(Reuters) - A man with end-stage renal disease who earlier this year became the first human to receive a new kidney from a genetically modified pig has died, Massachusetts General Hospital in Boston said.

"The Mass General transplant team is deeply saddened at the sudden passing of Mr. Rick Slayman," the hospital said in a statement on Saturday. "We have no indication that it was the result of his recent transplant."

Slayman, 62, of Weymouth, Massachusetts, received the transplant in March in a four-hour surgery that the hospital at the time called "a major milestone in the quest to provide more readily available organs to patients."

"Our family is deeply saddened about the sudden passing of our beloved Rick but take great comfort knowing he inspired so many," Slayman's family said in a statement.

Slayman had received a transplant of a human kidney at the same hospital in 2018 after seven years on dialysis, but the organ failed after five years and he had resumed dialysis treatments.

The kidney was provided by eGenesis of Cambridge, Massachusetts, from a pig that had been genetically edited to remove genes harmful to a human recipient and add certain human genes to improve compatibility, according to the hospital. The company also inactivated viruses inherent to pigs that have the potential to infect humans.

Kidneys from similarly edited pigs raised by eGenesis had successfully been transplanted into monkeys that were kept alive for an average of 176 days, and in one case for more than two years, researchers reported in October in the journal Nature.

Drugs used to help prevent rejection of the pig organ by the patient's immune system included an experimental antibody called tegoprubart, developed by Eledon Pharmaceuticals, according to the hospital.

According to a data tracker maintained by the United Network for Organ Sharing, more than 100,000 people in the U.S. await an organ for transplant, with kidneys in the greatest demand.

NYU surgeons had previously transplanted pig kidneys into brain-dead people.

A University of Maryland team in January 2022 transplanted a genetically modified pig heart into a 57-year-old man with terminal heart disease, but he died two months later.

(Reporting By Brendan Pierson in New York; Editing by Noeleen Walder and Nick Zieminski)

By Brendan Pierson