Ziring, David

Background/Objectives: This study aimed to establish the clinical utility of a therapeutic drug monitoring (TDM)-supported, model-informed precision dosing (MIPD) approach (precision-guided dosing [PGD]) by assessing the impact of pharmacokinetic (clearance [CL]) and clinical laboratory parameters on adalimumab (ADA) dosage adjustments during maintenance therapy for inflammatory bowel disease (IBD). Methods: In the EMPOWER study, blood was collected at any time post-ADA injection. Pharmacokinetic (PK) testing was conducted in an accredited lab. Inputs for the PGD test included ADA concentrations, antibodies to ADA, albumin levels, and the current dosing regimen. CL was calculated using nonlinear mixed-effect models. Results were reported to health care providers (HCPs) within 3 days. HCPs’ treatment decisions were recorded and classified as treatment reduction, continuation, intensification, or ADA discontinuation. The physician global assessment (PGA) of disease activity was collected. Relationships between drug concentrations, CL, disease activity, and physician decision-making were assessed using logistic regression. Results: A total of 213 cases were assessed by 21 HCPs. ADA treatment was intensified in 24% and discontinued in 13% of cases. An ADA concentration ≤ 10 μg/mL was associated with a 23.7-fold and 3.0-fold higher likelihood of therapy intensification and PGA > 0, respectively, compared to concentrations > 10 μg/mL. An ADA concentration < 5 μg/mL was associated with a 3.3-fold higher likelihood of treatment discontinuation. CL ≥ 0.318 L/day was associated with a 10.4-fold higher likelihood of therapy intensification. Higher CL (>0.8 L/day) was associated with a 3.5-fold and 4.2-fold higher likelihood of treatment discontinuation and PGA > 0, respectively. Conclusions: PGD enables earlier and precise optimization of ADA dosing by predicting trough levels at any time during the therapy cycle. Optimized dosing to achieve target ADA concentrations and low clearance is crucial to mitigate therapy discontinuation and active disease in IBD patients.

Objective Perianal Crohn’s disease (pCD) occurs in up to 40% of patients with CD and is associated with poor quality of life, limited treatment responses and poorly understood aetiology. We performed a genetic association study comparing CD subjects with and without perianal disease and subsequently performed functional follow-up studies for a pCD associated SNP in Complement Factor B ( CFB ). Design Immunochip-based meta-analysis on 4056 pCD and 11 088 patients with CD from three independent cohorts was performed. Serological and clinical variables were analysed by regression analyses. Risk allele of rs4151651 was introduced into human CFB plasmid by site-directed mutagenesis. Binding of recombinant G252 or S252 CFB to C3b and its cleavage was determined in cell-free assays. Macrophage phagocytosis in presence of recombinant CFB or serum from CFB risk, or protective CD or healthy subjects was assessed by flow cytometry. Results Perianal complications were associated with colonic involvement, OmpC and ASCA serology, and serology quartile sum score. We identified a genetic association for pCD (rs4151651), a non-synonymous SNP (G252S) in CFB , in all three cohorts. Recombinant S252 CFB had reduced binding to C3b, its cleavage was impaired, and complement-driven phagocytosis and cytokine secretion were reduced compared with G252 CFB. Serine 252 generates a de novo glycosylation site in CFB. Serum from homozygous risk patients displayed significantly decreased macrophage phagocytosis compared with non-risk serum. Conclusion pCD-associated rs4151651 in CFB is a loss-of-function mutation that impairs its cleavage, activation of alternative complement pathway, and pathogen phagocytosis thus implicating the alternative complement pathway and CFB in pCD aetiology.

AbstractBackgroundThe safety of a third dose of SARS-CoV-2 mRNA vaccination in patients with inflammatory bowel disease is unknown.MethodsWe compared symptoms following a third SARS-CoV-2 mRNA vaccine dose with symptoms after the second dose in IBD.ResultsThe study group included 594 patients (70% female, 58% BNT162b2). Overall, 41% reported symptoms after a third dose. Symptom frequency and severity were lower after the third dose relative to the second dose for every organ system, except for gastrointestinal symptoms which were marginally worse.ConclusionThe frequency and severity of symptoms after a third mRNA vaccine dose are generally similar or milder than after a second dose for most organ systems.

Abstract Background and Aims Ileal strictures are the major indication for resective surgery in Crohn’s disease [CD]. We aimed to define ileal gene programmes present at diagnosis and linked with future stricturing behaviour during 5-year follow-up, and to identify potential small molecules to reverse these gene signatures. Methods Antimicrobial serologies and pre-treatment ileal gene expression were assessed in a representative subset of 249 CD patients within the RISK multicentre paediatric CD inception cohort study, including 113 that are unique to this report. These data were used to define genes associated with stricturing behaviour and for model testing to predict stricturing behaviour. A bioinformatics approach to define small molecules which may reverse the stricturing gene signature was applied. Results A total of 19 of the 249 patients developed isolated B2 stricturing behaviour during follow-up, while 218 remained B1 inflammatory. Using deeper RNA sequencing than in our previous report, we have now defined an inflammatory gene signature including an oncostatin M co-expression signature, tightly associated with extra-cellular matrix [ECM] gene expression, in those who developed stricturing complications. We further computationally prioritise small molecules targeting macrophage and fibroblast activation and angiogenesis which may reverse the stricturing gene signature. A model containing ASCA and CBir1 serologies and a refined eight ECM gene set was significantly associated with stricturing development by Year 5 after diagnosis {AUC (area under the curve) (95th CI [confidence interval]) = 0.82 [0.7–0.94)}. Conclusions An ileal gene programme for macrophage and fibroblast activation is linked to stricturing complications in treatment of naïve pediatric CD, and may inform novel small molecule therapeutic approaches.