Anticorps anti-médicament, auto-anticorps et traitements biologiques du psoriasis

Anti-drug antibodies of IL-17 inhibitors for psoriasis: a systematic review

Biologics may elicit the production of anti-drug antibodies (ADAs), the clinical significance of which is not fully understood. ADA development in psoriasis patients on IL-17 inhibitors was evaluated by incidence, impact on efficacy, and relationship with adverse events. We systematically searched PubMed, Cochrane, and Embase databases, identifying 456 references. 17 studies met inclusion criteria. ADA incidence was: 0% to 5.5% (secukinumab), 11% to 19.4% (ixekizumab), 0% to 3.3% (brodalumab), and 19% to 39% (bimekizumab). Neutralizing antibody incidence was: 0% to 1.5% (secukinumab), 0% to 3.5% (ixekizumab), and 0% (brodalumab). ADA presence alone with secukinumab, ixekizumab, and bimekizumab did not impact drug efficacy. Brodalumab was the only one of the IL-17 inhibitors, which showed a reduction in efficacy in ADA + patients. In one analysis, high ADA titers to ixekizumab were associated with diminished treatment response. ADAs to secukinumab and bimekizumab were not associated with adverse events. There were limited data on ADAs and safety with ixekizumab or brodalumab. Overall, when monitoring patients on secukinumab, ADAs, titers, and the presence of neutralizing antibodies were not prognostic of outcomes. However, monitoring for ADAs with brodalumab and measuring titers with ixekizumab may be of value clinically.

Immunogenicity of biologic therapies in psoriasis: Myths, facts and a suggested approach

With biologic drugs dominating the therapeutic space for severe immune-mediated inflammatory disease, it is critical for clinicians to be familiar with the concept of drug immunogenicity, with the potential for our patients to develop antidrug antibodies (ADA) of clinical relevance. Whilst there are clear differences between different therapeutic biologics in terms of reported ADA rates, there is no accepted dermatology guideline or grouping of drugs by risk of clinically relevant ADA, nor a consensus on approach to ADA management. This is partly because making valid comparisons of immunogenicity across drugs is fundamentally flawed: the differing types of ADA assay, trial design and included patient population - as well as the molecular structure of the biologic molecules themselves - are all highly influential on reported ADA prevalence and impact on clinical response. Therefore, the first part of this article aims to give an overview of ADA that also clarifies common misconceptions on the subject, whilst the second part of this article outlines Phase III immunogenicity data on commonly used biologics for psoriasis, the most common dermatological indication. Based on this, and acknowledging current limitations in available evidence, we propose a working categorization of biologics together with a broad approach to management: Group 1 - biologics with higher risk of clinically relevant ADA; Group 2 - biologics with lower risk of clinically relevant ADA; and Group 3 - biologics with no established risk of clinically relevant ADA. However, these groupings represent a working concept only; more research is required, using comparable ADA assays and consistent reporting of related outcomes. Finally, there is an urgent need for better characterization of individuals at particular risk of developing ADA to inform future clinical decision-making.

Recognition of oxidized albumin and thyroid antigens by psoriasis autoantibodies. A possible role of reactive-oxygen-species induced epitopes in chronic plaque psoriasis

OBJECTIVES

To investigate the role of reactive-oxygen-species (ROS) induced epitopes on human-serum-albumin (HSA) and thyroid antigens in psoriasis autoimmunity.  

METHODS

This study was performed in the College of Medicine, Qassim University, Buraidah, Saudi Arabia between May 2014 and February 2015. The study was designed to explore the role of ROS-induced epitopes in psoriasis autoimmunity. Singlet-oxygen (or ROS)-induced epitopes on protein (ROS-epitopes-albumin) was characterized by in-vitro and in-vivo. Thyroid antigens were prepared from rabbit thyroid, and thyroglobulin was isolated from thyroid extract. Immunocross-reactions of protein-A purified anti-ROS-epitopes-HSA-immunoglobulin G (IgGs) with thyroid antigen, thyroglobulin, and their oxidized forms were determined. Binding characteristics of autoantibodies in chronic plaque psoriasis patients (n=26) against ROS-epitopes-HSA and also with native and oxidized thyroid antigens were screened, and the results were compared with age-matched controls (n=22). 

RESULTS

The anti-ROS-epitopes-HSA-IgGs showed cross-reactions with thyroid antigen, thyroglobulin and with their oxidized forms. High degree of specific binding by psoriasis IgGs to ROS-epitopes-HSA, ROS-thyroid antigen and ROS-thyroglobulin was observed. Immunoglobulin G from normal-human-controls showed negligible binding with all tested antigens. Moreover, sera from psoriasis patients had higher levels of carbonyl contents compared with control sera.  

CONCLUSION

Structural alterations in albumin, thyroid antigens by ROS, generate unique neo-epitopes that might be one of the factors for the induction of autoantibodies in psoriasis.

Immunogenicity and Lupus-Like Autoantibody Production Can Be Linked to Each Other along With Type I Interferon Production in Patients with Rheumatoid Arthritis Treated With Infliximab: A Retrospective Study of a Single Center Cohort

Besides anti-drug antibodies, anti-nuclear antibodies and anti-DNA antibodies are often induced in patients with rheumatoid arthritis treated with tumor necrosis factor inhibitors. We examined the association between immunogenicity, autoantibody production, and serum cytokine profiles in patients with rheumatoid arthritis treated with infliximab. Japanese patients with rheumatoid arthritis (n = 57) were retrospectively examined. Serum trough levels of infliximab, anti-drug antibody, anti-nuclear antibody, and anti-DNA (Farr), anti-single-stranded DNA and anti-double-stranded DNA antibodies were measured. Interleukin-6, interferon-γ, interferon-α, and B-cell activating factor levels were also measured in the same sera. Then, we validated the association between anti-drug antibody and these serum markers along with clinical response to infliximab. Anti-drug antibodies developed in twenty-one patients (36.8%), whose serum trough levels of infliximab were significantly lower than those in anti-drug antibody-negative patients (0.09 ± 0.03 vs. 2.48 ± 0.326 μg/mL, p < 0.0001). There were no significant differences in clinical backgrounds between the two groups. The anti-drug antibody-positive patients were more likely to develop anti-nuclear antibody titers of ≥ ×160 compared to the negative patients (14 to 57% vs. 17 to 33%). In addition, anti-DNA antibodies (Farr) (from 1.5 ± 0.4 to 35 ± 17 IU/mL, p = 0.0001), especially IgM-anti-double stranded DNA antibody (from 5.1 ± 0.7 to 41 ± 8.9 IU/mL, p < 0.0001), and IgG-anti-single stranded DNA antibody (from 13 ± 1.1 to 35 ± 13, p = 0.0145) were significantly increased in anti-drug antibody-positive but not in negative patients. Moreover, the anti-drug antibody-positive, but not the negative patients, showed significant increased levels of interferon-α (from 248.7 ± 102.3 to 466.8 ± 135.1 pg/mL, p = 0.0353) and B-cell activating factor (from 1073 ± 75.1 to 1387 ± 136.5 pg/mL, p = 0.0208) following infliximab treatment. The development of anti-drug antibody against infliximab and lupus-like autoantibody production in patients with rheumatoid arthritis treated with infliximab can be linked each other along with increased lupus-associated cytokine levels including type I interferons.

Experience and challenges for biologic use in the treatment of moderate-to-severe psoriasis in Africa and the Middle East region

The incidence of psoriasis in Africa and the Middle East (AfME) is high as in other regions and represents a significant problem for both dermatologists and patients. Psoriasis co-morbidities such as obesity, cardiovascular disease and psoriatic arthritis (PsA) are also particularly common in these regions and may be under-recognized and under-treated. Despite this, regional guidelines to aid physicians on the appropriate use of biologic agents in their clinical practice are limited. A group of expert dermatologists from across the AfME region were surveyed to help establish best practice across the region, alongside supporting data from the literature. Although biologics have significantly improved patient outcomes since their introduction, the results of this survey identified several unmet needs, including the lack of consensus regarding their use in clinical practice. Discrepancy also exists among AfME physicians concerning the clinical relevance of immunogenicity to biologics, despite increasing data across inflammatory diseases. Significant treatment and management of challenges for psoriasis patients remain, and a move towards individualized, tailored care may help to address these issues. The development of specific local guidelines for the treatment of both psoriasis and PsA could also be a step towards understanding the distinct patient profiles in these regions.

Immunological evaluation of rheumatoid arthritis patients treated with itolizumab

Rheumatoid arthritis is an autoimmune disease characterized by joint inflammation that affects approximately 1% of the general population. Itolizumab, a monoclonal antibody specific for the human CD6 molecule mainly expressed on T lymphocytes, has been shown to inhibit proliferation of T cells and proinflammatory cytokine production in psoriasis patients. We have now assessed the immunological effect of itolizumab in combination with methotrexate in rheumatoid arthritis by analyzing clinical samples taken from 30 patients enrolled in a clinical trial. T and B cell subpopulations were measured at different time points of the study. Plasma cytokine levels and anti-idiotypic antibody response to itolizumab were also evaluated. The combined treatment of itolizumab and methotrexate led to a reduction in the frequency of T cell subpopulations, and plasma levels of proinflammatory cytokines showed a significant decrease up to at least 12 weeks after treatment ended. No anti-idiotypic antibody response was detected. These results support the relevance of the CD6 molecule as a therapeutic target for the treatment of this disease.

Adalimumab in the treatment of immune-mediated diseases

Tumour necrosis factor (TNF) plays an important role in the pathogenesis of immune-mediated inflammatory diseases (IMIDs). TNF inhibition results in down-regulation of abnormal and progressive inflammatory processes, resulting in rapid and sustained clinical remission, improved quality of life and prevention of target organ damage. Adalimumab is the first fully human monoclonal antibody directed against TNF. In this article, we review the role and cost effectiveness of adalimumab in the treatment of IMIDs in adults and children. The efficacy and tolerability of adalimumab has been demonstrated in patients with a wide range of inflammatory conditions, leading to regulatory approval in rheumatoid arthritis (RA), psoriatic arthritis (PsA), plaque psoriasis, inflammatory bowel diseases (Crohn's disease, ulcerative colitis, paediatric Crohn's disease, and intestinal Behçet's disease), ankylosing spondylitis (AS), axial spondyloarthritis (SpA) and juvenile idiopathic arthritis. The major tolerability issues with adalimumab are class effects, such as injection site reactions and increased risk of infection and lymphoma. As with all anti-TNF agents, adalimumab is immunogenic, although less than infliximab, and some patients receiving long-term adalimumab will develop anti-drug antibodies, causing a loss of response. Comparisons of its clinical utility and cost effectiveness have shown it to be a valid treatment choice in a wide range of patients. Recent data from Italian economic studies show the cost effectiveness of adalimumab to be below the threshold value for health care interventions for most indications. In addition, analysis of indirect costs shows that adalimumab significantly reduces social costs associated with RA, PsA, AS, Crohn's disease and psoriasis. The fact that adalimumab has the widest range of approved indications, many often presenting together in the same patient due to the common pathogenesis, may further improve the utility of adalimumab. Current clinical evidence shows adalimumab to be a valuable resource in the management of IMIDs. Further research, designed to identify patients who may benefit most from this drug, will better highlight the role and cost-effectiveness of this versatile TNF inhibitor.

Immunological and histological evaluation of clinical samples from psoriasis patients treated with anti-CD6 itolizumab

Psoriasis is a chronic inflammatory disease with a prevalence of approximately 2-3% in the general population. The majority of diagnosed patients have plaque psoriasis, and about 20% have moderate-to-severe disease. Itolizumab, a new monoclonal antibody specific for the CD6 molecule mainly expressed on T lymphocytes, has demonstrated to inhibit in vitro ligand-induced proliferation and pro-inflammatory cytokine production. We assessed the immunological and histopathological effect of the antibody using clinical samples taken from 26 patients with moderate-to-severe psoriasis included in a clinical trial. The precursor frequency of lymphocytes activated with anti-CD2/CD3/CD28 beads, as well as the number of interferon (IFN)-γ-secreting T cells after stimulation, were measured at different time points of the study. Serum cytokine levels and anti-idiotypic antibody response to itolizumab were also evaluated. Additionally, lymphocyte infiltration and epidermis hyperplasia were studied in five patients. A significant reduction in T cell proliferation capacity and number of IFN-γ-producing T cells was found in treated patients. Serum levels of interleukin-6, tumor necrosis factor and IFN-γ showed an overall trend toward reduction. No anti-idiotypic antibody response was detected. A significant reduction in the epidermis hyperplasia was observed in analyzed patients. These results support the relevance of the CD6 molecule as a therapeutic target for the treatment of this disease.

Immunogenicity in biologic therapy: implications for dermatology

It is now known that all biologic drugs, even those that are fully human, are immunogenic, that is, they have the ability to induce an immune response in the treated patient. Since the presence of antidrug antibodies may influence the levels and function of the drug in the body, this immune response can alter the efficacy of the biologic treatment and even its safety profile, depending on the mechanism of action (neutralizing or nonneutralizing) and/or an accelerated clearance of the drug. Immunogenicity is a dynamic factor that should be taken into account when prescribing biologic therapy in psoriasis, especially in the case of long-term treatment and when assessing secondary loss of response. An understanding of the immunogenicity of biologic therapies and how this can be managed is useful not only for optimizing the treatment strategy used with each drug, but also for designing predictive models of response and even for tailoring therapy on a case-by-case basis.