Breakthrough in Xenotransplantation: First Genetically Modified Pig Kidney Transplanted into a Human
Surgeons at Massachusetts General Hospital transplanted a pig kidney with 69 genome edits into a 62-year-old patient, preventing rejection and preserving organ function for over two months.
Introduction
On March 16, 2024, surgeons at Massachusetts General Hospital in the US performed an operation that was considered science fiction just ten years ago. Richard "Rick" Slayman, 62, who suffered from end-stage renal failure, received a transplanted kidney from a genetically modified pig. The organ, created by eGenesis, carried 69 genome edits — the highest number of modifications ever performed in a human xenotransplant.
The operation was the fourth pig organ transplant into a living human in history, but the first conducted under an official clinical trial rather than a compassionate use protocol. The kidney functioned for 271 days — over nine months — setting a world record for the duration of a xenograft in a human body. For nearly 100,000 patients in the US alone waiting for a donor kidney, this breakthrough means that organ shortage is no longer a hopeless problem.
Event Details and Timeline
The Long Road to the First Transplant: The idea of using animals as donors for humans is not new — attempts at xenotransplantation date back to the 19th century. However, the main obstacle has always been the human immune response: the body attacks foreign tissues within minutes or hours.
The modern era began with the mastery of CRISPR-Cas9 genome editing technology. Scientists realized that to make a pig organ compatible with humans, three challenges had to be addressed:
- Eliminate immediate rejection — remove genes encoding the alpha-1,3-gal sugar, which the human immune system recognizes as foreign.
- Deactivate endogenous retroviruses — fragments of viral DNA embedded in the pig genome over millions of years of evolution and potentially dangerous to humans.
- Add human genes — to help the body accept the new organ as "self."
The 2024 Breakthrough: Slayman's operation was the culmination of these efforts. The kidney used came from a pig with 69 genetic modifications — a record number, including the removal of three genes responsible for rejection, the addition of seven human genes to improve compatibility, and the inactivation of all 59 endogenous retroviruses.
What Followed: The success of the operation triggered a chain reaction. In late 2025 to early 2026, a full clinical trial began under the leadership of Dr. Robert Montgomery from NYU Langone Health. In the initial phase, six patients are participating, whose organs were edited at ten DNA sites. Upon FDA approval, the program will expand to 44 transplants.
Impact and Significance (for the World / Industry / Society)
For Global Medicine: 271 days of functioning transplanted kidney is not just a record. It is proof that xenotransplantation can potentially provide years of quality life. Russian expert Anastasia Konyaeva called this result "encouraging" and confirmed that the timeline for creating commercially available animal donors by 2030 looks realistic.
For the Transplant Industry: The shortage of donor organs is a crisis that traditional methods cannot solve. In the UK alone, over the past ten years, more than 12,000 patients have died or been removed from the waiting list without receiving a transplant. Xenotransplantation offers a fundamentally different approach: organs can be grown "on demand" rather than waiting for a tragic coincidence.
Moreover, as Dr. Montgomery notes, pig organs may even be more effective than human ones. "Theoretically, such organs can be further improved — reducing the risk of rejection and increasing compatibility, which cannot be achieved with human organs." Transplanting a kidney together with a pig thymus may enhance immune tolerance and reduce the need for lifelong immunosuppressive therapy.
For Society: Behind the dry numbers lie human destinies. Dr. Montgomery himself underwent a heart transplant in 2018 after a series of cardiac arrests caused by hereditary cardiomyopathy — a disease that had previously killed his father and brother. Today, he does not rule out that in the future he would agree to a pig organ transplant — for himself and for his children, who inherited the same genetic disease.
Reactions of Key Players
US and Global Science: American researchers are leading the race. The FDA has already given the green light to clinical trials, meaning the technology is considered safe enough to test on living patients, not just those on the brink of death. Dr. Montgomery, leading one of the key studies, was named one of the most influential people of 2025 by Time Magazine.
Russia: Domestic scientists are not standing aside, although they acknowledge lagging behind global leaders. At the Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences in Novosibirsk, a team led by embryologist Eduard Chuiko is working. Their goal is to use CRISPR-Cas to create a pig whose organs are "completely invisible to the human immune system."
"We became the first in our country to obtain a pig after an IVF procedure. Before that, this had not been done in our country, so we have absolutely all the technologies," Chuiko stated. The team expects to obtain the first animals with the necessary genetic modifications in a year to a year and a half. The project has already been selected by the business incubator of the Novosibirsk Academpark and has received support in finding investors.
Economics and Accessibility: One of the key questions is cost. Russian developers expect that in the future, xenotransplants could be included in the compulsory health insurance system. In the first year of implementation, the project could provide about 200 kidney transplant operations, and later adapt the technology for heart, liver, and pancreas transplants. The full cycle — from development to obtaining a registration certificate and mass breeding — will take about 12 years.
Forecast and Conclusions
What We Have as of Early 2026: The first successful pig kidney transplant with 69 edits, functioning for 271 days, has launched official clinical trials in the US. Xenotransplantation has ceased to be an emergency measure for hopeless patients and is becoming a protocol procedure.
Main Challenges:
- Long-term safety. 271 days is a record, but not the norm. It is necessary to prove that pig organs function for years without chronic rejection and without transmitting hidden infections.
- Scaling. Even if the technology proves effective, infrastructure must be created to raise genetically modified pigs in sterile conditions under constant veterinary supervision.
- Ethical issues. Although pigs were chosen precisely because of their long history of use in agriculture, mass breeding of animals for organ harvesting raises new ethical debates.
Conclusion: The transplant of a pig kidney with 69 genetic edits is not just a medical curiosity. It is a demonstration that humanity has come close to solving a problem that seemed unsolvable: the shortage of donor organs. A pig whose organs are "invisible" to the immune system, raised in sterile conditions as a pharmaceutical product — this is a reality that is 5-10 years away.
As Dr. Montgomery summarizes: "Genetically modified pigs have become a key breakthrough." And this breakthrough is already changing the rules of the game in transplantology.
— Editorial Team
