Gene-Edited Pig Kidney Supports Man for Record Nine Months

 Scientists have recorded a major breakthrough in transplant medicine after a genetically modified pig kidney functioned inside a man for 271 days—nearly nine months—without the patient requiring dialysis.

Tim Andrews, from New Hampshire, was 66 when he received the experimental organ at Massachusetts General Hospital in January 2025. He had end-stage kidney disease and faced a long wait for a suitable human kidney because of his difficult-to-match blood type.

The transplanted kidney came from a pig named Wilma and was developed by biotechnology company eGenesis. Scientists made 69 genetic modifications to the animal to reduce the risk of rejection by the human immune system and limit the possibility of transmitting pig viruses.

Following the operation, the kidney filtered Andrews’ blood and allowed him to discontinue dialysis. Doctors monitored him closely and administered immunosuppressive medicines to prevent his immune system from attacking the organ.

The kidney was eventually removed on October 23, 2025, after its function declined because of inflammation and damage to its blood vessels. Andrews returned to dialysis but subsequently received a human donor kidney in January 2026.

Doctors reported that the human transplant was successful and that the earlier pig kidney had not created complications preventing him from receiving the human organ.

The case, reported in The Lancet, represents the first successful use of a genetically modified pig kidney as a temporary “bridge” while a patient waited for a human donor organ. It also significantly exceeded the previous pig-kidney record of 130 days. The Guardian⁠

The experimental procedure is part of a field known as xenotransplantation—the transplantation of living organs, tissues or cells from one species into another.

Scientists believe genetically modified pigs could eventually provide an alternative source of organs as countries struggle with severe donor shortages. Kidneys are the most frequently required transplant organs, and thousands of patients die each year while waiting for suitable donors.

However, medical experts have cautioned that one successful case does not establish the treatment’s long-term safety. Further clinical trials will be required to determine how long pig organs can function, improve the management of immune rejection and assess any risk of animal viruses infecting humans.

The case nevertheless provides evidence that a gene-edited pig kidney could support a patient for several months and potentially keep them alive and free from dialysis until a human organ becomes available.