{"entity":{"id":"idea-ai-her2-low-scoring","kind":"idea","name":"AI quantification of HER2-low and HER2-ultralow","aka":[],"tldr":"Pathologists disagree about faint HER2 staining, yet that decision unlocks Enhertu. Let a validated algorithm do the counting.","summary":"Pathologists disagree about faint HER2 staining, yet that call decides who receives trastuzumab deruxtecan, so this idea hands the counting to a validated algorithm. A continuous AI-derived HER2 membrane score is expected to predict T-DXd benefit better than pathologist-assigned IHC categories and to reclassify some IHC 0 tumours as eligible, because benefit depends on a continuous delivery threshold that binned human scoring discards. The test is a retrospective analysis of DESTINY-Breast04 and DESTINY-Breast06 slides with an AI scorer, then prospective companion-diagnostic validation. At early-clinical maturity it addresses the bottlenecks Biomarkers are not validated or standardised and AI that is built but not validated or deployed.","asOf":"2026-09-04","links":[{"label":"DESTINY-Breast04: trastuzumab deruxtecan works in HER2-low breast cancer, creating a new treatable group (New England Journal of Medicine 2022)","url":"https://doi.org/10.1056/NEJMoa2203690"}],"tags":[],"related":["her2-low-to-tdxd"],"cancers":["breast-hr-positive","tnbc"],"sections":[],"technologies":["digital-pathology-ai","histopathology-ihc"],"targets":[],"drugs":["trastuzumab-deruxtecan"],"companies":[],"institutions":[],"pathways":[],"terms":["her2-low","ihc"],"trials":["destiny-breast04","destiny-breast06","nct05950945"],"people":[],"bottlenecks":[],"keyPapers":["paper-trastuzumab-deruxtecan-breast-hr-positive-ann-oncol-2026","paper-trastuzumab-deruxtecan-tnbc-esmo-open-2021","paper-trastuzumab-deruxtecan-tnbc-expert-opin-biol-ther-2021"],"journals":[],"dependsOn":[],"notes":[],"hypothesis":"A continuous AI-derived HER2 membrane score predicts T-DXd benefit better than pathologist-assigned IHC categories, and reclassifies a meaningful fraction of IHC 0 tumours as eligible.","rationale":"T-DXd benefit depends on a delivery threshold, which is continuous; discretised human scoring loses information.","test":"Run a retrospective analysis of DESTINY-Breast04/06 slides with an AI scorer, then prospective companion-diagnostic validation.","maturity":"early-clinical"},"route":"/ideas/idea-ai-her2-low-scoring/","neighbours":{"pairing":[{"id":"her2-low-to-tdxd","kind":"pairing","name":"HER2-low scoring → T-DXd","route":"/pairings/her2-low-to-tdxd/"}],"cancer":[{"id":"breast-hr-positive","kind":"cancer","name":"HR-positive / HER2-negative breast cancer","route":"/cancers/breast-hr-positive/"},{"id":"tnbc","kind":"cancer","name":"Triple-negative breast cancer (TNBC)","route":"/cancers/tnbc/"}],"technology":[{"id":"digital-pathology-ai","kind":"technology","name":"Digital pathology & AI","route":"/technologies/digital-pathology-ai/"},{"id":"histopathology-ihc","kind":"technology","name":"Histopathology & immunohistochemistry","route":"/technologies/histopathology-ihc/"}],"drug":[{"id":"trastuzumab-deruxtecan","kind":"drug","name":"Trastuzumab deruxtecan","route":"/drugs/trastuzumab-deruxtecan/"}],"term":[{"id":"her2-low","kind":"term","name":"HER2-low and HER2-ultralow","route":"/terms/her2-low/"},{"id":"ihc","kind":"term","name":"Immunohistochemistry (IHC)","route":"/terms/ihc/"}],"trial":[{"id":"destiny-breast04","kind":"trial","name":"DESTINY-Breast04","route":"/trials/destiny-breast04/"},{"id":"destiny-breast06","kind":"trial","name":"DESTINY-Breast06","route":"/trials/destiny-breast06/"},{"id":"nct05950945","kind":"trial","name":"Trastuzumab Deruxtecan (T-DXd) in Patients Who Have Hormone Receptor-negative and Hormone Receptor-positive HER2-low or HER2 IHC 0 Metastatic Breast Cancer","route":"/trials/nct05950945/"}],"paper":[{"id":"paper-trastuzumab-deruxtecan-tnbc-expert-opin-biol-ther-2021","kind":"paper","name":"Antibody-drug conjugates in metastatic triple negative breast cancer: a spotlight on sacituzumab govitecan, ladiratuzumab vedotin, and trastuzumab deruxtecan","route":"/key-papers/paper-trastuzumab-deruxtecan-tnbc-expert-opin-biol-ther-2021/"},{"id":"paper-trastuzumab-deruxtecan-breast-hr-positive-ann-oncol-2026","kind":"paper","name":"Neoadjuvant trastuzumab deruxtecan alone or followed by paclitaxel, trastuzumab, and pertuzumab for high-risk HER2-positive early breast cancer (DESTINY-Breast11): a randomised, open-label, multicentre, phase III trial","route":"/key-papers/paper-trastuzumab-deruxtecan-breast-hr-positive-ann-oncol-2026/"},{"id":"paper-trastuzumab-deruxtecan-tnbc-esmo-open-2021","kind":"paper","name":"Sacituzumab govitecan and trastuzumab deruxtecan: two new antibody-drug conjugates in the breast cancer treatment landscape","route":"/key-papers/paper-trastuzumab-deruxtecan-tnbc-esmo-open-2021/"}],"bottleneck":[{"id":"b-ai-validation","kind":"bottleneck","name":"AI that is built but not validated or deployed","route":"/bottlenecks/b-ai-validation/"},{"id":"b-biomarker-validation","kind":"bottleneck","name":"Biomarkers are not validated or standardised","route":"/bottlenecks/b-biomarker-validation/"}],"idea":[{"id":"idea-fund-biomarker-validation-fund","kind":"idea","name":"A fund for prospective validation of academic biomarkers and companion diagnostics","route":"/ideas/idea-fund-biomarker-validation-fund/"},{"id":"idea-data-ai-pathology-evaluation-standard","kind":"idea","name":"A standard evaluation pathway for AI-assisted pathology, from reader study to deployment","route":"/ideas/idea-data-ai-pathology-evaluation-standard/"},{"id":"idea-acc-ai-first-pathology-common-cases","kind":"idea","name":"AI-first reading for high-volume common cancer diagnoses, pathologist for the exceptions","route":"/ideas/idea-acc-ai-first-pathology-common-cases/"},{"id":"idea-tr2-her2-low-reference-materials","kind":"idea","name":"Calibrated reference slides so every lab scores HER2-low the same way","route":"/ideas/idea-tr2-her2-low-reference-materials/"},{"id":"idea-tr2-ai-cdx-change-control","kind":"idea","name":"Version control and locked reference sets for AI algorithms used as companion diagnostics","route":"/ideas/idea-tr2-ai-cdx-change-control/"}]}}