Massachusetts General Hospital Performs Second Groundbreaking Xenotransplant of Genetically-Edited Pig Kidney into Living Recipient

BOSTON – Today, Massachusetts General Hospital (MGH), a founding member of the Mass General Brigham health care system, announced the successful completion of its second transplant of a genetically-edited pig (porcine) kidney into a living recipient (xenotransplant). The 2.5-hour procedure was performed on Saturday, January 25, by surgeons at the Mass General Transplant Center. This achievement builds on MGH’s historic milestone in March 2024, when it became the first hospital in the world to transplant a genetically-edited pig kidney into a living human. Xenotransplantation, the transplantation of organs from one species to another, is being hailed as a potential solution to the global organ shortage.

Under the leadership of Leonardo V. Riella, MD, PhD, Medical Director for Kidney Transplantation and lead surgeon Tatsuo Kawai, MD, PhD, Director of the Legorreta Center for Clinical Transplant Tolerance, along with Nahel Elias, MD, Surgical Director for Kidney Transplantation, and Shimul A. Shah, MD, Division Chief of Transplant and Clinical Director of the Mass General Transplant Center, a genetically-edited pig kidney with 69 genomic edits was successfully transplanted into a living patient.

“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 at the Mass General Transplant Center, their tireless efforts to advance the field of transplantation, and tremendous energy to find solutions to the worldwide organ shortage,” Shah said. “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.”
 

The recipient, 66-year-old Tim Andrews of Concord, NH, has been on dialysis for more than two years due to end-stage kidney disease (EKSD). The treatment took a significant toll on his daily life, leaving him feeling constantly fatigued and unable to keep up with his usual activities. In addition to the daily struggles of dialysis, Andrews faced severe complications, including a heart attack in July 2023. His path to a kidney transplant was further complicated by his O-group blood type, which significantly extended his wait time. While most patients wait 3 to 5 years for a kidney, those with O-positive or O-negative blood types often wait 5 to 10 years, making their chances of receiving a donor organ even more difficult.

The pig kidney was provided by eGenesis of Cambridge, Mass., from a pig donor that was genetically-edited using CRISPR-Cas9 technology to remove harmful pig genes and add certain human genes to improve its compatibility with humans. Additionally, scientists inactivated porcine endogenous retroviruses in the pig donor to eliminate any risk of infection in humans. eGenesis also provided the pig organ for the world’s first kidney xenotransplant in 2024 conducted at MGH. Apellis Pharmaceuticals of Waltham, Mass. and Eledon Pharmaceuticals of Irvine, Calif. provided novel immunosuppressant medications for this transplant.

“This second xenotransplant provides us with another excellent opportunity to learn how we can make genetically-edited pig organs a viable, long-term solution for patients. Although we have a long way to go to make that a reality, this transplant is an important next step that has given us optimism to achieve that goal,” Kawai said.

“This procedure is more than a scientific milestone – it represents a new frontier in medicine,” said Michael Curtis, PhD, CEO, eGenesis. “We stand at the beginning of a future where organ shortages may no longer dictate patient outcomes. We are immensely grateful to Mr. Andrews, who has placed his trust in our groundbreaking innovation. His willingness to participate in this pioneering effort will help turn the promise of human-compatible organs into a reality. We are thrilled to continue our collaboration with the remarkable team at MGH, whose expertise and dedication have been instrumental in making this vision possible.”

The procedure was performed under the FDA Expanded Access Protocol (EAP), commonly known as compassionate use. This pathway allows patients with serious, life-threatening illnesses or conditions to access experimental treatments when no comparable options are available. In December 2024, MGH received FDA approval to proceed with this transplant and plans to perform two additional xenotransplants this year, further advancing the field of xenotransplantation.

“I want to express my deepest gratitude to Mr. Andrews for his remarkable courage and selflessness in helping advance the xenotransplantation program at MGH and across Mass General Brigham,” said Riella, Andrews’ nephrologist. By embracing this groundbreaking transplant, he has become a medical pioneer and a source of hope for thousands of patients on dialysis waiting for a kidney. 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. Together, we are working toward a future where no one has to die waiting for a kidney.”

For more information about xenotransplantation at MGH, visit https://www.mghxenotransplant.org.

Photos from the surgery

About Massachusetts General Hospital

Massachusetts General Hospital, founded in 1811, is the original and largest teaching hospital of Harvard Medical School. The Mass General Research Institute conducts the largest hospital-based research program in the nation, with annual research operations of more than $1 billion and comprises more than 9,500 researchers working across more than 30 institutes, centers and departments. In July 2024, Mass General was named to the U.S. News & World Report Best Hospitals Honor Roll. MGH is a founding member of the Mass General Brigham health care system.

About Mass General Brigham

Mass General Brigham is an integrated academic health care system, uniting great minds to solve the hardest problems in medicine for our communities and the world. Mass General Brigham connects a full continuum of care across a system of academic medical centers, community and specialty hospitals, a health insurance plan, physician networks, community health centers, home care, and long-term care services. Mass General Brigham is a nonprofit organization committed to patient care, research, teaching, and service to the community. In addition, Mass General Brigham is one of the nation’s leading biomedical research organizations with several Harvard Medical School teaching hospitals. For more information, please visit massgeneralbrigham.org.