FDA Approves Transplant Trials for Gene-Edited Pig Kidneys
Two biotechnology companies will begin testing the procedures in patients suffering from kidney failure
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More than 90,000 patients in the United States are waiting for a kidney transplant. But, because of an ongoing shortage, only some of them will end up receiving the organ they need—and many will die waiting.
In the future, however, they may have another option: organs from genetically modified pigs.
The U.S. Food and Drug Administration has approved clinical trials for organ transplants from genetically modified pigs for people living with kidney failure.
Clinical trials are just the beginning of a long and complicated process. But, if successful, they could pave the way for the eventual more common use of pig organs in sick humans.
The FDA will allow two biotechnology companies to run clinical trials: United Therapeutics and eGenesis. United Therapeutics Corporation will start with six patients but could grow its trial to include up to 50 individuals, while eGenesis plans to begin with three patients.
“We are entering a transformative era in organ transplantation,” Mike Curtis, chief executive officer of eGenesis, wrote in an email to the Washington Post’s Rachel Pannett.
A handful of patients have already received organs from pigs. But those situations were dire—the patients had no other options—and the FDA allowed the experimental procedures to take place under a special “compassionate use” program.
So far, five patients in the U.S. have received organs from genetically modified pigs: two hearts and three kidneys. The longest-surviving person to receive a pig kidney is Towana Looney, a 53-year-old woman from Alabama who underwent a transplant procedure in November. The other four patients, who were all much sicker than Towana, died not long after their surgeries.
United Therapeutics expects to start its clinical trial this summer. It will begin with six patients who are suffering from kidney failure and have been on dialysis for at least six months, but are otherwise healthy. The participants are between 55 and 70 years old and either not eligible for a human kidney transplant or unlikely to receive one within the next five years, per Nature’s Smriti Mallapaty and Max Kozlov.
If those initial transplants are successful, then the company plans to grow the clinical trial to up to 50 patients.
All participants must agree to 24 weeks of post-procedure monitoring, as well as life-long follow-up appointments, reports the New York Times’ Roni Caryn Rabin.
United Therapeutics will transplant kidneys from animals with ten gene edits, which are meant to increase the likelihood that the human body will accept the organ. More specifically, the company’s scientists have added six human genes and deactivated four pig genes, including one that prevents the kidney from growing after it’s transplanted.
“Our goal is to increase the availability of transplantable organs to offer a therapeutic alternative to a lifetime on dialysis,” says Leigh Peterson, executive vice president of product development and xenotransplantation at United Therapeutics, in a statement.
The other firm, eGenesis, will start with one patient living with kidney failure who is unlikely to receive a human kidney transplant in the next five years. The company will wait six months before performing another transplant on a second participant, followed by a three-month waiting period before the third procedure.
Its kidneys will come from pigs with 69 gene edits, including 59 edits meant to deactivate porcine viruses. The pigs are a miniature breed, which helps ensure the organs do not grow after they are transplanted.
Xenotransplants—or transplants involving non-human tissues—are risky. One patient who received a genetically modified pig heart may have died, in part, because the organ was infected with an undetected porcine virus.
Medical ethicists have also raised concerns about other, unknown risks, as well as whether patients fully understand the potential consequences of their actions. Patients who are suffering from kidney failure are typically on dialysis, which means being hooked up to a blood-cleaning machine for several hours a day for the rest of their lives—or, at least until they’re approved for a human kidney transplant.
When faced with that prospect, “saying no [to a pig organ] would be incredibly difficult,” Christopher Bobier, a bioethicist and health policy expert at Central Michigan University tells the Times.
“Fully grasping the lifelong implications of that decision would be even harder,” he adds.
Looney, the woman who received a gene-edited pig kidney late last year, meanwhile, feels like “superwoman,” she told the Associated Press’ Lauran Neergaard in late January. Doctors say she is healthy and that her kidneys are functioning normally.
Since her story was shared around the world more than two months ago, Looney has been receiving messages from strangers who are suffering from kidney failure. She’s offered words of compassion and advice, encouraging one man who was considering a xenotransplant to follow his heart and lean into his faith.
“I love talking to people, I love helping people,” she tells the Associated Press.
