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RTR242 (autophagy)Retro Biosciences—Retro Biosciences—

Retro Biosciences

Cell-cleanup pill, young cell transplants, AI

US$1.8B privateest. 2021retro.bio (opens retro.bio)Checked 25 Sep

The brief

Analyst view
  • RTR242 went from choosing a disease to the first human dose in about 15 months (trial in Adelaide, Australia).
  • In 2025 Retro and OpenAI reported AI-designed versions of two Yamanaka factors that worked better in lab cells.
  • May 2026: first close of a new round at a $1.8B valuation, led by 4P Capital.

Technical approach

As reported
Autophagy

Restarting cell cleanup

Autophagy is how cells recycle junk, and it slows with age. RTR242 aims to restart it in brain cells to clear clumps linked to Alzheimer's.

Cell therapy

Replace aged cells

It uses reprogramming to make young blood stem cells and brain immune cells that could be transplanted to replace old ones.

AI design

AI-designed Yamanaka factors

GPT-4b micro, an AI trained on proteins, proposed versions of reprogramming factors with many changes at once, beyond normal lab methods.

Programs

Retro Biosciences, three programs

Updated 1 Dec 2025
RTR242 (autophagy)A new kind of pill designed to restart autophagy, the cell's recycling system. Alzheimer's is the first target.ProtoNextFinish safety trialUpdated 1 Dec 2025View program →GPT-4b micro (with OpenAI)A small AI model based on GPT-4o and trained on protein data, used to design better Yamanaka factors that reprogram cells more efficiently.ResearchNextUse them to make cell therapiesUpdated 1 Jan 2025View program →Blood and microglia replacementLab-made young blood stem cells to renew the blood system, and replacement brain immune cells aimed at brain diseases.ResearchNextStudies needed before trialsNo recent updatesView program →
Research · Proto · Pilot · Deploy · Scaling

Research & demos

2 items

Open technical problems

Open · Active · Partial
  • Does better cleanup slow Alzheimer's?Open

    Autophagy affects many things; proving that boosting it slows memory loss safely needs long trials.

  • Making transplanted cells takeActive research

    Transplanted cells need prep treatment to settle in, and must not turn cancerous or trigger the immune system.

Peers

Cellular reprogramming · 4

Company & funding

2 rounds · as reported
Valuation
$1.8Bprivate
Raised
$180Mdisclosed private rounds
Last round
New round (initial close)May 2026
HQ
US
Founded
2021
DateRoundAmountPost-moneyLead
May 2026New round (initial close)——4P Capital
2023Founding capital$180M—Sam Altman

Partners & customers

1 partner

People

Key people
Primer