Prospective Observational Evaluation of the Time-Dependency of Adalimumab Immunogenicity and Drug Concentration in Ulcerative Colitis Patients: the POETIC II Study.

BACKGROUND AND AIMS: Home self-injection of the human anti-tumour necrosis alpha [anti-TNFα] monoclonal adalimumab complicates prospective serial-sampling studies. Although a recent study examined adalimumab levels and immunogenicity in Crohn's disease [CD] patients, prospective real-world data from ulcerative colitis [UC] patients are lacking. METHODS: A three-monthly home-visit programme from induction was established prospectively for UC patients. Clinical scores were determined at each visit, and sera were obtained for assessment of drug and anti-adalimumab antibody levels. Calprotectin was measured using a smartphone-based app. This cohort was compared to a parallel prospective cohort of adalimumab-treated CD patients [POETIC1]. RESULTS: Fifty UC patients starting adalimumab [median follow-up 28 weeks] were compared to 98 adalimumab-treated CD patients [median follow-up 44 weeks]. Only 11/50 UC patients [22%] continued treatment to the end of the follow-up compared with 50/98 [51%] CD patients (odds ratio [OR] = 0.27, p = 0.001). Loss of response was significantly more common in UC patients [OR = 3.2, p = 0.001]. Seventeen patients [34%] in the UC cohort developed anti-adalimumab antibodies, 9/17 [52.9%] as early as week 2. There was no difference between patient cohorts in the overall development of anti-adalimumab antibodies [34% vs 30.6%, respectively, OR = 1.67, p = 0.67], nor was there a difference in early immunogenicity [OR = 1.39, p = 0.35]. There was no difference in low drug levels [<3 µg/mL] between the two cohorts [OR = 0.87, p = 0.83]. CONCLUSIONS: Loss of response to adalimumab therapy was significantly more common in the UC compared to the CD cohort and was driven by a higher rate of non-immunogenic, pharmacodynamic parameters.

Association of Vedolizumab Level, Anti-Drug Antibodies, and α4ß7 Occupancy With Response in Patients With Inflammatory Bowel Diseases.

BACKGROUND & AIMS: There are few data available on the real-life pharmacokinetic and pharmacodynamics features of vedolizumab, a monoclonal antibody against integrin α4ß7. We performed a prospective study of patients with inflammatory bowel diseases (IBDs) treated with vedolizumab to determine serum drug concentrations, formation of antivedolizumab antibodies (AVAs), and integrin α4ß7 saturation. METHODS: We performed a prospective study of 106 patients with IBD (67 with Crohn's disease and 39 with ulcerative colitis) treated with vedolizumab from September 2014 through March 2017 at 2 tertiary medical centers in Israel. Clinical data and serum samples were collected before and during induction and maintenance therapy. Clinical remission was defined as Harvey-Bradshaw index scores below 5 or as Simple Clinical Colitis Activity Index scores of 3 or less. We measured serum levels of vedolizumab, AVAs, and markers of inflammation. Peripheral blood mononuclear cells were obtained from some patients at designated trough time points and CD3+ CD45RO+ T cells were isolated from 36 samples. Cells were incubated with fluorescent-conjugated vedolizumab and flow cytometry was used to quantify α4ß7 integrin saturation. We also performed flow cytometry analyses of CD3+ CD45RO+ lamina propria T cells isolated from intestinal mucosa of patients without IBD (non-IBD controls, n = 6), patients with IBD not treated with vedolizumab (untreated IBD controls, n = 8), and patients with IBD treated with vedolizumab (n = 15). RESULTS: Clinical remission was achieved by 48 of 106 patients (45%) by week 6 and 50 of 106 patients (48%) by week 14 of treatment. The median level of vedolizumab at week 6 was higher in patients in clinical remission (40.2 µg/mL) than in patients with active disease (29.7 µg/mL; P = .05). The median serum level of vedolizumab was significantly higher in patients with a normal level of C-reactive protein (21.8 µg/mL vedolizumab) vs the level in those with a high level of C-reactive protein (11.9 µg/mL vedolizumab) during maintenance treatment (P = .0006). The other clinical outcomes measured were not associated with median serum level of vedolizumab at any time point examined. AVAs were detected in 17% of patients during induction therapy and 3% of patients during maintenance therapy, but did not correlate with clinical outcomes. Flow-cytometry analysis of peripheral blood memory T cells (n = 36) showed near-complete occupancy of α4ß7 integrin at weeks 2 and 14 and during the maintenance phase, regardless of response status or drug levels. Most intestinal CD3+CD45RO+ memory T cells of healthy and IBD controls expressed α4ß7 (72%; interquartile range, 56%-81%). In contrast, free α4ß7 was detectable on only 5.6% of intestinal memory cells (interquartile range, 4.4%-11.2%) (P < .0001) from vedolizumab-treated patients, regardless of response. CONCLUSIONS: In a prospective study of real-life patients with IBD, we associated vedolizumab drug levels with remission and inflammatory marker level. Integrin α4ß7 was blocked in almost all T cells from patients treated with vedolizumab, regardless of serum level of the drug or response to treatment. These findings indicate a need to explore alternative mechanisms that prevent response to vedolizumab.

Inflammatory bowel disease: an emergent disease among Ethiopian Jews migrating to Israel.

BACKGROUND: The development and characteristics of inflammatory bowel disease (IBD) in Ethiopian Jewish immigrants to Israel were investigated. METHODS: A case-control study was conducted in 7 tertiary care hospitals in Israel. Patients of Ethiopian origin with IBD >6 months were included. Time of disease onset after immigration and age at diagnosis were recorded. Randomly chosen patients with IBD of Ashkenazi Jewish origin served as controls. Demographics and clinical parameters were compared between the 2 cohorts. RESULTS: Thirty-two Ethiopian patients with IBD were compared with 33 Ashkenazi Jewish patients with IBD. Crohn's disease (CD) was more prevalent than ulcerative colitis (UC) in the Ethiopian group compared with the Ashkenazi group (94% versus 73%, P = 0.02). No Ethiopian-origin patient had a positive family history of IBD compared with 42% of Ashkenazi-origin patients (P < 0.001). Arthritis was more common in Ashkenazi than in Ethiopian patients (27% versus 3%, P < 0.01). One Ashkenazi patient with CD had upper gastrointestinal involvement compared with 7 (23%) in the Ethiopian group (P < 0.02). All other clinical measures were similar between the 2 cohorts. The Ethiopian group lived in Israel with a mean of 13 ± 5 years, and 75% were born in Ethiopia. The shortest time between immigration and developing IBD was 8 years (range, 8-26; median 16 yrs). No Ethiopian patient was diagnosed before immigration. CONCLUSIONS: Ethiopian Jews migrating to Israel are at risk of developing IBD. Larger cohorts are needed to determine the relative importance of environmental and genetic factors that cause IBD in these patients.

Clinical utility of antihuman lambda chain-based enzyme-linked immunosorbent assay (ELISA) versus double antigen ELISA for the detection of anti-infliximab antibodies.

BACKGROUND: Anti-infliximab antibodies (ATIs) are associated with lower serum infliximab (IFX) trough levels and diminished clinical response. The current most prevalent method for detection of ATI is a double-antigen (DA) enzyme-linked immunosorbent assay (ELISA) utilizing IFX for ligand and detection antibody. Serum IFX interferes with ATI measurement in this method. An alternative ELISA using antihuman lambda chain (AHLC) antibody for ATI detection may be less amenable to this interference. The aim of our study was to compare the performance of AHLC-ATI versus DA-ATI for prediction of clinical response and evaluate the clinical significance of positive ATI in the presence of detectable IFX levels in IFX-treated inflammatory bowel disease (IBD) patients. METHODS: In all, 63 patients' sera were analyzed for IFX levels and antibody levels by AHLC and DA. The results were compared with the clinical response to IFX. Percentage of patients with IFX+ATI+ status among IFX-treated patients and the clinical outcome of IFX+ATI+ patients were assessed. RESULTS: ATIs were demonstrated in 22/63 (34.9%) and 18/63 (28.5%) sera of patients by AHLC and DA assay, respectively (P = 0.6). Detectable ATI and in IFX was detected in four patients (6.3%) by AHLC but not by DA assay. IFX+ATI+ status was documented in 8.7% of available sera and was associated with a trend for loss of response. CONCLUSIONS: AHLC and DA ELISA are equally effective for ATI detection in patients with undetectable serum IFX. AHLC ELISA detects ATI in some patients with detectable serum IFX. This IFX+ATI+ status may be a harbinger of evolving loss of response to the drug.

The immunogenic part of infliximab is the F(ab')2, but measuring antibodies to the intact infliximab molecule is more clinically useful.

OBJECTIVES: To localise the immunogenic part of infliximab and evaluate the clinical usefulness of measuring antibodies against infliximab fragments. DESIGN: Observational study. SETTINGS: A specialised inflammatory bowel disease (IBD) centre in a tertiary hospital. INTERVENTIONS: Serum was collected from patients with IBD and controls. Antibodies against whole infliximab (ATI) and against the digested Fc, F(ab')(2) and F(ab') fragments were measured by a specifically developed ELISA and by western blotting. A separate ELISA was used to determine infliximab levels in serum. RESULTS: 109 serum samples from 62 infliximab-treated patients were tested along with 64 control samples. Anti-F(ab')(2) antibodies were found in 28/42 (67%) samples with positive ATI, all from infliximab-exposed patients. Anti-F(ab')(2) antibodies were also present in 26 of the remaining 67 (39%) samples from exposed patients despite absent ATI. No specific anti-Fc antibodies were detected. Low trough infliximab level and high ATI level was found in 10/12 patients (83%) with complete loss of response to infliximab, but in only 5/14 patients (36%, p=0.02) who regained response to intensified infliximab regimen and in 2/24 patients (8%, p<0.001) in maintained remission while on 5 mg/kg/8 week infliximab treatment. Although Anti-F(ab')(2) antibodies showed similar test characteristics to ATI in patients losing response to infliximab, they were also detected in 61% of patients in maintained remission, thereby limiting their clinical usefulness. No cross reactivity to adalimumab was noted. CONCLUSIONS: F(ab')(2) is the immunogenic fragment of infliximab. However, ATI level in serum--combined with measurement of trough infliximab level--is better correlated with the clinical response to infliximab or with its loss.