A year after receiving a genetically modified pig kidney, Tim Andrews has now received a human kidney transplant, offering a rare real-world glimpse into how experimental xenotransplants may act as a bridge to human organs for people with kidney failure. His journey highlights both the promise and the limits of this emerging science, and what patients and families should realistically expect.


A personal story at the edge of transplant medicine

When you live with advanced kidney disease, life can start to feel like a cycle of waiting: waiting for dialysis, waiting for lab results, waiting for “the call” that a compatible organ is finally available. Tim Andrews knew that feeling well. He became one of the first people in the world to receive a genetically modified pig kidney, and now, he is the first among that small pioneering group to go on to receive a human kidney.


Kidney transplant patient in a hospital room speaking with medical staff
Clinical teams are testing genetically modified pig kidneys as a bridge to human transplantation for patients with kidney failure.

His experience doesn’t mean xenotransplantation is ready for everyone. But it does offer a powerful case study in how this “bridge transplant” concept can work in real life, and how it might change the future of organ donation.


The bigger problem: Not enough kidneys for the people who need them

Tim’s story sits inside a much larger crisis: there are far more people who need kidney transplants than there are donated organs available.

According to recent U.S. data, tens of thousands of people remain on the kidney transplant waiting list at any given time, and thousands die each year while waiting. Dialysis can keep people alive, but it usually cannot restore the energy, flexibility, or long-term health that a successful transplant can provide.

  • Kidney disease is common and often silent until late stages.
  • Many patients are older or have other conditions that complicate transplant.
  • Deceased and living donation cannot meet current demand.
“The gap between the number of organs needed and those available remains substantial, despite significant advances in transplant medicine.”

This is the space where genetically modified pig organs—xenotransplants—are beginning to play a role, not as a cure-all, but potentially as a new tool when conventional options fall short.


Tim Andrews’ journey: From experimental pig kidney to human transplant

Tim was not a typical transplant candidate. By the time he was offered the experimental pig kidney, he had already faced serious health challenges, and traditional pathways to a human organ were limited or uncertain. The experimental procedure was structured as a carefully monitored, time-limited research effort.

After receiving the genetically modified pig kidney, Tim experienced improved kidney function compared with what dialysis alone could offer. That function was closely tracked: urine output, lab markers like creatinine, and overall clinical stability. Importantly, the pig kidney worked well enough, for long enough, that he remained alive and well to later receive a human kidney when it became available.

Kidney scan and medical chart being reviewed by a doctor
Intensive monitoring after both pig and human kidney transplants helps clinicians understand how well each organ is functioning over time.

When a human kidney did become available, his clinical team made the decision to proceed. He is now the first documented case from this early xenotransplant group to go on to receive a human kidney, giving researchers and patients invaluable insight:

  1. A pig kidney can temporarily support organ function in a human under strict research conditions.
  2. It may serve as a “bridge” to a later human transplant, not necessarily a permanent solution.
  3. Careful patient selection and very close monitoring are crucial.
“What Tim’s case tells us is that a genetically modified pig kidney can safely carry someone forward long enough to reach a human transplant, at least under the right conditions,” one transplant researcher involved in xenotransplant trials has noted.

The science behind genetically modified pig kidneys

Pigs are often used as potential organ donors because their organs are similar in size and function to those of humans, and pigs can be bred under controlled, pathogen-monitored conditions. However, a standard pig organ placed into a human would typically be rejected almost immediately.

Modern xenotransplant research focuses on genetic modification—editing the pig’s DNA to make its organs more compatible with the human immune system and to reduce specific risks.

  • Removing key pig genes that trigger immediate human immune reactions.
  • Adding human genes that help regulate blood clotting, inflammation, and rejection pathways.
  • Reducing viral risks by targeting porcine endogenous retroviruses (PERVs) and breeding in highly controlled facilities.
Scientist working in a lab with genetic samples
Gene editing tools, such as CRISPR-based technologies, are used to modify donor pigs so their organs are less likely to be rejected.

In early human cases like Tim’s, these modifications are combined with powerful immunosuppressive medications and intensive follow-up. Research published in recent years in journals such as Nature and New England Journal of Medicine has documented short-term function of pig kidneys and hearts transplanted into human recipients under strict experimental conditions. However, long-term outcomes are still largely unknown.


“Bridge” transplants: Buying time, not promising forever

Tim’s move from pig kidney to human kidney illustrates an important concept: using a temporary organ to keep someone stable until a more durable therapy is available. In heart disease, for example, mechanical heart pumps are sometimes used as a “bridge to transplant.” Pig kidneys may serve a similar role for select kidney patients in research settings.

Potential benefits of a pig kidney bridge

  • More time off intensive dialysis, which can improve energy and quality of life for some patients.
  • Medical stabilization, allowing patients to become better candidates for a human transplant.
  • New scientific insights that may improve transplant care for future patients.

Important limitations to understand

  • These procedures are highly experimental, with unknown long-term durability.
  • They require strong immune-suppressing drugs, which carry infection and cancer risks.
  • They are currently available to only a very small number of carefully selected patients.
Patient and doctor discussing treatment options in a hospital setting
For patients and families, decisions about experimental procedures require careful, honest conversations about risks and realistic goals.

Common concerns and obstacles for patients and families

Hearing about a case like Tim’s can bring up complex emotions: hope, anxiety, skepticism, or even frustration if you or someone you love is still waiting on dialysis. Those reactions are completely understandable.

1. “Will this be available for me soon?”

For most people, the honest answer right now is: probably not in the near term. Clinical trials for pig kidney transplants are small, highly selective, and concentrated at a few major research centers. It will likely take years—and positive results from larger studies—before regulators even consider broader approval.

2. Safety, ethics, and unknowns

Researchers and ethics boards are weighing:

  • Unknown long-term immune and infection risks.
  • Potential transmission of animal viruses, even if carefully screened.
  • Concerns about animal welfare and how donor pigs are raised.
  • Equity in access if these therapies eventually become more common.

3. Emotional toll and decision fatigue

For patients already coping with dialysis, fatigue, and lifestyle changes, the idea of adding an experimental procedure can feel overwhelming. It’s common to:

  • Worry about being a “test subject.”
  • Fear complications or regret.
  • Struggle to sort through complex medical information.
“Good experimental medicine never means asking patients to ‘be brave’ without also giving them clear, balanced information and strong support,” notes one transplant ethicist. “Hope has to be paired with honesty.”

Practical steps for patients with advanced kidney disease today

While xenotransplantation evolves mostly in the research realm, there are concrete, evidence-based steps you can take now if you’re living with serious kidney disease or supporting someone who is.

1. Get clear on your current options

  • Ask your nephrologist whether you’re a candidate for a standard kidney transplant.
  • Discuss both deceased and living donor options.
  • Request a referral to a transplant center even if you’re unsure; evaluations don’t obligate you to proceed.

2. Optimize your overall health

Many transplant centers look at your heart health, blood pressure, diabetes control, and weight status. While not all factors are under your control, you can often improve your candidacy by:

  • Taking medications as prescribed and keeping all follow-up appointments.
  • Working with a renal dietitian to follow a kidney-friendly diet.
  • Staying as physically active as your care team feels is safe for you.

3. If you’re curious about trials, proceed carefully

If you want to explore experimental options like pig kidney transplants:

  1. Start by asking your nephrologist or transplant physician if any reputable trials might fit your situation.
  2. Look at registries such as ClinicalTrials.gov and filter for kidney transplant or xenotransplantation studies.
  3. Be wary of clinics making bold promises or charging large fees for unproven “transplant” procedures.
Person researching medical information on a laptop with notes
Using trusted registries and talking with your care team helps distinguish legitimate clinical research from unsupported claims.

What Tim’s story might mean for the future of transplantation

Tim Andrews’ progression from a genetically modified pig kidney to a human kidney will likely be studied for years. His case provides concrete, lived evidence that:

  • A pig kidney can support meaningful kidney function in a human for a defined period.
  • That support may preserve a patient’s health long enough for a human organ to become available.
  • With careful planning, transitioning from a xenotransplant to a human transplant is possible.

At the same time, his experience underscores how much we still do not know:

  • How long pig kidneys can reliably function in different patients.
  • What the long-term infection and immune risks truly are.
  • How to fairly and safely scale this approach if it proves effective.
The most responsible way to interpret this milestone is not as a miracle cure, but as a carefully measured step forward—one built on rigorous science, close follow-up, and honest communication with patients.

Moving forward with grounded hope

If you or someone you love is living with kidney failure, stories like Tim Andrews’ can be both inspiring and emotionally complicated. It’s normal to want access to the very latest treatment, and just as normal to feel cautious about anything labeled “experimental.”

The healthiest stance right now is a blend of curiosity and caution: follow these breakthroughs, ask questions, and stay informed—while focusing your day-to-day energy on proven, available options such as optimal dialysis care, transplant evaluation, and lifestyle steps that keep you as strong as possible.

You do not have to navigate this alone. Your nephrologist, transplant team, and patient support organizations can help you understand how emerging advances like pig kidney transplants fit—or don’t fit—into your unique situation.

Your next step today:

  • Write down three questions you have about your current kidney care or transplant options.
  • Bring them to your next appointment and ask for clear, plain-language answers.
  • Ask your team how they stay updated on emerging treatments like xenotransplantation—and what that might mean for you over the coming years.

Medical science is moving quickly, but your story unfolds one step at a time. Grounded, well-informed choices—made with a team you trust—are still the most powerful tools you have.