ATLANTA — A Milestone in Organ Transplantation

Tim Andrews became one of the first people to receive a genetically modified pig kidney a year ago. Now, he’s also the first among that select group to receive a human kidney.

“I’m the first one that went across the bridge. … I’m the only person in the world that’s ever had a pig kidney and then had a human kidney after it,” he shared with CNN while in the hospital. “Nobody’s ever been across that bridge. That is cool!”

Andrews, 67, who deals with diabetes and was facing end-stage kidney disease, had his pig kidney implanted on January 25, 2025, and it functioned for a historic 271 days. After his body rejected the organ, it was taken out in October, leading him back to dialysis — a tough regimen that kept him alive but left him feeling miserable in the first place.

“I cried,” he said, recalling a moment when he confided in his family that he didn’t think he’d make it through the year.

But nearly at midnight on January 12, a call from Mass General Brigham brought news of a nearly perfect match for a human kidney. He was set for transplant surgery the next morning.

Andrews is now anticipating returning to his home in New Hampshire on Friday, just days after achieving a milestone organ transplant that exemplifies the potential of xenotransplantation — using animal organs to sustain human life while awaiting more permanent solutions.

The Organ Shortage Dilemma

Xenotransplantation, which entails transplanting organs from different species, is being explored as a possible remedy for the shortage of available organ donors. The pig organs used are genetically enhanced to mitigate rejection and size issues.

In the U.S., over 100,000 individuals are waiting for an organ, with approximately 80% requiring kidneys. However, only the most critically ill patients are on the list; just one in eight with end-stage renal disease qualifies.

Of more than 800,000 people experiencing kidney failure, nearly 70% are undergoing dialysis. This treatment attempts to mimic the body’s natural waste-clearing functions, but it only operates for a few hours each week instead of continuously. The five-year survival rate for dialysis patients is about 40%.

“Dialysis can’t replicate what the body needs to flush out waste,” said Dr. Leonardo Riella, the medical director of kidney transplantation at Mass General Brigham and Andrews’ physician. “It burdens patients, affecting both their quality of life and health.”

Andrews spent three days each week on dialysis, often for six hours. After just six months on this treatment, he suffered a heart attack. “It takes a toll on you emotionally and physically; you just get exhausted, and I got sick. I was throwing up all the time,” he reflected.

With the ongoing organ shortage, Riella believes xenotransplantation offers promise.

“Even if it is a bridge,” he noted, “it would be better than him just staying on dialysis.”

Before the human transplant, Andrews was thoroughly tested for new antibodies that could react with the new kidney and none were found. The latest transplant took about three hours, and he mentioned that his new immunosuppressant regimen is significantly lighter than what he took for the pig kidney.

A Contribution to Humanity

For Andrews, undergoing the xenotransplant was more than just a means to escape dialysis; it was a beacon of hope for others battling end-stage renal disease.

“This will do something for humanity,” he expressed in a documentary by CNN Chief Medical Correspondent Dr. Sanjay Gupta.

After the pig kidney transplant last year, Andrews felt a stark difference. “I was clear. I wasn’t what I call dialysis foggy. I wasn’t tired. All of a sudden, I had energy,” he recollected.

Yet, the journey had its own challenges. Andrews had to take 52 pills daily to help maintain harmony between his pig kidney, which he lovingly named Wilma, and his immune system. Over nine months, signs of rejection began to emerge, and he experienced two infections. Riella explained that while they adjusted Andrews’ immunosuppressant treatment, the kidneys sustained damage that couldn’t be reversed.

“There was some damage to the filters of the kidney that, unfortunately, were not reversible,” he said. Eventually, they removed Wilma, and Andrews had to resume dialysis.

Mike Curtis, CEO of eGenesis, the company that provided the donor pig for Andrews’ kidney, acknowledged that the rejection was a gradual process that scientists had anticipated.

“We just couldn’t figure out how to push it back,” Curtis remarked.

Nonetheless, the research stemming from Andrews’ experience may shed light on rejection causes and help future recipients.

“We have a much better idea of what was causing that low-level rejection, so we can then tune the suppression,” Curtis added.

Andrews’ journey has refined protocols for subsequent xenotransplant patients. Since his surgery in January 2025, Mass General and eGenesis have performed two additional xenotransplants and are gearing up for a clinical trial soon.

The Future Beyond Dialysis

Yet, Riella views Andrews’ journey with xenotransplantation as a success. Wilma kept him away from dialysis for nine months, but once back on it, his overall health declined, and he began losing muscle mass and energy.

He suggested comparing xenotransplantation not necessarily to a human kidney, but to dialysis. “It’s a much better treatment to maintain kidney function compared to what dialysis offers,” he stated. “Our goal is to basically ban dialysis as a long-term option.”

However, Dr. Robert Montgomery, director of the NYU Langone Transplant Institute who has also advanced the field of xenotransplantation, mentioned that an alternative to dialysis is not the ultimate goal.

“As this gets better and xenografts last longer, it will eventually become a destination,” he explained. Montgomery, the first to transplant pig organs into brain-dead patients, is leading the first FDA-approved clinical trial in xenotransplantation.

He envisions that within five years, xenotransplantation will emerge as a practical solution for patients. “In the future, I think a single patient with renal failure will cycle through both xenografts and allografts throughout their lifetime.”

Riella noted that it’s hard to predict what would have happened if Andrews never pursued the xenotransplant, but Andrews firmly believes that Wilma was key to his survival.

“If I didn’t take Wilma, I’d have been dead by now. I wasn’t gonna make it another year,” Andrews said. “I’m looking at years now. I can think ahead.”

These days, he’s focused on sharing his experience and encouraging others to consider becoming organ donors.

“People need to step up and help,” Andrews expressed.

In a recent social media post, he expressed gratitude to the family of his donor, whose identity remains undisclosed.

“I grieve with you. It’s got to tear you apart, but I’m here to tell you, the donation of a kidney has saved my life, and you have given hope to millions. Your family member is a hero,” he said.

“I’ll never be able to repay you, but I promise you it’ll be in my heart. And it will be cared for and loved as long as I live.”