eGenesis’ engineered pig kidney kept patients off dialysis for months, including record nine-month stretch before successful human transplant.
More than 800,000 Americans live with end-stage kidney disease, and the gap between who needs a transplant and who can get one has only widened. Just 28,000 kidney transplants were performed in the U.S. in 2024, a fraction of what’s needed. For everyone else, the fallback is dialysis, a treatment that keeps patients alive but comes with a five-year mortality rate of 60%, worse odds than many common cancers. That grim math has made growing organs in genetically modified pigs, once science-fiction territory, one of the more closely watched frontiers in medicine.
This week, Cambridge, Massachusetts-based eGenesis shared new results from an expanded access study that’s been quietly running since March 2024, offering some of the clearest evidence yet that the approach can work, and work for longer than expected [1].
Five patients with kidney failure have received eGenesis’ engineered pig kidney, called EGEN-2784, through the expanded access program, which allows compassionate use outside a formal clinical trial. Three of them have maintained sustained kidney function for more than eight months without needing dialysis. One patient has now gone more than nine months without dialysis, a new global record for a genetically engineered pig kidney transplant, and remains on study.
Two of the five patients have since transitioned successfully to human donor kidneys, a detail that may be even more significant than the raw survival numbers. It marks the first reported cases of patients moving from a pig kidney to a human one, evidence that a xenotransplant can function as a genuine bridge therapy, buying time on dialysis-free life while a patient waits for a matching human organ, rather than closing off that option.
One of those patients, Tim Andrews, achieved roughly nine months of dialysis independence with his pig kidney before receiving a human one 82 days after the pig organ was removed; his case was published this week in The Lancet.
Why a pig kidney doesn’t trigger rejection
The EGEN-2784 kidney isn’t simply transplanted from an unmodified pig. It carries three categories of genetic edits designed specifically to get a pig organ to behave, immunologically, as it belongs in a human body. Three glycan antigens, sugar molecules on cell surfaces that would normally trigger a violent immune attack, have been eliminated. Researchers inserted seven human genes to help regulate the recipient’s immune response, reduce inflammation, and improve blood compatibility.
Researchers also deactivated genetic material from endogenous retroviruses naturally present in pig DNA, addressing a long-standing safety concern about cross-species infection risk.
“These patient outcomes provide important evidence that genetically engineered organs may provide sustained kidney function and dialysis independence while preserving the opportunity for a subsequent human transplant,” said Dr Mike Curtis, president and chief executive officer of eGenesis. “Our goal is to make transplantation available to patients when they need it, without being constrained by the limited supply of human donor organs.”
From compassionate use to formal trial
The results are notable enough that the FDA has cleared eGenesis to move into a formal Phase 1/2/3 trial, called RESTORE, testing EGEN-2784 in 33 patients between the ages of 50 and 70 who have kidney failure and are on the waitlist for a human donor kidney. The trial is expected to begin in the first quarter of 2027.
Dr Leonardo V Riella, medical director for kidney transplantation at Massachusetts General Hospital, served as principal investigator on the expanded access work.
“The experience with these patients is providing invaluable insight into the potential role of xenotransplantation for people living with kidney failure,” he said. “The sustained periods of dialysis independence are highly encouraging, and the successful transplantation of human donor kidneys following xenotransplantation demonstrates that this approach can preserve future treatment options.”
The longevity math
Strip away the novelty and what’s left is a fairly direct longevity story: every month a patient spends off dialysis is a month with a functioning kidney doing what a healthy organ does, filtering, balancing, keeping the rest of the body’s systems from slowly degrading under the strain of kidney failure.
If engineered organs can reliably deliver eight, nine, or more months of that reprieve while a patient waits for a human match, the technology doesn’t need to replace human transplantation to be transformative. It just needs to keep more people alive, and living well, long enough to get there.
