Enzyme-linked immunosorbent assays for monitoring TNF-alpha inhibitors and antibody levels in people with rheumatoid arthritis: a systematic review and economic evaluation

BACKGROUND

Rheumatoid arthritis is a chronic autoimmune disease that primarily causes inflammation, pain and stiffness in the joints. People with severe disease may be treated with biological disease-modifying anti-rheumatic drugs, including tumour necrosis factor-α inhibitors, but the efficacy of these drugs is hampered by the presence of anti-drug antibodies. Monitoring the response to these treatments typically involves clinical assessment using response criteria, such as Disease Activity Score in 28 joints or European League Against Rheumatism. Enzyme-linked immunosorbent assays can also be used to measure drug and antibody levels in the blood. These tests may inform whether or not adjustments to treatment are required or help clinicians to understand the reasons for treatment non-response or a loss of response.

METHODS

Systematic reviews were conducted to identify studies reporting on the clinical effectiveness and cost-effectiveness of using enzyme-linked immunosorbent assays to measure drug and anti-drug antibody levels to monitor the response to tumour necrosis factor-α inhibitors [adalimumab (Humira^®; AbbVie, Inc., North Chicago, IL, USA), etanercept (Enbrel^®; Pfizer, Inc., New York, NY, USA), infliximab (Remicade^®, Merck Sharp & Dohme Limited, Hoddesdon, UK), certolizumab pegol (Cimzia^®; UCB Pharma Limited, Slough, UK) and golimumab (Simponi^®; Merck Sharp & Dohme Limited)] in people with rheumatoid arthritis who had either achieved treatment target (remission or low disease activity) or shown primary or secondary non-response to treatment. A range of bibliographic databases, including MEDLINE, EMBASE and CENTRAL (Cochrane Central Register of Controlled Trials), were searched from inception to November 2018. The risk of bias was assessed using the Cochrane ROBINS-1 (Risk Of Bias In Non-randomised Studies - of Interventions) tool for non-randomised studies, with adaptations as appropriate. Threshold and cost-utility analyses that were based on a decision tree model were conducted to estimate the economic outcomes of adding therapeutic drug monitoring to standard care. The costs and resource use were considered from the perspective of the NHS and Personal Social Services. No discounting was applied to the costs and effects owing to the short-term time horizon of 18 months that was adopted in the economic analysis. The impact on the results of variations in testing and treatment strategies was explored in numerous clinically plausible sensitivity analyses.

RESULTS

Two studies were identified: (1) a non-randomised controlled trial, INGEBIO, that compared standard care with therapeutic drug monitoring using Promonitor^® assays [Progenika Biopharma SA (a Grifols-Progenika company), Derio, Spain] in Spanish patients receiving adalimumab who had achieved remission or low disease activity; and (2) a historical control study. The economic analyses were informed by INGEBIO. Different outcomes from INGEBIO produced inconsistent results in both threshold and cost-utility analyses. The cost-effectiveness of therapeutic drug monitoring varied, from the intervention being dominant to the incremental cost-effectiveness ratio of £164,009 per quality-adjusted life-year gained. However, when the frequency of testing was assumed to be once per year and the cost of phlebotomy appointments was excluded, therapeutic drug monitoring dominated standard care.

LIMITATIONS

There is limited relevant research evidence and much uncertainty about the clinical effectiveness and cost-effectiveness of using enzyme-linked immunosorbent assay-based testing for therapeutic drug monitoring in rheumatoid arthritis patients. INGEBIO had serious limitations in relation to the National Institute for Health and Care Excellence scope: only one-third of participants had rheumatoid arthritis, the analyses were mostly not by intention to treat and the follow-up was 18 months only. Moreover, the outcomes might not be generalisable to the NHS.

CONCLUSIONS

Based on the available evidence, no firm conclusions could be made about the cost-effectiveness of therapeutic drug monitoring in England and Wales.

FUTURE WORK

Further controlled trials are required to assess the impact of using enzyme-linked immunosorbent assays for monitoring the anti-tumour necrosis factors in people with rheumatoid arthritis.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42018105195.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 8. See the NIHR Journals Library website for further project information.

New Approaches in Tumor Necrosis Factor Antagonism for the Treatment of Psoriatic Arthritis: Certolizumab Pegol

The pathogenesis of psoriatic arthritis (PsA) is still under discussion but great advances have been made in the last 2 decades that confirm the central role of tumor necrosis factor-α (TNF-α) in its inflammatory milieu. New therapeutic approaches have been proposed, and new molecules with anti-TNF-α activity have been chemically altered to improve their pharmacological properties. Certolizumab pegol (CZP) is a PEGylated Fc-free anti-TNF that has been shown clinically to be effective in the treatment of rheumatoid arthritis (RA), skin psoriasis, and PsA. This article summarizes available data on its clinical efficacy and safety profile in the treatment of patients with PsA.

Tuberculosis risk in patients treated with non-anti-tumor necrosis factor-α (TNF-α) targeted biologics and recently licensed TNF-α inhibitors: data from clinical trials and national registries

This review aimed to evaluate the risk of active tuberculosis (TB) occurrence in patients with rheumatic disorders receiving non-anti-tumor necrosis factor (TNF) targeted biologics anakinra (ANK), tocilizumab (TCZ), rituximab (RTX), abatacept (ABA), and recently approved anti-TNF golimumab (GOL), and certolizumab pegol (CTP). In recent findings, no cases of active TB were recorded in patients with rheumatoid arthritis (RA) and other rheumatic conditions treated with anti-CD20+ RTX and anti-CD28 ABA. No patient receiving anti-interleukin 1 (IL-1) ANK developed active TB, and an increased risk was excluded in a Canadian database. In contrast, 8 active TB cases were observed in 21 trials of patients with RA receiving anti-IL-6 TCZ, while no increased TB risk resulted from Japanese postmarketing surveillance. Among GOL-treated and CTP-treated patients, 8 and 10 active TB cases occurred, respectively, while no data are available from registries. However, all but 1 TB case recorded in patients treated with TCZ, GOL, and CTP occurred in TB-endemic countries. No TB risk resulted for ANK, RTX, and ABA, suggesting pretreatment screening procedures for latent TB infection detection are unnecessary. Because all TB cases occurred in countries at high risk for TB, where TB exposure could have occurred during treatment, no definitive conclusions can be drawn for TCZ, GOL, and CTP.

Vaccine responses in patients with rheumatoid arthritis treated with certolizumab pegol: results from a single-blind randomized phase IV trial

OBJECTIVE

To evaluate the humoral immune response to pneumococcal and influenza vaccination in adults with rheumatoid arthritis (RA) receiving certolizumab pegol (CZP).

METHODS

In this 6-week, single-blind, placebo-controlled trial with optional 6-month open-label extension (NCT00993668), patients were stratified by concomitant methotrexate (MTX) use and randomized to receive CZP 400 mg (loading dose; according to CZP label) or placebo at weeks 0, 2, and 4. Pneumococcal (polysaccharide 23) and influenza vaccines were administered at Week 2. Satisfactory humoral immune response, defined as ≥2-fold titer increase in ≥3 of 6 pneumococcal antigens and ≥4-fold titer increase in ≥2 of 3 influenza antigens, were assessed independently 4 weeks after vaccination.

RESULTS

Following pneumococcal vaccination, 62.5% of placebo patients and 54.5% of CZP patients without effective titers at baseline achieved a humoral response (difference in proportions was -8.0 percentage points; 95% CI -22.5 to 6.6%). Following influenza vaccination, 61.4% of placebo and 53.5% of CZP patients without effective titers at baseline achieved a humoral response (difference in proportions: -8.0 percentage points; 95% CI -22.9 to 7.0%). In all patients, including those with effective titers at baseline, 58.2% of placebo and 53.3% of CZP patients developed satisfactory pneumococcal titers, and 54.1% of placebo and 50.5% of CZP patients developed satisfactory influenza antibody titers. Vaccine responses to pneumococcal and influenza antigens were reduced similarly in both treatment groups with concomitant MTX use.

CONCLUSION

Humoral immune responses to pneumococcal and influenza vaccination are not impaired when given during the loading phase of CZP treatment in patients with RA. (ClinicalTrials.gov NCT00993668).