American biotechnology company United Therapeutics on Monday announced completing its first transplant of a gene-edited pig kidney into a human in a clinical trial at NYU Langone Health.

According to U.S. media reports, this is the first large-scale clinical trial of transplanting gene-edited pig kidneys into humans approved by the U.S. Food and Drug Administration (FDA), following several previous individual transplant surgeries under "compassionate use" protocols. 

It aims to systematically evaluate the safety and efficacy of gene-edited pig kidneys for patients with end-stage renal disease.

The research plan initially involves enrolling six participants, with surgeries performed at two transplant centers. After at least 12 weeks following the completion of the first surgeries, an independent data monitoring committee will review the safety and efficacy data to decide whether to proceed to the next phase of the study. 

The number of participants may potentially expand to about 50 in the future.

According to the study protocol, participants are between 55 and 70 years old, diagnosed with end-stage renal disease, and have undergone dialysis for at least six months. After receiving gene-edited pig kidneys, participants will be followed for 24 weeks to assess kidney function, survival rates, quality of life and safety indicators, among others. They will also undergo long-term monitoring to evaluate organ function and potential risks of animal-origin infections.

United Therapeutics stated that the gene-edited pig kidneys they produced have undergone 10 genetic modifications. This includes knocking out four genes that might trigger human rejection responses and adding six human genes to enhance the compatibility between the animal organ and the human immune system.

Dr. Robert Montgomery, director of the NYU Langone Transplant Institute and leader of the transplant team, said this clinical research is a critical turning point in transplant medicine, offering a new pathway to alleviate the global organ shortage through xenotransplantation – cross-species organ transplantation.

Global kidney transplants only fulfill a small portion of the total global need. Currently, there are a large number of patients worldwide waiting for kidney transplants. Scientists are genetically altering pigs so their organs are more humanlike, less likely to be immediately attacked and destroyed by human immune system.

Pig organs are considered ideal candidates for xenotransplantation due to their similarities in structure and physiological function to human organs. However, cross-species organ transplantation faces various risks and technical challenges.

In recent years, U.S. medical teams have conducted individual transplant trials under the FDA's "compassionate use" framework.

In January of this year, Massachusetts General Hospital, part of Mass General Brigham, completed a gene-edited pig kidney transplant surgery where the pig kidney maintained function in the human body for nearly nine months, setting a new record in similar trials. The patient is back on dialysis after the pig organ began declining and was removed in October.

In March, a medical team from China's Xijing Hospital of the Air Force Medical University successfully transplanted a gene-engineered pig kidney into a uremic patient.

(With input from agencies)