P317 Ustekinumab Trough Concentrations Associated with Biochemical Outcomes in Patients with Crohn’s Disease
Bibliographic record
Abstract
Abstract Background Ustekinumab (UST) is a monoclonal antibody which binds to the p40 subunit of interleukins-12/23 and is an effective and safe treatment for patients with Crohn’s disease (CD). An association between serum drug concentrations and therapeutic outcomes is required to justify Therapeutic Drug Monitoring (TDM). However, it is currently unknown if TDM is of additional value in UST treatment. We assessed the exposure-biochemical response relationship of UST trough concentrations at week, 8 in a prospective, real-world setting. Methods We performed a prospective study in CD patients with biochemical, radiologic or endoscopic disease activity in four academic centers in the Netherlands. All patients (n=90) received weight adjusted intravenously (IV) UST induction. First subcutaneous (SC), 90 mg induction dose was administered at week, 8 followed by a maintenance dose of, 90 mg SC every, 8 or, 12 weeks, at the discretion of the physician. Blood for drug levels were drawn at different time points during follow up (median follow up was, 52 weeks (IQR, 50–52)) with a median amount of, 2 measurements (IQR, 1–4) per patient. Plasma concentrations of UST were determined by means of a validated enzyme-linked immune assay. A population pharmacokinetic (PK) model was developed based on these measurements and the UST FDA review documents. Subsequently, the individual UST concentration time course during treatment were predicted using the developed model. Corticosteroid-free clinical remission (HBI ≤, 4) and biochemical remission (C-reactive protein (CRP) ≤5 mg/L or faecal calprotectin (FC) ≤, 250) were assessed at week, 12 and, 24. Quartile analysis and logistic regression was performed to analyse if UST concentration at week, 8 was associated with biochemical remission rates at week, 24. An independent cohort of, 34 patients was used to validate the primary outcomes. Results Basis characteristics of all patients are shown in table 1. Median estimated trough concentrations of UST were, 4.23 µg/mL (IQR, 2.79–5.83) and, 7.19 µg/mL (IQR, 3.30–10.67) at week, 8 in the primary and validation cohort respectively. Patients achieving biochemical remission at week, 12 and, 24 had statistically significantly higher UST levels at week, 8 (P<0.01) compared to patients without biochemical remission (fig, 1). Also, higher UST levels at week, 8 were associated with better biochemical remission rates at week, 12 and, 24 in quartile analysis and logistic regression (fig, 2,3). Associations of UST levels at week, 8 and biochemical remission at week, 12 and, 24 were confirmed in the validation cohort. No UST antibodies were detected. Conclusion In this real-world cohort of CD patients, ustekinumab levels of ≥5.9 µg/mL at week, 8 were associated with higher biochemical remission rates at week, 12 and, 24.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".