This case marks a breakthrough in medicine, signifying the longest time a pig organ has survived in a living human. The surgery is considered a turning point in xenotransplantation – the process of transplanting animal organs into humans – offering new hope for patients with organ failure.

The patient, Tim Andrews, suffered from end-stage renal disease and had been on dialysis for over two years before undergoing the surgery in January.

Since receiving the pig kidney, provided by the biotechnology company eGenesis (Cambridge, Massachusetts), Andrews no longer relies on dialysis.

Andrews is one of three patients who have received genetically modified pig kidneys for compassionate reasons.

Tim Andrews leaves the hospital in January after receiving a genetically modified pig kidney. Photo: *Kate Flock/Massachusetts General Hospital*

According to surgeon Wayne Hawthorne from the University of Sydney, Australia, Tim reaching the six-month milestone is "an incredible feat." He emphasized that the first six months after transplantation are the "highest risk period" due to potential complications such as anemia or rejection, when the immune system attacks the new organ.

"The six-month mark indicates that everything is going very well," Hawthorne observed, adding that if the kidney functions stably for 12 months, it will be a "fantastic long-term outcome."

Previously, the longest survival record after a pig organ transplant belonged to 53-year-old Towana Looney, whose pig kidney functioned in her body for four months and nine days. However, the pig kidney was removed earlier this year because her immune system began rejecting it.

My Y (*Nature*)