External validation of MAGIC-D in Taiwanese patients with advanced biliary tract cancer receiving durvalumab and chemotherapy.

Abstract

502 Background: The TOPAZ-1 trial established gemcitabine–cisplatin–durvalumab (GCD) as first-line therapy for advanced biliary tract cancer (BTC). The MAGIC-D model includes metastatic disease, hypoalbuminemia, elevated γ-glutamyl transferase, neutrophil-to-lymphocyte ratio (NLR) ≥3, and elevated carcinoembryonic antigen level to predict survival in GCD-treated patients. We aimed to validate MAGIC-D in a real-world Asian BTC cohort. Methods: We reviewed patients with unresectable or metastatic BTC receiving first-line GCD at four centers between 2021 and 2025. Baseline clinical, laboratory, treatment, and safety data were collected. Patients were classified into low-, intermediate-, and high-risk groups using MAGIC-D. Overall survival (OS) and progression-free survival (PFS) were estimated using Kaplan–Meier analysis with hazard ratios (HRs) from Cox regression. Model discrimination was assessed using area under the curve (AUC). Results: Of 172 patients, MAGIC-D classified 48 (27.9%) as low-risk, 80 (46.5%) intermediate-risk, and 44 (25.6%) as high-risk. Median OS and PFS were 13.8 and 5.1 months, respectively for the entire cohort. Median OS by risk group was 23.2 months (low), 16.3 months (intermediate; HR 1.95, 95% CI 1.04–3.67), and 4.9 months (high; HR 7.12, 95% CI 3.70–13.7). PFS times were 6.7, 5.1, and 2.2 months, respectively. MAGIC-D achieved AUCs of 0.755 and 0.749 for 6- and 12- months survival prediction, respectively, outperforming NLR and other baseline factors. Conclusions: In this first external validation in Asian BTC patients, MAGIC-D effectively stratified patients by survival and treatment response. MAGIC-D may aid in risk-adapted patient counseling, follow-up planning, and clinical trial stratification for GCD-treated BTC.