{"entity":{"id":"idea-bio2-ctc-clearance-go-nogo","kind":"idea","name":"Circulating tumour cell clearance as the phase 2 gate for anti-metastatic drugs","aka":[],"tldr":"Cancer cells travelling in the blood can be counted. If a drug clears them, that is an early sign it may stop spread, and it reads out in weeks rather than years.","summary":"CTC count is an established prognostic marker in metastatic breast, prostate and colorectal cancer, and CTC conversion from unfavourable to favourable has been used as a response measure in prostate cancer. Anti-metastatic mechanisms such as platelet cloaking, trap-mediated capture and cluster formation should show up as CTC and CTC-cluster clearance long before imaging changes. A standardised cluster readout would give small, cheap, fast phase 2 decisions.","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":[],"cancers":["breast-hr-positive","prostate"],"sections":[],"technologies":["liquid-biopsy","mrd-testing"],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["ctdna","mrd"],"trials":[],"people":["klaus-pantel","caroline-dive"],"bottlenecks":["b-metastasis-biology","b-biomarker-validation"],"keyPapers":["paper-dillekas-cancer-med"],"journals":[],"dependsOn":[],"notes":[],"hypothesis":"Failure to reduce CTC cluster burden by half at four weeks predicts absence of metastasis-free survival benefit with high negative predictive value, allowing most anti-metastatic candidates to be killed in trials of under 60 patients.","rationale":"Clusters rather than single cells carry most metastatic potential in mouse and human studies, and their abundance is dynamic and drug-responsive. Clearance-based go/no-go decisions already work in leukaemia through MRD and in prostate cancer through PSA and CTC conversion.","test":"Add a harmonised CTC and cluster assay to three ongoing perioperative or adjuvant trials, and test the association between four-week clearance and relapse; publish the assay and thresholds openly.","maturity":"early-clinical","actor":"industry","cost":"medium","horizonYears":4},"route":"/ideas/idea-bio2-ctc-clearance-go-nogo/","neighbours":{"cancer":[{"id":"breast-hr-positive","kind":"cancer","name":"HR-positive / HER2-negative breast cancer","route":"/cancers/breast-hr-positive/"},{"id":"prostate","kind":"cancer","name":"Prostate cancer","route":"/cancers/prostate/"}],"technology":[{"id":"liquid-biopsy","kind":"technology","name":"Liquid biopsy (ctDNA)","route":"/technologies/liquid-biopsy/"},{"id":"mrd-testing","kind":"technology","name":"MRD / molecular residual disease testing","route":"/technologies/mrd-testing/"}],"term":[{"id":"ctdna","kind":"term","name":"Circulating tumour DNA (ctDNA)","route":"/terms/ctdna/"},{"id":"mrd","kind":"term","name":"Minimal / molecular residual disease (MRD)","route":"/terms/mrd/"}],"person":[{"id":"caroline-dive","kind":"person","name":"Caroline Dive","route":"/people/caroline-dive/"},{"id":"klaus-pantel","kind":"person","name":"Klaus Pantel","route":"/people/klaus-pantel/"}],"bottleneck":[{"id":"b-biomarker-validation","kind":"bottleneck","name":"Biomarkers are not validated or standardised","route":"/bottlenecks/b-biomarker-validation/"},{"id":"b-metastasis-biology","kind":"bottleneck","name":"Metastasis is understood least and studied last","route":"/bottlenecks/b-metastasis-biology/"}],"paper":[{"id":"paper-dillekas-cancer-med","kind":"paper","name":"Are 90% of deaths from cancer caused by metastases?","route":"/key-papers/paper-dillekas-cancer-med/"}]}}