April 12, 2024

Patient with a transplanted pig kidney leaves the hospital and goes home

The first patient to receive a kidney transplant from a genetically modified pig has done so well that he was discharged from hospital on Wednesday, just two weeks after the groundbreaking operation.

The transplant and its encouraging outcome represent a remarkable moment in medicine, scientists say, potentially ushering in an era of interspecies organ transplants.

Two previous organ transplants from genetically modified pigs failed. Both patients received hearts and both died a few weeks later. In one patient, there were signs that the immune system had rejected the organ, an ongoing risk.

But the kidney transplanted into 62-year-old Richard Slayman produces urine, removes waste products from the blood, balances body fluids and performs other important functions, according to his doctors at Massachusetts General Hospital.

“This moment – ​​leaving the hospital today with one of the cleanest bills of health I’ve had in a long time – is one I’ve wished would come for years,” he said in a statement from the hospital. “Now it is reality.”

He said he had received “exceptional care” and thanked his doctors and nurses, as well as well-wishers who contacted him, including kidney patients waiting for an organ.

“Today marks a new beginning, not only for me, but for them as well,” Mr. Slayman said.

The procedure brings the prospect of xenotransplantation, or animal-to-human organ transplants, significantly closer to reality, said Dr. David Klassen, the chief physician of the United Network for Organ Sharing, which runs the country’s organ transplant system.

“While there is still a lot of work to be done, I think the potential of this will be realized for the benefit of a large number of patients, and that was a question mark hovering over the field,” said Dr. Classes.

Whether Mr. Slayman’s body will ultimately reject the transplanted organ is still unknown, Dr. Classes up. And there are more hurdles: A successful operation would need to be repeated in countless patients and studied in clinical trials before xenotransplants become widely available.

If these transplants are to be scaled up and integrated into the health care system, there are “daunting” logistical challenges, he said, starting with ensuring an adequate supply of organs from genetically engineered animals.

Cost, of course, can become a significant obstacle. “Is this something we can really realistically try as a health care system?” said dr. Classes. “We have to think about that.”

The treatment of kidney disease already entails enormous costs. End-stage kidney disease, the point at which organs fail, affects 1 percent of Medicare beneficiaries but is responsible for 7 percent of Medicare spending, according to the National Kidney Foundation.

Yet the medical potential for pig-to-human transplantation is enormous.

Mr. Slayman chose the experimental procedure because he had few options left. He had problems with dialysis due to problems with his blood vessels, and he had to wait a long time for a donated kidney.

The kidney transplanted into Mr. Slayman came from a pig genetically engineered by the biotech company eGenesis. Company scientists removed three genes that could cause organ rejection, added seven human genes to improve compatibility and took steps to inactivate retroviruses carried by pigs that can infect humans.

More than 550,000 Americans suffer from kidney failure and require dialysis, and well over 100,000 are on a waiting list to receive a transplanted kidney from a human donor.

In addition, tens of millions of Americans have chronic kidney disease, which can lead to organ failure. Black Americans, Hispanic Americans and Native Americans have the highest rates of end-stage kidney disease. Black patients generally fare worse than white patients and have less access to a donated kidney.

While dialysis keeps people alive, the treatment of choice for many patients is a kidney transplant, which dramatically improves quality of life. But only 25,000 kidney transplants are performed each year and thousands of patients die each year waiting for a human organ because there is a shortage of donors.

Xenotransplantation has been discussed as a possible solution for decades.

The challenge with any organ transplant is that the human immune system is primed to attack foreign tissue, which can cause life-threatening complications for the recipients. Patients who receive transplanted organs generally must take medications designed to suppress the immune system’s response and preserve the organ.

According to Dr. Leonardo V. Riella, medical director of kidney transplantation at Mass General, Mr. Slayman showed signs of rejection on the eighth day after surgery. (The hospital’s parent organization, Mass General Brigham, developed the transplant program.)

The rejection was a type called cellular rejection, which is the most common form of acute transplant rejection. It can happen at any time, but especially within the first year after an organ transplant. Up to 25 percent of organ recipients experience cellular rejection within the first three months.

The rejection was not unexpected, although it affected Mr. Slayman more quickly than normal, Dr. Riella said. Doctors managed to reverse the rejection with steroids and other drugs used to suppress the immune response.

“It was a roller coaster the first week,” said Dr. Riella. Reassuringly, he added, Mr. Slayman responded to treatment like patients who receive organs from human donors.

Mr. Slayman is taking several immunosuppressant medications and will be closely monitored with blood and urine tests three times a week, as well as doctor visits twice a week.

His doctors do not want Mr. Slayman to return to work at the state transportation department for at least six weeks, and he must take precautions to avoid infections because of the medications that suppress his immune system.

“Ultimately, we want patients to return to the things they love to do to improve their quality of life,” said Dr. Riella. “We want to avoid restrictions.”

By Wednesday, Mr. Slayman was clearly ready to go home, Dr. Riella said.

“When we first came in, he was very concerned and worried about what was going to happen,” said Dr. Riella. “But when we visited him at seven o’clock this morning, you could see a big smile on his face and he was making plans.”

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