There is huge momentum in the field of kidney xenotransplantation, as the FDA approves clinical trials for the first time and Massachusetts General Hospital (MGH) performs the fourth such operation on record.
United Therapeutics has announced that the U.S. Food and Drug Administration (FDA) has cleared its Investigational New Drug application to initiate a clinical study of the company’s UKidney, which is derived from a 10 gene-edited source pig. The United Therapeutics study will start by enrolling an initial cohort of six end-stage kidney disease patients, expanding to up to 50 participants, and is intended to support a Biologics License Application with the FDA.
Tim Andrews, of Concord, NH, recently became the fourth person in the world to receive a genetically-edited pig kidney and is one of two people currently living with one.
Andrews has been on dialysis for more than two years due to end-stage kidney disease. Andrews’ transplant at MGH used a pig kidney with 69 gene edits provided by U.S.-based biotech eGenesis. The company received the go-ahead from the FDA to start the study in December 2024.
“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.”
The transplant team lead is Leonardo V. Riella, MD, PhD, medical director for kidney transplantation, and the lead surgeon is Tatsuo Kawai, MD, PhD, director of the Legorreta Center for Clinical Transplant Tolerance Transplant Center.
“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,” said Shimul A. Shah, MD, division chief of transplant and clinical director of the Mass General Transplant Center. “I also want to thank our patient for his willingness to undergo this transplant.”
“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,” Andrews said.
The eGenesis kidney came from a pig 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.
“This second xenotransplant [at MGH] 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.
The procedure was performed under the FDA Expanded Access Protocol, 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.
