If you’re on the kidney transplant waiting list, the wait can feel endless. Some patients wait years, and tragically, some don’t survive long enough to receive a kidney. The shortage of donor organs is one of the hardest truths facing anyone with end-stage kidney disease. That’s why a landmark clinical trial starting this year is genuinely exciting. United Therapeutics has received FDA clearance to begin testing UKidney – a kidney grown from a pig with ten genetic edits designed to work safely in human recipients. The first transplants are expected around mid-2025, marking the first time a gene-edited animal organ will be tested in living patients.
What is xenotransplantation?
Xenotransplantation is transplanting an organ from one species into another – in this case, from a pig into a human. The challenge has always been rejection: our immune system recognises the pig organ as foreign and attacks it. United Therapeutics addressed this by adding six human genes to the pig’s genome to help the organ be accepted, and removing four pig genes that would trigger rejection or cause the organ to grow too large. The UKidney will be tested in patients with end-stage renal disease (ESRD) who either cannot receive a conventional human kidney transplant for medical reasons, or who have been waiting on the transplant list and are unlikely to receive a deceased donor kidney within five years.
You can read the full original article from United Therapeutics here: FDA Clearance of Investigational New Drug Application for the UKidney Xenotransplantation Clinical Trial.
Could gene-edited pig kidneys ease the transplant shortage?
The kidney transplant waiting list in the US alone includes around 93,000 people. Only about 21,000 deceased donor kidneys become available each year. For older patients or those with medical complications, the wait can be a death sentence – a 2009 study found that 52% of patients aged 60+ who were placed on the transplant waitlist died within five years before receiving a kidney. For these patients, xenotransplantation could be life-changing. Unlike dialysis, a functioning kidney transplant can extend life, improve quality of life, and reduce the risk of heart disease. Gene-edited animal organs offer a potentially unlimited supply.
Early days for xenotransplantation
This is a major milestone, but it’s the beginning of a long process. The trial will start with six patients at two centres, with a 12-week safety review before moving forward. Full results won’t be available until roughly 2028 or 2029. This is not yet a treatment option for patients – only six carefully selected people will participate initially, expanding to up to 50. Even if successful, xenotransplant organs won’t replace human donor transplants; they’ll offer hope to patients who have no other options.
It’s also important to know that xenotransplant recipients will need lifelong immunosuppressive medication to prevent rejection, just as with human organ transplants. There are also legitimate questions about long-term safety that only time and careful monitoring will answer. But for patients facing years on dialysis or death whilst waiting, the promise is substantial.
Learn more about transplantation and patient experiences, and organ donation options.
If you have questions about xenotransplantation or want to understand your transplant options, please speak with your renal team. For more information, contact MRIKPA at support@mrikpa.org.uk or 07745 242 684.
Source: United Therapeutics Corporation. “FDA Clearance of Investigational New Drug Application for the UKidney Xenotransplantation Clinical Trial.” Published February 3, 2025. https://ir.unither.com/press-releases/2025/02-03-2025-120011819
This article is provided for general information and awareness purposes only and was believed to be accurate at the time of publishing. It is not intended as medical advice – please always consult your doctor or renal team for guidance on your individual circumstances. Images used are for illustration purposes only and may not be medically or editorially accurate. While we take every care, errors can occur. If you spot an inaccuracy, please let us know at support@mrikpa.org.uk.
