Randomized controlled trial design in rheumatoid arthritis: the past decade

Inflammasome and Its Therapeutic Targeting in Rheumatoid Arthritis

Inflammasome is a cytoplasmic multiprotein complex that facilitates the clearance of exogenous microorganisms or the recognition of endogenous danger signals, which is critically involved in innate inflammatory response. Excessive or abnormal activation of inflammasomes has been shown to contribute to the development of various diseases including autoimmune diseases, neurodegenerative changes, and cancers. Rheumatoid arthritis (RA) is a chronic and complex autoimmune disease, in which inflammasome activation plays a pivotal role in immune dysregulation and joint inflammation. This review summarizes recent findings on inflammasome activation and its effector mechanisms in the pathogenesis of RA and potential development of therapeutic targeting of inflammasome for the immunotherapy of RA.

Spotlight on NLRP3 Inflammasome: Role in Pathogenesis and Therapies of Atherosclerosis

Inflammation is an intricate biological response of body tissues to detrimental stimuli. Cardiovascular disease (CVD) is the leading cause of death worldwide, and inflammation is well documented to play a role in the development of CVD, especially atherosclerosis (AS). Emerging evidence suggests that activation of the NOD-like receptor (NLR) family and the pyridine-containing domain 3 (NLRP3) inflammasome is instrumental in inflammation and may result in AS. The NLRP3 inflammasome acts as a molecular platform that triggers the activation of caspase-1 and the cleavage of pro-interleukin (IL)-1β, pro-IL-18, and gasdermin D (GSDMD). The cleaved GSDMD forms pores in the cell membrane and initiates pyroptosis, inducing cell death and the discharge of intracellular pro-inflammatory factors. Hence, the NLRP3 inflammasome is a promising target for anti-inflammatory therapy against AS. In this review, we systematically summarized the current understanding of the activation mechanism of NLRP3 inflammasome, and the pathological changes in AS involving NLRP3. We also discussed potential therapeutic strategies targeting NLRP3 inflammasome to combat AS.

NLRP3 Activation and Its Relationship to Endothelial Dysfunction and Oxidative Stress: Implications for Preeclampsia and Pharmacological Interventions

Preeclampsia (PE) is a specific syndrome of human pregnancy, being one of the main causes of maternal death. Persistent inflammation in the endothelium stimulates the secretion of several inflammatory mediators, activating different signaling patterns. One of these mechanisms is related to NLRP3 activation, initiated by high levels of danger signals such as cholesterol, urate, and glucose, producing IL-1, IL-18, and cell death by pyroptosis. Furthermore, reactive oxygen species (ROS), act as an intermediate to activate NLRP3, contributing to subsequent inflammatory cascades and cell damage. Moreover, increased production of ROS may elevate nitric oxide (NO) catabolism and consequently decrease NO bioavailability. NO has many roles in immune responses, including the regulation of signaling cascades. At the site of inflammation, vascular endothelium is crucial in the regulation of systemic inflammation with important implications for homeostasis. In this review, we present the important role of NLRP3 activation in exacerbating oxidative stress and endothelial dysfunction. Considering that the causes related to these processes and inflammation in PE remain a challenge for clinical practice, the use of drugs related to inhibition of the NLRP3 may be a good option for future solutions for this disease.

Therapeutic regulation of the NLRP3 inflammasome in chronic inflammatory diseases

Inflammasomes are cytosolic pattern recognition receptors that recognize pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs) derived from invading pathogens and damaged tissues, respectively. Upon activation, the inflammasome forms a complex containing a receptor protein, an adaptor, and an effector to induce the autocleavage and activation of procaspase-1 ultimately culminating in the maturation and secretion of IL-1β and IL-18 and pyroptosis. Inflammasome activation plays an important role in host immune responses to pathogen infections and tissue repair in response to cellular damage. The NLRP3 inflammasome is a well-characterized pattern recognition receptor and is well known for its critical role in the regulation of immunity and the development and progression of various inflammatory diseases. In this review, we summarize recent efforts to develop therapeutic applications targeting the NLRP3 inflammasome to cure and prevent chronic inflammatory diseases. This review extensively discusses NLRP3 inflammasome-related diseases and current development of small molecule inhibitors providing beneficial information on the design of therapeutic strategies for NLRP3 inflammasome-related diseases. Additionally, small molecule inhibitors are classified depending on direct or indirect targeting mechanism to describe the current status of the development of pharmacological inhibitors.

Role of the NLRP3 inflammasome in autoimmune diseases

NOD-like receptor family pyrin domain containing 3 (NLRP3) is an intracellular receptor that senses foreign pathogens and endogenous danger signals. It assembles with apoptosis-associated speck-like protein containing a CARD (ASC) and caspase-1 to form a multimeric protein called the NLRP3 inflammasome. Among its various functions, the NLRP3 inflammasome can induce the release of the pro-inflammatory cytokines interleukin (IL)-1β and IL-18 while also promoting gasdermin D (GSDMD)-mediated pyroptosis. Previous studies have established a vital role for the NLRP3 inflammasome in innate and adaptive immune system as well as its contribution to several autoimmune diseases including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), Sjögren's syndrome (SS), systemic sclerosis (SSc), and ankylosing spondylitis (AS). In this review, we briefly introduce the biological features of the NLRP3 inflammasome and present the mechanisms underlying its activation and regulation. We also summarize recent studies that have reported on the roles of NLRP3 inflammasome in the immune system and several autoimmune diseases, with a focus on therapeutic and clinical applications.

Noninferiority Trials to Evaluate Drug Effects in Rheumatoid Arthritis

OBJECTIVE

The increased availability of highly effective treatments in rheumatoid arthritis (RA) necessitates a reexamination of study designs evaluating new treatments. We undertook this study to discuss possible specifications and considerations of noninferiority (NI) trials assessing drug effects in RA.

METHODS

We focused on the use of approved tumor necrosis factor inhibitors (TNFi) as potential active controls and reviewed previous placebo-controlled studies. We summarized the similarities in baseline characteristics and study design of the historical placebo-controlled studies used. After performing meta-analyses to estimate the effects of TNFi on symptoms, physical function, and radiographic progression in RA, we proposed NI margins and evaluated the feasibility of NI trials in this therapeutic setting.

RESULTS

We determined that an NI trial comparing an experimental treatment to a TNFi using the symptomatic end point of the American College of Rheumatology 20% improvement criteria response can feasibly provide evidence of a treatment effect, with a 12% absolute difference as one possible appropriate NI margin. For change from baseline in the Health Assessment Questionnaire disability index score, reasonable margins range from 0.10 to 0.12. In evaluating radiographic progression, an appropriate margin and the corresponding feasibility of the trial are dependent on the selected active control and the expected variability in progression.

CONCLUSION

Active-controlled studies in RA with justified NI margins can provide persuasive evidence of treatment effects on symptomatic, functional, and radiographic end points. Such studies can also provide reliable, controlled safety data and relevant information for treatment decisions in clinical practice. Thus, we recommend considering NI designs in future clinical trials in RA.

Factors Influencing Placebo Responses in Rheumatoid Arthritis Clinical Trials: A Meta-Analysis of Randomized, Double-Blind, Placebo-Controlled Studies

BACKGROUND AND OBJECTIVE

A better understanding of placebo responses and the specific factors influencing these outcomes is important for clinical trial design. We investigated the magnitude of placebo responses at 3 months and the potential factors influencing these outcomes in rheumatoid arthritis (RA) clinical trials.

METHODS

We conducted a systematic review of randomized placebo-controlled trials of pharmacological agents for RA identified from PubMed, Embase, and Cochrane Central Register of Controlled Trials databases. The primary placebo outcome was American College of Rheumatology 20% response rate (ACR20). Data were pooled with a random-effects model. Factors influencing placebo response were assessed by meta-regression analyses. Subgroup analyses were performed for studies conducted in non-Western countries only versus in Western countries (North America and/or Europe) only or both.

RESULTS

The meta-analysis included 88 studies comprising 8406 patients receiving a placebo. The pooled estimate of placebo ACR20 was 29.0% (range 10.0-46.2; 95% confidence interval 27.2-30.9). Placebo ACR20 was negatively associated with trials in non-Western (Asian) countries and patient populations showing an inadequate response to biological disease-modifying antirheumatic drugs (DMARDs) in the multivariable analysis, whereas it was positively associated with the year of publication. No background DMARD treatment was also a negative predictor (albeit statistically non-significant). In subgroup analyses of Western and multiregional studies, study population and publication year were significant factors.

CONCLUSIONS

Our meta-analysis suggests that study location, patient population, and a background DMARD treatment influence placebo ACR20. These along with placebo response temporal profiles have important implications for designing and interpreting RA clinical trials.

Pharmacological Inhibitors of the NLRP3 Inflammasome

Inflammasomes play a crucial role in innate immunity by serving as signaling platforms which deal with a plethora of pathogenic products and cellular products associated with stress and damage. By far, the best studied and most characterized inflammasome is NLRP3 inflammasome, which consists of NLRP3 (nucleotide-binding domain leucine-rich repeat (NLR) and pyrin domain containing receptor 3), ASC (apoptosis-associated speck-like protein containing a caspase recruitment domain), and procaspase-1. Activation of NLRP3 inflammasome is mediated by highly diverse stimuli. Upon activation, NLRP3 protein recruits the adapter ASC protein, which recruits the procaspase-1 resulting in its cleavage and activation, inducing the maturation, and secretion of inflammatory cytokines and pyroptosis. However, aberrant activation of the NLRP3 inflammasome is implicated in various diseases including diabetes, atherosclerosis, metabolic syndrome, cardiovascular, and neurodegenerative diseases; raising a tremendous clinical interest in exploring the potential inhibitors of NLRP3 inflammasome. Recent investigations have disclosed various inhibitors of the NLRP3 inflammasome pathway which were validated through in vitro studies and in vivo experiments in animal models of NLRP3-associated disorders. Some of these inhibitors directly target the NLRP3 protein whereas some are aimed at other components and products of the inflammasome. Direct targeting of NLRP3 protein can be a better choice because it can prevent off target immunosuppressive effects, thus restrain tissue destruction. This paper will review the various pharmacological inhibitors of the NLRP3 inflammasome and will also discuss their mechanism of action.

Pharmacological Inhibitors of the NLRP3 Inflammasome

Inflammasomes play a crucial role in innate immunity by serving as signaling platforms which deal with a plethora of pathogenic products and cellular products associated with stress and damage. By far, the best studied and most characterized inflammasome is NLRP3 inflammasome, which consists of NLRP3 (nucleotide-binding domain leucine-rich repeat (NLR) and pyrin domain containing receptor 3), ASC (apoptosis-associated speck-like protein containing a caspase recruitment domain), and procaspase-1. Activation of NLRP3 inflammasome is mediated by highly diverse stimuli. Upon activation, NLRP3 protein recruits the adapter ASC protein, which recruits the procaspase-1 resulting in its cleavage and activation, inducing the maturation, and secretion of inflammatory cytokines and pyroptosis. However, aberrant activation of the NLRP3 inflammasome is implicated in various diseases including diabetes, atherosclerosis, metabolic syndrome, cardiovascular, and neurodegenerative diseases; raising a tremendous clinical interest in exploring the potential inhibitors of NLRP3 inflammasome. Recent investigations have disclosed various inhibitors of the NLRP3 inflammasome pathway which were validated through in vitro studies and in vivo experiments in animal models of NLRP3-associated disorders. Some of these inhibitors directly target the NLRP3 protein whereas some are aimed at other components and products of the inflammasome. Direct targeting of NLRP3 protein can be a better choice because it can prevent off target immunosuppressive effects, thus restrain tissue destruction. This paper will review the various pharmacological inhibitors of the NLRP3 inflammasome and will also discuss their mechanism of action.

Placebo Response in Rheumatoid Arthritis Clinical Trials

OBJECTIVE

Understanding the placebo response is critical to interpreting treatment efficacy, particularly for agents with a ceiling to their therapeutic effect, where an increasing placebo response makes it harder to detect potential benefit. The objective of this study is to assess the change in placebo responses over time in rheumatoid arthritis (RA) randomized placebo-controlled trials (RCT) for drug licensing authorization.

METHODS

The Cochrane Controlled Trials Register database was searched to identify RCT of biological or targeted synthetic disease-modifying antirheumatic drugs (DMARD) in RA. Studies were excluded if patients were conventional synthetic DMARD (csDMARD)-naive, not receiving background csDMARD therapy, or were biologic experienced. Metaregression model was used to evaluate changes in American College of Rheumatology (ACR) 20, ACR50, and ACR70 treatment response over time.

RESULTS

There were 32 trials in total: anti-tumor necrosis factor therapy (n = 15), tocilizumab (n = 4), abatacept (n = 2), rituximab (n = 2), and Janus kinase inhibitors (n = 9). From 1999 to 2018, there was no significant trend in the age or sex of patients in the placebo arm. Disease duration, swollen joint count, and 28-joint count Disease Activity Score using erythrocyte sedimentation rate at baseline all significantly declined over time. There was a statistically significant increase in placebo ACR50 and ACR70 responses (ACR50 β = 0.41, 95% CI 0.09-0.74, p = 0.01; ACR70 β = 0.18, 95% CI 0.04-0.31, p = 0.01) that remained significant after controlling for potential confounders.

CONCLUSION

There has been a rise in the placebo response in RA clinical trials over the last 2 decades. Shifting RA phenotype, changes in trial design, and expectation bias are possible explanations for this phenomenon. This observation has important implications when evaluating newer novel agents against established therapies.

MRI and Dose Selection in a Phase II Trial of Baricitinib with Conventional Synthetic Disease-modifying Antirheumatic Drugs in Rheumatoid Arthritis

OBJECTIVE

Magnetic resonance imaging (MRI) was used in a phase IIb study of baricitinib in patients with RA to support dose selection for the phase III program.

METHODS

Three hundred one patients with active RA who were taking stable methotrexate were randomized 2:1:1:1:1 to placebo or once-daily baricitinib (1, 2, 4, or 8 mg) for up to 24 weeks. One hundred fifty-four patients with definitive radiographic erosion had MRI of the hand/wrist at baseline and at weeks 12 and 24. Two expert radiologists, blinded to treatment and visit order, scored images for synovitis, osteitis, bone erosion, and cartilage loss. Combined inflammation (osteitis + 3× synovitis score) and total joint damage (erosion + 2.5× cartilage loss score) scores were calculated. Treatment groups were compared using ANCOVA adjusting for baseline scores.

RESULTS

Mean changes from baseline to Week 12 for synovitis were -0.10, -1.50, and -1.60 for patients treated with placebo, baricitinib 4 mg, and baricitinib 8 mg, respectively (p = 0.003 vs placebo for baricitinib 4 and 8 mg). Mean changes for osteitis were 0.00, -3.20, and -2.10 (p = 0.001 vs placebo for baricitinib 4 mg and p = 0.037 for 8 mg), respectively. Mean changes for bone erosion were 0.90, 0.10, and 0.40 (p = 0.089 for 4 mg and p = 0.275 for 8 mg), respectively, in these treatment groups.

CONCLUSION

MRI findings in this subgroup of patients suggest suppression of synovitis, osteitis, and combined inflammation by baricitinib 4 and 8 mg. This corroborates previously demonstrated clinical efficacy of baricitinib and increases confidence that baricitinib 4 mg could reduce the radiographic progression in phase III studies. [Clinical trial registration number (www.ClinicalTrials.gov): NCT01185353].

Early phase and adaptive design clinical trials in rheumatoid arthritis: a systematic review of early phase trials

Objective

Adaptive designs can enable highly sophisticated and efficient early phase trials, but the clinical inference from these trials is surrounded by complexity, and currently there is a paucity but steadily increasing amount of use of these designs in all fields of medicine. We aim to review early phase trials in RA to discover those that have used adaptive designs and benchmark trial characteristics.

Methods

From an OVID search for journal articles reporting the results of early phase trials in rheumatology, 35 studies were found, with 9 subsequently excluded; 11 were added from manual searches and 19 from searching the references. Study characteristics were extracted from the 56 papers (describing 62 trials), including the number of arms, number of patients, the primary outcome and when it was measured.

Result

One early phase trial using an adaptive design was found. The benchmark early phase trial in RA is a phase II double-blinded randomized trial, with four arms (one control and three intervention), each with 34 patients, and ACR20 measured at 16 weeks as the primary outcome.

Conclusion

The one adaptive design reviewed here, and a simulation study found in the search, both indicate that adaptive designs can be applied to early phase trials in RA. We have described the benchmark, which the efficiency of early phase trials using an adaptive design needs to exceed. These efficient designs could drive down numbers required, time for data collection and thus cost. Changes have been suggested, but more needs to be done.

The anti-CD6 antibody itolizumab provides clinical benefit without lymphopenia in rheumatoid arthritis patients: results from a 6-month, open-label Phase I clinical trial

Itolizumab is a humanized anti-CD6 monoclonal antibody (mAb) that has previously shown encouraging results, in terms of safety and positive clinical effects, in a 6-week monotherapy clinical trial conducted in rheumatoid arthritis (RA) patients. The current Phase I study evaluated the safety and clinical response for a longer treatment of 12 itolizumab intravenous doses in subjects with active RA despite previous disease-modifying anti-rheumatic drug (DMARD) therapy. Twenty-one subjects were enrolled into four dosage groups (0·1, 0·2, 0·4 and 0·8 mg/kg). Efficacy end-points including American College of Rheumatology (ACR)20, ACR50 and ACR70 response rates and disease activity score in 28 joints (DAS28) were monitored at baseline and at specific time-points during a 10-week follow-up period. Itolizumab was well tolerated up to the highest tested dose. No related serious adverse events were reported and most adverse events were mild. Remarkably, itolizumab treatment did not produce lymphopenia and, therefore, was not associated with infections. All patients achieved a clinical response (ACR20) at least once during the study. Eleven subjects (55%) achieved at least a 20% improvement in ACR just 1 week after the first itolizumab administration. The clinical response was observed from the beginning of the treatment and was sustained during 24 weeks. The efficacy profile of this 12-week treatment was similar to that of the previous study (6-week treatment). These results reinforce the safety profile of itolizumab and provide further evidence on the clinical benefit from the use of this anti-CD6 mAb in RA patients.

Randomised controlled trial of tumour necrosis factor inhibitors against combination intensive therapy with conventional disease-modifying antirheumatic drugs in established rheumatoid arthritis: the TACIT trial and associated systematic reviews

BACKGROUND

Rheumatoid arthritis (RA) is initially treated with methotrexate and other disease-modifying antirheumatic drugs (DMARDs). Active RA patients who fail such treatments can receive tumour necrosis factor inhibitors (TNFis), which are effective but expensive.

OBJECTIVE

We assessed whether or not combination DMARDs (cDMARDs) give equivalent clinical benefits at lower costs in RA patients eligible for TNFis.

DESIGN

An open-label, 12-month, pragmatic, randomised, multicentre, two-arm trial [Tumour necrosis factor inhibitors Against Combination Intensive Therapy (TACIT)] compared these treatment strategies. We then systematically reviewed all comparable published trials.

SETTING

The TACIT trial involved 24 English rheumatology clinics.

PARTICIPANTS

Active RA patients eligible for TNFis.

INTERVENTIONS

The TACIT trial compared cDMARDs with TNFis plus methotrexate or another DMARD; 6-month non-responders received (a) TNFis if in the cDMARD group; and (b) a second TNFi if in the TNFi group.

MAIN OUTCOME MEASURES

The Heath Assessment Questionnaire (HAQ) was the primary outcome measure. The European Quality of Life-5 Dimensions (EQ-5D), joint damage, Disease Activity Score for 28 Joints (DAS28), withdrawals and adverse effects were secondary outcome measures. Economic evaluation linked costs, HAQ changes and quality-adjusted life-years (QALYs).

RESULTS

In total, 432 patients were screened; 104 started on cDMARDs and 101 started on TNFis. The initial demographic and disease assessments were similar between the groups. In total, 16 patients were lost to follow-up (nine in the cDMARD group, seven in the TNFi group) and 42 discontinued their intervention but were followed up (23 in the cDMARD group and 19 in the TNFi group). Intention-to-treat analysis with multiple imputation methods used for missing data showed greater 12-month HAQ score reductions with initial cDMARDs than with initial TNFis [adjusted linear regression coefficient 0.15, 95% confidence interval (CI) -0.003 to 0.31; p = 0.046]. Increases in 12-month EQ-5D scores were greater with initial cDMARDs (adjusted linear regression coefficient -0.11, 95% CI -0.18 to -0.03; p = 0.009) whereas 6-month changes in HAQ and EQ-5D scores and 6- and 12-month changes in joint damage were similar between the initial cDMARD group and the initial TNFi group. Longitudinal analyses (adjusted general estimating equations) showed that the DAS28 was lower in the initial TNFi group in the first 6 months (coefficient -0.63, 95% CI -0.93 to -0.34; p < 0.001) but there were no differences between the groups in months 6-12. In total, 36 patients in the initial cDMARD group and 44 in the initial TNFi group achieved DAS28 remission. The onset of remission did not differ between groups (p = 0.085 on log-rank test). In total, 10 patients in the initial cDMARD group and 18 in the initial TNFi group experienced serious adverse events; stopping therapy because of toxicity occurred in 10 and six patients respectively. Economic evaluation showed that the cDMARD group had similar or better QALY outcomes than TNFi with significantly lower costs at 6 and 12 months. In the systematic reviews we identified 32 trials (including 20-1049 patients) on early RA and 19 trials (including 40-982 patients) on established RA that compared (1) cDMARDs with DMARD monotherapy; (2) TNFis/methotrexate with methotrexate monotherapy; and (3) cDMARDs with TNFis/methotrexate. They showed that cDMARDs and TNFis had similar efficacies and toxicities.

CONCLUSIONS

Active RA patients who have failed methotrexate and another DMARD achieve equivalent clinical benefits at a lower cost from starting cDMARDs or from starting TNFis (reserving TNFis for non-responders). Only a minority of patients achieve sustained remission with cDMARDs or TNFis; new strategies are needed to maximise the frequency of remission.

TRIAL REGISTRATION

Current Control Trials ISRCTN37438295.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 18, No. 66. See the NIHR Journals Library website for further project information.

Cost and effectiveness of biologics for rheumatoid arthritis in a commercially insured population

BACKGROUND

Administrative claims contain detailed medication, diagnosis, and procedure data, but the lack of clinical outcomes for rheumatoid arthritis (RA) historically has limited their use in comparative effectiveness research. A claims-based algorithm was developed and validated to estimate effectiveness for RA from data for adherence, dosing, and treatment modifications.

OBJECTIVE

To implement the claims-based algorithm in a U.S. managed care database to estimate biologic cost per effectively treated patient.

METHODS

The cohort included patients with RA aged 18-63 years in the Optum Research Database who initiated biologic treatment between January 2007 and December 2010 and were continuously enrolled 6 months before through 12 months after the first claim for the biologic (the index date). Patients were categorized as effectively treated by the claims-based algorithm if they met all of the following 6 criteria in the 12-month post-index period: (1) a medication possession ratio ≥ 80% for subcutaneous biologics, or at least as many infusions as specified in U.S. labeling for intravenous biologics; (2) no increase in biologic dose; (3) no switch in biologics; (4) no new nonbiologic disease-modifying antirheumatic drug; (5) no new or increased oral glucocorticoid treatment; and (6) no more than 1 glucocorticoid injection. Drug costs (all biologics) and administration costs (intravenous biologics) were obtained from allowed amounts on claims. Biologic cost per effectively treated patient was defined as total 1-year biologic cost divided by the number of patients categorized by the algorithm as effectively treated with that index biologic. Sensitivity analysis was conducted to examine the total health care costs per effectively treated patient during the first year of biologic therapy.

RESULTS

A total of 5,474 individuals were included in the analysis. The index biologic was categorized as effective by the algorithm for 28.9% of patients overall, including 30.6% for subcutaneous biologics and 22.1% for intravenous biologics. The index biologic was categorized as effective in the first year for 32.7% of etanercept (794/2,425), 32.3% of golimumab (40/124), 30.2% of abatacept (89/295), 27.7% of adalimumab (514/1,857), and 19.0% of infliximab (147/773) patients. Mean 1-year biologic cost per effectively treated patient, as defined in the algorithm, was lowest for etanercept ($43,935), followed by golimumab ($49,589), adalimumab ($52,752), abatacept ($62,300), and infliximab ($101,402). The rank order in the sensitivity analysis was the same, except for golimumab and etanercept. 

CONCLUSIONS

Using a claims-based algorithm in a large commercial claims database, etanercept was the most effective and had the lowest biologic cost per effectively treated patient with RA.

Interpreting trial results following use of different intention-to-treat approaches for preventing attrition bias: a meta-epidemiological study protocol

INTRODUCTION

When participants drop out of randomised clinical trials, as frequently happens, the intention-to-treat (ITT) principle does not apply, potentially leading to attrition bias. Data lost from patient dropout/lack of follow-up are statistically addressed by imputing, a procedure prone to bias. Deviations from the original definition of ITT are referred to as modified intention-to-treat (mITT). As yet, the impact of the potential bias associated with mITT has not been assessed. Our objective is to investigate potential bias and disadvantages of performing mITT and evaluate possible concerns when executing different mITT approaches in meta-analyses.

METHODS AND ANALYSIS

Using meta-epidemiology on randomised trials considered less prone to bias (ie, good internal validity) and assessing biological or targeted agents in patients with rheumatoid arthritis, we will meta-analyse data from 10 biological and targeted drugs based on collections of trials that would correspond to 10 individual meta-analyses.

ETHICS AND DISSEMINATION

This study will enhance transparency for evaluating mITT treatment effects described in meta-analyses. The intended audience will include healthcare researchers, policymakers and clinicians. Results of the study will be disseminated by peer-review publication.

PROTOCOL REGISTRATION

In PROSPERO CRD42013006702, 11. December 2013.

A clinical exploratory study with itolizumab, an anti-CD6 monoclonal antibody, in patients with rheumatoid arthritis

T cells are involved in the pathogenesis of rheumatoid arthritis (RA). CD6 is a co-stimulatory molecule, predominantly expressed on lymphocytes, that has been linked to autoreactive responses. The purpose of this study was to evaluate the safety, immunogenicity and preliminary efficacy of itolizumab, a humanized anti-CD6 monoclonal antibody, in patients with active rheumatoid arthritis. Fifteen patients were enrolled in a phase I, open-label, dose-finding study. Five cohorts of patients received a weekly antibody monotherapy with a dose-range from 0.1 to 0.8 mg/kg. Itolizumab showed a good safety profile, with no severe or serious adverse events reported so far. No signs or symptoms associated with immunosuppression were observed in the study. Objective clinical responses were achieved in more than 80% of patients after treatment completion, and these responses tend to be sustained afterwards. This clinical study constitutes the first evidence of the safety and positive clinical effect of a monotherapy using an anti-CD6 antibody in patients with rheumatoid arthritis.

Variation in the use of biologics in the management of rheumatoid arthritis across the UK

OBJECTIVES

Treatment options for rheumatoid arthritis (RA) include conventional synthetic disease-modifying antirheumatic drugs (sDMARDs) and newer biologic DMARDs (biologics). This study describes treatment patterns, adherence to guidance and outcomes at hospital/regional level in the UK.

METHODS

This was a retrospective cohort study of RA patients selected from six health regions and from four hospitals in each region, including at least one major teaching hospital and two to three district/general hospitals. Treatment with sDMARDs/biologics was examined between November 2009 and June 2010 in comparison with National Institute for Health and Clinical Excellence (NICE) guidance and in relation to disease activity.

RESULTS

NICE guidance focuses on initiation of therapy and recommends combination sDMARD/biologic therapy. Analysis of 588 patient records indicates that overall 23% of patients were receiving biologic monotherapy. NICE guidance recommends initiation of biologics in patients with active RA (DAS28 >5.1): average DAS28 score on initiation of biologic therapy was above six in all regions. Range of DAS28 improvement post-biologic therapy was similar across all regions. DAS28 scores were well recorded within patient records at baseline and 6 months but not at other time points.

CONCLUSIONS

Our data highlight that nearly a quarter of patients receiving biologic treatments are not receiving concomitant sDMARD therapy and that DAS28 is poorly documented in patient medical records other than when initiating biologics and at the 6-month review. Limitations of this study include the limited sample size, the retrospective rather than prospective nature of the audit and the use of medical records only rather than other records such as nursing and pharmacy data. Nevertheless, the reasons for our findings merit further investigation to ensure that optimum treatment regimes and long term outcomes are being achieved for patients.

Imaging in rheumatoid arthritis

The optimal management of rheumatoid arthritis (RA) requires tools that allow early and accurate disease diagnosis, prediction of poor prognosis and responsive monitoring of therapeutic outcomes. Conventional radiography has been widely used in both clinical and research settings to assess RA joint damage due to its feasibility, but it has limitations in early disease detection and difficulty distinguishing between active treatments in modern trials. Imaging modalities such as magnetic resonance imaging (MRI) and ultrasound (US) have the advantage of detecting both joint inflammation and damage and hence they can provide additional and unique information. This can be especially useful in the context of early and/or undifferentiated joint disease when detection of soft tissue and bone marrow abnormalities is desirable. This review focusses on the recent literature concerning modern imaging, and provides clinicians with an insight into the role of imaging in modern RA diagnosis, prognosis and monitoring.

A mixed treatment comparison of the efficacy of anti-TNF agents in rheumatoid arthritis for methotrexate non-responders demonstrates differences between treatments: a Bayesian approach

BACKGROUND

A number of tumour necrosis factor α (TNFα) antagonists (anti-TNFα) are available to treat rheumatoid arthritis. All of these have demonstrated considerable efficacy in placebo controlled trials, but few head-to-head comparisons exist to date. This work's objective is to estimate the relative efficacy among licensed anti-TNFs in patients who have had an inadequate response to methotrexate (MTX). Different outcome measures are used to highlight the advantages of continuous measures in such analyses.

METHODS

A systematic review identified randomised controlled trials comparing the efficacy of licensed anti-TNFα agents with placebo at 24 weeks in patients who have had an inadequate response to MTX. Relative efficacy was estimated using Bayesian mixed treatment comparison (MTC) models. Three different outcome measures were used: RR of achieving an American College of Rheumatology (ACR) 20 and ACR50 response and the percentage improvement in Health Assessment Questionnaire (HAQ) score.

RESULTS

16 published trials were included in the analysis. All anti-TNFs show considerably improved efficacy over placebo. The MTC results also provide evidence of some differences in efficacy of the TNFα antagonists. Etanercept appears superior to infliximab and golimumab, and certolizumab to infliximab and adalimumab. ACR results indicate improved efficacy of certolizumab over golimumab. On HAQ analysis, adalimumab, certolizumab, etanercept and golimumab appear superior to infliximab, and etanercept shows improved efficacy compared with adalimumab.

CONCLUSIONS

There are differences in efficacy among the TNFα antagonists. In a MTC, a continuous outcome measure has more strength to detect such differences than a binomial outcome measure because of its enhanced sensitivity to change.

Histone deacetylase inhibitors as suppressors of bone destruction in inflammatory diseases

OBJECTIVES

Despite progress in developing many new anti-inflammatory treatments in the last decade, there has been little progress in finding treatments for bone loss associated with inflammatory diseases, such as rheumatoid arthritis and periodontitis. For instance, treatment of rheumatic diseases with anti-tumour necrosis factor-alpha agents has been largely successful in reducing inflammation, but there have been varying reports regarding its effectiveness at inhibiting bone loss. In addition, there is often a delay in finding the appropriate anti-inflammatory therapy for individual patients, and some therapies, such as disease modifying drugs, take time to have an effect. In order to protect the bone, adjunct therapies targeting bone resorption are being developed. This review focuses on new treatments based on using histone deacetylase inhibitors (HDACi) to suppress bone loss in these chronic inflammatory diseases.

KEY FINDINGS

A number of selected HDACi have been shown to suppress bone resorption by osteoclasts in vitro and in animal models of chronic inflammatory diseases. Recent reports indicate that these small molecules, which can be administered orally, could protect the bone and might be used in combination with current anti-inflammatory treatments.

SUMMARY

HDACi do have potential to suppress bone destruction in chronic inflammatory diseases including periodontitis and rheumatoid arthritis.

Phase II study of tofacitinib (CP-690,550) combined with methotrexate in patients with rheumatoid arthritis and an inadequate response to methotrexate

OBJECTIVE

To compare the efficacy, safety, and tolerability of 4 doses of oral tofacitinib (CP-690,550) with placebo in Japanese patients with active rheumatoid arthritis (RA) receiving stable background methotrexate (MTX) who had an inadequate response to MTX alone.

METHODS

A total of 140 patients were randomized to receive tofacitinib 1, 3, 5, and 10 mg twice a day or placebo in this 12-week, phase II, double-blind study. All patients remained on background MTX. Efficacy and safety were assessed at weeks 1, 2, 4, 8, and 12. The primary efficacy end point was the American College of Rheumatology 20% improvement criteria (ACR20) response rate at week 12.

RESULTS

ACR20 response rates at week 12 were significant (P < 0.0001) for all tofacitinib treatment groups: 1 mg twice a day, 64.3%; 3 mg twice a day, 77.8%; 5 mg twice a day, 96.3%; and 10 mg twice a day, 80.8% versus placebo, 14.3%. A significant dose-response relationship for the ACR20 was observed (P < 0.0001). Low disease activity was achieved by 72.7% of patients with high baseline disease activity for tofacitinib 10 mg twice a day at week 12 (P < 0.0001). Significant improvements in the ACR50, ACR70, Health Assessment Questionnaire Disability Index, and Disease Activity Score 28-3 (C-reactive protein) were also reported. The most commonly reported adverse events (AEs) were nasopharyngitis (n = 13) and increased alanine aminotransferase (n = 12) and aspartate aminotransferase (n = 9) levels. These AEs were mild or moderate in severity. Serious AEs were reported by 5 patients. No deaths occurred.

CONCLUSION

In Japanese patients with active RA with an inadequate response to MTX, tofacitinib in combination with MTX over 12 weeks was efficacious and had a manageable safety profile.

Interpreting clinical trial results for moderate-to-severe rheumatoid arthritis: practical applications for rheumatology healthcare providers

PURPOSE

To provide a general overview of clinical trials and more specifically define measurements common to rheumatoid arthritis clinical trials for the purpose of providing a foundation for rheumatology healthcare providers to translate clinical trial findings into their clinical practice and enhance their patient education discussions.

DATA SOURCES

English-language publications cited in the MEDLINE database were used to develop the content of this review article.

CONCLUSIONS

The role of rheumatology healthcare providers has evolved to include numerous vital functions, such as expanding communication between specialists and primary care providers, patient education and counseling, assistance with coping strategies, monitoring response to therapy, and administration of therapy. Education regarding clinical trial design, rationale, and discussion of endpoints has not been strongly emphasized for rheumatology healthcare providers who are increasingly introduced to novel agents and need to assimilate findings from clinical trials into daily practice.

IMPLICATIONS FOR PRACTICE

Familiarity with the basics of clinical trial design and efficacy endpoints of new rheumatoid arthritis therapeutics, translation and application of that knowledge into daily practice, and the ability to explain this information with patients will further enhance the ability of the rheumatology healthcare provider to optimize care for their patients with rheumatoid arthritis.

Changes in patient characteristics in anti-tumour necrosis factor clinical trials for rheumatoid arthritis: results of an analysis of the literature over the past 16 years

OBJECTIVE

To evaluate changes in baseline patient characteristics and entry criteria of randomised, controlled studies of tumour necrosis factor alpha (TNFα) inhibitors in rheumatoid arthritis (RA) patients.

METHODS

A systematic literature review was performed using predefined inclusion criteria to identify randomised, double-blind, controlled trials that evaluated TNFα inhibitors in adult RA patients. Entry criteria and baseline clinical characteristics were evaluated over time for methotrexate-experienced and methotrexate-naive study populations. Enrolment start date for each trial was the time metric. The anchor time was the study with the earliest identifiable enrolment start date.

RESULTS

44 primary publications (reporting the primary study endpoint) from 1993 to 2008 met the inclusion criteria. Enrolment start dates of August 1993 and May 1997 were identified as time anchors for the 37 methotrexate-experienced studies and the seven methotrexate-naive studies, respectively. In methotrexate-experienced trials, no significant change was observed over the years included in this study in any inclusion criteria (including swollen joint counts and C-reactive protein (CRP)), but a significant decrease over time was observed in the baseline swollen joint count, CRP and total Sharp or van der Heijde modified Sharp score, but not in baseline tender joint counts. In the methotrexate-naive studies, significant decreases over the years were observed in swollen joint and tender joint inclusion criteria, but not in baseline tender joint count, baseline CRP, CRP inclusion criteria or baseline total Sharp or van der Heijde modified Sharp score.

CONCLUSION

Inclusion criteria and baseline characteristics of RA patients enrolled in studies of TNFα inhibitors have changed, with more recent trials enrolling cohorts with lower disease activity, especially in methotrexate-experienced trials.

Canadian Recommendations for Clinical Trials of Pharmacologic Interventions in Rheumatoid Arthritis: Inclusion Criteria and Study Design: Table 1

Objective.

Current clinical trial designs for pharmacologic interventions in rheumatoid arthritis (RA) do not reflect the innovations in RA diagnosis, treatment, and care in countries where new drugs are most often used. The objective of this project was to recommend revised entry criteria and other study design features for RA clinical trials.

Methods.

Recommendations were developed using a modified nominal group consensus method. Canadian Rheumatology Research Consortium (CRRC) members were polled to rank the greatest challenges to clinical trial recruitment in their practices. Initial recommendations were developed by an expert panel of rheumatology trialists and other experts. A scoping study methodology was then used to examine the evidence available to support or refute each initial recommendation. The potential influence of CRRC recommendations on primary outcomes in future trials was examined. Recommendations were finalized using a consensus process.

Results.

Recommendations for clinical trial inclusion criteria addressed measures of disease activity [Disease Activity Score 28 using erythrocyte sedimentation rate (DAS28-ESR) > 3.2 PLUS ≥ 3 tender joints using 28-joint count (TJC28) PLUS ≥ 3 swollen joint (SJC28) OR C-reactive protein (CRP) or ESR > upper limit of normal PLUS ≥ 3 TJC28 PLUS ≥ 3 SJC28], functional classification, disease classification and duration, and concomitant RA treatments. Additional recommendations regarding study design addressed rescue strategies and longterm extension.

Conclusion.

There is an urgent need to modify clinical trial inclusion criteria and other study design features to better reflect the current characteristics of people living with RA in the countries where the new drugs will be used.

Rheumatoid arthritis disease-modifying antirheumatic drug intervention and utilization study: safety and etanercept utilization analyses from the RADIUS 1 and RADIUS 2 registries

OBJECTIVE

to report the rates of serious adverse events (SAE), serious infectious events (SIE), and events of medical interest (EMI) in patients receiving etanercept; to identify the risk factors for SAE, SIE, and EMI; and to report time to switching from etanercept therapy, reasons for switching, and time to restarting treatment with etanercept in patients with rheumatoid arthritis (RA) in US clinical practice.

METHODS

adults ≥ 18 years of age who fulfilled the 1987 American Rheumatism Association criteria for RA were eligible for enrollment in 2 prospective, 5-year, multicenter, observational registries. RADIUS 1 (Rheumatoid Arthritis DMARD Intervention and Utilization Study) enrolled patients with RA who required a change in treatment [either an addition or a switch of a biologic or nonbiologic disease-modifying antirheumatic drug (DMARD)]. In RADIUS 2, patients with RA were required to start etanercept therapy at entry. Patients were seen at a frequency determined by their rheumatologist. RADIUS 1 and RADIUS 2 were registered under the US National Institutes of Health ClinicalTrials.gov identifiers NCT00116714 and NCT00116727, respectively.

RESULTS

in these patients, SAE, SIE, and EMI occurred at rates comparable to those seen in clinical trials. No unexpected safety signals were observed. Rates for SAE, SIE, and EMI in etanercept-treated patients were comparable to rates observed in patients receiving methotrexate monotherapy and did not increase with greater exposure to etanercept therapy.

CONCLUSION

the RADIUS registries provide a better understanding of the safety of etanercept in patients with RA in the US practice setting.