Treatment Response Patterns and Residual Disease in Inflammatory Bowel Disease: Mechanisms, Biomarkers, and Therapeutic Strategy

Advanced therapies have expanded treatment options for inflammatory bowel disease (IBD), but incomplete and inconsistent responses remain a challenge. Some patients never respond, others improve without reaching remission, and some lose an initially effective response. Clinical symptoms, biomarkers, endoscopy and histology may also show different degrees of improvement.These patterns can reveal what a treatment has controlled and what remains unresolved. A partial response may reflect suppression of one inflammatory component while others remain active, rather than complete failure of the therapeutic mechanism. Alternatively, incomplete response may result from inadequate drug exposure, immunogenicity, structural damage or non-inflammatory dysfunction. Understanding these differences could help clinicians decide whether to optimise treatment, switch mechanisms or investigate a complementary strategy. The physiological question is what sustains residual disease; the clinical question is what to do next.This Research Topic will connect treatment-response patterns with their biological explanations and therapeutic implications in ulcerative colitis, Crohn’s disease and IBD-unclassified, including multi-refractory disease. When predefined treatment outcomes are not achieved, what can the pattern and depth of response tell us about the residual biology of disease, and how can that information be used to optimise the next therapeutic step? The collection will examine whether identifying what has worked, alongside what remains uncontrolled, can improve treatment decisions beyond repeated empirical switching. It will welcome evidence supporting or challenging this approach.We welcome contributions addressing:Treatment-response patterns: primary non-response, partial response and secondary loss of response, including discordance between clinical, biochemical, endoscopic, histological and molecular outcomes.Residual disease mechanisms: immune pathway persistence, epithelial and barrier dysfunction, stromal remodelling, and microbial or neuroimmune processes that may explain incomplete recovery. Pharmacological assessment: drug exposure, immunogenicity, target engagement and therapeutic drug monitoring to distinguish underexposure from mechanistic resistance. Biomarkers and experimental models: longitudinal clinical and tissue measurements, imaging, single-cell and spatial biology, multi-omics and functional models that identify residual disease or predict subsequent response. Optimisation, switching and sequencing: dose intensification, within-class and between-class switching, and phenotype- or biomarker-informed strategies, particularly in patients with previous advanced therapy failures. Partial response and dual advanced therapy: whether a demonstrably beneficial mechanism should be preserved and complemented; biological rationale, patient selection, comparative effectiveness, safety and monitoring.Mechanistic studies, clinical cohorts, comparative analyses and evidence syntheses are welcome when they address a defined response pattern or therapeutic decision. .Contributions should distinguish persistent inflammation from structural damage and non-inflammatory causes of symptoms. Partial response alone should not be taken as proof that combination treatment is appropriate. Topic editors: Jonathan Soldera Source: https://www.frontiersin.org/research-topics/86670/treatment-response-patterns-and-residual-disease-in-inflammatory-bowel-disease-mechanisms-biomarkers-and-therapeutic-strategy