Johannan F. Brandse

Pharmacokinetic Features and Presence of Antidrug Antibodies Associate With Response to Infliximab Induction Therapy in Patients With Moderate to Severe Ulcerative Colitis

BACKGROUND & AIMS The pharmacokinetics of infliximab during induction treatment for ulcerative colitis (UC) have not been studied. We investigated serum concentrations of infliximab and the early appearance of antibodies to infliximab (ATI) during induction treatment in patients with moderate-to-severe UC. METHODS We performed a prospective analysis of 19 consecutive patients with moderate-severe UC (endoscopic Mayo ≥ 2) receiving induction therapy with infliximab (5 mg/kg at weeks 0, 2, and 6) at 2 centers in Amsterdam, The Netherlands, from July 2012 through March 2014. Serial serum and fecal samples were collected for 6 weeks and concentrations of infliximab, ATI, c-reactive protein (CRP), albumin, and fecal calprotectin were measured. Treatment success was defined as endoscopic response (≥ 1 point reduction in the endoscopic Mayo score) at week 8. RESULTS Eleven patients (58%) had an endoscopic response. The median serum concentrations of infliximab at week 6 were 8.1 μg/mL in responders (interquartile range, 3.0-13.7 μg/mL) and 2.9 μg/mL in nonresponders (interquartile range, 0.01-5.8 μg/mL) (P = .03). ATIs were detected in 7 patients as early as day 18 (median, 28 d; interquartile range, 18-42 d). Six of the 8 nonresponders tested positive for ATIs vs 1 of 11 responders (P < .01; odds ratio, 30.0; 95% CI, 2.2-406.2). Patients with a baseline concentration of CRP greater than 50 mg/L had lower drug exposure from weeks 0 to 6 (587 mg/L/d in patients with high levels of CRP vs 1361 mg/L/day in patients with low CRP; P = .001). The median area under the curve for serum concentration of infliximab during induction therapy was 1230 mg/L/d in nonresponders vs 1352 mg/L/d in responders (P = .65). CONCLUSIONS There is a significant difference in serum concentration of infliximab at week 6 of treatment between responders and nonresponders. Early development of ATIs during induction therapy reduces the serum concentration of infliximab and is associated with nonresponse to treatment. Patients with high baseline serum levels of CRP had lower serum concentrations of infliximab. CLINICAL TRIAL NUMBER NL39626.018.12.

157 Fecal Loss of Infliximab As a Cause of Lack of Response in Severe Inflammatory Bowel Disease

Background: The degree of association between homocysteine metabolism and inflammatory bowel diseases (IBD) remains unknown and the association between hyperhomocysteinemia and thrombosis and oncogenesis remains controversial in IBD. The aim of this study was to investigate the serum homocysteine levels in patients with Crohn’s disease (CD) and ulcerative colitis (UC) and the potential folate therapeutic regimen against hyperhomocysteinemia. Methods: Serum levels of homocysteine were measured in 55 patients with (IBD) (28/55 CD and 31/55 UC patients). Patients with hyperhomocysteinemia received 15mg folate/day for 2 12 months. Levels of serum homocysteine were measured during folate treatment. Results: Hyperomocysteinemia was prevalent in 28/55 (50.90%) of patients studied (13 CD and 15 UC patients). Mean homocysteine levels among the patients with hyperhomocysteinemia were 17.72mmol/L with range 14.23 29.88mmol/L (normal values 3.7 13.9mmol/L) (Table 1). Folate was administered in 24/28 patients and serum levels of homocysteine were re-measured in 17 patients. In 14/17 patients lower levels of homocysteine were observed with a mean reduction of 5.25mmol/L by folate treatment. The baseline levels of homocysteine in these patients were 17.01 mmol/L and posttreatment 11.75mmol/L.

Impact of disease location on fecal calprotectin levels in Crohn’s disease

Abstract Objective. The correlation between the Simple Endoscopic Score for Crohn’s Disease (SES-CD) and fecal calprotectin is well established in (ileo)colonic Crohn’s disease (CD). However, for ileal CD, existing data are conflicting. The aim of this study is to evaluate the biomarker profile in CD patients with varying severity and location of mucosal ulceration. Materials and methods. An electronic patient database search identified CD patients in whom ileocolonoscopy, fecal calprotectin (CALPRO), serum C-reactive protein (CRP) and blood leukocyte counts (LEU) were measured within a 4-week interval without changes in medication. Ileocolonoscopies were scored for the presence of ulcers in each segment as defined by the SES-CD and the sum of segmental ulcer scores resulted in a partial SES-CD (pSES-CD). Results. Fourty-four patients were identified, of whom 9/44 had ileal CD, 20/44 colonic and 15/44 ileocolonic CD based on the Montreal classification. In the total study population CALPRO correlated best with pSES-CD (r = 0.76, p < 0.0001), followed by LEU (r = 0.54, p = 0.0004) and CRP (r = 0.45, p = 0.0026). Patients with ileal CD had significantly lower CALPRO level than those with (ileo)colonic disease even in the presence of large and/or very large ulcers (mean ± SEM: 297 ± 81 μg/g vs. 1523 ± 97 μg/g, p < 0.0001). LEU was also significantly lower in the presence of large and/or very large ulcers in ileal CD compared to those with (ileo)colonic disease (mean ± SEM: 6.7 ± 0.9 × 109/l vs. 10.6 ± 0.8 × 109/l, p = 0.02). A similar trend was identified regarding CRP levels. Conclusions. Even in the presence of large or very large ulcers, patients with ileal Crohn’s may not have markedly elevated fecal calprotectin levels.

A Real-life Population Pharmacokinetic Study Reveals Factors Associated with Clearance and Immunogenicity of Infliximab in Inflammatory Bowel Disease.

Background: Several factors influencing the pharmacokinetics of infliximab (IFX) in inflammatory bowel disease (IBD) have been identified. We studied the impact of patient, disease, and treatment characteristics on clearance and immunogenicity of IFX in a real-world patient-with-IBD cohort. Methods: Serum concentrations of IFX and antibodies to IFX (ATIs) were measured in patients with IBD at a single center using an enzyme-linked immunosorbent assay and radioimmunoassay. Patient, disease, and treatment characteristics were retrospectively collected along with laboratory values. Pharmacokinetics and ATI titer were analyzed simultaneously by nonlinear mixed-effects modeling. Results: Nine hundred ninety-seven IFX concentrations and 756 ATI measurements from 332 patients with IBD (253 Crohns disease and 79 ulcerative colitis) were included. Mean (SD) IFX dose was 5.47 ± 1.33 mg/kg. ATIs were detected in 75/332 (23%) patients; insufficient exposure below an IFX trough level of 3 &mgr;g/mL was the most predictive factor of developing ATI and resulted in a 4-fold increased risk of ATI development. ATI titer was a better predictor of IFX clearance than ATI as a dichotomous parameter. ATI titers >30 AU/mL were consistently associated with undetectable IFX concentrations. IFX clearance was affected by body weight (40–149 kg) ranging from 0.27 to 0.53 L/d, serum albumin (2–5.4 g/dL) from 0.93 to 0.24 L/d, and titers of ATIs (0–53,000 AU/mL) from 0.36 L/d to 15.93 L/d (P < 0.001). Previously biologic-treated patients exhibited a higher clearance of IFX. Conclusions: IFX exposure below 3 &mgr;g/mL increases risk of ATIs. Identification of influential pharmacokinetics and ATI factors improves prediction of IFX levels, potentially allowing individualized dosing and cost reduction.

Serum Concentration of Anti-TNF Antibodies, Adverse Effects and Quality of Life in Patients with Inflammatory Bowel Disease in Remission on Maintenance Treatment

BACKGROUND AND AIMS High serum concentrations of infliximab [IFX] and adalimumab [ADA] may be associated with adverse effects in patients with inflammatory bowel disease [IBD]. We aimed to investigate whether high anti-tumour necrosis factor [TNF] trough levels [TLs] were associated with toxicity and impaired quality of life [QoL]. METHODS We conducted a prospective cohort study in IBD patients in clinical and biochemical remission on IFX or ADA maintenance therapy. Trough serum concentrations and antidrug antibodies were measured in addition to biochemical markers of inflammation in serum and stool to confirm quiescent disease. QoL was assessed using the Inflammatory Bowel Disease Questionnaire and 36-item short form]. Side effects such as fatigue and arthralgia were measured with a visual analogue score [VAS]. Skin toxicity was reported with a European Organization for Research and Treatment of Cancer-derived score. RESULTS In all, 252 IBD patients on maintenance anti-TNF therapy were screened, of whom 95 [73 with Crohns disease, 22 with ulcerative colitis; 72 on IFX, 23 on ADA] were in clinical and biochemical remission and were included. Median TLs were 5.5 µg/ml and 6.6 µg/ml for IFX and ADA, respectively. Patients with anti-TNF TLs above median had lower IBDQ scores than patients with lower TLs [IBDQ 176 vs 187, p = 0.02], particularly regarding systemic symptoms and emotional status. A trend towards lower SF-36 and higher fatigue scores was observed in the higher anti-TNF TL group. Skin and arthralgia scores were not significantly different between the groups. CONCLUSIONS IBD patients with higher anti-TNF serum concentrations had significantly lower disease-specific QoL. Fatigue, arthralgia, and skin lesions do not occur more often in these patients. These data are reassuring that high serum concentrations of anti-TNF antibodies are not toxic.

The association of infliximab trough levels with disease activity in pediatric inflammatory bowel disease.

Abstract Objective. Low serum trough levels (TLs) of infliximab (IFX) and antibodies to IFX (ATIs) are associated with the loss of therapeutic response in adults with inflammatory bowel disease (IBD) receiving IFX. Until now, pediatric data are scarce. Therefore, we aimed to cross-sectionally investigate the association between ATIs and IFX TLs, and clinical and biochemical disease activity in children receiving IFX for IBD. Material and methods. Children aged <18 years receiving IFX maintenance treatment for Crohn’s disease (CD) or ulcerative colitis (UC) at three Dutch hospitals were included. Prior to two consecutive IFX infusions, IFX TLs and ATI levels were measured. Clinical disease activity was determined by Pediatric Crohn’s Disease Activity Index (PCDAI) and Pediatric Ulcerative Colitis Activity Index (PUCAI), for CD and UC, respectively. Biochemical disease activity was assessed by serum C-reactive protein (CRP) and fecal calprotectin (FC). Clinical remission was defined as a PUCAI or PCDAI score of <10. Therapeutic range of IFX was considered 3–7 µg/ml. Results. Thirty-nine patients were included (31 CD; 16 females). Median age was 15 years. Median IFX TL was 3.5 µg/ml [IQR 2–7]. Subtherapeutic and supratherapeutic TLs were found in 38% and 23% of children, respectively. ATIs were detected in four patients. A correlation was found between IFX TL and CRP [rs = −0.51; p < 0.01] and FC [rs = −0.49; p < 0.01]. However, when only clinical disease activity was considered, no difference in median TL was found between remission and active disease (resp. 3.5 µg/ml [IQR 2–5] and 2.3 µg/ml [IQR 0.3–4.6]; p = 0.2). Conclusions. IFX TLs are related to biochemical markers of disease activity. This could provide a rationale for monitoring TLs in children receiving IFX for IBD.

Effects of infliximab retreatment after consecutive discontinuation of infliximab and adalimumab in refractory Crohn's disease.

Background:Switches between anti–tumor necrosis factor agents in the treatment of Crohns disease (CD) occur in case of treatment failure, intolerance, or patient preference. No data are currently available on the usefulness of a second infliximab treatment after earlier discontinuation and previous switch to an alternative anti–tumor necrosis factor agent. In this study, we evaluated the clinical benefit of infliximab retreatment in patients with CD after sequential use of both infliximab and adalimumab. Methods:Twenty-nine patients with CD who had received earlier treatments with sequential infliximab and adalimumab and were then restarted on infliximab were retrieved from a multicenter registry designed for the follow-up of adalimumab treatment for CD. Short-term and sustained effects of infliximab retreatment were evaluated retrospectively by reviewing clinical records. Follow-up was 18 months for all patients. Results:In 13/29 (45%) patients, infliximab was reintroduced at intensified dosing schedule (>5 mg/kg or <8 wk) for 23/29 (79%) of patients similar to the schedule who were on at time of previous discontinuation. During the second infliximab treatment course, dosing was further intensified in 11 out of 29 (38%) patients. After 18 months 18/29 (62%), patients were still on continued therapy of their second infliximab treatment. Infliximab was discontinued (after a median of 7 mo) in 11 out of 29 patients for loss of response (n = 7 [24%]), intolerance (n = 3 [10%]), or non-compliance (n = 1 [3%]). Use of induction schedule or concomitant immunomodulators were not significantly associated with treatment benefit. Conclusions:The majority of patients with CD benefit from a second treatment with infliximab after previous treatment with infliximab and adalimumab, which offer a meaningful therapeutic option in often highly refractory patients.

786 The Pharmacokinetics of Infliximab Induction Therapy in Patients With Moderate to Severe Ulcerative Colitis

G A A b st ra ct s of anti-inflammatory M2 BMDM, determined by expression of Arg1 and Fizz1 that are classical M2 markers, was impaired in Il10rb-/mice. These Mφ also expressed significantly higher levels of pro-inflammatory cytokines following LPS stimulation, suggesting that IL10R signaling regulates TLR4-dependent responses in murine anti-inflammatory Mφ. Il10rb-/M2 Mφ also produced less IL10 and promoted less generation of Tregs in-vitro, perhaps due to decreased surface expression of PD-L1 and PD-L2. Moreover, transfer of WT but not Il10rb-/M2 Mφ ameliorated CD4+-induced colitis in Il10rb-/-Rag2-/mice. Similar to murine studies, the generation of M2 Mφ was severely impaired in human IL10R deficient patients. These Mφ also secreted significantly higher levels of TNF, IL6 and IL12 following LPS stimulation, and promoted less generation of Tregs. Conclusion: IL10R-dependent signals play a critical role in the generation and function of blood borne and tissue resident anti-inflammatory Mφ in mice and humans. Therapeutics and cell-based therapies aimed at augmenting anti-inflammatory Mφ may have clinical utility.

Infusion reactions during infliximab treatment are not associated with IgE anti-infliximab antibodies

Objectives Controversy exists on the role of IgE antidrug antibodies (IgE-ADA) in infusion reactions (IR) on infliximab treatment, partly due to the lack of a positive control used for assay validation. We sought to (1) develop a robust assay to measure IgE-ADA, including a positive control, (2) determine the association between IgE-ADA and IR and (3) determine the incidence of IgE-ADA in infliximab treated patients. Methods A recombinant human IgE anti-infliximab monoclonal antibody was developed as standard and positive control. With this antibody, we set up a novel robust assay to measure IgE-ADA. IgE-ADA was determined in three retrospective cohorts (n=159) containing IR+ (n=37) and IR− (n=39), and longitudinal sera of 83 spondyloarthritis. Results IgE-ADA was found in 0/39 IR−, whereas 4/37 (11%) IR+ showed low levels (0.1–0.3 IU/mL, below the 0.35 IU/mL threshold associated with elevated risk of allergic symptoms). All patients who were IgE-ADA positive also had (very) high IgG-ADA levels. The incidence of IgE-ADA in patients with infliximab-treated spondyloarthritis was estimated at less than approximately 1%. Conclusions IgE-ADA is rarely detected in infliximab-treated patients. Moreover, the absence of IgE-ADA in the majority of IR+ patients suggests that IgE-ADA is not associated with infusion reactions.

Benzimidazoles Promote Anti-TNF Mediated Induction of Regulatory Macrophages and Enhance Therapeutic Efficacy in a Murine Model

Abstract Background and Aims Regulatory macrophages play a critical role in tissue repair, and we have previously shown that anti-tumour necrosis factor [TNF] antibodies induce these macrophages in vitro and in vivo in IBD patients. The induction of regulatory macrophages can be potentiated using the combination of anti-TNF and thiopurines, consistent with the enhanced efficacy of this combination therapy described in clinical trials. As thiopurines are unfortunately associated with significant side effects, we here aimed to identify alternatives for combination therapy with anti-TNF, using the macrophage induction model as a screening tool. Methods Mixed lymphocyte reactions were treated with anti-TNF and a library of 1600 drug compounds. Induction of CD14+CD206+ macrophages was analysed by flow cytometry. Positive hits were validated in vitro and in the T cell transfer model of colitis. Results Among the 98 compounds potentiating the induction of regulatory macrophages by anti-TNF were six benzimidazoles, including albendazole. Albendazole treatment in the presence of anti-TNF resulted in alterations in the tubulin skeleton and signalling though AMPK, which was required for the enhanced induction. Combination therapy also increased expression levels of the immunoregulatory cytokine IL-10. In vivo, albendazole plus anti-TNF combination therapy was superior to monotherapy in a model of colitis, in terms of both induction of regulatory macrophages and improvement of clinical symptoms. Conclusions Albendazole enhances the induction of regulatory macrophages by anti-TNF and potentiates clinical efficacy in murine colitis. Given its favourable safety profile, these data indicate that the repurposing of albendazole may be a novel option for anti-TNF combination therapy in IBD.