# Ex vivo drug sensitivity screening in blood cancers (EXALT)

Source: https://onco.cc/technologies/functional-precision-medicine-haematology/  
OnCo record `functional-precision-medicine-haematology` (Technology). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Blood cancer cells taken from a patient's blood or marrow are exposed within days to a panel of approved drugs, and the ones that kill the cancer cells while sparing healthy ones are offered back to the patient; a Vienna trial found this beat the previous treatment in more than half of heavily treated patients.

## Summary

What it measures. Leukaemia and lymphoma cells survive a few days outside the body, long enough to test a hundred or more approved drugs directly on them. Two laboratory approaches dominate: viability screening of purified cells in 384-well plates, developed at the Institute for Molecular Medicine Finland (FIMM) in Helsinki as drug sensitivity and resistance testing, and image-based single-cell screening (pharmacoscopy) at CeMM in Vienna, which reads how each drug shifts the ratio of malignant to normal cells in a mixed sample so the result reflects selective killing. The readout is a ranked list of drugs the patient's own cells respond to.

Evidence. In the Vienna EXALT trial (Cancer Discovery 2022), 56 patients with relapsed aggressive blood cancers were treated on the basis of image-based screening; 54 per cent had a progression-free survival at least 1.3 times longer than on their previous line of therapy, and a group of exceptional responders emerged. The Helsinki group runs a functional precision medicine tumour board for acute myeloid leukaemia and reported similar feasibility. Randomised trials comparing functional selection with standard choice are underway.

Who should have it and what changes. Today this is offered inside trials and at a few academic centres for patients with relapsed or refractory leukaemia, lymphoma or myeloma who have exhausted standard options. A positive screen points to a repurposed or off-label drug that the treating team may use; a negative screen argues for a trial of something new. Turnaround is under a week, faster than organoid testing for solid tumours, and the cost is that of a specialised laboratory assay. No screening platform of this kind is regulator-cleared as a diagnostic.

## Fields

- Kind: Technology
- Status: phase-2
- Last checked: 2026-09-17
- Also known as: drug sensitivity and resistance testing; DSRT; functional precision medicine; single-cell functional screening; pharmacoscopy
- Principle: Fresh malignant cells from blood or marrow are plated against a library of approved and investigational drugs; viability or high-content single-cell imaging quantifies selective killing of malignant versus normal cells within days.
- Since: 2022
- Strengths: Result within days, before the next treatment decision; Tests real drugs on real cancer cells, capturing what genomics misses; Prospective trial evidence of longer progression-free intervals in refractory patients
- Limitations: Blood cancers only; solid tumours need organoids or slices; No stroma or immune context in the dish; Randomised proof and regulatory recognition still pending

## Sources

- Cancer Discovery 2022: Functional precision medicine provides clinical benefit in advanced aggressive hematologic cancers and identifies exceptional responders (EXALT): https://doi.org/10.1158/2159-8290.CD-21-0538

## Connected records

- ideas: [Hold organoid drug tests to the same standard as a diagnostic test](https://onco.cc/ideas/idea-bio1-organoid-assay-clinical-validation/)
- technologies: [BCL-2 inhibitors](https://onco.cc/technologies/bcl2-inhibitors/), [BH3 profiling (functional apoptosis testing)](https://onco.cc/technologies/bh3-profiling/), [Functional (ex vivo) drug testing](https://onco.cc/technologies/functional-drug-testing/), [High-throughput screening and DNA-encoded libraries](https://onco.cc/technologies/high-throughput-screening-libraries/), [Organoid-guided therapy at scale](https://onco.cc/technologies/organoid-guided-therapy-scale/), [Patient-derived organoids](https://onco.cc/technologies/organoids/), [PDAC organoid pharmacotyping](https://onco.cc/technologies/pdac-organoid-pharmacotyping/)
- cancers: [Acute lymphoblastic leukaemia](https://onco.cc/cancers/all-leukemia/), [Acute myeloid leukaemia](https://onco.cc/cancers/aml/), [Chronic lymphocytic leukaemia](https://onco.cc/cancers/cll/), [Diffuse large B-cell lymphoma](https://onco.cc/cancers/dlbcl/), [Leukaemia (all types)](https://onco.cc/cancers/leukaemia/), [Multiple myeloma](https://onco.cc/cancers/multiple-myeloma/), [Myelodysplastic syndromes / neoplasms (MDS)](https://onco.cc/cancers/mds/)
- fronts: [Diagnostics & Biomarkers](https://onco.cc/fronts/diagnostics/), [Drug Discovery Platforms](https://onco.cc/fronts/drug-discovery/)
- drugs: [Azacitidine](https://onco.cc/drugs/azacitidine/), [Venetoclax](https://onco.cc/drugs/venetoclax/)
- companies: [Notable Labs](https://onco.cc/companies/notable-labs/)

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