Primary biliary cholangitis (PBC) is a chronic autoimmune liver disease marked by cholestasis and progressive fibrosis. While ursodeoxycholic acid (UDCA) remains the first-line therapy, approximately 30–40% of patients have an inadequate biochemical response, increasing the risk of disease progression. Obeticholic acid (OCA), a potent farnesoid X receptor (FXR) agonist, was the first second-line agent approved by the only Food and Drug Administration (FDA) and has demonstrated moderate biochemical efficacy but limited tolerability due to dose-dependent pruritus and safety concerns in cirrhosis. Fenofibrate, a peroxisome proliferator-activated receptor alpha (PPAR-α) agonist, showed substantial alkaline phosphatase (ALP) reductions when added to UDCA, although its long-term benefit remains unconfirmed in large-scale trials and its use remains off-label in the United States, unlike FDA-approved agents. Seladelpar, a selective peroxisome proliferator-activated receptor delta (PPAR-δ) agonist, and elafibranor, a dual PPAR-α/δ agonist, have both recently received FDA accelerated approval after demonstrating significant improvements in ALP, biochemical response rates, and pruritus relief in phase 3 trials. This review summarizes these second-line therapies’ mechanisms, efficacy, safety, and limitations emphasizing the need for individualized treatment decisions and ongoing research into long-term clinical outcomes.

Acute severe ulcerative colitis (ASUC) is a medical emergency affecting up to 25% of patients with ulcerative colitis (UC), with colectomy required in approximately 25–30% of cases during the initial admission. Intravenous corticosteroids remain the first-line therapy, though one-third of patients do not respond, necessitating rescue with infliximab or calcineurin inhibitors, which are both supported by randomized trials and guideline recommendations. Comparative studies and meta-analyses have shown similar efficacy between these agents, while sequential use is associated with higher adverse event rates and should be restricted to specialized centers. Recent data have refined infliximab use, with the PREDICT-UC trial showing no superiority of intensified dosing over standard regimens. Emerging therapies are under investigation: vedolizumab has been used as maintenance following calcineurin induction; ustekinumab has shown benefits in retrospective UC cohorts, particularly after cyclosporine; and Janus kinase (JAK) inhibitors represent the most recent addition. The randomized TACOS trial and the prospective TRIUMPH study demonstrated an improved short-term response with tofacitinib in steroid-refractory ASUC, and real-world reports suggest promising outcomes with upadacitinib. While infliximab and cyclosporine remain as standard rescue therapies, ongoing trials with novel agents are likely to broaden treatment options. This review summarizes the clinical features, initial management, and the role of advanced therapies in ASUC.

Background: Perianal fistulizing Crohn’s disease (CD) is associated with significant morbidity and remains difficult to treat. Although advanced medical therapies are widely used, much of the available evidence derives from heterogeneous fistula populations or luminal CD trials, with limited perianal-specific synthesis and inconsistent outcome definitions. We conducted a systematic review focusing exclusively on perianal-specific clinical, radiologic, and composite outcomes in adults with perianal fistula (PAF) CD. Methods: We performed a systematic review in accordance with PRISMA 2020. Electronic databases were searched from inception through November 2025. We included randomized controlled trials and cohort studies enrolling adults with CD reporting outcomes specific to PAF. Interventions included biologics and small-molecule therapies, compared with placebo or other therapies. Due to substantial heterogeneity in outcome definitions and study designs, a meta-analysis was not performed. Risk of bias was assessed using Risk of Bias 2 (RoB 2) for randomized trials and the Newcastle–Ottawa Scale for observational studies. Results: Seven studies including >1200 participants with PAF-CD met inclusion criteria. Follow-up ranged from 24 weeks to 5 years. Across studies, outcome definitions and assessment modalities varied. Upadacitinib demonstrated significantly higher clinical fistula closure compared with placebo across multiple dose regimens at 52 weeks. In observational comparisons, ustekinumab and vedolizumab were associated with higher clinical closure rates than anti-TNF therapies. However, infliximab demonstrated higher closure rates than adalimumab as a first-line treatment. The definition for radiologic remission was less consistent across studies and often did not parallel clinical outcomes. Composite clinical–radiologic remission and response were reported in a limited number of studies, with filgotinib showing higher composite outcomes in comparison to placebo in a phase 2 trial. Surgical interventions, relapse outcomes, biomarkers [C-reactive protein (CRP)/fecal calprotectin (FCP)], and patient-reported outcomes were variably reported and not consistently significant across comparisons. Conclusions: Evidence for advanced therapies in PAF CD remains limited by heterogeneity in endpoint definitions, subjectivity in clinical observation, inconsistent radiologic reporting, and reliance on subgroup or observational comparisons. While anti-TNF therapy remains the most established option in guidelines, emerging data suggest significant benefits with ustekinumab, vedolizumab, and JAK inhibitors in selected patients. There is a need for PAF-specific, adequately powered randomized trials using standardized composite clinical and radiologic endpoints.

Eosinophilic esophagitis (EoE) and inflammatory bowel disease (IBD) are immune-mediated disorders of the gastrointestinal (GI) tract that, despite involving different tissues, are increasingly recognized to coexist. Epidemiologic studies demonstrate a bidirectional association, with patients affected by one condition showing a higher-than-expected prevalence of the other, suggesting shared susceptibility rather than incidental overlap. Genetic and epigenetic data support partial convergence in immune regulatory pathways, while epithelial barrier dysfunction and antigen-driven immune activation emerge as common upstream features. Overlapping cytokine networks, including IL-4, IL-13, and IL-23 signaling, contribute to chronic inflammation in both diseases, although differences in tissue environment and immune dominance give rise to distinct inflammatory phenotypes and clinical behavior. Clinical outcomes in patients with dual diagnoses appear heterogeneous, with available data suggesting neither uniformly worsened nor clearly protective disease courses, underscoring the complexity of shared immune mechanisms operating within different anatomic contexts. Beyond inflammatory activity, coexistence of EoE and IBD poses important nutritional and quality-of-life challenges, as overlapping dietary restrictions and chronic symptoms increase the risk of malnutrition, micronutrient deficiencies, and psychosocial burden. Current therapies remain disease-specific, with strong evidence supporting proton pump inhibitors, swallowed topical steroids, dietary therapy, and dupilumab in EoE, and biologics and small molecules targeting TNF-α, IL-12/23, IL-23, integrins, and JAK–STAT signaling in IBD, while evidence guiding treatment in patients with dual diagnosis remains limited. Together, current evidence supports a framework of shared immune machinery with tissue-specific expression that explains coexistence while preserving the distinct identities of EoE and IBD. By integrating emerging genetic, immunologic, and clinical evidence, this review aims to provide a framework for understanding and managing patients with coexisting EoE and IBD.