{"entity":{"id":"window-of-opportunity-trial","kind":"term","name":"Window-of-opportunity trial","aka":["window-of-opportunity","window of opportunity","window trial","window trials","window study","presurgical trial","pre-surgical","pre-operative window","biomarker window","pharmacodynamic study","paired biopsies","serial biopsies","on-treatment biopsy","pre- and post-treatment biopsies","on-treatment biopsies","window studies","window-of-opportunity trials"],"tldr":"Giving a new drug for a few weeks in the gap between diagnosis and scheduled surgery, then examining the removed tumour to see what the drug did to it. Patients lose nothing (surgery proceeds as planned) and researchers get a direct look at the drug's biological effect.","summary":"Window trials compare the diagnostic biopsy with the resected tumour after 2-6 weeks of drug, measuring proliferation (Ki-67 in breast cancer, the basis of POETIC and other endocrine studies), immune infiltration after checkpoint inhibitors, target engagement and early resistance signals; they use tens of patients rather than hundreds and can rank candidate drugs or combinations quickly. They cannot measure survival benefit and short exposure may miss slow effects, and delaying surgery must be justified. Neoadjuvant trials with pathological response endpoints are the longer, efficacy-oriented relative; the site's ideas include window designs for ctDNA, neural and microbiome interventions.","asOf":"2026-09-09","wikipedia":"https://en.wikipedia.org/wiki/Neoadjuvant_therapy","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Neoadjuvant_therapy"}],"tags":[],"related":["neoadjuvant-adjuvant","pcr","first-in-human","core-needle-biopsy","seamless-adaptive","trial-lifecycle","biomarker-stratified-design"],"cancers":[],"sections":["drug-discovery"],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"category":"Trials"},"route":"/terms/window-of-opportunity-trial/","neighbours":{"term":[{"id":"core-needle-biopsy","kind":"term","name":"Core needle biopsy and fine-needle aspiration (FNA)","route":"/terms/core-needle-biopsy/"},{"id":"biomarker-stratified-design","kind":"term","name":"Enrichment and biomarker-stratified designs","route":"/terms/biomarker-stratified-design/"},{"id":"first-in-human","kind":"term","name":"First-in-human (FIH) trial","route":"/terms/first-in-human/"},{"id":"neoadjuvant-adjuvant","kind":"term","name":"Neoadjuvant / adjuvant / perioperative","route":"/terms/neoadjuvant-adjuvant/"},{"id":"pcr","kind":"term","name":"Pathologic complete response (pCR)","route":"/terms/pcr/"},{"id":"seamless-adaptive","kind":"term","name":"Seamless, adaptive and Bayesian trial designs","route":"/terms/seamless-adaptive/"},{"id":"trial-lifecycle","kind":"term","name":"Trial lifecycle: from protocol to label","route":"/terms/trial-lifecycle/"}],"section":[{"id":"drug-discovery","kind":"section","name":"Drug Discovery Platforms","route":"/fronts/drug-discovery/"}]}}