Therapeutic drug monitoring and immunogenetic factors associated with the use of adalimumab in Crohn's disease patients

Abstract

Crohn's disease (CD) involves immune system interactions with intestinal tissue, driven by pro-inflammatory cytokines like Tumor Necrosis Factor (TNF-α). Adalimumab, targeting TNF-α, regulates associated inflammatory responses. Despite being humanized, it may induce immunogenic processes, affecting treatment effectiveness. Thus, monitoring serum adalimumab and anti-drug antibody (ADA) levels can optimize therapy. Understanding genetic factors influencing adalimumab response can enhance personalized treatment and improve patient quality of life. We aimed to quantify adalimumab serum levels, assess test interchangeability, detect ADA, examine immune complex formation, and investigate genetic phenotypes related to immunogenicity in CD patients. Seventy CD patients in the maintenance phase with adalimumab were classified into active (CDA) and remission (CDR) groups. Adalimumab concentration was determined via enzyme-linked immunosorbent assay (ELISA-Promonitor) and lateral flow assay (Quantum Blue), with assay interchangeability assessed statistically. ADA and immune complex formation were quantified using ELISA assays. DNA was genotyped for the genes ATG16L1, CD96, and CD155. No significant differences in adalimumab serum concentrations were observed between groups, regardless of the assay. However, a statistical difference between the tests indicated measurement disparity (P = 0.003), with moderate agreement (Lin's correlation of 0.247). ADA was detected in 4 of 27 of the patients with infratherapeutic levels, 3 in the CDA group and 1 in the CDR group. Analysis of immune complexes revealed significantly higher concentrations in the CDA group (P = 0.0125). The genotypic evaluation revealed significant associations for the CD96 CC (wild-type) genotype with higher CRP levels, colonic involvement, and infratherapeutic levels of adalimumab. ATG16L1 CC genotype was associated with higher CDEIS and fecal calprotectin values, while the variant (TT) genotype had lower platelet counts. The effectiveness of treatment with adalimumab was not directly related to higher medication levels in this cohort. The disparity between tests indicates the need to use only one test in patient follow-up to ensure accuracy in therapeutic monitoring. Genotypic differences highlight the correlation between the wild genotype for CD96 and ATG16L1 with unfavorable laboratory and endoscopic response to adalimumab. Finally, the more significant levels of immune complexes in the CDA group indicate an association with a worse response to adalimumab.

Keywords: Crohn’s disease; drug monitoring; immunogenetics; serum levels.

Figure 1.

Adalimumab monitoring in patients with active or remission Crohn’s disease. Serum levels were measured using the Quantum-Blue (a) and Promonitor (b) assays. CDA: n = 43, CDR: n = 27. (c) Serum levels of adalimumab in CD patients with and without immunomodulators, measured by the Quantum-Blue assay, and (d) Promonitor assay. For patients whose measurements exceeded the upper limit of quantification (ULOQ), we assigned a value of ULOQ + 1 (13 for the ELISA method and 36 for the lateral flow assay). For those whose measurements fell below the lower limit of quantification (LLOQ), we recorded the value as 0 in both assays. For patients without immunomodulators (IMM−): n = 35; for those with immunomodulators (IMM+): n = 34. CDA: active Crohn’s disease; CDR: Crohn’s disease in remission; IMM: immunomodulator. P < 0.05 is considered statistically significant.

Figure 2.

Interchangeability between assays. (a) Box plots compare adalimumab concentrations (mg/mL) between Quantum-Blue and Promonitor tests, wherein the horizontal line denotes the median (*P = 0.003), indicative of a statistically significant difference. (b) Linear regression analysis for adalimumab levels using the Passing Bablok method revealed Lin’s correlation coefficient of agreement of 0.247. (c) The Bland-Altman plot was used to represent the comparative analysis between the two measurements, where the difference between the measured concentrations (in mg/L) is plotted on the y-axis. In comparison, the average of the two measurements (also in mg/L) is represented on the x-axis. The Spearman coefficient between the differences and the mean of the measurements corresponds to −0.603, with P = 0.002.

Figure 3.

Immunogenicity in Crohn’s disease patients under adalimumab. (a) The Venn diagram shows positive ADA among patients with infratherapeutic adalimumab levels, determined by two diagnostic assays. The green region represents the patients (n = 3) identified as infratherapeutic exclusively by the Quantum-Blue test. The yellow region denotes the patients (n = 6) identified as infratherapeutic solely by the Promonitor test. The intersection area indicates the patients (n = 9) classified as infratherapeutic by both diagnostic tests. (b) The immune complex formation in patients with Crohn’s disease was measured using the ELISA assay. Source: Created with BioRender.com. ADA: antidrug antibodies; CDA; active Crohn’s disease; CDR: Crohn’s disease in remission. *P < 0.05 is considered statistically significant.

Figure 4.

Precision medicine in the context of adalimumab therapy for Crohn’s disease entails a comprehensive approach to treatment optimization. A proposal with a personalized approach for CD patients under adalimumab includes meticulous therapeutic monitoring (trough-level drug monitoring and anti-drug antibody detection), immune complexes assessment, and genetic polymorphisms evaluation, which may improve patients’ outcomes and quality of life. These integrated strategies may contribute to optimizing the use of adalimumab, ensuring tailored therapeutic regimens that align with individual patient characteristics and precision medicine. Source: Created with BioRender.com.