Richard Slayman made history last Saturday: he became the first living person to successfully receive a genetically modified kidney from a pigsurgeons at Massachusetts General Hospital in Boston reported Thursday.
Slayman, 62, whose kidneys had failed and who had been on dialysis, underwent the four-hour operation Saturday to receive the pig kidney, said his nephrologist, Dr. Winfred Williams, associate chief of the division of Mass General nephrology.
“It really is a milestone,” Williams said. “If the kidney continues to function well and this is a success, I think it represents a huge advance in a number of different areas.”
The first successful pig kidney transplant into a living recipient – a milestone in the field of so-called xenotransplants, or animal-to-human transplants – could offer hope to the tens of thousands of people in the US on the waiting list for organ transplants, as well as countless others around the world.
More than 100,000 people in the United States are on the waiting list for a transplant, of which 90,000 need a kidney, according to the United Network for Organ Sharing, a nonprofit organization that manages the American organ transplant system.
But xenotransplants still carry significant risks. In the United States, two pig-to-human heart transplants have been performed; 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 his doctors hope to send him home this weekend, as long as no complications arise.
So far, there have been no signs that his body’s immune system is rejecting the kidney, Williams added.
“His blood pressure, his vital signs are very stable,” he said. “It looks like he’s making an almost complete recovery.”
Still, doctors are collecting samples of Slayman’s blood 24 hours a day, looking for signs of a dangerous virus, which is believed to have killed the man who received the first genetically modified heart from a pig in 2022.
It remains to be seen how long the kidney will last.
“It will be really interesting to know if the xenograft is ultimately a bridge, that is, if it lasts a short time until a human allograft can be found, or if it is going to be what we call a destination, that is, if it will last the rest of this person’s life,” said Dr. Jayme Locke, a transplant surgeon at the University of Alabama Birmingham Heersink School of Medicine.
Still, “it’s a game-changer,” Locke says.
Something exceptional, for now
Xenotransplants are not approved by the FDA. Although it has been touted as a possible 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 is to get to early clinical trials, where there are multiple patients receiving xenografts and multiple centers participating, so we can really test a hypothesis and see how safe it is 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 illnesses to access experimental treatments when nothing else is available.
“This is a unique transplant,” said Karen Maschke, a researcher at the Hastings Center, a bioethics research institute that studies the ethical, regulatory and political issues related to the use of new biomedical technologies.
Slayman had previously received a kidney transplant in 2018 from a deceased human donor after being on dialysis for seven years. The transplant, however, showed signs of failure last year, and he resumed dialysis. Williams noted that putting Slayman back on the waiting list for a new kidney was an option, although that would have meant a wait of six to seven years, a time frame he doubted Slayman would have survived.
“I was in a desperate situation”Williams said.
So Dr. Leonardo Riella, medical director of kidney transplants at Mass General, proposed another option: a porcine kidney transplant, which Williams said Slayman accepted, adding that he was frustrated with dialysis.
Riella explained that the hospital obtained the genetically modified kidney from the pharmaceutical company eGenesis, based in Cambridge, Massachusetts.
The kidney contained a total of 69 genetic modifications, he said, 10 of which were made to reduce the risk of rejection. The other 59 modifications were made to reduce the risk of virus infection.
Dr. Tatsuo Kawai, the surgeon who performed the operation, reported that the operating room erupted in applause when people realized that the transplant had been successful.
“Immediately after we restored blood flow to the kidney, it turned pink and started producing urine,” Kawai explained. “It was the most beautiful kidney I had ever seen.”
