Scientists move closer to pig-to-human transplants as trials begin
The US FDA has approved clinical trials for genetically modified pig kidney transplants, moving the field from one-off cases into larger patient studies.
Biotech firm eGenesis said on Monday it had received FDA clearance to begin human trials using kidneys from its gene-edited pigs.
The company plans to transplant 33 patients over two and a half years, with the first procedure expected before year end.
Mike Curtis, president and chief executive of eGenesis, said: “The one-offs, or the single-patient studies, are super helpful to kind of understand where we are in a rough sens.
“But the big question is, how does this perform in a variety of different patients?
“The only way to answer how this is going to behave in a multitude of patients is to run a larger study.”
The pigs are altered using CRISPR gene-editing to knock out the gene that produces alpha gal, a carbohydrate that triggers immediate rejection in humans.
More than 100,000 people in the US are waiting for organ transplants, 86 per cent of them for kidneys.
The average waiting time is three to five years, though people with type O blood can wait up to 10 years.
Until now, xenotransplants – animal-to-human organ transplants – have been limited to compassionate use cases for patients with no other options.
On Monday, Massachusetts General Hospital reported its third experimental pig kidney transplant, performed on Bill Stewart, a 54-year-old from New Hampshire, on 14 June. Stewart has since returned home and to work.
“There’s so few of us who have done this, and they’re writing the protocol as we go, so to speak,” Stewart said.
“But I’m feeling good.”
Stewart had been on dialysis three days a week for more than two years after kidney failure caused by high blood pressure.
The five-year mortality rate for people on dialysis is over 50 per cent.
The hospital’s first recipient was 62-year-old Rick Slayman in March 2024, the world’s first living recipient of a gene-edited pig kidney.
He died two months later of cardiac issues not linked to the transplant.
Tim Andrews, 67, received a pig kidney at Mass General in January and it continues to support him.
He remains the world’s longest-living pig kidney recipient.
At NYU Langone, Dr Robert Montgomery and his team have also carried out pig kidney transplants.
In April 2024, they implanted both a mechanical heart pump and a pig kidney in 54-year-old Lisa Pisano.
The kidney was removed in May after doctors concluded it was “no longer contributing enough to justify continuing the immunosuppression regimen.”
Pisano died in July.
In November 2024, Montgomery’s group transplanted a pig kidney into 53-year-old grandmother Towana Looney.
It supported her without dialysis for 130 days before being removed after an unrelated infection reduced her kidney function.
The University of Maryland School of Medicine has carried out two pig heart transplants in living recipients.
Trials will also allow researchers to study the technology in patients earlier in kidney disease, said Dr Leonardo Riella, a transplant nephrologist at Mass General who helped perform all three xenotransplants there.
