# Select patients for cell therapy by whether their tumour holds reactive T cells

Source: https://onco.cc/ideas/idea-bio2-til-reactivity-selection/  
OnCo record `idea-bio2-til-reactivity-selection` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Growing a patient's own tumour-fighting cells only works if those cells are there to start with. A test for them would spare futile treatment.

## Summary

Tumour-infiltrating lymphocyte therapy is approved in melanoma but works in a minority, and manufacturing takes weeks and costs a great deal. Markers of genuinely tumour-reactive T cells, notably CD39 and CD69 co-expression and CXCL13 expression, distinguish reactive from bystander cells in human tumours. A pre-manufacture biopsy assay could predict product potency and patient benefit.

## Fields

- Kind: Idea
- Last checked: 2026-09-08
- Hypothesis: A pre-manufacture reactivity assay predicts objective response to tumour-infiltrating lymphocyte therapy, allowing at least a third of patients unlikely to benefit to avoid a costly and toxic procedure.
- Rationale: Bystander T cells dominate many tumours, so total lymphocyte density is a poor proxy for reactivity. Product potency assays are standard in cell therapy manufacture in other diseases, and the markers here are well characterised in human tissue.
- Proposed test: Retrospective analysis of banked pre-manufacture biopsies from treated patients for association with response; if positive, use the assay prospectively as an eligibility criterion in one arm of a trial.
- Maturity: preclinical-evidence
- Actor: industry

## Sources

- Bottleneck evidence (No one can predict who responds to immunotherapy): Haslam & Prasad (JAMA Network Open 2019): https://doi.org/10.1001/jamanetworkopen.2019.2535

## Connected records

- cancers: [Melanoma](https://onco.cc/cancers/melanoma/), [Non-small-cell lung cancer](https://onco.cc/cancers/nsclc/)
- technologies: [Multiparameter flow cytometry MRD](https://onco.cc/technologies/flow-cytometry-mrd/), [Single-cell & spatial profiling](https://onco.cc/technologies/single-cell-spatial/), [TIL therapy](https://onco.cc/technologies/til-therapy/)
- drugs: [Lifileucel](https://onco.cc/drugs/lifileucel/)
- companies: [Iovance Biotherapeutics](https://onco.cc/companies/iovance/)
- terms: [Tumour-infiltrating lymphocytes (TILs)](https://onco.cc/terms/tils/)
- people: [John Haanen](https://onco.cc/people/john-haanen/), [Ton Schumacher](https://onco.cc/people/ton-schumacher/)
- bottlenecks: [Biomarkers are not validated or standardised](https://onco.cc/bottlenecks/b-biomarker-validation/), [Manufacturing cost and time for living and radioactive medicines](https://onco.cc/bottlenecks/b-manufacturing-cell-therapy/), [No one can predict who responds to immunotherapy](https://onco.cc/bottlenecks/b-immunotherapy-response/)
- key papers: [Estimation of the Percentage of US Patients With Cancer Who Are Eligible for and Respond to Checkpoint Inhibitor Immunotherapy Drugs](https://onco.cc/key-papers/paper-haslam-jama-netw-open/)

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