# TROP2 PET to choose and sequence TROP2 ADCs

Source: https://nuclide.cc/ideas/idea-trop2-pet-selection/  
Nuclide record `idea-trop2-pet-selection` (Idea). Data CC BY-NC 4.0, attribute "Data from Nuclide (nuclide.cc)"; commercial use needs a licence.

## TL;DR

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.

## Fields

- Kind: Idea
- Last checked: 2026-09-04
- 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.
- Proposed 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

## Sources

- ASCENT: sacituzumab govitecan doubles survival in heavily pretreated metastatic triple-negative breast cancer (New England Journal of Medicine 2021): https://doi.org/10.1056/NEJMoa2028485

## Connected records

- pairings: [PSMA PET → PSMA radioligand therapy](https://nuclide.cc/pairings/psma-pet-to-rlt/)
- isotopes: [Gallium-68](https://nuclide.cc/isotopes/ga-68/), [Zirconium-89](https://nuclide.cc/isotopes/zr-89/)
- technologies: [Immuno-PET](https://nuclide.cc/technologies/immuno-pet/), [TROP2 PET](https://nuclide.cc/technologies/trop2-pet/)
- targets: [TROP2](https://nuclide.cc/targets/trop2/)

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