First Clinical Trial of Gene-Edited Pig Kidneys in Humans Begins — Initial Transplant Successful at NYU

First formal xenotransplantation trial gets underway

WASHINGTON (AP) — The first formal clinical trial testing gene-edited pig kidneys in humans has begun, with United Therapeutics announcing that the study’s initial transplant was successfully performed at NYU Langone Health.

The trial marks a major step in efforts to develop animal-to-human organ transplants, known as xenotransplantation. A second U.S. company, eGenesis, is preparing to launch a similar pig kidney trial within months. These appear to be the world’s first known clinical trials of this approach.

To protect the patient’s privacy, researchers are not disclosing when the NYU procedure took place or additional personal details.

Trial design and scale: NYU’s transplant team, led by Dr. Robert Montgomery, said the small study will initially enroll six participants. If outcomes are favorable and more centers join, the trial could expand to as many as 50 patients.

Why regulators approved the study: The Food and Drug Administration has allowed these controlled trials after several earlier "compassionate use" cases produced mixed results. The first two gene-edited pig kidney transplants lasted only briefly, prompting researchers to adjust patient selection and protocols.

Doctors shifted to transplanting pig kidneys into patients who urgently need a kidney but are not as critically ill as earlier recipients. At NYU, a woman from Alabama kept a pig kidney for 130 days before returning to dialysis. The longest-recorded survival so far was 271 days for a man treated at Massachusetts General Hospital; that organ later failed and was removed. Other known recipients include another Mass General patient and a woman in China.

“This thing is moving in the right direction,” said Dr. Robert Montgomery, noting that each case provides clinical lessons and that the ability to resume dialysis offers an important safety net if a transplanted organ fails.

More than 100,000 people are on the U.S. transplant waiting list — most need kidneys — and thousands die while waiting. As a potential long-term solution, scientists are genetically modifying pigs so their organs more closely resemble human organs and are less likely to be immediately attacked by a recipient’s immune system.

What United Therapeutics is testing: The company’s trial uses pig kidneys that carry 10 gene edits. Those edits include removing pig genes that can trigger rapid rejection and excessive organ growth, and adding several human genes intended to improve compatibility with human immune systems.

Outlook and oversight: Researchers emphasize that these trials will collect detailed safety and efficacy data and are being conducted under regulatory oversight. Continued monitoring, careful patient selection and multi-center collaboration will determine whether pig kidneys can become a viable supplement to human organ donation.

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