Israel Medical Association Journal

Background: Up to 60% of inflammatory bowel disease (IBD) patients treated with infliximab develop antibodies to infliximab (ATI), which are associated with low drug levels and loss of response (LOR). Hence, mapping out predictors of immunogenicity toward infliximab is essential for tailoring patient-specific therapy. Jewish Sephardi ethnicity, in addition to monotherapy, has been previously identified as a potential risk factor for ATI formation and infliximab failure.

Objectives: To explore the association between Jewish sub-group ethnicity among patients with IBD and the risk of infliximab immunogenicity and therapy failure. To confirm findings of a previous cohort that addressed the same question.

Methods: This retrospective cohort study included all infliximab-treated patients of Jewish ethnicity with regular prospective measurements of infliximab trough levels and ATI. Drug and ATI levels were prospectively measured, clinical data was retrieved from medical charts.

Results: The study comprised 109 Jewish patients (54 Ashkenazi, 55 Sephardi) treated with infliximab. There was no statistically significant difference in proportion of ATI between Sephardi and Ashkenazi patients with IBD (32% Ashkenazi and 33% Sephardi patients developed ATI, odds ratio [OR] 0.944, P = 0.9). Of all variables explored, monotherapy and older age were the only factors associated with ATI formation (OR 0.336, 95% confidence interval 0.145–0.778, P = 0.01, median 34 vs. 28, interquartile range 28–48, 23–35 years, P = 0.02, respectively).

Conclusions: Contrary to previous findings, Sephardi Jewish ethnicity was not identified as a risk factor for ATI formation compared with Ashkenazi Jewish ethnicity. Other risk factors remained unchanged.

Background: Biological agents for anti-tumor necrosis factor-α therapy have revolutionized treatments for autoimmune diseases; however, approximately 20% of rheumatology and 40% of gastroenterology patients do not respond to the therapy, or they show reduced drug efficacy because of anti-drug antibody (ADA) formation.

Objectives: To evaluate laboratory tools for individual monitoring of infliximab therapy and the relationship between ADA and infliximab serum levels, ADA and clinical response, and ADA and autoantibodies.

Methods: Our study comprised patients treated with infliximab and affected by selected rheumatology and gastroenterology diseases. Sera were analyzed for infliximab, total-anti-drug antibodies (Total-ADA), and free-anti-drug antibodies (Free-ADA) serum levels and for the detection of specific autoantibodies.

Results: We analyzed 73 patients. Total-ADA were detected in 26 rheumatology and 21 gastroenterology patients. Serum infliximab levels were significantly lower in Total-ADA positive patients (P = 0.01 for rheumatology group, P = 0.02 for gastroenterology group). A lack of response was observed in 7 rheumatology and 15 gastroenterology samples. Total-ADA serum levels were statistically significantly higher in patients with treatment failure in both groups (P = 0.01 and P = 0.001, respectively). There was no significant association between the presence of Total-ADA and other autoantibodies. Free-ADA were detected in only 27 rheumatology patients. Results showed a significant correlation with clinical outcome (P = 0.006).

Conclusions: The correlation with clinical response suggests that the presence of ADA could interfere with efficacy of therapy. The tests for monitoring therapy may be an important tool to assist clinicians in early detection and prevention of therapy failure.

Objectives: To assess the changes in ACPA titers in patients with RA after treatment with infliximab as a first biological agent, and to correlate these variations with non-infusion-related adverse effects.

Methods: In a prospective multicenter observational study involving 48 research centers, we assessed 139 patients with established moderate-to-severe RA diagnosed according to American College of Rheumatology criteria. Samples were collected before and 6–12 months after treatment.

Results: The mean age of the study patients was 50.6 years old, and 118 were female (84.9%). Statistically significant variations in ACPA titers were noted in 47 patients (before and after treatment) (P = 0.012). Overall, ACPA titers were decreased in 32 (65.3%) and increased in 15 (34.7%). No correlation was found between severe or mild adverse effects in patients presenting variations in ACPA titers.

Conclusions: The present study showed that infliximab affected ACPA titers, promoting mainly a decrease; however, this was not related to the occurrence of non-infusion-related adverse effects.

There has been a paradigm shift in the treatment of rheumatoid arthritis in recent years. Early and aggressive treatment with good control of disease activity has improved the prognosis of the disease, however, there is significant variability in the response of patients to different therapeutic agents. Hence it is essential to find the predictors of response to a drug at baseline so that we can avoid the delay in achieving remission and improve the outcome. Here we review the literature on available predictors for treatment response in general and specifically for methotrexate and biological agents. We also look at specific scores or indices that can help predict the response in individual patients.