pig kidney successfully transplanted into 62-year-old man / Doctors say they expect to send him home this weekend / The question remains how long the kidney will last

Richard Slayman made history: Last Saturday, he became the first living person to receive a genetically modified kidney from a pig, surgeons at Massachusetts General Hospital in Boston announced Thursday, reports nbcnews.com

Slayman, 62, whose kidneys were failing and on dialysis, underwent a four-hour operation Saturday to receive the pig kidney, said his nephrologist, Dr. Winfred Williams, associate chief of the division of nephrology from Mass General.

“This is truly a revolutionary stage,” said William. “If the kidney continues to work well and this is successful, I think it represents progress in many different areas.”

The first successful transplant of a pig kidney into a living recipient — a milestone in the field of so-called xenotransplantation, or animal-to-human transplantation — could offer hope to the tens of thousands of people in the U.S. on the transplant waiting list. organs as well as countless others around the world.

More than 100,000 people in the U.S. are on transplant waiting lists, including about 90,000 who need kidneys, according to the United Network for Organ Sharing, a non-profit group that manages the U.S. organ transplant system.

But xenotransplantation still carries significant risks. Two pig-to-human heart transplants have taken place in the US; in both cases, the patients did not live more than two months.

Slayman’s surgery was five days ago. He is still recovering at Mass General, but Williams said doctors hope to send him home this weekend as long as there are no complications.

So far, there have been no signs that his body’s immune system would reject the kidney, Williams said.

“His blood pressure, his vital signs are very stable,” he said. “He seems almost completely on the road to a full recovery.”

However, doctors are collecting 24 hours out of 24 samples of Slayman’s blood, looking for signs of a dangerous virus believed to have killed the man who received the first genetically modified heart from a pig in 2022.

The question remains how long the kidney will last.

“It will be very interesting to find out whether or not the xenograft will be a bridge, meaning it will take a short period of time until a human allograft can be found, or whether it will be what we call a destination, meaning it will take for the rest of that individual’s life,” said Dr. Jayme Locke, a transplant surgeon at the University of Alabama Birmingham Heersink School of Medicine.

Even so, “it’s a game changer,” Locke said.
A unique case, for now

Xenotransplantation is not approved by the Food and Drug Administration. Although it has been touted as a potential solution to the global organ shortage, it could be years before the procedure is widely used, as much more data is needed.

“What we really want to do is get to initial clinical trials, where we have more patients receiving xenografts and more centers participating, where we can really test a hypothesis and see how safe this is thing and how well it works,” said Dr. Robert Montgomery, director of the NYU Langone Transplant Institute.

Slayman’s transplant was performed under the FDA’s compassionate use program, which allows patients with serious, life-threatening conditions to access experimental treatments when nothing else is available.

“It’s a unique transplant,” said Karen Maschke, a researcher at the Hastings Center, a bioethics research institute that studies the ethical, regulatory and political issues surrounding the use of new biomedical technologies.

While Slayman was unique in being chosen for a pig kidney transplant, his condition is far from rare: About 800,000 people in the U.S. have kidney failure and need dialysis, often a process that it takes a lot of time for patients.

Slayman had previously received a kidney transplant from a deceased human donor in 2018 after undergoing dialysis for seven years. But the transplant showed signs of failure last year, and he resumed dialysis.

Williams said putting Slayman back on the waiting list for a new kidney was an option, although that would have involved a six- to seven-year wait, a time frame Williams doubts Slayman would be survived.

“He was in a desperate situation,” Williams said.

So Dr. Leonardo Riella, the medical director of kidney transplants at Mass General, proposed another option: a pig kidney transplant, which Williams said Slayman agreed to, adding that he was frustrated with dialysis .

“Our hope is that dialysis will become obsolete,” Riella told a news conference Thursday.

The hospital received the genetically modified kidney from drugmaker eGenesis in Cambridge, Mass., Riella said.

The kidney contained a total of 69 genetic changes, he said, 10 of which were made to reduce the risk of rejection. The other 59 changes were made to reduce the risk of virus infection.

The pig kidney was about the same size as a human kidney, and “when you look at it under a microscope, it looks exactly like a human kidney,” Riella said. “But based on the divergence 80 million years ago between humans and pigs that are different, the genetic changes that have been made allow us to have a much more compatible kidney.”

Dr. Tatsuo Kawai, the surgeon who performed the operation, said the operating room erupted in applause when people realized the transplant was a success.

“Immediately after blood flow to the kidney was restored, the kidney immediately reddened and began to produce urine,” Kawai said. “It was the most beautiful kidney I have ever seen.”
Berkeley Lovelace Jr.

Berkeley Lovelace Jr. is a medical and health reporter for NBC News. He covers the Food and Drug Administration, with a special focus on Covid vaccines, prescription drug pricing and health care. He previously covered the biotech and pharmaceutical industries at CNBC.