First in Humans: Cellular Rejuvenation by Gene Therapy Begins in the Eye

What has been tested for years only in mice and monkeys is now being tested in humans for the first time: in June 2026, the Boston biotech company Life Biosciences treated the first trial participant with ER-100. The gene therapy is intended to epigenetically reset ageing nerve cells in the optic nerve – an approach known as “partial reprogramming” and regarded as one of the most exciting in ageing research.

The idea: giving cells back their youthful programme

Every cell in the body carries the same genome. Which genes are active in a cell is controlled by chemical marks on the DNA and its packaging proteins – the so-called epigenome. These marks change with age: genes that a cell needs are read less strongly, while others are wrongly activated. Many researchers see this as a central cause of ageing; some speak of a “loss of information” in the cell.

In 2006, the Japanese researcher Shinya Yamanaka showed that four transcription factors – OCT4, SOX2, KLF4 and c-MYC – can return mature cells to an embryonic state. He received the Nobel Prize for this in 2012. However, complete reprogramming erases the cell’s identity and carries a risk of tumours.

In partial reprogramming, therefore, only three of the four factors (OSK) are used, and their activity is controlled. c-MYC, known as an oncogene, is left out. The aim is to restore the epigenetic patterns of a younger cell without the cell forgetting what it is.

The background in the laboratory

In 2020, a team led by David Sinclair at Harvard Medical School reported in Nature that OSK gene therapy was able to regenerate damaged optic nerves in mice and improve vision in models of glaucoma and ageing. The effect depended on enzymes that remove DNA methylation – an indication that the epigenome had indeed been “reset”. Life Biosciences, which Sinclair co-founded, developed ER-100 on this basis and tested it in non-human primates. There, according to the company, controlled OSK expression restored methylation patterns and improved visual function.

The trial

• Product: ER-100, as an injection into the vitreous body of the eye (intravitreal)
• Conditions: open-angle glaucoma and non-arteritic anterior ischaemic optic neuropathy (NAION)
• Phase: phase 1, first-in-human use (NCT07290244)
• Objectives: safety, tolerability and immune reactions; vision tests are also evaluated
• Timeline: clearance by the US Food and Drug Administration (FDA) in February 2026, first patient treated in June 2026

The two conditions

Glaucoma

In glaucoma, nerve cells of the retina and their fibres in the optic nerve gradually die, often promoted by raised intraocular pressure. The visual field shrinks from the outside inwards, often unnoticed for a long time. Current treatments – eye drops, laser, surgery – lower the pressure and slow progression but cannot replace lost nerve cells. Glaucoma is one of the most common causes of blindness worldwide.

NAION

In non-arteritic anterior ischaemic optic neuropathy, the front part of the optic nerve suddenly receives an insufficient blood supply. Those affected usually notice painless loss of vision in one eye in the morning. There is no effective treatment so far. Risk factors include high blood pressure, diabetes and sleep apnoea.

Why the eye?

The eye is a well-enclosed organ: the therapy remains largely local, the amount required is small, and the effect can be measured precisely with established vision tests and imaging procedures. In addition, the other eye is available for comparison. For an entirely new class of therapy, this is a comparatively controllable starting point.

Sinclair speaks of the “first opportunity to test whether restoring this information can alleviate human disease”.

Risks and open questions

• Tumour risk: even without c-MYC, excessive or prolonged activity of the reprogramming factors is a theoretical risk. Controllability of gene activity is therefore crucial.
• Immune reactions: gene therapies usually use viruses as gene vectors. Inflammation in the eye is a known side effect of such therapies.
• Long-term effect: how long an epigenetic “restart” lasts and whether it needs to be repeated is unknown.
• Transferability: results from animal experiments cannot automatically be transferred to humans.

Assessment: a milestone, but an early one

A phase 1 trial mainly tests safety; whether ER-100 actually preserves or improves vision will only become clear in larger, controlled trials. The efficacy data so far come from animal experiments and company statements. Even in the best case, several years would pass before possible approval.

Success would nevertheless be significant far beyond ophthalmology. Several companies are working on similar approaches, for example for the liver or brain. ER-100 is the first test in humans of whether the theory of “epigenetic information loss” can be used therapeutically.

As of October 2026: no results from the trial have yet been published. We will update this article as soon as new data become available.

Frequently asked questions

Can I be treated with ER-100?

No. ER-100 is an experimental therapy that is used only within the clinical trial in the USA. Experts strongly advise against offers that promise “rejuvenation gene therapies” outside controlled trials.

Does this mean that ageing will soon be reversible?

No. The trial is testing whether one particular cell type in the eye can benefit from epigenetic rejuvenation. Research is a long way from rejuvenating the whole body.

Note: This article is for general information only and does not replace medical advice. ER-100 is an experimental therapy and is not approved. Last updated: October 2026.

Sources

• Life Biosciences: First Patient Dosed in Phase 1 Trial of ER-100 (09.06.2026)
• Lifespan.io: FDA Clearance of IND for ER-100 (February 2026)
• Healio: FDA clears investigational new drug application for ER-100 (2026)
• Nature Biotechnology: FDA go-ahead to test cellular rejuvenation therapy in humans (2026)
• Lu Y et al.: Reprogramming to recover youthful epigenetic information and restore vision. Nature 2020
• Takahashi K, Yamanaka S: Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors. Cell 2006