FDA approves first clinical trials transplanting pig organs into humans

The FDA has approved the first clinical trials for human use of genetically modified pig organs to address the severe organ shortage crisis.

The move comes after three patients in the US successfully received genetically engineered pig kidneys, known as an EGEN-2784 kidneys, in the past year.

Massachusetts-based biotech company eGenesis and Mass General Brigham in Boston will provide the same gene-edited pig kidney transplants to 30 people age 50 or older who are on dialysis and the organ transplant list.

Genetically modified kidneys for xenotransplantation (the process of grafting or transplanting organs or tissues between members of different species) are created by using gene-editing technology, such as CRISPR/Cas9, to alter the DNA of pig embryos before they are born.

This involves removing pig genes that can trigger a strong immune response or cause the organ to grow too large, inactivating pig viruses that could infect humans, and adding human genes to improve compatibility with the human immune system.

All US transplants of animal organs into living humans have received FDA approval on the grounds of 'compassionate use,' which is meant for cases in which the person's life is at risk and there are no comparable treatments.

But so far, there have not been clinical studies for widespread human use.

Bill Stewart, 54, from New Hampshire, is been the latest patient to receive a gene-edited pig kidney and he is faring well after his June 14 operation.

Meanwhile, a pig kidney has kept another New Hampshire man, Tim Andrews, off dialysis for a record seven months, and Richard Slayman, then aged 62, was the first ever patient to have survived after an organ transplant from an animal in 2024.

Slayman died two months later.

In January 2022, surgeons performed a heart transplant from a pig to human for the first time ever. The patient died after two months with the organ.

Until now, the longest that a gene-edited pig organ transplant was known to last was 130 days.

Based on lessons from the New Hampshire men and a handful of other one-off attempts, the FDA approved pig producer eGenesis to begin a rigorous study of kidney xenotransplants.

'Right now we have a bottleneck' in finding enough human organs, said Mass General kidney specialist Dr Leonardo Riella, who will help lead the new clinical trial.

More than 100,000 people are on the US transplant list, most of whom need a kidney, and thousands die waiting.

As an alternative, scientists are genetically altering pigs so their organs are more humanlike, less likely to be immediately attacked and destroyed by people's immune system.

Initial experiments, involving two hearts and two kidneys, were short-lived and included very ill patients. Chinese researchers also recently announced a lung xenotransplant but released little information.

Then an Alabama woman whose pig kidney lasted 130 days before rejection prompted its removal, sending her back to dialysis, helped researchers shift to not-as-sick patients.

It can take up to seven years for people to find a matching kidneys from a deceased or living human donor.

Dr Riella said it's far too early to predict how long pig kidneys might be able to last — but it would be useful even if initially they can buy people time off dialysis until they get a matching human organ.

'A year, hopefully longer than that – that's already a huge advantage,' he said.

Rejection is always a risk with transplantation, and can occur from the first week after the transplant to three months or even years afterward.

Patients have to take immune-suppressing drugs for several months to mitigate the risk of rejection.

Mike Curtis, CEO of the the company that provided the pig, eGenesis, said: 'This represents a new frontier in medicine and demonstrates the potential of genome engineering to change the lives of millions of patients globally suffering from kidney failure.'

Following in eGenesis' footsteps, another developer of gene-edited pig organs, United Therapeutics, is about to start enrolling people in a similar FDA-approved study.