# Nobody has tested whether reversing measured biological ageing changes anything

Source: https://onco.cc/bottlenecks/rejuv-agenda-biological-age-as-an-untested-target/  
OnCo record `rejuv-agenda-biological-age-as-an-untested-target` (Bottleneck). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Cancer treatment measurably accelerates several markers of biological ageing. No trial has ever asked whether moving one of those markers makes any difference to a person, and an entire retail industry rests on the assumption that it would.

## Summary

The frontier facet of this round documented the acceleration and then documented the hole underneath it. Epigenetic clocks run fast in survivors; p16INK4a, a marker of cellular senescence, rises after chemotherapy; physiological frailty appears decades early in childhood cancer survivors. Those are measurements, and they are reasonably well made.

What does not exist is the next step. No clock is validated as a clinical test, none is used to make a treatment decision, and no trial has shown that moving a clock changes what happens to a person. The same applies one marker down: no trial has shown that lowering p16INK4a changes a person's health, and no intervention has been shown to lengthen telomeres in people in a way that changes health. No trial has shown that an intervention reverses established frailty in survivors.

Meanwhile the market has not waited. Senolytics have no completed randomised trial in cancer survivors and the one properly randomised trial of adequate design in another disease missed its primary endpoint. The trial designed to test metformin as a geroprotector has been proposed for a decade and has not started. A 48-week randomised trial of intermittent rapamycin in healthy ageing adults left its primary endpoint unchanged. There is no randomised trial of an NAD+ precursor in cancer survivors for recovery, fatigue or biological age, and a Europe PMC search for randomised trials of intravenous NAD+ in cancer survivors returns none. Clocks sold direct to consumers are not the clocks in this literature and are not interpretable against it.

The design problem is real and is worth stating rather than treating the absence as negligence. A trial with a clock as its primary endpoint proves nothing a person would notice. A trial with a clinical endpoint in survivors needs years and hundreds of participants. The way through is a trial with a function endpoint and the clock as a prespecified secondary, so that the two can be compared in the same people; one such trial is recruiting now, and it is the reason the fisetin trial record exists on this front.

## Fields

- Kind: Bottleneck
- Last checked: 2026-10-02
- Tags: rejuvenation; survivorship; open-problem; biological-ageing
- Stage: trials
- Severity: major
- Metrics: Trials showing that moving a biological-age marker changes a clinical outcome in cancer survivors: None (OnCo frontier facet, rejuv-age-epigenetic-clocks and rejuv-age-telomere-length); Randomised trials of an NAD+ precursor or intravenous NAD+ in cancer survivors for any rejuvenation outcome: None found in Europe PMC (OnCo frontier facet, rejuv-frontier-nad-precursors and rejuv-frontier-nad-infusions); Status of TAME, the trial designed to test metformin as a geroprotector: Proposed for a decade, not started (OnCo frontier facet, rejuv-frontier-metformin-ageing)
- Causes: A biomarker endpoint is cheap and meaningless on its own; a clinical endpoint is meaningful and expensive, and almost nobody funds the second.; The clocks disagree with each other, so a trial would have to prespecify which one it believes before anyone has shown that any of them matters.; Several candidate interventions are supplements or off-patent drugs with no sponsor who would recover the cost of a trial.; Clearing senescent cells could in principle remove a barrier to tumour regrowth, which no human trial has addressed, so a trial in survivors carries a theoretical oncological risk nobody has quantified.; The market does not need the trial: the measurement alone is enough to sell a product, which removes the commercial pressure to run one.

## Sources

- Qin et al., Epigenetic age acceleration and chronic health conditions among adult survivors of childhood cancer (JNCI 2021;113:597-605): https://doi.org/10.1093/jnci/djaa147
- Ness et al., Physiologic frailty as a sign of accelerated aging among adult survivors of childhood cancer: a report from the St Jude Lifetime cohort study (JCO 2013;31:4496-4503): https://doi.org/10.1200/JCO.2013.52.2268
- ClinicalTrials.gov NCT06113016: https://clinicaltrials.gov/study/NCT06113016

## Connected records

- technologies: [Epigenetic age after cancer treatment](https://onco.cc/technologies/rejuv-age-epigenetic-clocks/), [Frailty and late effects in survivors](https://onco.cc/technologies/rejuv-age-frailty-and-late-effects/), [Metformin as an anti-ageing drug after cancer](https://onco.cc/technologies/rejuv-frontier-metformin-ageing/), [NAD+ precursors taken by mouth](https://onco.cc/technologies/rejuv-frontier-nad-precursors/), [Rapamycin and mTOR inhibition for ageing](https://onco.cc/technologies/rejuv-frontier-rapamycin-ageing/), [Senescent cells and p16 after chemotherapy](https://onco.cc/technologies/rejuv-age-senescent-cells-after-treatment/), [Senolytics after cancer treatment](https://onco.cc/technologies/rejuv-frontier-senolytics/), [Telomere length after treatment](https://onco.cc/technologies/rejuv-age-telomere-length/), [What actually works after treatment](https://onco.cc/technologies/rejuv-frontier-what-works/)
- ideas: [Put a biological-age marker in a trial that also measures something a person would notice](https://onco.cc/ideas/idea-rejuv-biological-age-as-a-randomised-endpoint/)
- trials: [PROFFi: fisetin and exercise to prevent frailty in breast cancer survivors](https://onco.cc/trials/rejuv-trial-proffi/)
- roadmaps: [Recovery and rejuvenation roadmap: cure is not enough → survivorship gets a name → the cohorts that measured the cost → exercise proven as treatment → biological ageing measured and sold → repair, if anyone funds it](https://onco.cc/roadmaps/rejuvenation-roadmap/)
- fronts: [Recovery & Rejuvenation](https://onco.cc/fronts/rejuvenation/), [Supportive Care & Survivorship](https://onco.cc/fronts/supportive-care/)

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