Pig Kidney Transplants in 2025: What the Six-Month Milestone Means
- Sean Hashmi, MD
- 3 days ago
- 4 min read
For decades, the transplant community has asked a single question: can a pig kidney keep a human alive long enough to matter? In 2025, we finally got an answer. Multiple patients in the United States and China survived more than six months with gene-edited pig kidneys functioning inside them — crossing a threshold that changes how we think about xenotransplantation and the future of kidney failure treatment.
Key Takeaways
Multiple humans have now lived more than six months with pig kidney transplants, with one patient's kidney functioning for 271 days before removal due to chronic rejection.
The six-month mark is a critical benchmark in transplantation — grafts that survive this window have significantly better odds of long-term function.
Formal clinical trials are now underway in the United States, moving xenotransplantation from experimental "hero surgeries" to systematic data collection.
Overview
The Organ Shortage Crisis
Right now, more than 100,000 Americans are waiting for a kidney. Thousands die every year because a human organ never becomes available. Dialysis keeps people alive, but it does not replace the quality of life or survival advantage that a transplant provides.
The question researchers have chased for decades is straightforward: can we safely transplant an organ from another species into a human and have it last long enough to actually help?
Why 2025 Was Different
Before this year, no one with a pig kidney transplant had survived more than two months. Organs failed from rejection or patients developed other complications. The six-month mark matters because it defines the highest-risk window in transplantation. If a graft is still working after six months, the odds of continued function increase substantially.
In 2025, multiple patients crossed that threshold — in different countries, with different surgical teams, using different protocols. The field took notice.
The Massachusetts General Hospital Case
The clearest example is Tim Andrews, a 67-year-old man with end-stage kidney disease and no viable human donor options. In January 2025, he received a gene-edited pig kidney. By July, he had crossed six months off dialysis with the kidney still functioning.
What made this kidney different from a standard farm pig organ? Scientists had made 69 total gene edits: three pig genes knocked out to prevent immediate immune attack, seven human genes inserted to improve compatibility and reduce clotting and inflammation, and 59 retrovirus sequences inactivated to eliminate infection risk.
In October 2025, Andrews' kidney was removed after 271 days due to chronic rejection. But nine months of function gave researchers critical data on what works and what needs improvement.
Parallel Results From China
Almost simultaneously, researchers at Xijing Hospital in China reported a 69-year-old woman living more than six months with a gene-edited pig kidney. She received her transplant in March 2025, and as of the latest reports, her kidney is still functioning after eight months.
This parallel success matters for two reasons. First, it shows the biology is reproducible across different systems, teams, and protocols. Second, it creates momentum for international standards on safety and monitoring.
Animal Data Predicted This
2024, Chinese scientists kept a macaque monkey alive for 184 days with a gene-edited pig kidney using an advanced immunosuppression regimen designed specifically for xenotransplantation. That experiment told the field: if we control immunity well enough, a pig kidney can provide long-term filtration in a primate.
When the 2025 human cases matched this timeline, researchers knew they were on the right curve.
What Remains Challenging
This is not a cure. Even with 69 gene edits, the human immune system can still recognize and slowly damage pig tissue. Chronic rejection and antibody-mediated rejection remain real concerns. Teams are watching closely for pig endogenous retroviruses and other pathogens. These pigs are raised in biosecure facilities, but regulators want multi-year follow-up.
Patients still require lifelong immunosuppression. And as of late 2025, this is available only at a few US centers and selected Chinese centers, mostly through clinical trials.
Clinical Trials Are Underway
What has changed is that formal clinical trials have begun. Massachusetts General Hospital, NYU Langone, and companies like eGenesis and United Therapeutics are enrolling small numbers of patients — three to six initially — with plans to expand if safety and graft survival endpoints are met.
The primary endpoints: graft survival at six months, kidney function markers like creatinine, immune response, and any evidence of pig-borne viruses. The field is moving from one-off compassionate use cases to systematic data collection.
What You Can Do
Ask your nephrologist about eligibility: If you are on dialysis, highly sensitized, or have no living donor options, ask whether xenotransplantation trials might be appropriate for your situation.
Stay informed about clinical trial enrollment: Centers like MGH and NYU Langone are actively enrolling. ClinicalTrials.gov lists current studies.
Continue standard kidney protection: Whether or not xenotransplantation becomes an option for you, protecting remaining kidney function through blood pressure control, diabetes management, and medication adherence remains essential.
The Bottom Line
Pig kidney transplants will not solve the organ shortage tomorrow. But for patients who have run out of options — older dialysis patients, highly sensitized patients, those without living donors — this is the first real alternative we have seen in decades. The six-month milestone tells us the biology can work. The formal trials will tell us whether it can scale.
Scientific References
Montgomery, R. A., et al. (2022). Results of two cases of pig-to-human kidney xenotransplantation. New England Journal of Medicine, 386(20), 1889-1898.
Porrett, P. M., et al. (2022). First clinical-grade porcine kidney xenotransplant using a human decedent model. American Journal of Transplantation, 22(4), 1037-1053.
Lu, T., et al. (2024). Long-term survival of pig-to-primate kidney xenografts with optimized immunosuppression. Nature Communications, 15, 2847.
Locke, J. E., et al. (2023). Xenotransplantation: Current status and future directions. Transplantation, 107(5), 1025-1033.
Cooper, D. K. C., & Pierson, R. N. (2023). Milestones on the path to clinical pig organ xenotransplantation. American Journal of Transplantation, 23(3), 326-335.
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Medical Disclaimer
This article is for educational purposes only and is not medical advice, diagnosis, or treatment. Always consult your healthcare provider before making changes to your health routine. The views expressed are Dr. Hashmi's personal professional opinions and do not represent any employer or affiliated organization.
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