Which and How Many Patients Should Be Included in Randomised Controlled Trials to Demonstrate the Efficacy of Biologics in Primary Sjögren's Syndrome?

Development and Application of the Placebo Response Model in Clinical Trials for Primary Sjögren's Syndrome

This study aimed to develop a placebo response model for pharmaceutical clinical trials of primary Sjogren's syndrome,and to quantitatively analyze the distribution and related factors influencing the placebo response to further optimize the design of clinical trials and evaluate the results of single-arm clinical trials. Public databases, including PubMed, Embase, and Cochrane Library were searched for reports on randomized placebo-controlled trials for Sjögren's syndrome which used the change from baseline in ESSDAI score as the primary outcome. The model-based meta-analysis method was used to evaluate the time course and the related influencing factors of the placebo response for ESSDAI in such clinical trials. A virtual placebo control group was constructed based on the final placebo response model to determine the treatment efficacy of belimumab and cyclosporine A for primary Sjögren's syndrome in a single-arm study. A total of 12 studies involving 450 subjects were included in the analysis. The established model described the time-course characteristics of the changes in ESSDAI score from the baseline in the 48 weeks placebo group. We found that the onset time of placebo response was approximately 12 weeks, and its efficacy plateaued at 48 weeks. The baseline ESSDAI score had a significant effect on the maximum value of the placebo response; the maximum value of the placebo response decreased by 0.552 for every 1 score rise in the baseline ESSDAI score. The efficacy of belimumab and cyclosporine A in the single-arm trial was comparable to that of the placebo response at the same baseline; no significant therapeutic advantage was observed. The placebo response model established in this study could provide a basis for designing clinical trials for primary Sjogren's syndrome in the future. It may also provide a reliable external efficacy control standard for single-arm clinical trials.

Current and future therapies for primary Sjögren syndrome

Primary Sjögren syndrome (pSS) is a systemic autoimmune disease that is characterized by a triad of symptoms that affect all patients (dryness, pain and fatigue). In addition, systemic involvement can affect between one-third and one-half of patients. The management of patients with pSS has been negatively affected by a lack of effective treatments; however, knowledge of the epidemiology of pSS has increased, and advances in developing classification criteria, systemic disease activity scoring and patient-reported outcomes have been made during the past decade. Progress has also been made in understanding the mechanisms that underlie the pathogenesis of pSS, which has enabled a more targeted therapeutic approach to be taken. At present, therapeutic decisions rely on the evaluation of symptoms and systemic manifestations and are mostly formed on the basis of experience rather than evidence, and on similarities with other autoimmune diseases, although the 2019 management recommendations from EULAR are now being used to inform clinical management of pSS. This Review summarizes the available evidence for systemic treatments for pSS and includes discussions of advances in outcome assessment, the current evidence for DMARD use and an overview of promising future therapeutics.

Go Ask Your Patients! PSS-QoL Reported Perception of Dryness Correlates With Lacrimal and Salivary Flow in Primary Sjögren's Syndrome

Introduction/Objectives: The patient perspective is an essential outcome parameter in the quest for effective therapy in primary Sjögren's Syndrome (PSS). The EULAR Sjögren's Syndrome Patient Reported Index (ESSPRI) is recommended by EULAR to quantify patient's symptom burden and has been used in several clinical trials. Surprisingly, the patient's perception of dryness quantified with ESSPRI does not correlate with objective measures of salivary or lacrimal flow. Thus, we evaluated a newly developed assessment tool-the Primary Sjögren's Syndrome Quality of Life Questionnaire (PSS-QoL)-for quantifying symptoms of dryness in comparison with the ESSPRI and objective measurements of salivary and lacrimal flow. Methods: Data of patients from the PSS registry of the Medical University of Graz fulfilling the 2016 ACR/EULAR classification criteria for PSS were analyzed. The patient perspective was analyzed by PSS-QoL, ESSPRI, Xerostomia Inventory (XI) and Ocular Surface Disease Index (OSDI). Sicca signs were measured with Schirmer's test, unstimulated salivary flow test (USF) and stimulated salivary flow test (SSF). ESSDAI (EULAR Sjögren's Syndrome Disease Activity Index) and EGA (Evaluator Global Assessment, numeric rating scale from 0 to 10) were obtained. In addition, free light chains (FLC) κ and λ, rheumatoid factor (RF) IgM and IgA were determined. Results: Data from 123 PSS patients were analyzed; 91.9% (n = 113) were female, with a mean disease duration of 6.2 (±5.3) years and mean age of 60.1 (±12.4) years. PSS-QoL-dryness revealed significant negative correlations with Schirmer's test (r = -0.31, p < 0.05) and SSF-test (r = -0.390, p < 0.01). In contrast, we found no significant correlation between ESSPRI-dryness and any objective dryness test. Lower perceived dryness was associated with higher immunological activity determined by increased levels of IgG, FLC and RF-IgA. Whereas patients with only subjective signs of dryness had lower immunological activity. Discussion: Patients' perception of dryness assessed by PSS-QoL correlates with objective measurements of salivary gland function while ESSPRI-dryness did not. Based on the PSS-QoL and objective measures of dryness two distinct groups of PSS patients could be distinguished, which may have implications in daily practice and future clinical studies.

Interleukin 6 receptor inhibition in primary Sjögren syndrome: a multicentre double-blind randomised placebo-controlled trial

OBJECTIVES

No immunomodulatory drug has been approved for primary Sjögren's syndrome, a systemic autoimmune disease affecting 0.1% of the population. To demonstrate the efficacy of targeting interleukin 6 receptor in patients with Sjögren's syndrome-related systemic complications.

METHODS

Multicentre double-blind randomised placebo-controlled trial between 24 July 2013 and 16 July 2018, with a follow-up of 44 weeks, involving 17 referral centres. Inclusion criteria were primary Sjögren's syndrome according to American European Consensus Group criteria and score ≥5 for the EULAR Sjögren's Syndrome Disease activity Index (ESSDAI, score of systemic complications). Patients were randomised to receive either 6 monthly infusions of tocilizumab or placebo. The primary endpoint was response to treatment at week 24. Response to treatment was defined by the combination of (1) a decrease of at least 3 points in the ESSDAI, (2) no occurrence of moderate or severe activity in any new domain of the ESSDAI and (3) lack of worsening in physician's global assessment on a Visual Numeric Scale ≥1/10, all as compared with enrolment.

RESULTS

110 patients were randomised, 55 patients to tocilizumab (mean (SD) age: 50.9 (12.4) years; women: 98.2%) and 55 patients to placebo (54.8 (10.7) years; 90.9%). At 24 weeks, the proportion of patients meeting the primary endpoint was 52.7% (29/55) in the tocilizumab group and 63.6% (35/55) in the placebo group, for a difference of -11.4% (95% credible interval -30.6 to 9.0) (Pr[Toc >Pla]=0.14).

CONCLUSION

Among patients with primary Sjögren's syndrome, the use of tocilizumab did not improve systemic involvement and symptoms over 24 weeks of treatment compared with placebo.

TRIAL REGISTRATION NUMBER

NCT01782235.

Efficacy and safety of abatacept in active primary Sjögren's syndrome: results of a phase III, randomised, placebo-controlled trial

OBJECTIVES

To evaluate efficacy and safety of abatacept in adults with active primary Sjögren's syndrome (pSS) in a phase III, randomised, double-blind, placebo-controlled trial.

METHODS

Eligible patients (moderate-to-severe pSS [2016 ACR/European League Against Rheumatism (EULAR) criteria], EULAR Sjögren's Syndrome Disease Activity Index [ESSDAI] ≥5, anti-SS-related antigen A/anti-Ro antibody positive) received weekly subcutaneous abatacept 125 mg or placebo for 169 days followed by an open-label extension to day 365. Primary endpoint was mean change from baseline in ESSDAI at day 169. Key secondary endpoints were mean change from baseline in EULAR Sjögren's Syndrome Patient Reported Index (ESSPRI) and stimulated whole salivary flow (SWSF) at day 169. Other secondary clinical endpoints included glandular functions and patient-reported outcomes. Selected biomarkers and immune cell phenotypes were examined. Safety was monitored.

RESULTS

Of 187 patients randomised, 168 completed double-blind period and 165 continued into open-label period. Mean (SD) baseline ESSDAI and ESSPRI total scores were 9.4 (4.3) and 6.5 (2.0), respectively. Statistical significance was not reached for primary (ESSDAI -3.2 abatacept vs -3.7 placebo, p=0.442) or key secondary endpoints (ESSPRI, p=0.337; SWSF, p=0.584). No clinical benefit of abatacept over placebo at day 169 was seen with other clinical and PRO endpoints. Relative to baseline, abatacept was associated with significant differences vs placebo in some disease-relevant biomarkers (including IgG, IgA, IgM-rheumatoid factor) and pathogenic cell subpopulations (post hoc analyses). No new safety signals were identified.

CONCLUSIONS

Abatacept treatment did not result in significant clinical efficacy compared with placebo in patients with moderate-to-severe pSS, despite evidence of biological activity.

Phosphatidylinositol 3-kinase delta pathway: a novel therapeutic target for Sjögren's syndrome

Background

The phosphatidylinositol 3-kinase delta isoform (PI3Kδ) belongs to an intracellular lipid kinase family that regulate lymphocyte metabolism, survival, proliferation, apoptosis and migration and has been successfully targeted in B-cell malignancies. Primary Sjögren’s syndrome (pSS) is a chronic immune-mediated inflammatory disease characterised by exocrine gland lymphocytic infiltration and B-cell hyperactivation which results in systemic manifestations, autoantibody production and loss of glandular function. Given the central role of B cells in pSS pathogenesis, we investigated PI3Kδ pathway activation in pSS and the functional consequences of blocking PI3Kδ in a murine model of focal sialoadenitis that mimics some features of pSS.

Methods and results

Target validation assays showed significant expression of phosphorylated ribosomal protein S6 (pS6), a downstream mediator of the phosphatidylinositol 3-kinase delta (PI3Kδ) pathway, within pSS salivary glands. pS6 distribution was found to co-localise with T/B cell markers within pSS aggregates and the CD138+ plasma cells infiltrating the glands. In vivo blockade of PI3Kδ activity with seletalisib, a PI3Kδ-selective inhibitor, in a murine model of focal sialoadenitis decreased accumulation of lymphocytes and plasma cells within the glands of treated mice in the prophylactic and therapeutic regimes. Additionally, production of lymphoid chemokines and cytokines associated with ectopic lymphoneogenesis and, remarkably, saliva flow and autoantibody production, were significantly affected by treatment with seletalisib.

Conclusion

These data demonstrate activation of PI3Kδ pathway within the glands of patients with pSS and its contribution to disease pathogenesis in a model of disease, supporting the exploration of the therapeutic potential of PI3Kδ pathway inhibition in this condition.

Incidence and Mortality of Physician-Diagnosed Primary Sjögren Syndrome: Time Trends Over a 40-Year Period in a Population-Based US Cohort

OBJECTIVE

To estimate the incidence and mortality rates, and their evolution over time, of physician-diagnosed primary Sjögren syndrome (pSS) in residents of Olmsted County, Minnesota.

PATIENTS AND METHODS

Medical records of patients with a diagnosis or suspicion of SS in Olmsted County from January 1, 2006, through December 31, 2015, were reviewed to identify incident cases of pSS (defined by physician diagnosis). These cases were combined with those from a 1976 through 2005 incident cohort (n=111) from the same population. Incidence rates were age and sex adjusted to the 2010 US white population. Survival rates were compared with the expected rates in the population of Minnesota.

RESULTS

With 61 incident cases of pSS diagnosed in Olmsted County from 2006 through 2015, the total cohort included 172 patients with incident pSS from 1976 through 2015. Of the 172 patients, 151 (88%) were women and 161 (94%) were white, with a mean ± SD age at diagnosis of 58.3±16.7 years. The average age- and sex-adjusted annual incidence for 2006 through 2015 was 5.9 per 100,000 population (95% CI, 4.4-7.4 per 100,000 population), and the overall incidence for the entire period was 5.8 per 100,000 (95% CI, 4.9-6.6 per 100,000). The incidence increased with calendar time over the 40-year period (P=.005). There was no difference in mortality in the pSS cohort compared with expected (standardized mortality ratio, 1.15; 95% CI, 0.86-1.50).

CONCLUSION

The average annual incidence of pSS in this population-based cohort was 5.8 per 100,000, with a progressive increase over the 40 years of the study. Overall survival of patients with pSS was not different from that of the general population.

Treating the Underlying Pathophysiology of Primary Sjögren Syndrome: Recent Advances and Future Prospects

Sjögren Syndrome (SS) is a systemic autoimmune disease with a wide clinical spectrum that extends from sicca symptoms of the mucosal surfaces to extra-glandular systemic manifestations. Understanding of the pathophysiology of primary SS has advanced over recent years, and this, in turn, has presented new targeted treatment options. We provide a brief, up-to-date description of the pathophysiology of SS and the main etiopathogenic pathways implicated in the disease process and review clinical evidence in support of new treatment options targeting these pathways, highlighting successes and failures, and concluding with a summary of gaps in knowledge and where future research should be focused. Direct and indirect B-cell targeted therapies are currently the most promising biological agents in primary SS, especially for systemic involvement, but other pathways (T-cell co-stimulation, cytokine-based therapies, intracellular pathways and gene therapies) are under development. The next 10 years may witness a disruptive therapeutic scenario in primary SS.

Present and future of biologic drugs in primary Sjögren's syndrome

INTRODUCTION

Primary Sjögren's (pSS) syndrome is a chronic, autoimmune, and systemic disease characterized by xerostomia, xerophthalmia, muscle pain and fatigue. The disease may be complicated by a systemic involvement, such as a pulmonary fibrosis or the development of lymphoma which severely worsens the prognosis. Actually, there are no recommendations for the management of pSS. However, recent advances in the understanding of its pathogenesis have uncovered some pathways that have potential as therapeutic targets. Areas covered: In this review, the authors present the biologic drugs potentially valuable to the treatment of pSS in light of its physiopathology with a 'bird's eye' view of future prospects. The authors took into account relevant studies published from 2004 to 2016. Expert opinion: Biological treatment in pSS is a promising opportunity to potentially control disease activity and prevent its complication. Currently, inhibition of B-cell and IL-17 pathways seem to be the most promising avenues. New achievements in the knowledge of pSS pathophysiology are necessary in order to try to simultaneously predict the predominant pathogenic pathway, the kind of patients at major risk to develop a more severe disease, and the appropriate biological therapy to use.

Treatment of primary Sjögren syndrome

Primary Sjögren syndrome (pSS) is a progressive autoimmune disease characterized by sicca and systemic manifestations. In this Review, we summarize the available data on topical and systemic medications, according to clinical signs and disease activity, and we describe the ongoing studies using biologic drugs in the treatment of pSS. Expanding knowledge about the epidemiology, classification criteria, systemic activity scoring (ESSDAI) and patient-reported outcomes (ESSPRI) is driving active research. Treatment decisions are based on the evaluation of symptoms and extraglandular manifestations. Symptomatic treatment is usually appropriate, whereas systemic treatment is reserved for systemic manifestations. Sicca is managed by education, environment modification, elimination of contingent offending drugs, artificial tears, secretagogues and treatments for complications. Mild systemic signs such as fatigue are treated by exercise. Pain can require short-term moderate-dose glucocorticoid therapy and, in some cases, disease-modifying drugs. Severe and acute systemic manifestations indicate treatment with glucocorticoids and/or immunosuppressant drugs. The role for biologic agents is promising, but no double-blind randomized controlled trials (RCTs) proving the efficacy of these drugs are available. Targets for new treatments directed against the immunopathological mechanisms of pSS include epithelial cells, T cells, B-cell overactivity, the interferon signature, proinflammatory cytokines, ectopic germinal centre formation, chemokines involved in lymphoid cell homing, and epigenetic modifications.

Sjögren syndrome

Sjögren syndrome (SjS) is a systemic autoimmune disease that primarily affects the exocrine glands (mainly the salivary and lacrimal glands) and results in the severe dryness of mucosal surfaces, principally in the mouth and eyes. This disease predominantly affects middle-aged women, but can also be observed in children, men and the elderly. The clinical presentation of SjS is heterogeneous and can vary from sicca symptoms to systemic disease (characterized by peri-epithelial lymphocytic infiltration of the affected tissue or the deposition of the immune complex) and lymphoma. The mechanism underlying the development of SjS is the destruction of the epithelium of the exocrine glands, as a consequence of abnormal B cell and T cell responses to the autoantigens Ro/SSA and La/SSB, among others. Diagnostic criteria for SjS include the detection of autoantibodies in patient serum and histological analysis of biopsied salivary gland tissue. Therapeutic approaches for SjS include both topical and systemic treatments to manage the sicca and systemic symptoms of disease. SjS is a serious disease with excess mortality, mainly related to the systemic involvement of disease and the development of lymphomas in some patients. Knowledge of SjS has progressed substantially, but this disease is still characterized by sicca symptoms, the systemic involvement of disease, lymphocytic infiltration to exocrine glands, the presence of anti-Ro/SSA and anti-La/SSB autoantibodies and the increased risk of lymphoma in patients with SjS.

Recent advances in primary Sjogren's syndrome

Primary Sjögren's syndrome, a chronic inflammatory process, is among the most commonly occurring rheumatologic diseases. The clinical hallmark of this disease is exocrine gland dysfunction, resulting predominately in dry eyes and dry mouth. However, the disease often extends beyond the exocrine glands to seriously affect other organs systems, such as the lungs, kidneys, and nervous system. Moreover, patients with primary Sjögren's syndrome develop non-Hodgkin's B cell lymphoma at a substantially higher rate than the general population. New research has improved our understanding of disease mechanisms, with notable advances in our knowledge about the genetic susceptibility of disease, the molecular details of the chronic inflammatory response in the salivary glands, and the complex role of the type 1 interferon pathway. The pipeline of drugs under development for the treatment of primary Sjögren's syndrome is enriched with novel biologics and small molecular entities targeting the pathogenic process. Herein, we summarize the latest advances in elucidating the pathogenesis of primary Sjögren's syndrome and highlight new drugs in clinical development aiming to reverse the glandular dysfunction and favorably impact the systemic features of this disease.

New biological therapies in Sjögren's syndrome

Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease characterized by dryness and systemic involvement in more than a third of the patients. Patient management has suffered from the lack of effective treatments. However, progresses made in the understanding of pSS pathogenesis have allowed a move to a more targeted approach to therapeutic intervention. Given the key role of chronic B cell activation, B cell-targeted therapies were the first candidate. New pathways are currently investigated including costimulation and ectopic germinal centre formation. In this review, we have summarized the new tools available in clinical research in the field of pSS, the current evidence regarding B cell-targeted therapies and an overview of the promising drugs in the pipeline.