# Add a cheap-drug factorial arm to every cooperative-group adjuvant cancer trial

Source: https://onco.cc/ideas/idea-reg-factorial-addon-arms-cooperative-trials/  
OnCo record `idea-reg-factorial-addon-arms-cooperative-trials` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Large adjuvant trials already follow thousands of patients for years. Adding a second randomisation to a cheap old drug would answer repurposing questions almost for free.

## Summary

Factorial designs randomise the same patients to two independent questions, sharing recruitment, follow-up and infrastructure. Add-Aspirin ran as a standalone trial; embedding similar questions as second factors in cooperative-group adjuvant trials (breast, colorectal, lung, prostate) would multiply the number of repurposing questions answered at a small marginal cost. The proposal is a policy by public trial funders (NCI cooperative groups, CRUK, EORTC) that every new large adjuvant trial include, where feasible, a factorial randomisation to a prioritised off-patent candidate, with a central committee selecting candidates and monitoring interactions.

## Fields

- Kind: Idea
- Last checked: 2026-09-08
- Hypothesis: Factorial add-ons answer at least one repurposing question per two adjuvant trials at less than 10% additional cost per trial, without compromising the primary question's power or recruitment.
- Rationale: The main cost of an adjuvant trial is following patients for years; a second factor uses that investment twice. Interaction between factors is a manageable statistical risk when candidates are chosen for independent mechanisms.
- Proposed test: Embed factorial arms in the next three cooperative-group adjuvant trials and report recruitment, cost increment and analysability against the groups' previous trials.
- Maturity: early-clinical
- Actor: research

## Sources

- Bottleneck evidence (No incentive to repurpose cheap drugs): Pantziarka et al., The Repurposing Drugs in Oncology (ReDO) Project (ecancer 2014): https://doi.org/10.3332/ecancer.2014.442

## Connected records

- institutions: [Cancer Research UK](https://onco.cc/institutions/cruk/), [National Cancer Institute (NIH)](https://onco.cc/institutions/nci/)
- terms: [Neoadjuvant / adjuvant / perioperative](https://onco.cc/terms/neoadjuvant-adjuvant/)
- bottlenecks: [No incentive to repurpose cheap drugs](https://onco.cc/bottlenecks/b-generic-repurposing/), [Trial design, endpoints and cost](https://onco.cc/bottlenecks/b-trial-design/)
- key papers: [The Repurposing Drugs in Oncology (ReDO) Project](https://onco.cc/key-papers/paper-pantziarka-ecancermedicalscience/)

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