A avaliação de níveis sérios de infliximabe favorece a manutenção do tratamento em pacientes com doença inflamatória intestinal / The evaluation of infliximab trough level favors maintenance therapy of patients with inflammatory bowel disease

ABSTRACT Background: Crohn's disease (CD) and ulcerative colitis (UC) are chronic diseases that result from the deregulation of the mucosal immune system of the gastrointestinal tract. The use of biological therapies, including infliximab (IFX), is one of the strategies to treat both CD and UC. The IFX treatment is monitored by complementary tests, namely: fecal calprotectin (FC); C-reactive protein (CRP); and endoscopic and cross-sectional imaging. Besides, serum IFX evaluation and antibody detection are also used. Objective: To evaluate trough levels (TL) and antibodies in a population with inflammatory bowel (IBD) disease undergoing treatment with IFX, and the factors that might impact the treatment effectiveness. Methods: Retrospective, cross-sectional study with patients with IBD that were assessed for TL and antibody (ATI) levels in a southern Brazilian hospital, from June 2014 to July 2016. Results: The study assessed 55 patients (52.7% female) submitted to serum IFX and antibody evaluations (95 blood samples, 55 first test; 30 second test, and 10 as third testing. Forty-five (47.3%) cases were diagnosed with CD (81.8%), and ten with UC (18.2%). Serum levels were adequate in 30 samples (31.57%), subtherapeutic in 41 (43.15%), and supratherapeutic in 24 (25.26%). IFX dosages were optimized for 40 patients (42.10%), maintained for 31 (32.63%), and discontinued for 7 (7.60%). The intervals between infusions were shortened in 17.85% of the cases. In 55 tests (55.79%), the therapeutic approach was exclusively defined according to IFX and/or serum antibody levels. The assessment of patients one year later indicated that: the approach was maintained with IFX for thirty-eight patients (69.09%); the class of biological agent was changed for eight (14.54%); changes using the same class of biological agent occurred for two patients (3.63%); the medication was discontinued and not replaced for three patients (5.45%), and four patients (7.27%) were lost to follow-up. Conclusion: There were no differences in TL between groups with or without immunosuppressants, serum albumin (ALB), erythrocyte sedimentation rate (ESR), FC, CRP, and endoscopic and imaging examinations. Current therapeutic approach could be maintained for almost 70% of patients. Thus, serum and antibody levels are a useful tool in the follow-up of patients undergoing maintenance therapy and after treatment induction in patients with inflammatory bowel disease.

RESUMO Contexto: A doença de Crohn e a colite ulcerativa são doenças crônicas nas quais existem desregulação do sistema imune da mucosa do trato gastrointestinal. Uma das terapias usadas no tratamento dessas doenças são as medicações biológicas, entre elas o Infliximabe. A monitorização do tratamento dos pacientes com Iinfliximabe é feita por exames complementares: calprotectina fecal, pesquisa de atividade inflamatória, exames endoscópicos e imagem. Utiliza-se, também a dosagem do nível sérico do Infliximabe e a pesquisa de anticorpos. Objetivo: Analisar uma população com doenças inflamatórias intestinais, em tratamento com Infliximabe, submetida a avaliação do nível sérico do Infliximabe e do anticorpo, além de possíveis fatores que possam alterar ou contribuir no tratamento. Métodos: Trata-se de estudo retrospectivo, transversal, realizado por meio da revisão dos prontuários dos pacientes com doença inflamatória intestinal, em um hospital sul-brasileiro, no período de junho de 2014 até julho de 2016, que foram submetidos a avaliação dos níveis séricos de Infliximabe e do anticorpo. Resultados: Foram incluídos 55 pacientes, submetidos a dosagem do Infliximabe e do anticorpo, totalizando 95 coletas sanguíneas. Destes, 55 realizaram uma primeira coleta, 30 tiveram uma segunda amostra coletada e 10 coletaram uma terceira vez. Vinte e nove pacientes eram do sexo feminino (52,7%) e vinte e seis do sexo masculino (43.2%). Quarenta e cinco (47,3%) casos tinham diagnóstico de doença de Crohn (81,8%) e 10 de colite ulcerativa (18,2%). Em relação ao nível sérico encontrou-se nível adequado em 30 coletas (31,57%), subterapêutico em 41 coletas (43,15%) e supraterapêutico em 24 coletas (25,26%). A prescrição foi otimizada em 40 (42,10%) casos, mantida em 31 (32,63%) pacientes, suspensa em 7 (7,60%) ou que o intervalo entre as infusões fosse aumentado (17,85%). Na análise geral, em 53 coletas (55,79%) a conduta foi definida em função exclusivamente da dosagem sérica do Infliximabe e/ou do anticorpo, já em relação, apenas a primeira coleta obteve-se 33 (60%) pacientes. Avaliando-se os pacientes um ano após, obteve-se: em 38 (69,09%) pacientes a conduta foi mantida com Infliximabe e, em 8 (14,54%) foi optado por troca de classe, em 2 (3,63%) foi optado por troca da medicação na mesma classe, em 3 (5,45%) pacientes a medicação foi suspensa e não foi substituída e, em 4 (7,27%), perdeu-se o seguimento. Conclusão: Não encontrou-se diferença entre os níveis de Infliximabe entre os grupos com ou sem imunossupressor, albumina sérica, velocidade de hemossedimentação, Calprotectina, Proteína C reativa, exames endoscópicos e exames de imagem. A conduta atual pode ser mantida em quase 70% dos pacientes. Concluindo, a dosagem do nível sérico e do anticorpo é ferramenta útil no acompanhamento dos pacientes em terapia de manutenção e após a indução de tratamento em pacientes com Doença Inflamatória Intestinal.

Infliximab and biosimilar infliximab in psoriasis: efficacy, loss of efficacy, and adverse events.

Psoriasis is a chronic immune-mediated skin disease affecting multiple systems, and tumor necrosis factor-α (TNF-α) plays a significant role in the initiation and progression of the disease process. Psoriasis has a high prevalence rate in the Western world, especially in the USA and Australia; in China, although the prevalence rate is much lower, there is still a large number of patients suffering from psoriasis and its comorbidities. As TNF-α is thought to be crucial in the pathogenesis of psoriasis, specific therapy blocking TNF-α may be beneficial in the treatment of this disease. Infliximab, a murine-human monoclonal antibody, is highly efficacious in the treatment of moderate-to-severe psoriasis, with better skin clearance and faster onset of action than topical medications such as methotrexate, narrow-band ultraviolet B, and calcipotriol. Lack of adherence to infliximab therapy is mainly due to loss of response (LOR) over time and adverse events, particularly because infusion reactions are usually encountered. Anti-infliximab antibody is thought to be responsible for the LOR and infusion reactions. However, the mechanism underlying the formation of anti-infliximab antibody and its side effects remains unclear. Further studies identifying patients at risk for LOR will probably help clinicians to select the right patients for anti-TNF-α therapy and to increase the durability of the treatment. This review discusses the efficacy of infliximab as demonstrated by various clinical trials, LOR to infliximab, combatting LOR, as well as the adverse events usually faced during the use of infliximab therapy and the infliximab biosimilar Remsima®. We hope that we can discover a better way to use infliximab in the therapy of psoriasis from the current research data.

IL-6 is an independent predictive factor of drug survival after dose escalation of infliximab in patients with rheumatoid arthritis.

OBJECTIVE: We aimed to investigate factors predictive of increased serum infliximab (IFX) concentration with improvement of disease activity, as well as better 1-year continuation rate after dose escalation, in patients with rheumatoid arthritis (RA) who showed inadequate response to 3 mg/kg IFX. METHODS: Among 42 patients allotted to receive 3 mg/kg IFX, 13 patients showed adequate response (DAS28 < 3.2) and 29 patients required dose escalation to 4.5 or 6 mg/kg after inadequate response (DAS28 ≥ 3.2) to 3 mg/kg IFX. DAS28, mHAQ, serum level of CRP, interleukin (IL)-6, IL-17, anti-infliximab antibody (AIA) titers and IFX concentration before and on average 2.7 months after dose escalation were examined to explore the baseline factors predictive of a clinically beneficial increase of serum IFX concentration and drug survival. RESULTS: One year after IFX dose escalation, 25 patients completed the study protocol, and 16 patients (64%) continued to show a good response for one year, while 9 patients (36%) required switching of biologics because of inadequate response. Multivariate analyses revealed that a serum IL-6 level of less than 4.0 pg/mL at baseline was the only factor predictive of a clinically beneficial increase of serum IFX concentration in patients who required dose escalation. Receiver operating characteristic analysis revealed that 5.16 pg/mL of IL-6 was the cut-off value with sensitivity 0.833 and specificity of 0.769 (95%CI for AUC: 0.712-1.006). In patients with IL-6 levels of less than 5.16 pg/mL at baseline, the serum IFX concentration significantly increased after dose escalation with adequate response. The 1-year drug survival rates of patients with IL-6 levels less than 5.16 pg/mL and in those with levels greater than or equal to 5.16 pg/mL at baseline were 83.3% and 30.8%, respectively (log-rank test, p = .011). CONCLUSIONS: The results of our study indicated that a baseline serum level of IL-6 below 5.16 pg/mL might be a predictive factor for a clinically beneficial increase of serum IFX concentration with improvement of disease activity and better 1-year continuation rate after IFX dose escalation.

Detection of anti-infliximab antibodies is impacted by antibody titer, infliximab level and IgG4 antibodies: a systematic comparison of three different assays.

BACKGROUND: There is scant information on the accuracy of different assays used to measure anti-infliximab antibodies (ADAs), especially in the presence of detectable infliximab (IFX). We thus aimed to evaluate and compare three different assays for the detection of IFX and ADAs and to clarify the impact of the presence of circulating IFX on the accuracy of the ADA assays. METHODS: Blood samples from 79 ulcerative colitis (UC) patients treated with infliximab were assessed for IFX levels and ADAs using three different assays: an in-house assay and two commercial kits, Immundiagnostik and Theradiag. Sera samples with ADAs and undetectable levels of IFX were spiked with exogenous IFX and analyzed for ADAs. RESULTS: The three assays showed 81-96% agreement for the measured IFX level. However, the in-house assay and Immundiagnostik assays detected ADAs in 34 out of 79 samples, whereas Theradiag only detected ADAs in 24 samples. Samples negative for ADAs with Theradiag, but ADA-positive in both the in-house and Immundiagnostik assays, were positive for IFX or IgG4 ADAs. In spiking experiments, a low concentration of exogenous IFX (5 µg/ml) hampered ADA detection with Theradiag in sera samples with ADA levels of between 3 and 10 µg/ml. In the Immundiagnostik assay detection interference was only observed at concentrations of exogenous IFX higher than 30 µg/ml. However, in samples with high levels of ADAs (>25 µg/ml) interference was only observed at IFX concentrations higher than 100 µg/ml in all three assays. Binary (IFX/ADA) stratification of the results showed that IFX+/ADA- and IFX-/ADAs+ were less influenced by the assay results than the double-positive (IFX+/ADAs+) and double-negative (IFX-/ADAs-) combination. CONCLUSIONS: All three methodologies are equally suitable for measuring IFX levels. However, erroneous therapeutic decisions may occur when patients show double-negative (IFX-/ADAs-) or double-positive (IFX+/ADAs+) status, since agreement between assays is significantly lower in these circumstances.