P582 Association between serum ustekinumab concentrations and endoscopic disease activity in Crohn’s disease
Bibliographic record
Abstract
Abstract Background Therapeutic drug monitoring, the measurement of serum biologic concentrations and immunogenicity, has become an important method in guiding the management of biologic therapy in patients with Crohn’s disease (CD). Ustekinumab, an inhibitor of the p40 subunit of interleukins 12 and 23, is an approved therapy for patients with CD. However, few studies have explored the relationship between serum ustekinumab drug levels and outcomes in CD. Thus, the utility of serum ustekinumab drug levels in the management of CD remains unknown. The primary objective of the study was to evaluate the association between serum ustekinumab drug levels and endoscopic remission (ER) in CD. Secondary outcomes included evaluating the association between serum ustekinumab drug levels and clinical (CR), biochemical, and histological remission (HR). Methods Adult patients with CD maintained on ustekinumab were prospectively recruited at the time of routine colonoscopy from 2019 to 2021 at the Montreal University Health Centre, Montreal, Quebec. Clinical and demographic information was obtained from chart and patient review. CD symptom severity was assessed by the Harvey-Bradshaw Index (HBI), with clinical remission defined as an HBI score less than 5. Blood samples were drawn for measurement of serum ustekinumab drug level and C-reactive protein. Stool samples for fecal calprotectin were also collected. Elevated C-reactive protein and fecal calprotectin were defined as a value greater than 5 mg/L and 200 ug/g, respectively. Endoscopic remission was evaluated by the Simplified Endoscopic Score for Crohn’s Disease (SES-CD), with ER defined by an SES-CD score less than 3. If biopsies were taken, histological outcomes were recorded. HR was defined as inactive colitis. Results 53 patients were included in the study, of which 22 (41.5%) were in ER. Median [interquartile range] ustekinumab drug levels were not associated with ER (Figure 1. ER = 5.4 mg/L [2.6–9.4 mg/L], no ER = 4.3 mg/L [2.3–9.4 mg/L]; P=0.843). There was also no association between quartiles of ustekinumab drug levels and ER (P=0.772). In addition, there was no association observed between median ustekinumab drug level and CR (CR = 4.7 mg/L [2.7–8.3 mg/L], no CR = 3.8 mg/L [2.1–9.6 mg/L]; P=0.993) or HR (HR = 6.4 mg/L [3.5–9.5 mg/L], no HR = 3.7 mg/L [2.2–8.0 mg/L]); P=0.168). There was no association observed between median ustekinumab drug level and C-reactive protein or fecal calprotectin as well (P=0.158 and 0.923, respectively). Conclusion There was no association observed between serum ustekinumab drug levels and endoscopic remission. Further studies are required to validate our findings.
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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 | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".