{"entity":{"id":"idea-bio2-cns-cohort-mandate","kind":"idea","name":"Stop excluding brain metastases from cancer trials","aka":[],"tldr":"One in five people with advanced cancer has brain spread, yet most trials refuse them. Requiring brain cohorts would give those patients evidence instead of guesswork.","summary":"Brain metastasis exclusion criteria persist by habit, and regulators and professional bodies have issued guidance encouraging inclusion of patients with stable treated brain metastases. Making a CNS cohort with CNS-specific response endpoints a default expectation for registrational trials in CNS-tropic cancers, unless justified otherwise, would generate labelled intracranial data rather than post-approval retrospectives.","asOf":"2026-09-08","links":[{"label":"ASCO-Friends eligibility criteria work","url":"https://www.asco.org"}],"tags":[],"related":[],"cancers":[],"sections":[],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":["asco","esmo"],"pathways":[],"terms":["her2-brain-metastases"],"trials":["her2climb","alina"],"people":[],"bottlenecks":["b-brain-delivery","b-trial-enrolment","b-trial-design"],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"hypothesis":"A default-inclusion policy raises the proportion of new oncology approvals with intracranial activity data in the label from a minority to over half within five years, without slowing accrual.","rationale":"Inclusion of patients with treated brain metastases has been feasible where sponsors have tried it, and the resulting intracranial data changed practice in HER2-positive breast cancer and ALK-positive lung cancer. The barrier is convention and risk aversion, not science.","test":"Audit exclusion criteria in the last 200 registrational oncology protocols, publish the rate, then have one regulator or cooperative group adopt default CNS cohorts for CNS-tropic diseases and measure accrual, safety and labelling outcomes.","maturity":"speculative","actor":"regulator","cost":"small","horizonYears":4},"route":"/ideas/idea-bio2-cns-cohort-mandate/","neighbours":{"institution":[{"id":"asco","kind":"institution","name":"American Society of Clinical Oncology (ASCO)","route":"/institutions/asco/"},{"id":"esmo","kind":"institution","name":"European Society for Medical Oncology (ESMO)","route":"/institutions/esmo/"}],"term":[{"id":"her2-brain-metastases","kind":"term","name":"HER2-positive brain metastases","route":"/terms/her2-brain-metastases/"}],"trial":[{"id":"alina","kind":"trial","name":"ALINA","route":"/trials/alina/"},{"id":"her2climb","kind":"trial","name":"HER2CLIMB","route":"/trials/her2climb/"}],"bottleneck":[{"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/"},{"id":"b-trial-enrolment","kind":"bottleneck","name":"Trials enrol too few, too slowly","route":"/bottlenecks/b-trial-enrolment/"}]}}