Second Xenotransplant with Gene-Edited Pig Kidney Performed at Mass General

Shimul Shah, MD

Credit: Massachusetts General Hospital

Massachusetts General Hospital has announced the successful completion of its second transplant of a genetically edited pig kidney into a living recipient.¹

According to a February 7, 2025, press release, the 2.5-hour xenotransplant procedure was performed on January 25 by surgeons at the Mass General Transplant Center using a kidney with 69 genomic edits provided by eGenesis. It was successfully transplanted into a 66-year-old male patient who had been on dialysis for more than 2 years due to end-stage kidney disease.¹

In March 2024, Massachusetts General Hospital became the first hospital in the world to transplant a genetically edited pig kidney into a living human. The latest procedure was performed under the US Food and Drug Administration Expanded Access Protocol granted in December 2024, which is planned to support 2 additional xenotransplants this year.¹

“I am extremely proud of our surgical and clinical teams for taking on this endeavor and completing it with great precision and professionalism. Their work is a testament to the high standards set within the Mass General Brigham system, their tireless efforts to advance the field of transplantation, and tremendous energy to find solutions to the worldwide organ shortage,” Shimul Shah, MD, division chief of transplant and clinical director of the Mass General Transplant Center, said in a press release.¹ “I also want to thank our patient for his willingness to undergo this transplant. None of this would have been possible without him, and we are grateful for his enthusiasm for spreading awareness of xenotransplantation.”

According to a release from Mass General, the patient, 66-year-old Tim Andrews, was successfully discharged on February 1 and is now recovering, off dialysis for the first time in more than 2 years, and with his new kidney functioning as expected. He is now the fourth person in the world to receive a genetically edited pig kidney and is one of 2 people currently living with one.¹

“As soon as I woke up after the surgery, the cloud of dialysis disappeared. I felt re-energized and revitalized. It was a miracle. The magnitude of what these doctors and nurses accomplished is unbelievable and I want to thank them for giving me a new lease on life,” Andrews said.¹ “But this transplant isn’t about me. It’s about all the people who I met at the dialysis clinic, and I saw what they were going through. There are more than 500,000 people on dialysis, and I want to inspire them to never give up hope because that’s what this transplant provides. It’s a glimmer of hope.”

In addition to genetic editing of the pig kidney to improve its compatibility with humans, scientists also inactivated porcine endogenous retroviruses in the pig donor to eliminate any risk of infection in humans. Apellis Pharmaceuticals and Eledon Pharmaceuticals provided novel immunosuppressant medications for the transplant.¹

Tegoprubart, an investigational anti-CD40L antibody from Eledon Pharmaceuticals, is being administered to the patient as part of a regimen designed to prevent rejection of the transplanted pig organ. It is also being evaluated in 3 global clinical studies for the prevention of organ rejection in patients receiving kidney transplants and in a separate investigator-sponsored trial for the prevention of islet transplant rejection in patients with type 1 diabetes.²

“This milestone reminds us of the transformative potential of xenotransplantation, and we remain committed to learning from this experience to make it a safe, viable option for every patient in need,” said Leonardo Riella, MD, PhD, medical director for kidney transplantation and lead surgeon.¹ “Together, we are working toward a future where no one has to die waiting for a kidney.”

References

1. ^{Massachusetts General Hospital. Massachusetts General Hospital Performs Second Groundbreaking Xenotransplant of Genetically-Edited Pig Kidney into Living Recipient. February 7, 2025. Accessed February 7, 2025. https://www.massgeneral.org/news/press-release/mgh-performs-second-xenotransplant-of-genetically-edited-pig-kidney-into-living-recipient}
2. ^{Eledon Pharmaceuticals. Eledon Pharmaceuticals Announces Use of Tegoprubart as Key Component of Immunosuppression Regimen in its Second Transplant of a Genetically Modified Pig Kidney into a Human. February 7, 2025. Accessed February 7, 2025. https://ir.eledon.com/news-releases/news-release-details/eledon-pharmaceuticals-announces-use-tegoprubart-key-component}