{"entity":{"id":"idea-gbc-report-gallbladder-separately-in-biliary-trials","kind":"idea","name":"Report gallbladder cancer as its own population in every biliary trial","aka":[],"tldr":"Every drug gallbladder cancer patients receive was tested in mixed bile duct trials where they were a subgroup. Requiring trials to pre-specify and publish gallbladder results, with a minimum number enrolled, would give the disease its own evidence at almost no cost.","summary":"ABC-02, BILCAP, ABC-06, TOPAZ-1 and KEYNOTE-966 enrolled gallbladder cancer alongside intrahepatic and extrahepatic cholangiocarcinoma and reported it, if at all, in forest plots. Yet the diseases differ: HER2 positivity runs at 9 to 20 percent in gallbladder and extrahepatic cancers against 5 percent intrahepatic; immune profiles differ by population; and the UK CAPBIL cohort saw no adjuvant benefit in a mostly gallbladder population. A reporting standard (pre-specified gallbladder stratum, minimum enrolment, mandatory subgroup publication) could be asked of sponsors by regulators and journals and would cost the trials almost nothing.","asOf":"2026-09-24","links":[{"label":"Galdy et al.: HER2 in biliary tract cancers by site (Cancer Metastasis Rev 2017)","url":"https://europepmc.org/article/MED/27981460"},{"label":"Zhu et al.: population-specific immunogenomics of gallbladder cancer (Mod Pathol 2025)","url":"https://europepmc.org/article/MED/40541865"}],"tags":["gallbladder-evidence"],"related":[],"cancers":["gallbladder","biliary-tract-cancer"],"sections":[],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["hazard-ratio"],"trials":["topaz-1","keynote-966","bilcap","abc-06","acticca-1","nct06109779"],"people":[],"bottlenecks":["b-rare-cancers","b-trial-design","b-negative-results"],"keyPapers":["paper-galdy-her2-biliary-tract-meta-analysis-cancer-metastasis-rev-2017","paper-zhu-population-specific-immunogenomics-gallbladder-cancer-mod-pathol-2025","paper-mcclements-capbil-surgical-outcomes-gallbladder-cancer-hpb-2026"],"journals":[],"dependsOn":[],"notes":[],"hypothesis":"Mandating a pre-specified gallbladder cancer stratum with published results in biliary tract cancer trials will reveal clinically meaningful differences in treatment effect between gallbladder cancer and cholangiocarcinoma within five years.","rationale":"Prevalence of HER2, immune profile and recurrence pattern already differ between sites; pooled analyses hide effect modification. The cost of a stratum is small; the cost of a wrong extrapolation is borne by every gallbladder patient.","test":"Retrospective: obtain gallbladder-stratum results from TOPAZ-1, KEYNOTE-966, BILCAP and ABC-06 and test for interaction with site. Prospective: ACTICCA-1 and ARTEMIDE-Biliary01 publish gallbladder strata as primary-paper tables.","maturity":"speculative","actor":"regulator","cost":"small","horizonYears":3},"route":"/ideas/idea-gbc-report-gallbladder-separately-in-biliary-trials/","neighbours":{"cancer":[{"id":"biliary-tract-cancer","kind":"cancer","name":"Biliary tract cancer (all types)","route":"/cancers/biliary-tract-cancer/"},{"id":"gallbladder","kind":"cancer","name":"Gallbladder cancer","route":"/cancers/gallbladder/"}],"term":[{"id":"hazard-ratio","kind":"term","name":"Hazard ratio (HR)","route":"/terms/hazard-ratio/"}],"trial":[{"id":"abc-06","kind":"trial","name":"ABC-06","route":"/trials/abc-06/"},{"id":"acticca-1","kind":"trial","name":"ACTICCA-1","route":"/trials/acticca-1/"},{"id":"bilcap","kind":"trial","name":"BILCAP","route":"/trials/bilcap/"},{"id":"keynote-966","kind":"trial","name":"KEYNOTE-966","route":"/trials/keynote-966/"},{"id":"nct06109779","kind":"trial","name":"Rilvegostomig + Chemotherapy as Adjuvant Therapy for Biliary Tract Cancer After Resection (ARTEMIDE-Biliary01)","route":"/trials/nct06109779/"},{"id":"topaz-1","kind":"trial","name":"TOPAZ-1","route":"/trials/topaz-1/"}],"bottleneck":[{"id":"b-negative-results","kind":"bottleneck","name":"Failures are hidden","route":"/bottlenecks/b-negative-results/"},{"id":"b-rare-cancers","kind":"bottleneck","name":"Rare and paediatric cancers without markets","route":"/bottlenecks/b-rare-cancers/"},{"id":"b-trial-design","kind":"bottleneck","name":"Trial design, endpoints and cost","route":"/bottlenecks/b-trial-design/"}],"paper":[{"id":"paper-galdy-her2-biliary-tract-meta-analysis-cancer-metastasis-rev-2017","kind":"paper","name":"HER2/HER3 pathway in biliary tract malignancies; systematic review and meta-analysis: a potential therapeutic target?","route":"/key-papers/paper-galdy-her2-biliary-tract-meta-analysis-cancer-metastasis-rev-2017/"},{"id":"paper-zhu-population-specific-immunogenomics-gallbladder-cancer-mod-pathol-2025","kind":"paper","name":"Population-Specific Immunogenomic Alterations in Gallbladder Cancer and Prognostic Significance","route":"/key-papers/paper-zhu-population-specific-immunogenomics-gallbladder-cancer-mod-pathol-2025/"},{"id":"paper-mcclements-capbil-surgical-outcomes-gallbladder-cancer-hpb-2026","kind":"paper","name":"Surgical outcomes in gallbladder cancer: evidence from the UK nationwide CAPBIL study","route":"/key-papers/paper-mcclements-capbil-surgical-outcomes-gallbladder-cancer-hpb-2026/"}],"roadmap":[{"id":"gallbladder-cancer-roadmap","kind":"roadmap","name":"Gallbladder cancer roadmap: from a chance finding at gallstone surgery to a disease with its own trials","route":"/roadmaps/gallbladder-cancer-roadmap/"}]}}