# Registry-embedded randomisation of treatment order in routine care

Source: https://onco.cc/ideas/idea-tr2-pragmatic-sequence-randomisation/  
OnCo record `idea-tr2-pragmatic-sequence-randomisation` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

When two approved drugs are both reasonable next steps and nobody knows which should come first, let the clinic flip a coin and record what happens.

## Summary

Point-of-care randomisation embedded in the electronic record (as in the TASTE trial in cardiology and the NHS PRINCIPLE platform) can answer sequencing questions about approved drugs with thousands of patients at low cost. Consent is simplified because both options are standard of care; follow-up uses routine data.

## Fields

- Kind: Idea
- Last checked: 2026-09-08
- Hypothesis: A registry-embedded randomisation of sequence (for example CDK4/6 inhibitor then oral SERD versus the reverse) enrols at least ten times faster per site than a conventional sequencing trial and yields a survival comparison with adequate power within four years.
- Rationale: Cardiology and infectious disease have used registry-randomised trials at scale. Oncology has the registries (national cancer registries, Flatiron-type databases) but has not embedded randomisation.
- Proposed test: Pilot in one national health system for one sequencing question where equipoise is documented in guidelines; measure enrolment rate and data completeness.
- Maturity: speculative
- Actor: clinic

## Sources

- Bottleneck evidence (Too many combinations to test): Palmer & Sorger, Combination cancer therapy can confer benefit via patient-to-patient variability without drug additivity or synergy (Cell 2017): https://doi.org/10.1016/j.cell.2017.11.009

## Connected records

- ideas: [A registry of every treatment sequence patients actually receive, with outcomes](https://onco.cc/ideas/idea-tr2-sequence-registry/), [Payers cover off-label combinations only inside registry-randomised trials](https://onco.cc/ideas/idea-tr2-payer-combo-cwe/), [Sequential multiple-assignment randomised trials to find the best order of ADCs](https://onco.cc/ideas/idea-tr2-smart-sequencing-adc/)
- cancers: [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/)
- terms: [ADC sequencing](https://onco.cc/terms/adc-sequencing/), [Real-world evidence](https://onco.cc/terms/real-world-evidence/)
- bottlenecks: [Too many combinations to test](https://onco.cc/bottlenecks/b-combination-space/), [Weak real-world evidence and registries](https://onco.cc/bottlenecks/b-real-world-evidence/)
- key papers: [Combination Cancer Therapy Can Confer Benefit via Patient-to-Patient Variability without Drug Additivity or Synergy](https://onco.cc/key-papers/paper-palmer-cell/)

---
JSON: https://onco.cc/api/v1/entities/idea-tr2-pragmatic-sequence-randomisation.json