{"entity":{"id":"idea-bio2-brain-met-prevention-trials","kind":"idea","name":"Prevention trials aimed only at brain metastasis","aka":[],"tldr":"Some cancers reach the brain in up to a quarter of patients. Prevention trials could aim specifically at stopping that, instead of treating it once it has happened.","summary":"Brain-penetrant agents reduce central nervous system progression in metastatic disease, and adjuvant trials have shown CNS event reductions as secondary endpoints. No trial yet uses CNS-metastasis-free survival as a primary endpoint in a population prospectively defined as CNS-high-risk by subtype and risk score. This is a designable, ownable clinical setting rather than a new mechanism.","asOf":"2026-09-08","links":[{"label":"Bottleneck evidence (Metastasis is understood least and studied last): Dillekås et al., Are 90% of deaths from cancer caused by metastases? (Cancer Medicine 2019)","url":"https://doi.org/10.1002/cam4.2474"}],"tags":[],"related":["lung-cancer-evidence-roadmap","idea-lung-brain-metastasis-prevention-as-a-primary-endpoint"],"cancers":["breast-her2-positive","nsclc"],"sections":[],"technologies":["mri"],"targets":[],"drugs":["tucatinib","osimertinib","alectinib","lorlatinib"],"companies":[],"institutions":[],"pathways":[],"terms":["her2-brain-metastases"],"trials":["alina","adaura","her2climb"],"people":[],"bottlenecks":["b-metastasis-biology","b-brain-delivery","b-trial-design"],"keyPapers":["paper-adaura-8-year-os-jto-2026","paper-flaura-nejm-2018","paper-dillekas-cancer-med"],"journals":[],"dependsOn":[],"notes":[],"hypothesis":"In prospectively identified CNS-high-risk resected disease, such as HER2-positive breast cancer with heavy nodal involvement or ALK-positive lung cancer, a brain-penetrant adjuvant regimen improves CNS-metastasis-free survival by an absolute 10% at three years.","rationale":"Adjuvant osimertinib and alectinib trials both showed large reductions in CNS events as secondary findings. Preventing brain metastasis sidesteps the delivery problem entirely by acting before the barrier becomes the obstacle.","test":"Estimate CNS event rates and effect sizes retrospectively in existing adjuvant datasets to size the trial, then run a randomised CNS-metastasis-free survival trial with protocol-mandated MRI surveillance.","maturity":"speculative","actor":"industry","cost":"large","horizonYears":8},"route":"/ideas/idea-bio2-brain-met-prevention-trials/","neighbours":{"roadmap":[{"id":"lung-cancer-evidence-roadmap","kind":"roadmap","name":"Lung cancer roadmap: from Doll and Hill and the naming of tobacco, through the cytotoxic plateau, computed tomography screening, EGFR and ALK, immunotherapy by PD-L1, the perioperative trials and PACIFIC, to DLL3 in small-cell disease and a 2032 registry watch","route":"/roadmaps/lung-cancer-evidence-roadmap/"}],"idea":[{"id":"idea-lung-brain-metastasis-prevention-as-a-primary-endpoint","kind":"idea","name":"Measure brain metastasis prevention as a primary endpoint, not as a secondary one","route":"/ideas/idea-lung-brain-metastasis-prevention-as-a-primary-endpoint/"}],"cancer":[{"id":"breast-her2-positive","kind":"cancer","name":"HER2-positive breast cancer","route":"/cancers/breast-her2-positive/"},{"id":"nsclc","kind":"cancer","name":"Non-small-cell lung cancer","route":"/cancers/nsclc/"}],"technology":[{"id":"mri","kind":"technology","name":"MRI","route":"/technologies/mri/"}],"drug":[{"id":"alectinib","kind":"drug","name":"Alectinib","route":"/drugs/alectinib/"},{"id":"lorlatinib","kind":"drug","name":"Lorlatinib","route":"/drugs/lorlatinib/"},{"id":"osimertinib","kind":"drug","name":"Osimertinib","route":"/drugs/osimertinib/"},{"id":"tucatinib","kind":"drug","name":"Tucatinib","route":"/drugs/tucatinib/"}],"term":[{"id":"her2-brain-metastases","kind":"term","name":"HER2-positive brain metastases","route":"/terms/her2-brain-metastases/"}],"trial":[{"id":"adaura","kind":"trial","name":"ADAURA","route":"/trials/adaura/"},{"id":"alina","kind":"trial","name":"ALINA","route":"/trials/alina/"},{"id":"her2climb","kind":"trial","name":"HER2CLIMB","route":"/trials/her2climb/"}],"bottleneck":[{"id":"b-metastasis-biology","kind":"bottleneck","name":"Metastasis is understood least and studied last","route":"/bottlenecks/b-metastasis-biology/"},{"id":"b-brain-delivery","kind":"bottleneck","name":"The brain: barrier and sanctuary","route":"/bottlenecks/b-brain-delivery/"},{"id":"b-trial-design","kind":"bottleneck","name":"Trial design, endpoints and cost","route":"/bottlenecks/b-trial-design/"}],"paper":[{"id":"paper-adaura-8-year-os-jto-2026","kind":"paper","name":"ADAURA: exploratory eight-year overall survival update for adjuvant osimertinib in resected EGFR-mutated stage IB to IIIA lung cancer","route":"/key-papers/paper-adaura-8-year-os-jto-2026/"},{"id":"paper-dillekas-cancer-med","kind":"paper","name":"Are 90% of deaths from cancer caused by metastases?","route":"/key-papers/paper-dillekas-cancer-med/"},{"id":"paper-shaw-crown-lorlatinib-crizotinib-nejm-2020","kind":"paper","name":"First-line lorlatinib or crizotinib in advanced ALK-positive lung cancer","route":"/key-papers/paper-shaw-crown-lorlatinib-crizotinib-nejm-2020/"},{"id":"paper-flaura-nejm-2018","kind":"paper","name":"FLAURA: osimertinib as first treatment for EGFR-mutated lung cancer","route":"/key-papers/paper-flaura-nejm-2018/"},{"id":"paper-auperin-prophylactic-cranial-irradiation-sclc-nejm-1999","kind":"paper","name":"Prophylactic cranial irradiation for patients with small-cell lung cancer in complete remission","route":"/key-papers/paper-auperin-prophylactic-cranial-irradiation-sclc-nejm-1999/"}]}}