Treatment response to ursodeoxycholic acid in primary biliary cholangitis: A systematic review and meta-analysis.

BACKGROUND: Several ursodeoxycholic acid (UDCA) treatment response definitions have been introduced in primary biliary cholangitis (PBC). However, the lack of a gold standard results in heterogeneity in second-line treatment research and clinical practice. AIMS: This study aimed to explore which UDCA treatment response endpoint serves as the most accurate predictive model of long-term outcome. METHODS: A systematic review and meta-analysis of UDCA treatment response endpoints (and corresponding validations) were performed. RESULTS: Sixteen individual UDCA treatment response endpoints and 96 external validations were found. Barcelona, Paris-1, Paris-2, Rotterdam, Toronto and GLOBE and UK-PBC Risk Scores are currently most robustly validated in external populations. The results show that the continuous models (GLOBE and UK-PBC Risk Scores) serve as the most accurate predictive models. Besides standard UDCA treatment response endpoints, the alkaline phosphatase and total bilirubin normalization has been suggested as a new therapeutic target. CONCLUSIONS: The GLOBE and UK-PBC Risk Scores are the most suitable for the real-world allocation of second-line therapies (obeticholic acid and fibrates). However, in the wake of the recent findings, alkaline phosphatase and total bilirubin normalization should be the primary outcome in trial research in PBC.

The relationship between disease activity and UDCA response criteria in primary biliary cholangitis: A cohort study.

BACKGROUND: Uncertainty exists about how best to identify primary biliary cholangitis (PBC) patients who would benefit from second-line therapy. Existing, purely clinical, ursodeoxycholic acid (UDCA) response criteria accept degrees of liver biochemistry abnormality in responding patients, emerging data, however, suggest that any degree of ongoing abnormality may, in fact, be associated with an increased risk of adverse outcomes. This cohort study explores the link between response status, the biology of high-risk disease and its implications for clinical practice. METHODS: Proteomics, exploring 19 markers previously identified as remaining elevated in PBC following UDCA therapy, were performed on 400 serum samples, from participants previously recruited to the UK-PBC Nested Cohort between 2014 and 2019. All participants had an established diagnosis of PBC and were taking therapeutic doses of UDCA for greater than 12 months. UDCA response status was assessed using Paris 1, Paris 2 and the POISE criteria, with additional analyses using normal liver blood tests stratified by bilirubin level. Statistical analysis using parametric t tests and 1-way ANOVA. FINDINGS: Disease markers were statistically significantly higher in UDCA non-responders than in responders for all the UDCA response criteria, suggesting a meaningful link between biochemical disease status and disease mechanism. For each of the criteria, however, marker levels were also statistically significantly higher in responders with ongoing liver function test abnormality compared to those who had normalised their liver biochemistry. IL-4RA, IL-18-R1, CXCL11, 9 and 10, CD163 and ACE2 were consistently elevated across all responder groups with ongoing LFT abnormality. No statistically significant differences occurred between markers in normal LFT groups stratified by bilirubin level. INTERPRETATION: This study provides evidence that any ongoing elevation in alkaline phosphatase levels in PBC after UDCA therapy is associated with some degree of ongoing disease activity. There was no difference in activity between patients with normal LFT when stratified by bilirubin. These findings suggest that if our goal is to completely control disease activity in PBC, then normalisation of alkaline phosphatase and bilirubin should be the treatment target. This would also simplify messaging around goals of therapy in PBC, benefiting both patients and clinicians. FUNDING: Funding by the UK Medical Research Council (Stratified Medicine Programme) and an independent research grant by Pfizer. The study funders played no role in the study design, data collection, data analyses, data interpretation or manuscript writing.