Infliximab serum concentrations in luminal Crohn's disease and its relationship with disease activity: A multicentric cross-sectional study.

OBJECTIVES: In Latin America, experience with monitoring serum Infliximab (IFX) concentrations is scarce. Our study aimed to compare IFX serum concentrations between patients with active disease or in remission. PATIENTS AND METHODS: A cross-sectional study was performed in patients with luminal Crohn's disease (CD) during maintenance treatment with IFX. Patients were classified as in remission or disease activity according to clinical scores and endoscopic, radiological, and laboratory markers. A comparison of IFX trough levels between the two groups was performed. RESULTS: 80 CD patients were included [41 (51%) in remission and 39 (49%) with active disease]. In the analysis of general disease activity, the median serum levels of IFX in patients with remission and with active CD were 5.63 [0.03-14.40] vs. 3.84 [0.03-14.40] (p=0.287). Furthermore, there was no difference in serum IFX concentrations in endoscopic, radiological, and laboratory activities. Only in the clinical evaluation there was a significant difference in the median serum IFX levels between patients in remission and disease activity, 5.63 [0.03-14.40] vs. 2.14 [0.32-10.54] (p=0.042). CONCLUSIONS: IFX serum concentrations during maintenance treatment were similar in patients with luminal CD in remission and general, endoscopic, radiological, and laboratory disease activity. Patients with clinically active disease had lower IFX concentrations than patients in remission.

THE EVALUATION OF INFLIXIMAB TROUGH LEVEL FAVORS MAINTENANCE THERAPY OF PATIENTS WITH INFLAMMATORY BOWEL DISEASE.

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.

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.

IMPORTANCE OF MEASURING LEVELS OF INFLIXIMAB IN PATIENTS TREATING INFLAMMATORY BOWEL DISEASE IN A BRAZILIAN COHORT.

BACKGROUND: Crohn's disease and ulcerative colitis are chronic inflammatory bowel diseases. In such pathologies, there is an increased production of alpha tumor necrosis factor (TNF-α). Patients, in whom the conventional immunosuppressant treatment fails, require the use of immunobiological therapy, such as anti-TNF-α, a monoclonal antibody. Infliximab is an anti-TNF-α drug, a chimerical immunoglobulin, with a murine component, which is responsible for the generation of immunogenicity against the drug and formation of anti-TNF-α antibodies. The presence of anti-drug antibodies may be responsible for adverse events and reduction of the drug's effectiveness. Patients with inflammatory bowel diseases undergoing therapy with biological medication, such as infliximab, can relapse overtime and this may not be translated into clinical symptoms. Thus, there is a need for a method to evaluate the efficacy of the drug, through the measurement of serum infliximab levels, as well as antibodies research. OBJECTIVE: This study aimed to measure serum infliximab levels and anti-infliximab antibodies in patients with inflammatory bowel diseases post-induction phase and during maintenance therapy, and describe the therapeutic modifications that took place based on the serum levels results. METHODS: It was a retrospective study, that included forty-five patients, with a total of 63 samples of infliximab measurement. RESULTS: Twenty-one patients had an adequate infliximab serum level, 31 had subtherapeutic levels and 11 had supratherapeutic levels. Seven patients had their medication suspended due to therapeutic failure or high levels of antibodies to infliximab. CONCLUSION: In conclusion, only a third of the patients had adequate infliximab levels and 36% presented with subtherapeutic levels at the end of the induction phase. Therapy optimization occurred based in about 46% of the samples results, demonstrating the importance of having this tool to help the clinical handling of patients with inflammatory bowel diseases ongoing biologic therapy.