The tree · Replacing lost cells and parts
An organ from a gene-edited pig keeps a person alive
Pigs' organs are the right size for people, and gene editing can take out the pig genes that make a human body reject them at once and add human ones that calm the rest. In January 2022 a man too ill for a human heart lived two months on a pig's; since 2024 several people have lived on pig kidneys, the longest for most of a year. The United States regulator cleared two formal trials in 2025, and the first began that October. It is a first human, several times over, and the first step towards organs made to order, which is why it sits on the branch for replacing what ageing wears out.
What would count
A person receives a heart, kidney, liver or lung from a pig whose genes were edited for the purpose and lives for at least thirty days with that organ doing its job, in a report by the transplant centre or a peer-reviewed paper. For the clinic rung: a regulator approves such an organ for use outside a trial. For wide use: pig organs are a routine option on the transplant list in at least one country.
Who settles it: The transplant centre's own release naming the patient, the peer-reviewed case report, and the regulator's trial clearance or approval record.
Where it stands
First human. Reached 7 January 2022, on the record of medschool.umaryland.edu. Next rung within 1 to 5 years.
This is one of the 5 treatments shared with the sister site The Upgrade Tree, which keeps its own record of it at the same test and the same stage. The weekly reading checks that the two stages agree.
When it reaches the clinic: the project's estimate
This is the one thing on this page that is a judgment rather than a record. The project's estimate of the year it reaches the clinic is 2032, no earlier than 2028 and no later than 2045; the model draws from that range every run, with the likely year the most probable draw. Set 16 October 2026, a first pass awaiting an outside review.
| Rung | No earlier than | Most likely | No later than | |
|---|---|---|---|---|
| In clinical use | 2028 | 2032 | 2045 | feeds the year at the top |
| In wide use | 2033 | 2040 | 2065 |
Why. Two registered trials were enrolling in 2025 and 2026 with a 24-week main follow-up and lifelong monitoring; an approval needs the larger groups of patients to show that most patients keep the kidney for a year or more. The likely year assumes the trials grow to their full size by 2028 and an approval for kidneys follows around 2032; the earliest assumes an approval on the first few patients; the latest allows for a safety stop (a pig virus, late rejection) that sends the field back a decade.
Changes to this record
None since it was written on 16 October 2026. Every change to the stage or the estimate lands here with its date, the old value, the new one and the reason, and a change to the estimate never happens because a number looked wrong: it needs a dated reason and a source.
The last readings
- 17 October 2026 Quiet
Nothing in the window. The searches returned the EXPAND trial's first transplant (United Therapeutics, announced 2025-11-03, at NYU Langone, NCT06878560), which the record already knows as the first trial beginning in 2025-10, and coverage of Tim Andrews, whose pig kidney at Massachusetts General Hospital worked for 271 days from 2025-01-25 before removal in 2025-10 and a human kidney in 2026-01, reported in The Lancet on a date the search results did not show; neither is a regulator's approval for use outside a trial, which the next rung needs. United Therapeutics' and eGenesis' newsrooms could not be opened because the session's web fetching was refused, so a release in the window cannot be ruled out by this searcher.
What the story so far says about it
On the record
Notes
The record is the University of Maryland's own announcement of David Bennett's pig heart transplant; the peer-reviewed case report followed in June 2022. Pig kidneys followed in 2024 (Boston, then New York). The Upgrade Tree keeps the same leaf at first human; the weekly reading checks the two stages agree. The next rung, in clinical use, needs a regulator's approval for use outside a trial; the trials cleared in 2025 are the step before.