eGenesis Pig Kidney Transplanted into Living Patient at Massachusetts General

This story stopped me in my tracks. On March 16, 2024, surgeons at Massachusetts General Hospital (MGH) transplanted a genetically modified pig kidney into Rick Slayman, a 62-year-old man with end-stage kidney disease. The kidney, developed by Cambridge-based biotech company eGenesis, featured an unprecedented 69 genomic edits made using CRISPR technology — the most extensively edited pig organ ever transplanted into a human. After a family member needed a kidney transplant, I follow every one of these cases like it's personal. Because it is.

The Science

The eGenesis kidney underwent three categories of genetic modifications. First, three pig genes responsible for producing sugars that trigger human immune rejection were knocked out. Second, seven human genes were inserted to improve compatibility with the human immune system. Third, 59 copies of porcine endogenous retroviruses (PERVs) — viral DNA embedded in the pig genome — were inactivated to eliminate the risk of viral transmission to the recipient.

"This is a historic moment in transplantation. We are witnessing the dawn of a new era where genetically engineered animal organs can provide a bridge — or even a permanent solution — for patients in need." — Dr. Leonardo Riella, MGH transplant nephrologist

The Patient

Rick Slayman had previously received a human kidney transplant that began to fail after five years. Back on dialysis and facing a long wait for another human kidney, he volunteered for the experimental procedure under an FDA compassionate use authorization. Think about that choice: the system couldn't offer him a human kidney fast enough, so he said yes to a pig kidney engineered with 69 gene edits. The surgery lasted four hours, and the pig kidney began producing urine almost immediately — a sign of proper function.

Outcome and Significance

Slayman was discharged from the hospital about two weeks after surgery. Tragically, he passed away approximately two months later; his family and medical team stated that there was no indication his death was related to the transplant. Despite this outcome, the case was considered a significant success — the kidney functioned throughout, and the data gathered will inform future xenotransplant procedures.

"Mr. Slayman was a pioneer. His courage and willingness to participate in this experimental procedure will help countless future patients." — MGH statement

The Road Ahead

eGenesis and MGH are planning additional pig kidney transplants, with the goal of eventually launching formal clinical trials. I'm rooting for them. But here's what I need people to understand: xenotransplantation is a future solution. Opt-out organ donation is a solution for right now. Changing the default saves lives — today, not in ten years. That's why we at YCOD are pushing Bill A07954 with everything we have. Rick Slayman shouldn't have had to volunteer for an experimental pig kidney because the system couldn't get him a human one. This is a policy problem, not a medical one.