Long-Term Efficacy and Safety of Low-Dose Rituximab in Patients with Refractory Myasthenia Gravis

INTRODUCTION

Rituximab is a monoclonal chimeric antibody against CD20+ B cells. We aimed to assess the long-term efficacy and safety of CD20+ B cell-guided treatment with low-dose rituximab in refractory myasthenia gravis patients.

METHODS

Patients with refractory myasthenia gravis treated with rituximab for more than 2 years were included. Rituximab was administered when CD20+ B cells were greater than 1%. We analysed the efficacy of rituximab, treatment interval, side effects, prognosis, and treatment course.

RESULTS

A total of 22 patients were included. All patients received 2-12 doses of rituximab, and the median follow-up time was 48.5 months. The scores of the Myasthenia Gravis Activities of Daily Living and Myasthenia Gravis Composite were significantly lower than those at baseline (p < 0.05). MGFA-PIS was significantly improved in 21 (95.45%) patients and 14 (63.64%) patients have reached MGFA-PIS minimal manifestations. The average daily dose of prednisone and pyridostigmine bromide and the proportion of immunosuppressants were significantly lower (p < 0.05). Seven patients suffered from 14 worsenings. Eight patients terminated rituximab due to good efficacy. Most patients tolerated rituximab well, although 1 patient had opportunistic infection and hypogammaglobulinemia, 1 patient had an intracranial mass.

CONCLUSION

Long-term CD20+ B-cell-guided low-dose rituximab showed good efficacy and tolerance in patients with refractory myasthenia gravis.

Review of an Anti-CD20 Monoclonal Antibody for the Treatment of Autoimmune Diseases of the Skin

Biologic therapies targeting B-cells are emerging as an effective strategy to treat a variety of immune-mediated diseases. One of the most studied B-cell-targeted therapies is rituximab, an anti-CD20 monoclonal antibody that exemplifies B-cell depletion therapy and has served as the prototype for other anti-CD20 monoclonal antibodies and the development of biosimilars. While there are multiple studies on the use of rituximab in dermatology, a comprehensive review of rituximab therapy in autoimmune skin conditions is lacking. In this literature review, we summarize indications, treatment efficacy, and safety of rituximab among common autoimmune diseases of the skin: pemphigus vulgaris, cutaneous lupus erythematous, dermatomyositis, systemic sclerosis, thyroid dermopathy, autoimmune pemphigoid diseases, and cutaneous vasculitis diseases. Existing data on rituximab support the approach of rituximab, biosimilars, and newer B-cell-targeting therapies in immune-mediated cutaneous diseases. Overall, rituximab, which targets CD20, provides an effective alternative or concomitant option to traditional immunosuppressants in the management of various autoimmune diseases of the skin. Further studies are necessary to expand the understanding and possible utility of B-cell-targeted therapies among autoimmune skin diseases.

Autoinflammation and autoimmunity across rheumatic and musculoskeletal diseases

Most rheumatic and musculoskeletal diseases (RMDs) can be placed along a spectrum of disorders, with autoinflammatory diseases (including monogenic systemic autoinflammatory diseases) and autoimmune diseases (such as systemic lupus erythematosus and antiphospholipid syndrome) representing the two ends of this spectrum. However, although most autoinflammatory diseases are characterized by the activation of innate immunity and inflammasomes and classical autoimmunity typically involves adaptive immune responses, there is some overlap in the features of autoimmunity and autoinflammation in RMDs. Indeed, some 'mixed-pattern' diseases such as spondyloarthritis and some forms of rheumatoid arthritis can also be delineated. A better understanding of the pathogenic pathways of autoinflammation and autoimmunity in RMDs, as well as the preferential cytokine patterns observed in these diseases, could help us to design targeted treatment strategies.

Current and Emerging Drug Therapies for Connective Tissue Disease-Interstitial Lung Disease (CTD-ILD)

Interstitial lung disease (ILD) can be associated with all connective tissue diseases and is an important cause of morbidity and mortality. The management of connective tissue disease-interstitial lung disease (CTD-ILD) is challenging due substantial heterogeneity in disease behaviour and paucity of controlled clinical trials to guide treating clinicians. Not all patients require treatment, and the decision to treat needs to be individualised based on a patient's observed disease behaviour, baseline and longitudinal lung function measurements, extent of lung involvement on radiology and patient factors including age, co-morbidities and personal preference. If indicated, treatment of the CTD-ILD is largely with immunomodulation, with the aim to prevent progression of the ILD before further irreversible lung injury and disability occurs. Corticosteroids, cyclophosphamide, mycophenolate mofetil and azathioprine are the most common immunosuppressive agents currently used to treat CTD-ILD, demonstrating stability of lung function in case series and a small number of randomised controlled trials in ILD associated with systemic sclerosis. Biological and non-biological disease-modifying anti-rheumatic drugs, and the anti-fibrotics nintedanib and pirfenidone, have revolutionised the treatment of connective tissue diseases and idiopathic ILD, respectively. Furthermore, anti-fibrotics have recently demonstrated safety and efficacy in ILD associated with systemic sclerosis. There remains a critical unmet need to clarify when and in whom to initiate treatment, and which agent(s) to utilise to achieve optimal outcomes for CTD-ILD patients whilst minimising harms through prospective multicentre trials. This review highlights the challenges faced when treating patients with CTD-ILD and summarises available evidence for current, emerging and novel therapies.

Low-dose rituximab every 6 months for the treatment of acetylcholine receptor-positive refractory generalized myasthenia gravis

INTRODUCTION

In this prospective, open-label study we explore the effectiveness of low-dose rituximab every 6 months in treating refractory generalized myasthenia gravis (GMG).

METHODS

Twelve patients with acetylcholine receptor (AChR)-positive refractory GMG were enrolled for the study. The primary endpoint was the change in quantitative myasthenia gravis (QMG) score from baseline to the study end. Secondary endpoints included changes in manual muscle testing (MMT), MG-Related Activities of Daily Living (MG-ADL), and 15-item Quality-of-Life (MGQOL-15) scores, as well as prednisolone reduction.

RESULTS

MG decreased from 18.25 ± 4.03 to 8.42 ± 3.99 (P = .0001), MMT from 27.50 ± 17.78 to 4.58 ± 4.34 (P = .0001), ADL from 8.50 ± 2.84 to 1.17 ± 1.27 (P < .0001), MGQOL-15 from 37.25 ± 13.78 to 17.50 ± 9.73 (P = .0015), and prednisolone dose from 29.38 ± 11.92 mg/day to 8.86 ± 1.88 mg/day (P ≤ .01).

DISCUSSION

Low-dose rituximab every 6 months is effective in treating refractory GMG patients.

Rituximab therapy is more effective than cyclophosphamide therapy for Japanese patients with anti-topoisomerase I-positive systemic sclerosis-associated interstitial lung disease

Systemic sclerosis-associated interstitial lung disease (SSc-ILD) is the most frequent cause of death for SSc but there is still no sufficient treatment available. Although cyclophosphamide (CYC) therapy is a common treatment which has shown statistical efficacy against SSc-ILD to date, its effects are temporary and not enough. Rituximab (RTX), the anti-CD20 monoclonal antibody, has recently shown efficacy in many autoimmune diseases. In SSc-ILD, RTX is also considered to be one of the novel treatment candidates. However, studies of SSc-ILD in Japanese treated with RTX have only a few case reports. Therefore, in this study, we retrospectively compared nine patients treated with RTX and 30 patients treated with CYC to investigate the efficacy of RTX treatment for Japanese anti-topoisomerase I-positive SSc-ILD patients. At the 24-month evaluation, the improvement rates of percent predicted of forced vital capacity and percent predicted of diffusing capacity of the lung carbon monoxide in the RTX-treated group were significantly higher than those in the CYC-treated group (20.6 ± 8.8% vs 1.1 ± 3.9%; P < 0.05 and 34.0 ± 6.0% vs -1.5 ± 2.8%; P < 0.01, respectively). In addition, skin thickness scores also showed a marked improvement from 13.5 points before the start of treatment to 5.8 points after 24 months by RTX therapy (P < 0.05). These results suggest that RTX treatment is more effective for Japanese SSc-ILD patients than CYC treatment. In the future, it is expected that large-scale clinical trials will show the usefulness of RTX treatment for SSc-ILD.

Dkk1: A key molecule in joint remodelling and fibrosis

Dickkopf-1 (Dkk-1) is a Wnt signaling pathway inhibitor that has been shown to play an important role in joint remodeling, in experimental models of arthritis and in humans. Recent data suggest that this molecule is involved in the fibrotic process as well.

Tocilizumab is a promising treatment option for therapy resistant juvenile localized scleroderma patients

Introduction

Juvenile localized scleroderma (jlSc) usually responds well to treatment with methotrexate or mycophenolate. In case of nonresponse or partial response, tocilizumab (TOC) appears to be a promising option.

Methods

Participants of the Pediatric Rheumatology Email Board were asked to report patients with jlSc treated with TOC.

Results

Six centers responded and reported 11 patients. The mean age at disease onset was 5.5 years. Disease duration at time of the initiation of TOC was 4.5 years. A total of 5 patients had linear subtype, 2 Parry Romberg syndrome, and 1 morphea en coup de sabre. Three had a generalized subtype, 2 a mixed subtype, and 1 a limited subtype/morphea. Before starting TOC, 10 of 11 patients received methotrexate, 7/11 combination methotrexate and mycophenolate, 1 abatacept, and 1 antitumor necrosis factor therapy. The indications for starting TOC were: (i) an increase in the score of the Localized Scleroderma Activity Index (mLoSSI) in 9 patients; and (ii) evidence of increased extra-cutaneous activity in 2 patients. The mean duration of TOC therapy was 14.75 months. Three of 11 patients received TOC as monotherapy, and 8/11 as combination therapy. Therapy success was reflected by a decreased mLoSSI in 9/11 patients, no new lesion occurrence, and – with Parry Romberg syndrome subtype – no increase in facial atrophy. In 8/8 patients, both the physicians’ and patients’ global assessment of disease activity decreased. In 3/3 patients, the number of active joints decreased. The mean modified Rodnan skin score decreased from 8.7 to 5.6.

Conclusions

In this small cohort of patients, TOC seems to be a promising rescue medication.

Rheumatology around the world: perspectives from Australia and New Zealand

Rheumatology continues to be an exciting and vibrant specialty for specialists practising in New Zealand and Australia. Clinicians follow treat-to-target regimens to manage peripheral and axial inflammatory arthritides using conventional and biological agents, which have revolutionised management of rheumatic disease over the past two decades. However, optimal clinical practice has significant pharmacoeconomic implications which impact on health funding at a national level, and the advent of biosimilars is keenly awaited. The management of non-inflammatory rheumatic disease and the lack of effective disease-suppressing pharmacologic therapy for osteoarthritis continue to challenge clinicians. We are fortunate in having world-class rheumatology research in our region with basic scientists and clinical rheumatologists spearheading investigations, the ultimate aim of which is to improve the quality of life for our patients.

Rituximab treatment in patients with systemic sclerosis and interstitial lung disease

There is increasing interest in rituximab (RTX) as an alternative to cyclophosphamide for the treatment of interstitial lung diseases (ILDs) associated with systemic sclerosis (SSc). However, no report has addressed its efficacy in Saudi patients with SSc-ILD. To assess the efficacy of RTX treatment in Saudi patients with SSc-ILD, hospital records were reviewed between 2013 and 2016. Four female patients received at least 4 cycles of RTX (I cycle, consisting of two infusions of 1000 mg 2 weeks apart). Pulmonary function tests (PFTs) and chest high-resolution computed tomography (HRCT) were performed before and after treatment to assess the response. HRCT revealed improvement in one patient, stable disease in two patients, and worsening in one patient. Moreover, RTX prevented the further decline of forced vital capacity significantly in PFT. These results provide further evidence that RTX is an effective treatment for SSc-ILD.

A multicenter, open-label, comparative study of B-cell depletion therapy with Rituximab for systemic sclerosis-associated interstitial lung disease

OBJECTIVES

Rituximab (RTX) may favorably affect lung function and skin fibrosis in patients with systemic sclerosis (SSc). We aimed to assess long-term efficacy and safety of RTX in SSc compared to standard treatment.

METHODS

A total of 51 patients with SSc-associated interstitial lung disease were recruited and treated with RTX (n = 33) or conventional treatment (n = 18). Median follow-up was 4 years (range: 1-7). Conventional treatment consisted of azathioprine (n = 2), methotrexate (n = 6), and mycophenolate mofetil (n = 10).

RESULTS

Patients in the RTX group showed an increase in FVC at 2 years (mean ± SD of FVC: 80.60 ± 21.21 vs 86.90 ± 20.56 at baseline vs 2 years, respectively, p = 0.041 compared to baseline). In sharp contrast, patients in the control group had no change in FVC during the first 2 years of follow-up. At the 7 year time point the remaining patients in the RTX group (n = 5) had higher FVC compared to baseline (mean ± SD of FVC: 91.60 ± 14.81, p = 0.158 compared to baseline) in contrast to patients in the control group (n = 9) where FVC deteriorated (p < 0.01, compared to baseline). Direct comparison between the 2 groups showed a significant benefit for the RTX group in FVC (p = 0.013). Improvement of skin thickening was found in both the RTX and the standard treatment group; however, direct comparison between groups strongly favored RTX at all-time points. Adverse events were comparable between groups.

CONCLUSIONS

Our data indicate that RTX has a beneficial effect on lung function and skin fibrosis in patients with SSc. Randomized controlled studies are highly needed.

B cell depletion therapy upregulates Dkk-1 skin expression in patients with systemic sclerosis: association with enhanced resolution of skin fibrosis

BACKGROUND

Rituximab (RTX) may favorably affect skin and lung fibrosis in patients with systemic sclerosis (SSc); however, the underlying molecular mechanisms remain unknown. We aimed to explore the hypothesis that RTX may mediate its antifibrotic effects by regulating the expression of Dickkopf-1 (Dkk-1), an inhibitor of the Wnt pathway.

METHODS

Fourteen patients with SSc and five healthy subjects were recruited. Dkk-1 expression was immunohistochemically assessed in skin biopsies obtained from 11 patients with SSc (8 treated with RTX and 3 with standard treatment), whereas DKK1 gene expression was assessed in 3 patients prior to and following RTX administration.

RESULTS

In baseline biopsies obtained from all patients with SSc but not in healthy subjects, Dkk-1 was undetectable in skin fibroblasts. Following RTX treatment, four out of eight patients had obvious upregulation of Dkk-1 skin expression. Similarly, RTX treatment correlated with a significant 4.8-fold upregulation of DKK1 gene expression (p = 0.030). In contrast, TGFβ expression in the upper dermis was significantly attenuated following treatment. Moreover, this decreased expression of TGFβ in the skin was significantly more pronounced in the subgroup of patients with Dkk-1 upregulation. In this subgroup TGFβ was downregulated by 50.88 % in contrast to only 15.98 % in patients who did not have Dkk-1 upregulation (p = 0.022).

CONCLUSIONS

This is the first study demonstrating a link between B cell depletion and skin Dkk-1 upregulation in patients with SSc. RTX-mediated B cell depletion may mechanistically function via the recently established TGFβ-Dkk-1 axis in improving skin fibrosis.

Systemic sclerosis: The need for structured care

Autoimmune connective tissue diseases (CTDs) have a propensity to affect multiple organ systems as well as physical function, quality of life, and survival. Their clinical heterogeneity, multisystem involvement, and low worldwide prevalence present challenges for researchers to establish a study design to help better understand the course and outcomes of CTDs. Systemic sclerosis (SSc) is a notable example of a CTD, wherein longitudinal cohort studies (LCS) have enabled us to elucidate disease manifestations, disease course, and risk and prognostic factors for clinically important outcomes, by embedding research in clinical practice. Nevertheless, further efforts are needed to better understand SSc especially with regard to recognizing organ involvement early, developing new therapies, optimizing the use of existing therapies, and defining treatment targets. The heterogeneous multi-organ nature of SSc would lend itself well to a structured model of care, wherein step-up treatment algorithms are used with the goal of attaining a prespecified treatment target. In this chapter, we discuss the rationale for a structured treatment approach in SSc and propose possible treatment algorithms for three of the more common disease manifestations, namely skin involvement, digital ulcers and gastrointestinal tract involvement. We discuss possible strategies for evaluating and implementing these algorithms in the setting of LCS. We conclude by presenting a research agenda for the development of structured models of care in SSc.

Treatment of Rapidly Progressive Systemic Sclerosis: Current and Futures Perspectives

INTRODUCTION

Systemic Sclerosis (SSc) is a systemic autoimmune disease characterized by severe and often progressive cutaneous, pulmonary, cardiac and gastrointestinal tract fibrosis, cellular and humoral immunologic alterations, and pronounced fibroproliferative vasculopathy. There is no effective SSc disease modifying therapy. Patients with rapidly progressive SSc have poor prognosis with frequent disability and very high mortality.

AREAS COVERED

This paper reviews currently available therapeutic approaches for rapidly progressive SSc and discuss novel drugs under study for SSc disease modification.

EXPERT OPINION

The extent, severity, and rate of progression of SSc skin and internal organ involvement determines the optimal therapeutic interventions for SSc. Cyclophosphamide for progressive SSc-associated interstitial lung disease and mycophenolate for rapidly progressive cutaneous involvement have shown effectiveness. Methotrexate has been used for less severe skin progression and for patients unable to tolerate mycophenolate. Rituximab was shown to induce improvement in SSc-cutaneous and lung involvement. Autologous bone marrow transplantation is reserved for selected cases in whom poor survival risk outweighs the high mortality rate of the procedure. Novel agents capable of modulating fibrotic and inflammatory pathways involved in SSc pathogenesis, including tocilizumab, pirfenidone, tyrosine kinase inhibitors, lipid lysophosphatidic acid 1, and NOX4 inhibitors are currently under development for the treatment of rapidly progressive SSc.