Doctors at Massachusetts General Hospital recently performed a life-saving transplant on a 62-year-old man using a genetically edited pig kidney developed by biotech startup “eGenesis.” While it’s not the first attempt to use organs from pigs in humans, it is the first pig kidney transplanted into a living human. Surgeons say that many unknowns remain about the viability of the newly transplanted organ but so far, the man is reportedly doing well.
The patient, Richard Slayman, was suffering from end-stage kidney disease, meaning that a transplant was his only hope of survival. Slayman had received a human kidney transplant previously but the organ showed signs of failure after just five years. “I saw it not only as a way to help me, but a way to provide hope for the thousands of people who need a transplant to survive,” Slayman said in a statement released by the hospital.
Slayman’s new kidney came from a pig created by Massachusetts-based eGenesis, which was approved to carry out the transplant under the Food and Drug Administration’s (FDA) “compassionate use” program designed to help patients who are out of options.
So-called “xenotransplantation,” or the transplantation of living organs or tissue from one species to another, has been attempted in several other cases in recent years. That includes two patients who received pig heart transplants, though both passed away after less than two months due to complications. The two biggest risks from xenotransplant are that the human host will reject the donor organ or will contract an infection.
The pigs eGenesis has developed are bred with 69 genetic modifications using CRISPR-Cas9 gene-editing technology, including the addition of seven human genes. The modifications are designed to remove pig genes that can provoke a negative human immune system response, aka “transplant rejection.” Scientists at eGenesis also inactivated pig viruses that could potentially infect recipients.
Tatsuo Kawai, a Harvard Medical School surgeon who led the procedure, says in the school’s statement that they are hoping the transplanted kidney lasts for more than two years. That could allow Slayman time to receive another human kidney transplant. Notably, a monkey with a kidney from a pig with the same gene edits was kept alive for two years.
Slayman’s transplant, if all continues to go well, could also mark a turning point for non-human organ transplants that doctors hope can fill the void for those in desperate need. More than 100,000 people are on the national organ transplant list, though less than half that many transplants are done each year. There are even more in need of an organ that never even makes it on the list because they are not good candidates for a transplant or they die first. Fewer than a quarter survive the five years that most have to wait on the transplant list.
Of the estimated 36 million people in the U.S. affected by chronic kidney disease, some 800,000 have end-stage kidney disease or kidney failure, a terminal condition that requires either a new kidney or dialysis, which is done three times a week, three hours each. According to Dr. Leonardo Riella, medical director for kidney transplantation at Massachusetts General, dialysis was never intended to become a lifelong solution, but it has now become a “last resort” for hundreds of thousands of patients.
Older patients typically struggle with dialysis, so the pig kidneys could particularly offer opportunities for them, the doctor said. “Our hope is that dialysis will become obsolete,” said Riella. “We feel strongly that xenotransplantation is a reasonable option either as a bridge [on the way to receiving a human kidney] or hopefully in the future as a permanent treatment.”
As for the cost, doctors say that Slayman’s procedure was “enormously expensive” because it’s an experimental procedure. However, transplants are usually cheaper than dialysis in the long run and doctors believe as pig transplants become more normalized, the costs will steadily come down. Some have hope that a more ready supply of organs could push costs even lower than what they are now for standard human-to-human transplants.
Full FDA approval is still a long way off and will require many more pig-to-human transplants conducted under full-fledged FDA clinical trials rather than the “compassionate use” program. eGenesis is now in discussions with the FDA about planning clinical trials for pig kidney and pediatric heart transplants. The company is also seeking approval for the use of pig livers that would be connected to the recipient from outside the body. Learn more about eGenesis HERE. (Sources: Smithsonian, The Harvard Crimson, Wired)
