# Efficacy and safety of trastuzumab deruxtecan in patients with HER2-expressing biliary tract or pancreatic tumors: a subgroup analysis of DESTINY-PanTumor02

Source: https://onco.cc/key-papers/paper-oh-destiny-pantumor02-biliary-pancreatic-esmo-open-2026/  
OnCo record `paper-oh-destiny-pantumor02-biliary-pancreatic-esmo-open-2026` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

In the tumour-agnostic trial that led to the HER2 IHC 3+ approval, trastuzumab deruxtecan shrank about a quarter of 41 pretreated biliary cancers overall and more than half of those with the strongest HER2 stain, while pancreatic tumours barely responded.

## Summary

DESTINY-PanTumor02 (NCT04482309) Part 1 evaluated trastuzumab deruxtecan 5.4 mg/kg in locally advanced or metastatic HER2 IHC 3+ or 2+ tumours (local or central testing) that had progressed after systemic treatment or had no treatment options. The primary endpoint was investigator-assessed objective response rate; this report covers the biliary tract (41 patients) and pancreatic (25 patients) cohorts, with median follow-up of 6.0 and 5.0 months.

By investigator, objective response rate was 22.0% (95% CI 10.6 to 37.6) in biliary tract cancer and 4.0% (0.1 to 20.4) in pancreatic cancer; by independent central review 26.8% and 12.0%. Responses were seen across most biliary subgroups, with the highest rate, 56.3% (95% CI 29.9 to 80.2), in centrally confirmed HER2 IHC 3+ tumours. Stable disease was the best response in 61.0% of the biliary cohort; median overall survival was 7.0 months (95% CI 4.6 to 10.2). Adjudicated drug-related interstitial lung disease or pneumonitis occurred in 17.1% of biliary patients and 4.0% of pancreatic patients.

## Fields

- Kind: Key paper
- Last checked: 2026-09-24
- Journal: ESMO Open
- Year: 2026
- DOI: 10.1016/j.esmoop.2026.108344
- Authors: Oh DY, Lugowska I, Stroyakovskiy D, et al.
- Findings: Biliary cohort (n = 41): objective response rate 22.0% by investigator, 26.8% by central review; 56.3% in centrally confirmed IHC 3+ tumours.; Pancreatic cohort (n = 25): 4.0% by investigator.; Interstitial lung disease or pneumonitis in 17.1% of biliary patients; median overall survival 7.0 months.
- What it means: The IHC 3+ subgroup result is why the tumour-agnostic label is written at 3+ and not 2+, and why a gallbladder cancer with a strong HER2 stain now has two on-label choices (zanidatamab, trastuzumab deruxtecan) after chemotherapy. Lung toxicity again ran higher than in breast cancer.
- Caveats: Subgroup of a single-arm basket study; local and central HER2 testing were both allowed.; Short follow-up and small IHC 3+ subgroup (16 patients).

## Sources

- Oh et al., ESMO Open 2026: trastuzumab deruxtecan in the biliary and pancreatic cohorts of DESTINY-PanTumor02: https://doi.org/10.1016/j.esmoop.2026.108344
- PubMed: https://pubmed.ncbi.nlm.nih.gov/42531802/
- ClinicalTrials.gov NCT04482309: https://clinicaltrials.gov/study/NCT04482309

## Connected records

- cancers: [Biliary tract cancer (all types)](https://onco.cc/cancers/biliary-tract-cancer/), [Biliary tract cancer (cholangiocarcinoma)](https://onco.cc/cancers/cholangiocarcinoma/), [Gallbladder cancer](https://onco.cc/cancers/gallbladder/), [Pancreatic ductal adenocarcinoma](https://onco.cc/cancers/pancreatic/)
- targets: [HER2](https://onco.cc/targets/her2/)
- drugs: [Trastuzumab deruxtecan](https://onco.cc/drugs/trastuzumab-deruxtecan/)
- companies: [AstraZeneca](https://onco.cc/companies/astrazeneca/), [Daiichi Sankyo](https://onco.cc/companies/daiichi-sankyo/)
- trials: [DESTINY-PanTumor02](https://onco.cc/trials/destiny-pantumor02/)
- people: [Do-Youn Oh](https://onco.cc/people/oh-do-youn/)
- biomarkers: [HER2 IHC 3+ (HER2-positive by immunohistochemistry)](https://onco.cc/biomarkers/her2-ihc-3-plus/)

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