Hope from Pig Kidney Transplant

Tim Andrews spent nearly nine months living with a genetically modified pig kidney before he received a human transplant in January. This case is shedding new light on treatment options for those navigating the challenges of dialysis, as detailed in a recent paper published in The Lancet.

According to reports from The New York Times, Andrews, who was 66 at the time, faced severe health issues due to diabetes and high blood pressure that led to the failure of his kidneys. Having already survived two heart attacks, he struggled with a lack of appetite and was often too weak to walk. “I was dying,” he reflected. His rare blood type made it even more difficult to find a suitable human kidney donor, as he was among approximately 90,000 individuals on the waitlist in the U.S., where an average of 11 people tragically pass away daily while waiting, as per the United Network for Organ Sharing.

Instead of waiting helplessly, Andrews opted to join the experimental pig kidney transplant program at Mass General Brigham. “I thought, if I’m going to die, I could at least contribute to something bigger and be part of this experiment,” he said. In January 2025, he received a kidney from a genetically modified pig, engineered with various alterations meant to reduce the chance of organ rejection and viruses from the pig DNA.

The kidney functioned effectively. “It gave me life,” Andrews shared. However, his journey wasn’t without complications; he was hospitalized multiple times during the nine months he had the pig kidney, and, unfortunately, blood clots formed within the organ’s vessels, ultimately damaging it irreversibly. This led to the kidney’s removal, and he returned to dialysis temporarily. In January, he finally received a human kidney from a matched donor. Now, he enjoys spending time at a cabin by a pond, swimming, kayaking, and biking.

Dr. Leonardo V. Riella, who led the study and serves as the associate director of the Legorreta Center for Clinical Transplant Tolerance at Mass General Brigham, noted that the pig kidney served as a critical bridge, preventing further damage from dialysis. He explained, “Dialysis inflicts so much strain on patients that they can become too ill to receive a transplant or may die waiting.” He mentioned that many patients express their reasons for participating in these trials, candidly stating, “Life on dialysis is no life,” signifying a strong desire for alternatives.

Mike Curtis, president and CEO of eGenesis, the biotechnology firm responsible for the pig used in Andrews’s procedure, noted that Andrews’s experience, along with another case, indicates that having a pig kidney doesn’t adversely affect the body’s response to a subsequent human kidney transplant. “It doesn’t seem to change how you react to human tissue at all,” he stated, adding that the initial assumption was uncertain.

Currently, five patients at Mass General Brigham have received pig kidneys through an FDA expanded access program meant for those lacking treatment options. Three of those patients, including Andrews, had their pig kidneys for over eight months. One patient did face complications that led to death shortly after the transplant, while another was transplanted in June. EGenesis intends to launch a formal clinical trial involving 33 patients next year.

The pace of advancement in this field has been remarkable. In March 2024, surgeons performed the first kidney transplant from a gene-edited pig to a human patient, Rick Slayman, who was discharged after two weeks but sadly passed away from an unrelated heart issue two months later. Before this, genetically modified pig hearts had also been transplanted into humans in 2022, although those recipients with significant health challenges did not survive for long.

Dr. Muhammad Mohiuddin, a surgery professor at the University of Maryland School of Medicine and a key figure in xenotransplantation, reflected on his long journey of transplanting pig hearts into baboons before finally witnessing a human transplant. “I never imagined I would see this during my lifetime,” he remarked, noting that earlier progress in the lab with nonhuman primates was quite slow.