The transplant of genetically-edited pig kidneys into human patients has shown promising results, with one recipient, Richard Slayman, making history as the first living person to receive such an organ. Surgeons at Massachusetts General Hospital successfully conducted the four-hour procedure on March 16, transplanting a pig kidney with 69 genomic edits. This breakthrough marks a major milestone in the field of xenotransplantation, which aims to address the critical shortage of human organs for transplant.
Slayman's operation was performed under the FDA's compassionate use program, an avenue for patients with serious, life-threatening conditions to access experimental treatments when other options are unavailable. The pig kidney was provided by eGenesis, which used CRISPR-Cas9 technology to modify the pig's DNA, removing harmful pig genes and adding human genes to improve compatibility, as well as inactivating porcine endogenous retroviruses to mitigate infection risk. This procedure immediately showed positive signs, with the kidney "pink[ing] up" and beginning to produce urine after being connected to Slayman's blood vessels.
While the procedure was a success, with Slayman recovering well and expected to be discharged, doctors are continuously monitoring his blood for any signs of dangerous viruses. This development offers significant hope for the more than 100,000 people in the U.S. currently on transplant waiting lists, including about 90,000 who need kidneys. Despite the positive outcomes, xenotransplantation still carries significant risks; previous pig-to-human heart transplants saw patients survive for no more than two months. The FDA has not yet approved xenotransplantation for widespread use, emphasizing the need for more data and clinical trials involving multiple patients and centers to fully assess its safety and efficacy. Still, the success of these transplants, including another instance where a pig kidney has kept a patient off dialysis for a record seven months, has led the FDA to approve eGenesis to begin rigorous clinical trials for kidney xenotransplants.
