Clinical utility of therapeutic drug monitoring in biological disease modifying anti-rheumatic drug treatment of rheumatic disorders: a systematic narrative review

INTRODUCTION

Biological Disease Modifying Anti-Rheumatic Drugs (bDMARDs) have improved the treatment outcomes of inflammatory rheumatic diseases including Rheumatoid Arthritis and spondyloarthropathies. Inter-individual variation exists in (maintenance of) response to bDMARDs. Therapeutic Drug Monitoring (TDM) of bDMARDs could potentially help in optimizing treatment for the individual patient. Areas covered: Evidence of clinical utility of TDM in bDMARD treatment is reviewed. Different clinical scenarios will be discussed, including: prediction of response after start of treatment, prediction of response to a next bDMARD in case of treatment failure of the first, prediction of successful dose reduction or discontinuation in case of low disease activity, prediction of response to dose-escalation in case of active disease and prediction of response to bDMARD in case of flare in disease activity. Expert opinion: The limited available evidence does often not report important outcomes for diagnostic studies, such as sensitivity and specificity. In most clinical relevant scenarios, predictive value of serum (anti-) drug levels is absent, therefore the use of TDM of bDMARDs cannot be advocated. Well-designed prospective studies should be done to further investigate the promising scenarios to determine the place of TDM in clinical practice.

Low disease activity (DAS28≤3.2) reduces the risk of first cardiovascular event in rheumatoid arthritis: a time-dependent Cox regression analysis in a large cohort study

OBJECTIVE

Systemic inflammation appears to contribute to the excess risk of cardiovascular disease (CVD) in rheumatoid arthritis (RA). The objective of this study was to investigate the effect of different levels of disease activity over time, particularly low disease activity and remission, on CVD risk in patients with RA.

METHODS

Data from the Nijmegen early RA inception cohort were used. The primary outcome was first CVD events within the first 10 years of follow-up. Cut points of the DAS28 for remission (<2.6) and low (≤3.2), moderate (3.2-5.1) and high (>5.1) disease activity were used. The effect of disease activity on CVD risk was analysed using Cox-proportional hazards regression with DAS28 as a time-dependent covariate and also conventionally with time-averaged DAS28 as the primary dependent variable.

RESULTS

Low DAS28 (≤3.2) was significantly associated with a reduced risk of CVD (HR 0.65, 95% CI 0.43 to 0.99) compared with DAS28 >3.2, both when included as a time-dependent covariate and as time-averaged DAS28 ≤3.2 (HR 0.52, 95% CI 0.33 to 0.81). Remission had a modest, non-significant protective effect against CVD (HR 0.67, 95% CI 0.43 to 1.07).

CONCLUSION

Results of this study suggest that low disease activity is sufficient to achieve a protective effect against CVD in RA. Apparently, remission defined as DAS28 <2.6 has no additional protective effect against CVD compared with low disease activity. Our results strengthen the use of tight control strategies in daily clinical practice to achieve low stable disease activity or remission in patients with RA as soon as possible.

De-intensifying treatment in established rheumatoid arthritis (RA): Why, how, when and in whom can DMARDs be tapered?

As more patients with established rheumatoid arthritis (RA) achieve remission or low disease activity, strategies such as tapering and withdrawal of disease-modifying antirheumatic drugs (DMARDs) are being investigated. In several trials, DMARD discontinuation was associated with a higher risk of relapse, ranging from 56% to 87% at 1 year. Tapering, either by dose reduction or by injection spacing, may limit the risk of relapse. Half-dose etanercept (ETN) versus full-dose continuation was not associated with an increased relapse risk at 1 year in two trials. Progressive antitumor necrosis factor injection spacing was shown to be equivalent to full regimen continuation in terms of persistent flare and disease activity at 18 months in one trial, but not in another one. Reintroduction of a DMARD at previous dose/regimen was usually associated with remission re-induction. The risk of relevant structural damage progression was not increased. Safety improvement has not yet been demonstrated. The annual cost reduction when tapering biologic DMARDs (bDMARDs) was 3500-6000 €/patient. Research questions to be addressed include defining flare that requires reinitiation of treatment, such that patients facilitate the maintenance of remission during tapering by timely communication with their rheumatology team.

A tight control treatment strategy aiming for remission in early rheumatoid arthritis is more effective than usual care treatment in daily clinical practice: a study of two cohorts in the Dutch Rheumatoid Arthritis Monitoring registry

There is strong evidence from clinical trials that a 'treat to target' strategy is effective in reaching remission in rheumatoid arthritis (RA). However, the question is whether these results can be translated into daily clinical practice and clinical remission is a reachable target indeed.

OBJECTIVE

The study aims to investigate whether in early RA a treatment strategy aiming at Disease Activity Score (DAS) 28 <2.6 is more effective than 'usual care' treatment for reaching clinical remission after 1 year.

METHODS

Two early RA inception cohorts from two different regions including patients who fulfilled the American College of Rheumatology criteria for RA were compared. Patients in the tight-control cohort (n=126) were treated according to a DAS28-driven step-up treatment strategy starting with methotrexate, addition of sulphasalazine (SSZ) and exchange of SSZ by anti-tumour necrosis factor in case of failure. Patients in the usual-care cohort (n=126) were treated with methotrexate or SSZ, without DAS28-guided treatment decisions. The primary outcome was the percentage remission (DAS28<2.6) at 1 year. Time to first remission and change in DAS28 were secondary outcomes.

RESULTS

After 1 year, 55% of tight-control patients had a DAS28<2.6 versus 30% of usual care patients (OR 3.1, 95% CI 1.8 to 5.2). The median time to first remission was 25 weeks for tight control and more than 52 weeks for usual care (p<0.0001). The DAS28 decreased with -2.5 in tight control and -1.5 in usual care (p<0.0001).

CONCLUSION

In early RA, a tight control treatment strategy aiming for remission leads to more rapid DAS28 remission and higher percentages of remission after 1 year than does a usual care treatment.