{"entity":{"id":"idea-trop2-pet-selection","kind":"idea","name":"TROP2 PET to choose and sequence TROP2 ADCs","aka":[],"tldr":"Use a whole-body TROP2 scan instead of a single tissue stain to decide which patients get a TROP2 ADC, which one, and when to switch.","summary":"The proposal is to use a whole-body TROP2 PET scan, rather than a single tissue stain, to decide which patients receive a TROP2 ADC, which agent they get and when to switch. Baseline uptake and heterogeneity would predict benefit, and a fall in uptake at progression would signal antigen loss that should prompt a move to a non-TROP2 ADC rather than a second TROP2 agent. IHC on archival tissue failed to predict sacituzumab govitecan benefit, whereas PSMA PET already plays this role for Pluvicto and 89Zr-antibody and 68Ga-nanobody tracers image human tumours. The test is an imaging sub-study inside a first-line TNBC ADC trial, then a randomised PET-guided versus standard sequencing trial. At early-clinical maturity, it bears on the bottleneck Biomarkers are not validated or standardised.","asOf":"2026-09-04","links":[{"label":"ASCENT: sacituzumab govitecan doubles survival in heavily pretreated metastatic triple-negative breast cancer (New England Journal of Medicine 2021)","url":"https://doi.org/10.1056/NEJMoa2028485"}],"tags":[],"related":["psma-pet-to-rlt","ga-68","zr-89"],"indications":[],"sections":[],"technologies":["trop2-pet","immuno-pet"],"targets":["trop2"],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"hypothesis":"Baseline TROP2 PET uptake (SUV, heterogeneity index) predicts PFS on TROP2 ADCs better than IHC, and a fall in uptake at progression indicates antigen-loss resistance that should prompt a switch to a non-TROP2 ADC rather than a second TROP2 agent.","rationale":"PSMA PET does exactly this for Pluvicto. TROP2 is internalising and abundant; 89Zr-antibody and 68Ga-nanobody tracers already image human tumours.","test":"Prospective imaging sub-study in a first-line TNBC ADC trial (e.g., a TROPION-Breast05 or sac-TMT cohort) correlating baseline and on-treatment TROP2 PET with response and PFS; then a randomised PET-guided vs standard sequencing trial.","maturity":"early-clinical"},"route":"/ideas/idea-trop2-pet-selection/","neighbours":{"pairing":[{"id":"psma-pet-to-rlt","kind":"pairing","name":"PSMA PET → PSMA radioligand therapy","route":"/pairings/psma-pet-to-rlt/"}],"isotope":[{"id":"ga-68","kind":"isotope","name":"Gallium-68","route":"/isotopes/ga-68/"},{"id":"zr-89","kind":"isotope","name":"Zirconium-89","route":"/isotopes/zr-89/"}],"technology":[{"id":"immuno-pet","kind":"technology","name":"Immuno-PET","route":"/technologies/immuno-pet/"},{"id":"trop2-pet","kind":"technology","name":"TROP2 PET","route":"/technologies/trop2-pet/"}],"target":[{"id":"trop2","kind":"target","name":"TROP2","route":"/targets/trop2/"}]}}