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# Massachusetts General Transplants Gene-Edited Pig Kidney Into Living Patient, a First for Xenotransplantation
- URL: https://www.theamericanquorum.com/taq-historical-2024-03-23-healthcare/
- Published: 2024-03-24T03:59:00.000Z
- Updated: 2024-03-24T03:59:00.000Z
- Description: Massachusetts General Hospital transplanted a gene-edited pig kidney into a living 62-year-old patient, a first that could test whether xenotransplantation can ease organ shortages.
- Author: Kenneth R. Deans Jr.
- Tags: Healthcare, #Import 2026-09-01 12:55

BOSTON — Surgeons at Massachusetts General Hospital have transplanted a genetically edited pig kidney into a living human recipient for the first time, moving xenotransplantation from a series of experimental procedures in deceased recipients and critically ill patients toward a potentially repeatable treatment for end-stage kidney disease. The four-hour operation was performed March 16 on 62-year-old Richard Slayman of Weymouth, Massachusetts, who had previously received a human kidney transplant and later returned to dialysis. The hospital publicly announced the procedure Thursday, saying the organ began producing urine soon after blood flow was restored and was functioning well. A [Harvard Gazette report](https://news.harvard.edu/gazette/story/2024/03/first-ever-transplant-of-pig-kidney-to-patient-a-success/?ref=theamericanquorum.com) based on Massachusetts General communications described the operation as a milestone in the effort to make animal organs medically usable for people.

The kidney came from a donor pig produced by biotechnology company eGenesis and carried 69 genomic edits. Some edits removed pig genes associated with immune rejection; others added human genes intended to improve compatibility; still others inactivated endogenous viral sequences embedded in the pig genome. The procedure was authorized by the Food and Drug Administration under its expanded-access pathway rather than as a standard approved therapy. Contemporary accounts by the [Associated Press](https://apnews.com/article/c7fb54b1b1f1ece3b41b85f105fe4b98?ref=theamericanquorum.com) and [Reuters](https://www.reuters.com/business/healthcare-pharmaceuticals/first-pig-to-human-kidney-transplant-performed-boston-2024-03-21/?ref=theamericanquorum.com) emphasized both the technical achievement and the uncertainty that remains about how long the kidney can function safely.

## A patient with few conventional options

Slayman's medical history illustrates why investigators are pursuing xenotransplantation. He had lived with type 2 diabetes and hypertension and spent years on dialysis before receiving a deceased-donor human kidney in 2018\. That graft eventually failed, and he returned to dialysis in 2023\. Vascular-access complications made ongoing dialysis increasingly difficult, according to the hospital team. Rather than wait for another human organ with no guarantee that one would become available in time, Slayman agreed to the experimental pig-kidney transplant.

The clinical rationale extends far beyond one patient. More than 100,000 people in the United States are on the national transplant waiting list, most of them seeking kidneys, while thousands die each year before an organ becomes available. Dialysis can keep patients alive for years but carries substantial cardiovascular, infectious and quality-of-life burdens. If genetically modified pig kidneys can function for long periods without unacceptable immune or infectious complications, they could create a new organ supply that is not constrained by human donation.

## Gene editing targets the barriers that defeated earlier attempts

Transplanting animal organs into humans has been attempted for decades, but immune rejection has been a fundamental barrier. Humans carry naturally occurring antibodies that can rapidly attack pig cells. The eGenesis kidney was altered to remove several major molecular targets of those antibodies and to add human genes that regulate complement, coagulation and inflammatory pathways. Reporting in the [Washington Post](https://www.washingtonpost.com/health/2024/03/21/gene-edited-pig-kidney-transplant/?ref=theamericanquorum.com) detailed how the large package of edits is intended to address multiple biological failure points simultaneously rather than relying on a single modification.

Immunosuppression remains essential. The Massachusetts General team used conventional anti-rejection drugs together with tegoprubart, an investigational antibody designed to block the CD40 ligand pathway involved in immune activation. Eledon Pharmaceuticals disclosed the drug's use in a March 21 [announcement](https://ir.eledon.com/news-releases/news-release-details/eledon-pharmaceuticals-announces-use-tegoprubart-first-ever?ref=theamericanquorum.com). That combination matters because xenotransplant recipients may need sufficiently strong immune suppression to protect the organ without creating intolerable infection risk.

## What this procedure proves — and what it does not

The immediate function of the kidney is an important proof of principle, but it is not evidence of durable success. Previous xenotransplant milestones have included genetically modified pig hearts transplanted into two patients at the University of Maryland and pig kidneys tested in deceased human recipients. Those experiments established that modern gene editing and immunosuppression can prevent the hyperacute rejection that once made such procedures impossible. They also demonstrated that serious complications can emerge later.

Massachusetts General investigators are therefore watching Slayman closely for rejection, infection, clotting abnormalities and changes in kidney function. The transplant is not a clinical trial, and one successful early result cannot establish safety or effectiveness for a broader population. STAT's contemporaneous [coverage](https://www.statnews.com/2024/03/21/first-xenotransplantation-crispr-gene-edited-pig-kidney-egenesis/?ref=theamericanquorum.com) described the case as an important bridge between highly controlled experiments and the eventual trials regulators would require before xenotransplantation could become routine.

## A potential answer to a structural organ shortage

The public-health attraction is unusually clear. Kidney disease is common, the supply of transplantable human kidneys is permanently limited, and dialysis is both expensive and burdensome. A reliable source of pig kidneys could allow transplantation to occur earlier, reduce waiting-list mortality and make organ availability less dependent on geography, blood type and the unpredictable timing of human donation.

But a scalable xenotransplant program would need more than organs that work. Regulators would have to establish standards for breeding and pathogen surveillance, long-term recipient monitoring, manufacturing consistency, informed consent and tracing of potential animal-to-human infections. Hospitals would need protocols for selecting patients and managing immune suppression. Insurers and public programs would eventually face questions about payment if the therapy advances beyond experimental access. [WBUR's report](https://www.wbur.org/news/2024/03/21/boston-pig-kidney-transplant-surgery-mgh?ref=theamericanquorum.com) on the Boston procedure underscored how carefully the team is treating the operation as both a scientific milestone and an individual patient's medical decision.

For now, the significance is narrower but still substantial. A living patient with end-stage kidney disease has received a gene-edited pig kidney, the organ is functioning in the immediate postoperative period, and the procedure has crossed a line that researchers have spent decades trying to reach. Whether that line leads to a durable new source of transplantable organs will depend on what happens over the coming weeks and months — evidence that, as of Saturday, does not yet exist.