# No incentive to repurpose cheap drugs

Source: https://onco.cc/bottlenecks/b-generic-repurposing/  
OnCo record `b-generic-repurposing` (Bottleneck). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Old, cheap drugs with anti-cancer signals never get the trials they need because no one profits from the result.

## Summary

Hundreds of licensed non-cancer drugs, including metformin, aspirin, statins, beta-blockers, antihistamines, antifungals and antihelminthics, have preclinical or observational anti-cancer signals, and the ReDO project has catalogued more than 300 of them. Because they are off-patent, no company will fund the phase 3 trials needed to change practice or the label, and academic funders have limited budgets for large pragmatic trials. When trials are run, results can go either way: metformin failed to improve survival in breast cancer (MA.32), while aspirin halved colorectal cancer in Lynch syndrome (CAPP2) and eflornithine, an old antiparasitic, was approved in 2023 for neuroblastoma maintenance after a single-arm trial with an external control. The regulatory route to a new indication for a generic, and the reimbursement of an off-label use, remain unclear in most countries, so even positive results diffuse slowly.

## Fields

- Kind: Bottleneck
- Last checked: 2026-09-08
- Stage: regulation-manufacturing
- Severity: major
- Metrics: Licensed non-cancer drugs with published evidence of anticancer activity catalogued in ReDO_DB: More than 300 (Pantziarka et al., ecancermedicalscience 2018); Effect of metformin on invasive disease-free survival in high-risk operable breast cancer (MA.32, 3,649 patients): HR 1.01 (no benefit) (Goodwin et al., JAMA 2022); Colorectal cancer reduction with aspirin in Lynch syndrome carriers at 10-year follow-up (CAPP2, per-protocol): HR 0.56 (Burn et al., Lancet 2020)
- Causes: Off-patent drugs cannot recoup trial costs through exclusivity, so no commercial sponsor exists.; Academic and charity funders cannot afford many multi-thousand-patient phase 3 trials.; Observational signals are confounded, and many repurposing hypotheses fail when tested properly, discouraging funders.; Regulatory and reimbursement pathways for new indications of generics are unclear and vary by country.; Clinicians are reluctant to prescribe off-label without a label change and guideline endorsement.

## Sources

- Pantziarka et al., The Repurposing Drugs in Oncology (ReDO) Project (ecancer 2014): https://doi.org/10.3332/ecancer.2014.442
- Goodwin et al., Effect of metformin vs placebo on invasive disease-free survival in breast cancer (MA.32, JAMA 2022): https://doi.org/10.1001/jama.2022.6147
- Burn et al., Cancer prevention with aspirin in hereditary colorectal cancer (CAPP2, Lancet 2020): https://doi.org/10.1016/S0140-6736(20)30366-4
- NHS England Medicines Repurposing Programme: https://www.england.nhs.uk/medicines-2/medicines-repurposing-programme/

## Connected records

- collections: [DrugBank & ChEMBL](https://onco.cc/collections/drugbank-chembl/), [Open Targets Platform](https://onco.cc/collections/open-targets/)
- ideas: [A $50 million prize for the first off-patent drug proven to extend cancer survival](https://onco.cc/ideas/idea-reg-repurposing-prize/), [A biomarker-directed trial of vitamin D after surgery for digestive tract cancers](https://onco.cc/ideas/idea-reg-vitamin-d-digestive-cancer-biomarker-trial/), [A cheap old tablet to restore appetite](https://onco.cc/ideas/idea-bio2-low-dose-olanzapine-appetite/), [A delinked market-entry reward paid by payers when a repurposed generic wins approval](https://onco.cc/ideas/idea-reg-delinked-market-entry-reward/), [A DRUP-style protocol for off-label generic targeted drugs in rare tumours](https://onco.cc/ideas/idea-reg-generic-targeted-therapy-drup/), [A fast route to the matched drug when it is licensed for another cancer](https://onco.cc/ideas/idea-bio1-mechanism-matched-access/), [A guideline fast track for repurposed drugs with phase 3 evidence but no manufacturer](https://onco.cc/ideas/idea-reg-guideline-fast-track-repurposed/), [A non-profit company to hold marketing authorisations for repurposed cancer drugs](https://onco.cc/ideas/idea-reg-nonprofit-marketing-authorisation-holder/), [A platform trial of very-low-cost metronomic chemotherapy in LMIC common cancers](https://onco.cc/ideas/idea-acc-metronomic-lmic-platform-trial/), [A pragmatic trial of statins to prevent liver cancer in people with cirrhosis](https://onco.cc/ideas/idea-reg-statin-hcc-prevention-trial/), [A public fund and label pathway to trial generic drugs against cancer](https://onco.cc/ideas/idea-moon-generics-for-cancer-fund/), [A public fund that pays for phase 3 trials of cheap, off-patent drugs against cancer](https://onco.cc/ideas/idea-reg-global-repurposing-fund/), [A RECOVERY-style permanent platform trial of cheap drugs added to cancer care](https://onco.cc/ideas/idea-reg-recovery-style-platform-repurposing/), [A repurposing label pathway with short exclusivity that non-profits can hold](https://onco.cc/ideas/idea-fund-repurposing-indication-exclusivity/), [A social impact bond: investors fund a repurposing trial, payers repay from savings](https://onco.cc/ideas/idea-reg-repurposing-social-impact-bond/), [A strategic reserve of essential generic cancer drugs to end recurring shortages](https://onco.cc/ideas/idea-reg-generic-chemo-strategic-reserve/), [A structured registry for every off-label cancer drug use](https://onco.cc/ideas/idea-data-off-label-outcomes-registry/), [Add a cheap-drug factorial arm to every cooperative-group adjuvant cancer trial](https://onco.cc/ideas/idea-reg-factorial-addon-arms-cooperative-trials/), [An automated pipeline emulating trials of every common drug against every cancer](https://onco.cc/ideas/idea-reg-target-trial-emulation-pipeline/), [Block the complement signal that recruits tumour-protecting cells](https://onco.cc/ideas/idea-bio2-complement-c5ar-blockade/), [Block the recycling that keeps dormant cells alive](https://onco.cc/ideas/idea-bio2-autophagy-block-mrd/), [Cheap perioperative beta-blocker plus anti-inflammatory to blunt surgical stress](https://onco.cc/ideas/idea-bio2-perioperative-betablocker-nsaid/), [Confirm low-dose olanzapine for appetite and weight in advanced cancer worldwide](https://onco.cc/ideas/idea-reg-olanzapine-cachexia-global-confirmation/), [Factorial trials that test several cheap generics at once in the adjuvant setting](https://onco.cc/ideas/idea-tr2-factorial-adjuvant-generics/), [Fund regulator-ready evidence dossiers for the 20 best-supported off-patent drugs](https://onco.cc/ideas/idea-reg-regulator-ready-repurposing-dossiers/), [Get biomarker-directed aspirin after colorectal surgery into labels and guidelines](https://onco.cc/ideas/idea-reg-aspirin-pik3ca-implementation/), [Let non-profits and academics add a cancer indication to an off-patent drug's label](https://onco.cc/ideas/idea-reg-third-party-label-update/), [Losartan to loosen the stroma of pancreatic cancer before chemotherapy: a phase 3](https://onco.cc/ideas/idea-reg-losartan-pancreatic-stroma/), [Low-dose olanzapine and generic antiemetic bundles in every guideline and formulary](https://onco.cc/ideas/idea-moon-olanzapine-antiemetic-everywhere/), [Open-source dossier-building software for academic sponsors and generic makers](https://onco.cc/ideas/idea-reg-open-source-dossier-tools/), [Patent-free open-source development of repurposed and off-patent cancer drugs](https://onco.cc/ideas/idea-fund-open-source-repurposing-leads/), [Payers pre-commit to cover off-label generics when a definitive trial is positive](https://onco.cc/ideas/idea-reg-payer-coverage-off-label-generic-commitment/), [Perioperative beta-blocker plus COX-2 inhibitor to reduce metastasis after surgery](https://onco.cc/ideas/idea-reg-perioperative-propranolol-etodolac/), [Pre-registered, publicly scored AI ranking of repurposing candidates for cancer](https://onco.cc/ideas/idea-reg-preregistered-ai-repurposing-scoring/), [Protect the gut flora of patients about to start immunotherapy](https://onco.cc/ideas/idea-bio2-antibiotic-stewardship-io/), [Randomise a cheap antihistamine alongside immunotherapy](https://onco.cc/ideas/idea-reg-antihistamine-plus-io-trial/), [Require genetic and target-trial evidence before funding any repurposing phase 3](https://onco.cc/ideas/idea-reg-evidence-gate-before-repurposing-phase3/), [Strip the platelet coat off travelling tumour cells in ctDNA-positive patients](https://onco.cc/ideas/idea-bio2-platelet-cloak-aspirin-mrd/), [Take high-dose testosterone to phase 3, with progression-free survival through the second line as the primary endpoint](https://onco.cc/ideas/idea-prostate-bipolar-androgen-therapy-phase-3-on-pfs2/), [Test a high-fibre diet as an immunotherapy adjunct](https://onco.cc/ideas/idea-bio2-fibre-diet-io-trial/), [Three years of indication-specific exclusivity for proving a new cancer use of an old drug](https://onco.cc/ideas/idea-reg-new-indication-exclusivity-off-patent/), [Train the bone marrow to make better anti-tumour immune cells](https://onco.cc/ideas/idea-bio2-trained-immunity-priming/), [Transparent cost-plus pricing for every oral oncology generic](https://onco.cc/ideas/idea-cost-transparent-generic-pricing/), [Validate low-cost metronomic oral regimens in phase 3 and carry them into guidelines](https://onco.cc/ideas/idea-reg-metronomic-lmic-phase3-to-label/)
- cancers: [Colorectal cancer](https://onco.cc/cancers/colorectal/), [Erdheim-Chester disease, Rosai-Dorfman disease and other histiocytic neoplasms](https://onco.cc/cancers/histiocytoses/), [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/), [Neuroblastoma (paediatric)](https://onco.cc/cancers/neuroblastoma/), [Prostate cancer](https://onco.cc/cancers/prostate/)
- technologies: [AI-driven drug & target discovery](https://onco.cc/technologies/ai-drug-design/), [Aspirin for cancer prevention and adjuvant therapy](https://onco.cc/technologies/aspirin-cancer-prevention/), [Cachexia pharmacotherapy: GDF-15 blockade, anamorelin, olanzapine](https://onco.cc/technologies/cachexia-appetite-pharmacotherapy/), [Chemoprevention & risk-reducing surgery](https://onco.cc/technologies/chemoprevention/), [Fasting and fasting-mimicking diets around chemotherapy](https://onco.cc/technologies/fasting-mimicking-diet/), [Fenbendazole, ivermectin and other internet 'repurposed cures'](https://onco.cc/technologies/fenbendazole-ivermectin-repurposing-claims/), [High-dose intravenous vitamin C](https://onco.cc/technologies/high-dose-vitamin-c/), [PSK (Krestin) mushroom polysaccharide as adjuvant therapy](https://onco.cc/technologies/psk-krestin-adjuvant/)
- drugs: [Eflornithine (DFMO)](https://onco.cc/drugs/eflornithine/), [Ivermectin](https://onco.cc/drugs/ivermectin/), [Mebendazole](https://onco.cc/drugs/mebendazole/)
- companies: [Canadian Cancer Trials Group (CCTG)](https://onco.cc/companies/cctg/), [Recursion Pharmaceuticals](https://onco.cc/companies/recursion/), [US WorldMeds](https://onco.cc/companies/us-worldmeds/)
- institutions: [Cancer Research UK](https://onco.cc/institutions/cruk/), [KWF Dutch Cancer Society](https://onco.cc/institutions/kwf/), [National Cancer Institute (NIH)](https://onco.cc/institutions/nci/), [The University of Kansas Cancer Center](https://onco.cc/institutions/ku-cancer-center/)
- terms: [Bipolar androgen therapy (BAT)](https://onco.cc/terms/bipolar-androgen-therapy/), [Hatch-Waxman Act 1984](https://onco.cc/terms/hatch-waxman/), [Lynch syndrome](https://onco.cc/terms/lynch-syndrome/), [Real-world evidence](https://onco.cc/terms/real-world-evidence/)
- trials: [Add-Aspirin](https://onco.cc/trials/add-aspirin/), [ALASCCA](https://onco.cc/trials/alascca/), [ICONIC: ivermectin combined with immune checkpoint inhibition in cancer (University of Florida phase 2)](https://onco.cc/trials/nct07487805/), [Ivermectin with balstilimab or pembrolizumab in metastatic triple-negative breast cancer (Cedars-Sinai phase 1/2)](https://onco.cc/trials/nct05318469/), [Low-dose olanzapine for cancer anorexia (Tata Memorial)](https://onco.cc/trials/olanzapine-appetite-tmh/), [METRO PLUS (Tata Memorial Centre, Varanasi)](https://onco.cc/trials/metro-plus-varanasi/), [NMTRC003/003B (DFMO maintenance)](https://onco.cc/trials/nmtrc003/), [Oral metronomic chemotherapy vs intravenous cisplatin (Tata Memorial)](https://onco.cc/trials/metronomic-vs-cisplatin-tmh/), [Peritumoral lidocaine before breast cancer surgery (Tata Memorial)](https://onco.cc/trials/lidocaine-peritumoral-tmh/), [Single-injection depot progesterone before breast surgery (Tata Memorial)](https://onco.cc/trials/progesterone-preop-tmh/)
- key papers: [CAPP2: two years of aspirin cuts bowel cancer in Lynch syndrome by more than a third over 10 years](https://onco.cc/key-papers/paper-capp2-aspirin-lynch-lancet-2020/), [CHALLENGE: a structured exercise programme after chemotherapy improves survival in colon cancer](https://onco.cc/key-papers/paper-challenge-exercise-nejm-2025/), [Effect of Metformin vs Placebo on Invasive Disease-Free Survival in Patients With Breast Cancer: The MA.32 Randomized Clinical Trial](https://onco.cc/key-papers/paper-goodwin-jama/), [Identification of the transforming EML4-ALK fusion gene in non-small-cell lung cancer](https://onco.cc/key-papers/paper-soda-eml4-alk-fusion-nature-2007/), [Ivermectin treatment for gynecologic cancers: hope versus hype](https://onco.cc/key-papers/paper-straughn-ivermectin-hope-versus-hype-2025/), [RESTORE: bipolar androgen therapy after progression on enzalutamide in metastatic castration-resistant prostate cancer](https://onco.cc/key-papers/paper-teply-restore-bipolar-androgen-therapy-lancet-oncol-2018/), [Single-injection depot progesterone before surgery and survival in operable breast cancer](https://onco.cc/key-papers/paper-badwe-progesterone-jco-2011/), [STAMPEDE: adding abiraterone to hormone therapy at diagnosis of advanced prostate cancer](https://onco.cc/key-papers/paper-stampede-abiraterone-nejm-2017/), [The Repurposing Drugs in Oncology (ReDO) Project](https://onco.cc/key-papers/paper-pantziarka-ecancermedicalscience/)
- roadmaps: [Chemotherapy roadmap: mustard gas → curative combinations → the warhead inside smarter drugs](https://onco.cc/roadmaps/chemotherapy-roadmap/), [Diet, exercise and lifestyle roadmap: causes established → interventions that disappointed → exercise proven as treatment](https://onco.cc/roadmaps/nutrition-lifestyle-roadmap/), [Global access and affordability roadmap: essential medicines and generics → biosimilars and frugal trials → reliance, pooling and homegrown innovation](https://onco.cc/roadmaps/global-access-roadmap/)

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