The Absolute Effect / Oncology Evidence / Evidence Index
KEYNOTE-966
In previously untreated unresectable or metastatic biliary tract cancer, does pembrolizumab added to gemcitabine-cisplatin improve overall survival?
Registry: NCT04003636 · Evidence reviewed 9 November 2026 · Aliases and follow-up publications consolidated.
Phase III double-blind placebo-controlled; n=1,069.Primary-source evidence summaryStudy design, population and eligibility
Phase III double-blind placebo-controlled; n=1,069.
Previously untreated unresectable locally advanced/metastatic BTC.
Treatment and comparator
Intervention: Pembrolizumab + gemcitabine/cisplatin.
Comparator: Placebo + gemcitabine/cisplatin.
Endpoints
OS primary.
Key efficacy and clinical outcomes
Median OS 12.7 vs 10.9 mo (HR 0.83; 95% CI 0.72–0.95); grade 3–4 treatment-related AEs 70% vs 69%; extended follow-up HR 0.86.
Source-reported outcome visualization
Values are reproduced from the cited report; bars are scaled within this figure. First-line unresectable locally advanced/metastatic biliary tract cancer
Median survival and hazard ratios are not fixed-time event risks; NNT is not inferred from them.
Toxicity and treatment burden
High grade 3–4 toxicity in both arms; immune-related events added with pembrolizumab.
Absolute effect and NNT/NNH
Modest median OS difference; do not cross-compare directly with TOPAZ-1 due design/schedule differences.
NNT/NNH is not calculated unless a directly reported, comparable fixed-time risk difference supports it. Median survival and hazard ratios alone do not provide an NNT.
Critical interpretation and limitations
Modest median OS difference; do not cross-compare directly with TOPAZ-1 due design/schedule differences.
This page is an evidence summary, not a substitute for multidisciplinary assessment or patient-specific decision-making.
Current-practice context
Review date: 9 November 2026. Primary publication and selected follow-up sources were reviewed. Full disease-specific guideline, regulatory-label and sequencing audit remains pending; verify current local recommendations and biomarker eligibility before clinical application.