Clinical trials in rheumatic diseases: designs and limitations

Medical Rehabilitation: Guidelines to Advance the Field With High-Impact Clinical Trials

The purpose of this Special Communication is to summarize guidelines and recommendations stemming from an expert panel convened by the National Institutes of Health, National Center for Medical Rehabilitation Research (NCMRR) for a workshop entitled The Future of Medical Rehabilitation Clinical Trials, held September 29-30, 2016, at the NCMRR offices in Bethesda, Maryland. The ultimate goal of both the workshop and this summary is to offer guidance on clinical trials design and operations to the medical rehabilitation research community, with the intent of maximizing the effect of future trials.

Clinical trials: Kids are not just little people

Clinical trials are the backbone of modern evidence-based medicine. They are the vital bridge between research-based discovery and cutting edge patient care. Randomized, controlled clinical trials are the gold standard of medical research, providing a method for evaluation and discovery of novel therapies that improve and even save lives. Despite an increase in the number of pediatric and adult clinical trials over recent decades, this growth has not been equal among these populations. The volume of clinical trials involving children lags substantially behind their adult counterparts. Children are not simply little adults. As a result, extrapolating results from adult clinical trials to the treatment of children may be inappropriate and, possibly, harmful. In this review, we discuss the intricacies of performing clinical trials in all patients and stress the unique distinguishing characteristics of pediatric clinical trials.

Generalizability of Patients With Rheumatoid Arthritis in Biologic Agent Clinical Trials

OBJECTIVE

Randomized controlled trials (RCTs) have consistently demonstrated the efficacy of biologic agents in treating patients with rheumatoid arthritis (RA) who satisfy strict eligibility criteria, yet studies report that a majority of RA patients in the US have had biologic treatment exposure. We identified the proportion of RA patients in clinical practice satisfying entry criteria for biologic agent RCTs.

METHODS

Eligibility criteria of 30 RCTs of 10 Food and Drug Administration-approved biologic agents to treat RA were reviewed, summarized, and applied to 2 observational clinical cohorts: the Veterans Affairs Rheumatoid Arthritis registry (VARA; n = 1,523) and the Rheumatology and Arthritis Investigational Network Database (RAIN-DB; n = 1,548). Patients at a single clinical encounter were assessed for overall trial eligibility as well as eligibility across 3 domains: demographics, disease activity, and medication exposure.

RESULTS

The mean percentage of patients that satisfied eligibility criteria was 3.7% (interquartile range [IQR] 1.5-3.1) in VARA and 7.1% (IQR 4.4-7.7) in RAIN-DB. Ineligibility was most often due to low disease activity, specifically low joint counts. The mean Disease Activity Score in 28 joints at enrollment was 6.59 (range 6.1-7.1) across RCTs versus 3.87 (0.07-8.69) in VARA and 3.65 (0.49-7.21) in RAIN-DB. RCTs for non-tumor necrosis factor (TNF) inhibitor biologic agents were more restrictive than RCTs for TNF inhibitors. There was no trend in eligibility by RCT study publication or drug approval date.

CONCLUSION

The vast majority of RA patients from our clinical cohorts did not satisfy criteria for participation in biologic agent RCTs. These findings underscore the need for caution in extrapolating trial results to day-to-day management of RA patients and may provide insight into the differential responses to biologic agents reported in prior observational studies.

Clinical trials documenting the efficacy of low-dose glucocorticoids in rheumatoid arthritis

Twelve clinical trials have documented that prednisone or prednisolone in doses of 10 mg/day or less is efficacious to improve function, maintain status and/or slow radiographic progression in patients with rheumatoid arthritis (RA). An early trial reported by de Andrade et al. [Ann Rheum Dis 1964;23:158-162] in 1964 indicated that 5 mg of prednisolone at night was preferred to 5 mg of prednisone in the morning. Harris et al. [J Rheumatol 1983;10:713-721] documented the efficacy of 5 mg/day of prednisone in a non-double-blind trial in 1983. Two important trials in the 1990s by Kirwan [N Engl J Med 1995;333:142-146] using 7.5 mg/day, and the COBRA study by Boers et al. [Lancet 1997;350:309-318] with step-down from 60 mg rapidly tapered to 5 mg/day led to strong advocacy of low-dose glucocorticoids. In 2002, the first Utrecht Study [Ann Intern Med 2002;136:1-12] indicated that 10 mg/day prednisone slowed radiographic progression, a finding confirmed and extended in 2005 by Svensson et al. [Arthritis Rheum 2005;52:3360-3370] with 7.5 mg/day, and Wassenberg et al. [Arthritis Rheum 2005;52:3371-3380] with 5 mg/day of prednisolone. In 2008, Buttgereit et al. [Lancet 2008;371:205-214] reported CAPRA-1, which documented that modified-release prednisone or prednisolone taken at bedtime led to lower morning stiffness and IL-6 levels compared to usual morning prednisone. In 2009, Pincus et al. [Ann Rheum Dis 2009;68:1715-1720] reported a withdrawal clinical trial, in which patients who took 3 mg/day were gradually withdrawn to placebo, and dropped out at a significantly higher rate than control patients who were 'withdrawn' to prednisone. In 2012, a second Utrecht Study [Ann Intern Med 2012;156:329-339], CAMERA-II, documented that 10 mg of prednisone added to a 'treat-to-target' strategy with methotrexate provided incremental slowing of radiographic progression. An Italian study of patients with early RA who received step-up disease-modifying antirheumatic drug therapy over 2 years plus prednisolone or not indicated higher rates of clinical remission and sustained remission associated with 7.5 mg/day of prednisolone [Arthritis Res Ther 2012; 14:R112]. The CAPRA-2 trial [Ann Rheum Dis 2013;72:204-210] documented that modified-release nighttime prednisone or prednisolone was significantly more efficacious than placebo. Taken together, these 12 clinical trials indicate that low-dose glucocorticoids prednisone or prednisolone provides symptomatic relief, improved functional status and slowing of radiographic progression for patients with RA. © 2014 S. Karger AG, Basel.

The past versus the present, 1980-2004: reduction of mean initial low-dose, long-term glucocorticoid therapy in rheumatoid arthritis from 10.3 to 3.6 mg/day, concomitant with early methotrexate, with long-term effectiveness and safety of less than 5 mg/day

Quantitative observations are presented concerning treatment with glucocorticoids of 308 patients with rheumatoid arthritis (RA) at a weekly academic rheumatology setting over 25 years from 1980 to 2004. A database of all visits included medications and multidimensional health assessment questionnaire scores for physical function, pain and routine assessment of patient index data (RAPID3; and a surrogate RAPID3-EST), completed by each patient at each visit in routine care. Over the 5-year periods of 1980-1984, 1985-1989, 1990-1994, 1995-1999 and 2000-2004, the mean initial prednisone daily dose declined from 10.3 to 6.5, 5.1, 4.1 and 3.6 mg/day, as initial doses were >5 mg/day in 49, 16, 7, 7 and 3% of patients, 5 mg/day in 51, 80, 70, 26 and 10%, and <5 mg/day in 0, 4, 23, 67 and 86%. Reduction of prednisone doses in the respective five-year periods was accompanied by increased and earlier use of methotrexate as the first disease-modifying antirheumatic drug (DMARD) in 10, 26, 57, 71 and 78%, and methotrexate treatment in 10, 26, 74, 82 and 92% of patients within the first year of disease. Higher methotrexate doses in the respective five-year periods were used after 1990, along with lower prednisone doses. Most patients were treated indefinitely with both low-dose prednisone and methotrexate; 80% continued both medications for more than 5 years. The primary adverse events were skin-thinning and bruising. New hypertension, diabetes and cataracts were seen in fewer than 10% of patients. While efficacy and safety cannot be analyzed definitively from observational data, the data suggest that many patients with RA might be treated effectively with weekly low-dose methotrexate along with initial and long-term, low-dose prednisone of <5 mg/day.

Comparative persistence of the TNF antagonists in rheumatoid arthritis--a population-based cohort study

Objective

To compare persistence with tumor necrosis factor alpha (TNF) antagonists among rheumatoid arthritis patients in British Columbia. Treatment persistence has been suggested as a proxy for real-world therapeutic benefit and harm of treatments for chronic non-curable diseases, including rheumatoid arthritis. We hypothesized that the different pharmacological characteristics of infliximab, adalimumab and etanercept cause statistically and clinically significant differences in persistence.

Methods

We conducted a population-based cohort study using administrative health data from the Canadian province of British Columbia. The study cohort included rheumatoid arthritis patients who initiated the first course of a TNF antagonist between 2001 and 2008. Persistence was measured as the time between first dispensing to discontinuation. Drug discontinuation was defined as a drug-free interval of 180 days or switching to another TNF antagonist, anakinra, rituximab or abatacept. Persistence was estimated and compared using survival analysis.

Results

The study cohort included 2,923 patients, 63% treated with etanercept. Median persistence in years (95% confidence interval) with infliximab was 3.7 (2.9–4.9), with adalimumab 3.3 (2.6–4.1) and with etanercept 3.8 (3.3–4.3). Similar risk of discontinuation was observed for the three drugs: the hazard ratio (95% confidence interval) was 0.98 (0.85–1.13) comparing infliximab with etanercept, 0.95 (0.78–1.15) comparing infliximab with adalimumab and 1.04 (0.88–1.22) comparing adalimumab with etanercept.

Conclusions

Similar persistence was observed with infliximab, adalimumab and etanercept in rheumatoid arthritis patients during the first 9 years of use. If treatment persistence is a good proxy for the therapeutic benefit and harm of these drugs, then this finding suggests that the three drugs share an overall similar benefit-harm profile in rheumatoid arthritis patients.

Early treatment with, and time receiving, first disease-modifying antirheumatic drug predicts long-term function in patients with inflammatory polyarthritis

OBJECTIVES

To investigate the influence of early disease-modifying antirheumatic drug (DMARD) treatment on long-term functional outcome in patients with recent-onset inflammatory polyarthritis (IP), and the impact of the duration of first and subsequent DMARD treatment.

METHODS

642 subjects from a primary care registry of patients with new-onset IP, recruited 1990-4, were followed up for 10 years. Mean change in Health Assessment Questionnaire (HAQ) scores between baseline and 10 years were compared by time to, and time receiving, first DMARD treatment and total time receiving treatment, using linear regression. Adjustment for time-dependent confounders and censoring was performed using marginal structural weights.

RESULTS

When adjusted for baseline and subsequent disease severity, those treated early (<6 months from symptom onset) experienced a non-significant improvement in function compared with those never treated (adjusted mean difference in change (adj_MDIC) in HAQ -0.24; 95% CI -0.58 to 0.09); and a significant benefit for each additional month of treatment within 6 months of the onset of symptoms (adj_MDIC -0.10; 95% CI -0.19 to -0.02). Patients who discontinued their first DMARD within 6 months experienced a significant deterioration in long-term function (adj_MDIC in HAQ 0.28; 95% CI 0.04 to 0.52), while those who continued their first treatment for > 3 years experienced an improvement (adj_MDIC in HAQ -0.37; 95% CI -0.77 to 0.04).

CONCLUSIONS

The importance of time to, and response to, first DMARD treatment and total duration of DMARD treatment in modifying the 10-year function in patients with IP has been demonstrated.

Stable occurrence of knee and hip total joint replacement in Central Finland between 1986 and 2003: an indication of improved long-term outcomes of rheumatoid arthritis

BACKGROUND

Total joint replacement (TJR) surgery is an important severe long-term outcome of rheumatoid arthritis, but relatively little is known about changes of its incidence in patients with rheumatoid arthritis over the past two decades.

METHODS

A population-based, retrospective, incidence case review was conducted to analyse the frequency of primary TJR surgery of the knee and hip in all patients, and specifically in patients with rheumatoid arthritis in Central Finland between 1986 and 2003. Patients with TJR surgery of the knee and hip were identified in hospital databases over the 18-year period. Age-standardised incidence rate ratios for the primary TJR of the knee and hip were calculated, stratified to sex and diagnosis, with 1986 as the reference value.

RESULTS

In patients without rheumatoid arthritis the age-adjusted incidence rate ratios (with 95% CI) for TJR of the knee increased 9.8-fold from 1986 to 2003 in women and men, and for TJR of the hip 1.8-fold in women and 2-fold in men. By contrast, no meaningful change was seen over this period, in age-adjusted incidence rate ratios for TJR of the knee or hip in patients with rheumatoid arthritis, ranging from 0.7 to 1.2 in 2003 compared with 1986.

CONCLUSION

The prevalence of TJR surgery has increased 2-10-fold in patients without rheumatoid arthritis patients, associated with an ageing population, but has not increased in patients with rheumatoid arthritis between 1986 and 2003. These data are consistent with emerging evidence that long-term outcomes of rheumatoid arthritis have improved substantially, even before the availability of biological agents.

Risks of solid cancers in patients with rheumatoid arthritis and after treatment with tumour necrosis factor antagonists

BACKGROUND

Existing studies of solid cancers in rheumatoid arthritis (RA) reflect cancer morbidity up until the early 1990s in prevalent cohorts admitted to hospital during the 1980s.

OBJECTIVE

To depict the cancer pattern of contemporary patients with RA, from updated risk data from prevalent and incident RA populations. To understand the risk of solid cancer after tumour necrosis factor (TNF) treatment by obtaining cancer data from cohorts treated in routine care rather than trials.

METHODS

A population based study of three RA cohorts (one prevalent, admitted to hospital 1990-2003 (n = 53,067), one incident, diagnosed 1995-2003 (n = 3703), and one treated with TNF antagonists 1999-2003 (n = 4160)), which were linked with Swedish nationwide cancer and census registers and followed up for cancer occurrence through 2003.

RESULTS

With 3379 observed cancers, the prevalent RA cohort was at marginally increased overall risk of solid cancer, with 20-50% increased risks for smoke related cancers and +70% increased risk for non-melanoma skin cancer, but decreased risk for breast (-20%) and colorectal cancer (-25%). With 138 cancers, the incident RA cohort displayed a similar cancer pattern apart from non-decreased risks for colorectal cancer. TNF antagonist treated patients displayed solid cancer (n = 67) risks largely similar to those of other patients with RA.

CONCLUSION

The cancer pattern in patients treated with TNF antagonists mirrors those of other contemporary as well as historic RA cohorts. The consistent increase in smoking associated cancers in patients with RA emphasises the potential for smoking cessation as a cancer preventive measure in RA.