# Quantitative systems pharmacology (QSP)

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

## TL;DR

Mechanistic computer models that join a drug's pharmacology to the biology of the tumour and the body, used by developers and regulators to pick doses, predict combinations and explain why a trial failed.

## Summary

Quantitative systems pharmacology couples pharmacokinetics with mechanistic models of signalling pathways, cell populations and organ systems. In oncology it has been used to predict the exposure-response of checkpoint inhibitors, to design bispecific and CAR-T dosing that limits cytokine release, to simulate resistance to targeted drugs and to support regulatory submissions under the FDA's model-informed drug development programme. Project Optimus, the FDA's 2021 initiative to end maximum-tolerated-dose defaults for targeted drugs, leans on these models to justify lower doses.

## Fields

- Kind: Technology
- Status: established
- Last checked: 2026-09-17
- Tags: mathematical-model
- Principle: Systems of differential equations link drug concentration to receptor occupancy, pathway activity, cell kill and clinical markers, calibrated to preclinical and clinical data and used to simulate untested regimens.
- Since: 2011
- Strengths: Accepted by regulators for dose justification; Predicts combinations before trials; Integrates disparate data
- Limitations: Large models are hard to validate; Parameter uncertainty is often understated; Expertise concentrated in industry

## Sources

- FDA Project Optimus: https://www.fda.gov/about-fda/oncology-center-excellence/project-optimus

## Connected records

- fronts: [AI & Computation](https://onco.cc/fronts/ai-computation/), [Drug Discovery Platforms](https://onco.cc/fronts/drug-discovery/)
- technologies: [Digital twins and virtual control arms](https://onco.cc/technologies/digital-twins-trials/), [Patient digital twins](https://onco.cc/technologies/digital-twin-patient-models/), [Pharmacogenomic testing before chemotherapy](https://onco.cc/technologies/oncology-pharmacogenomics/), [Pharmacokinetic and pharmacodynamic modelling](https://onco.cc/technologies/pkpd-modelling/), [Tumour-immune dynamics models](https://onco.cc/technologies/immune-tumour-dynamics-models/)

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