{"entity":{"id":"paper-zebra-pembrolizumab-small-bowel-adenocarcinoma-ccr-2021","kind":"paper","name":"ZEBRA: pembrolizumab in advanced small bowel adenocarcinoma","aka":[],"tldr":"Immunotherapy on its own helped only a few patients with advanced small bowel adenocarcinoma, mainly those whose tumours had mismatch repair deficiency, so the drug is reserved for that group.","summary":"Multicentre single-arm phase 2 study of 40 patients with previously treated advanced small bowel adenocarcinoma given pembrolizumab every three weeks.\n\nThe objective response rate was 8 percent and the study did not meet its primary endpoint; responses clustered in patients with mismatch repair deficient or microsatellite instability high tumours, while microsatellite stable disease rarely responded.","asOf":"2026-09-18","links":[{"label":"Clin Cancer Res 2021","url":"https://doi.org/10.1158/1078-0432.CCR-21-0159"},{"label":"PubMed","url":"https://pubmed.ncbi.nlm.nih.gov/33883178/"}],"tags":[],"related":[],"cancers":["advanced-small-bowel-adenocarcinoma"],"sections":[],"technologies":[],"targets":[],"drugs":["pembrolizumab"],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":["clinical-cancer-research"],"dependsOn":[],"notes":[],"journal":"Clinical Cancer Research","year":2021,"doi":"10.1158/1078-0432.CCR-21-0159","pmid":"33883178","authors":"Pedersen KS, Foster NR, Overman MJ, et al.","paperType":"observational","findings":["Objective response 8 percent overall; the primary endpoint was not met.","Responses were seen in mismatch repair deficient tumours and rarely in microsatellite stable disease."],"whatItMeans":"Every small bowel adenocarcinoma should be tested for mismatch repair deficiency, because immunotherapy is worthwhile for those patients and of little use to the rest.","caveats":["Small single-arm study.","Few dMMR patients were included, so the estimate of benefit in that group is imprecise."],"changedPractice":false,"participants":40},"route":"/key-papers/paper-zebra-pembrolizumab-small-bowel-adenocarcinoma-ccr-2021/","neighbours":{"cancer":[{"id":"advanced-small-bowel-adenocarcinoma","kind":"cancer","name":"Advanced and metastatic small bowel adenocarcinoma","route":"/cancers/advanced-small-bowel-adenocarcinoma/"}],"drug":[{"id":"pembrolizumab","kind":"drug","name":"Pembrolizumab","route":"/drugs/pembrolizumab/"}],"journal":[{"id":"clinical-cancer-research","kind":"journal","name":"Clinical Cancer Research","route":"/journals/clinical-cancer-research/"}]}}