sclerosis score in participants with diffuse cutaneous systemic sclerosis).

Results

Patients will be enrolled across more than 150 centres in over 25 countries. Recruitment started on 15 April 2024.

Conclusion

As the first platform clinical trial in the rheumatology field, CONQUEST aims to meaningfully accelerate the development of new therapies for early active systemic sclerosis. Depending on regimen-specific results, trial data could be used to plan and design a Phase 3 trial or may be used alone or together with another registrational trial to establish substantial evidence of effectiveness and safety. The first molecules to be studied, amlitelimab and nerandomilast, both have a strong scientific rationale to modify underlying disease processes in systemic sclerosis.

ClinicalTrialsgov

Platform Clinical Study for Conquering Scleroderma (CONQUEST); NCT06195072; https://www.clinicaltrials.gov/study/NCT06195072.

Emerging diagnostic and therapeutic challenges for skin fibrosis in systemic sclerosis

Systemic sclerosis (also called scleroderma, SSc) is a chronic autoimmune disorder characterized by excessive collagen deposition leading to skin fibrosis and various internal organ manifestations. The emergent diagnostics and therapeutic strategies for scleroderma focus on early detection and targeted interventions to improve patient outcomes and quality of life. Diagnostics for SSc have evolved significantly in recent years, driven by advancements in serological markers and imaging techniques. Autoantibody profiling, especially antinuclear antibodies (ANA) and specific scleroderma-associated autoantibodies, aids in identifying subsets of scleroderma and predicting disease progression. Furthermore, novel imaging modalities, such as high-frequency ultrasonography and optical coherence tomography, enable early detection of skin fibrosis and internal organ involvement, enhancing the diagnostic precision and allowing for tailored management. Therapeutic strategies for SSc are multifaceted, targeting immune dysregulation, vascular abnormalities, and fibrotic processes. Emerging biologic agents have shown promise in clinical trials, including monoclonal antibodies directed against key cytokines involved in fibrosis, such as transforming growth factor-β (TGF-β) and interleukin-6 (IL-6). Additionally, small-molecule inhibitors that disrupt fibrotic pathways, like tyrosine kinase inhibitors, have exhibited potential in limiting collagen deposition and preventing disease progression. Stem cell therapy, cell ablation and gene editing techniques hold great potential in regenerating damaged tissue and halting fibrotic processes. Early intervention remains crucial in managing SSc, as irreversible tissue damage often occurs in advanced stages. Novel diagnostic methods, such as biomarkers and gene expression profiling, are being explored to identify individuals at high risk for developing progressive severe disease and intervene proactively. Furthermore, patient-tailored therapeutic approaches, employing a combination of immunosuppressive agents and targeted anti-fibrotic therapies, are being investigated to improve treatment efficacy while minimizing adverse effects. The emergent diagnostics and therapeutic strategies in scleroderma are transforming the management of this challenging disease. Nevertheless, ongoing research and clinical trials are needed to optimize the efficacy and safety of these novel approaches in the complex and diverse spectrum of SSc manifestations.

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.

Improving outcomes in scleroderma: recent progress of cell-based therapies

Scleroderma is a rare, potentially fatal, clinically heterogeneous, systemic autoimmune connective tissue disorder that is characterized by progressive fibrosis of the skin and visceral organs, vasculopathy and immune dysregulation. The more severe form of the disease, diffuse cutaneous scleroderma (dcSSc), has no cure and limited treatment options. Haematopoietic stem cell transplantation has emerged as a potentially disease-modifying treatment but faces challenges such as toxicity associated with fully myeloablative conditioning and recurrence of autoimmunity. Novel cell therapies-such as mesenchymal stem cells, chimeric antigen receptor-based therapy, tolerogenic dendritic cells and facilitating cells-that may restore self-tolerance with more favourable safety and tolerability profiles are being explored for the treatment of dcSSc and other autoimmune diseases. This narrative review examines these evolving cell therapies.

Pulmonary 5-HT2B receptor expression in fibrotic interstitial lung diseases

Pulmonary fibrosis is a severe condition in interstitial lung diseases (ILD) such as idiopathic pulmonary fibrosis (IPF) and systemic sclerosis-ILD, where the underlying mechanism is not well defined and with no curative treatments available. Serotonin (5-HT) signaling via the 5-HT_2B receptor has been recognized as a promising preclinical target for fibrosis. Despite this, the involvement of the 5-HT_2B receptor in fibrotic ILD is widely unexplored. This work highlights the spatial pulmonary distribution of the 5-HT_2B receptor in patients with IPF and systemic sclerosis-ILD. We show that the 5-HT_2B receptor is located in typical pathological structures e.g. honeycomb cysts and weakly in fibroblast foci. Together with immunohistochemistry and immunofluorescence stainings of patient derived distal lung tissues, we identified cell targets for 5-HT_2B receptor interference in type II alveolar epithelial cells, endothelial cells and M2 macrophages. Our results emphasize the role of 5-HT_2B receptor as a target in lung fibrosis, warranting further consideration in targeting fibrotic ILDs.

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.

New promising drugs for the treatment of systemic sclerosis: pathogenic considerations, enhanced classifications, and personalized medicine

Introduction: Systemic sclerosis (SSc), also known as scleroderma, is a complex orphan disease characterized by early inflammatory features, vascular hyper-reactivity, and fibrosis of the skin and internal organs. Although substantial progress has been made in the understanding of the pathogenesis of SSc, there is still no disease-modifying drug that could significantly impact the natural history of the disease.Areas covered: This review discusses the rationale, preclinical evidence, first clinical eevidence,and pending issues concerning new promising therapeutic options that are under investigation in SSc. The search strategy was based on PubMed database and clinical trial.gov, highlighting recent key pathogenic aspects and phase I or II trials of investigational drugs in SSc.Expert opinion: The identification of new molecular entities that potentially impact inflammation and fibrosis may constitute promising options for a disease modifying-agent in SSc. The early combinations of antifibrotic drugs (such as pirfenidone) with immunomodulatory agents (such as mycophenolate mofetil) may also participate to achieve such a goal. A more refined stratification of patients, based on clinical features, molecular signatures, and identification of subpopulations with distinct clinical trajectories, may also improve management strategies in the future.