Impact of Alkaline Phosphatase Normalization on Complication-Free Survival in Primary Biliary Cholangitis

INTRODUCTION: Despite the widespread use of ursodeoxycholic acid (UDCA) in primary biliary cholangitis (PBC), many patients remain at risk of progression. Emerging data suggest that normalization of alkaline phosphatase (ALP) and total bilirubin (TB)-particularly when TB < 0.6 times the upper limit of normal (× ULN)-is associated with improved outcomes compared with ALP reduction to < 1.5 × ULN. This study investigated the association between ALP normalization in response to UDCA and long-term clinical outcomes in a real-world cohort of patients with PBC. METHODS: We compared complication-free survival in patients achieving an ALP > ULN and < 1.5 × ULN (adequate response) with those with an ALP ≤ ULN on UDCA monotherapy. Complication-free survival was defined as the absence of serious liver-related clinical events. Restricted mean survival time was used to quantify survival time gained. RESULTS: Patients achieving normal ALP and/or TB ≤ 0.6 × ULN demonstrated significantly improved complication-free survival compared with those with an adequate ALP response. Event-free survival was extended by 1.34 years (95% CI: 0.56, 2.11; P = 0.001) for ALP normalization alone, 3.7 years (95% CI: 3.11, 4.29; P < 0.001) for TB ≤ 0.6 × ULN, and 4.51 years (95% CI: 4.13, 4.88; P < 0.001) for those meeting both criteria. The risk of severe clinical events was reduced in patients achieving ALP normalization (hazard ratio [HR] 0.34; 95% CI: 0.15, 0.80; P = 0.01), TB ≤ 0.6 × ULN (HR 0.23; 95% CI: 0.09, 0.55; P = 0.001), or both (HR 0.14; 95% CI: 0.05, 0.38; P < 0.001). High-risk patients, defined by liver stiffness measurement ≥ 10 kPa or clinical, histological, or laboratory evidence of cirrhosis or portal hypertension, derived the greatest benefit. DISCUSSION: Achieving normal ALP and TB ≤ 0.6 × ULN is associated with significantly improved complication-free survival, particularly in high-risk patients. These findings highlight the potential of biochemical thresholds as a meaningful therapeutic goal in PBC management.