After once losing hope because of end-stage kidney disease, a 62-year-old man is now the first living person to receive a genetically edited kidney from a pig, according to doctors at Massachusetts General Hospital who performed the landmark surgery Saturday.

Richard Slayman, whom doctors praised for his courage, is doing well after the four-hour surgery and is expected to be discharged from the Boston hospital soon, officials said.

The advance, which builds on decades of work, gives hope to the hundreds of thousands of Americans who depend on dialysis machines to do the work of their failing kidneys. Each day, 17 Americans die awaiting a kidney transplant, a problem further complicated by unequal access given to Black and other patients. Doctors expressed hope that using pigs to vastly increase the supply of kidneys might correct the inequity.

The pig kidney was specially engineered by researchers at the Cambridge, Mass., biotechnology company eGenesis, which has the potential to propel medicine into a new era in which the limited supply of human kidneys is no longer a barrier to transplantation and “no patient dies waiting for an organ,” said Mike Curtis, the company’s CEO.

One doctor at Massachusetts General called the effort to develop the genetically modified organ “a mini-Manhattan project.”

Although human and pig kidneys are similar in size, researchers had to make 69 different edits to the pig’s genetic code, removing some genes and inserting others, to reduce the risk that the patient’s immune system would attack the transplanted organ.

Saturday’s surgery represented an advance on earlier procedures involving transplanting organs from pigs in patients. In January 2022, surgeons at the University of Alabama at Birmingham transplanted a genetically modified pig kidney into a brain-dead man. Also that month, a critically ill patient in Baltimore received a genetically modified pig heart.

The latest surgery brought to bear some of the most significant technological coups of recent decades: a gene-editing system developed in 2012; accurate and speedy sequencing of our massive genetic code; and improved methods of suppressing the immune system.

Doctors at Massachusetts General spent a year planning the groundbreaking procedure and going through required approvals, including one from the Food and Drug Administration that allowed the surgery under its “compassionate use” rules.

Slayman, who works for the Massachusetts Department of Transportation, had suffered from kidney disease for well over a decade. He had gone on dialysis and survived a human kidney transplant in 2018 but had grown desperately ill and was near despair.

“He literally said, ‘I just can’t go on like this. I don’t want to go on like this,’” said Winfred Williams, the hospital’s associate chair of nephrology and Slayman’s longtime doctor.

Doctors said Slayman was one of a handful of severely ill patients whom they spoke to about possibly undergoing the procedure. The majority were very receptive to the idea of receiving a genetically modified pig’s kidney “because they didn’t have other options.”

While the idea of transplanting a pig organ might seem futuristic or strange, the notion is well over a century old and was first attempted in 1906 on a 48-year-old woman in Lyon, France. The same doctor tried to transplant a goat kidney into another woman; both attempts failed.

The world’s first successful human kidney transplant was performed at Brigham and Women’s Hospital in Boston in 1954.

But human organs available for transplant have been in short supply for decades, leading researchers to continue efforts to transplant pig organs. As a result, some 600,000 kidney patients in the United States make several trips a week to receive dialysis.

“Our hope is that dialysis will become obsolete,” said Leonardo V. Riella, medical director for kidney transplantation at Massachusetts General.

In announcing the successful transplant, David F.M. Brown, president of Academic Medical Centers at Mass General Brigham, stressed how long patients, families, surgeons and scientists have clung to hope that a safe, ready supply of organs fit for human transplantation could be found.

“Last Saturday, following years and years of study, decades of study, months of planning and hours of surgery,” Brown said, “hope became a reality for our patient Rick Slayman.”