A genetically modified pig kidney kept a man off dialysis for 271 days before he received a human kidney earlier this year – the longest dialysis-free survival reported after a pig-kidney transplant in a living person.
The case has given researchers one of the clearest indications yet that genetically engineered animal organs may eventually help bridge the gap between patients needing transplants and the limited supply of human donor organs.
India is now preparing to build expertise in this emerging field.
Sir Ganga Ram Hospital (SRGH) in the capital has established a dedicated Department of Xenotransplantation Sciences, with a focus on developing scientific, translational and institutional capabilities required for establishing the sophisticated technique, while the Union health ministry is working towards developing guidelines for it, according to people familiar with the developments.
The moves come as xenotransplantation – the transplantation of organs, tissues or cells between different species – is moving beyond decades of laboratory research and into early-stage human use in countries such as the US.
The immediate focus is on kidneys, but researchers are also working on genetically modified pig hearts, livers and other organs.
Experts agree that if organs from specially bred animals can eventually be made safe, effective and affordable, they could provide an additional source of organs for patients who otherwise face long waits for a human donor.
ORGAN SHORTAGE BEHIND THE PUSH
The urgency becomes clearer from India’s transplant numbers.
As of March this year, 89,839 people were on the national waiting list for major organs, according to data from the National Organ and Tissue Transplant Organisation (NOTTO) cited by the Union health ministry.
India performed 20,138 organ transplants in 2025 – the highest ever in a year. Yet only around 18% of transplants currently use organs donated after death, meaning the country’s transplant system continues to depend heavily on living donors for various organs.
Kidneys account for the largest share of this demand. NOTTO data for 2024 show that 13,476 kidney transplants were performed that year – 11,558 using living donors and 1,918 using deceased-donor organs.
These figures also need to be read against the much larger number of people who may medically need a transplant but are not necessarily registered on the national waiting list.
That is where xenotransplantation could, in principle, change the equation. Instead of waiting for a suitable human donor to become available, patients could eventually have access to organs produced from a controlled supply of genetically modified animals.
And that possibility, though some distance away, is not very far.
HOW A PIG KIDNEY BECOMES COMPATIBLE
Xenotransplantation itself is not new. What has changed dramatically is the ability to genetically engineer the donor animal.
The modern approach does not involve taking an ordinary pig, removing its kidney and putting it into a human. Pigs intended for xenotransplantation are specifically bred and maintained under tightly controlled conditions. Their genetic material is altered so that the organs they develop are better able to function in the human body.
Some pig genes are knocked out using CRISPR Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR associated) technology, a type of genome editing system, because they produce molecules that trigger a strong human immune response.
Other genetic changes introduce human genes that can help regulate processes involved in complement activation, coagulation and immune responses. Researchers may also inactivate endogenous pig retroviruses because of concerns about cross-species infection.
The aim is mainly to remove or reduce some of the biological barriers that have historically made cross-species transplantation extremely difficult.
Dr Shikhar Tripathi, who has joined as director of the new department at SRGH and is also affiliated with the Thomas E. Starzl Transplantation Institute in the US, told India Today that the process starts well before a transplant operation.
According to him, pigs have emerged as the leading candidate because their organs are broadly comparable in size to human organs, also they can be bred relatively quickly, their genetic material can be manipulated, and they are easier to handle during the procedures.
The field has accelerated sharply in recent years, with research groups and biotechnology companies developing increasingly sophisticated gene-edited pigs.
A KIDNEY THAT LASTED 271 DAYS
The latest milestone came from Massachusetts General Hospital in the US.
Tim Andrews, 66, received a genetically engineered pig kidney from eGenesis on January 25, 2025, under an FDA-authorised expanded-access programme. The kidney began functioning immediately and kept him free of dialysis for 271 days before it was removed.
In January 2026, Andrews received a deceased-donor human kidney, making his case the first reported transition from a pig-kidney xenotransplant to a human kidney transplant.
The case was significant, but it also illustrated the limits of current xenotransplantation.
Andrews experienced an early episode of T-cell-mediated rejection, which was treated. Later, after immunosuppression was reduced in the setting of an infection, the transplanted kidney developed microvascular injury and inflammation that eventually led to graft failure.
Researchers did not detect transmission of pig pathogens, and the patient was subsequently able to receive a human kidney without evidence of clinically significant sensitisation from the xenotransplant.
The challenge, as the episode showed, remained, but it also opened the possibility that a genetically engineered animal organ can sustain a human for a substantial period – at least till the other barriers are removed, and the recipients show better immune response to the donated organ.
Scientists, in the meantime, are working on what needs to be tackled.
Dr Tripathi and colleagues, including Dr David KC Cooper, known as the father of xenotransplantation, recently published research examining possible mechanisms behind proteinuria – excess protein in the urine – after pig-kidney xenotransplantation. The work adds to efforts to understand why these organs can develop complications even after the initial immune barriers have been overcome.
As Dr Tripathi put it, early attempts cannot be expected to solve every problem at once but work is moving at a fast pace to understand why grafts develop complications and how scientists can engineer the next generation of donor organs to overcome them.
“That is precisely where translational research becomes critical,” he said.
That iterative approach is central to xenotransplantation. If a problem arises from a particular feature of the donor organ, researchers can potentially alter the animal’s genetic make-up in the next generation rather than simply searching for a different human donor.
WHY INDIA NEEDS A RULEBOOK
India’s interest in the field, meanwhile, is not entirely new.
The country, rather, has seen a controversial episode involving xenotransplantation nearly three decades ago. In 1997, Assam-based surgeon Dr Dhaniram Baruah transplanted a pig heart into a human recipient.
The patient died days later and the procedure triggered legal and ethical controversy. Contemporary xenotransplantation, however, is fundamentally different from that episode because it relies on extensive genetic engineering, controlled donor-animal facilities, sophisticated immunosuppression and detailed monitoring for rejection and infection.
India’s regulatory system had already identified xenotransplantation as an area requiring specialised oversight more than a decade ago. In 2010, the health ministry constituted an expert panel to advise the drug regulator on regulatory pathways for technologies including human gene manipulation and xenotransplantation.
A dedicated stem cell division was subsequently established within the Central Drugs Standard Control Organisation (CDSCO) in 2012 to support evaluation of such proposals.
The new push could be mainly about building the scientific and regulatory framework that would be needed before such a procedure could be considered.
The proposed guidelines would have to address questions that do not arise in conventional human-to-human transplantation in quite the same way: how genetically modified donor animals are produced and monitored; patient selection; clinical-trial requirements; infection and biosafety risks; long-term surveillance; immunosuppression; animal welfare; and what happens if a patient develops an infection that could potentially cross the species barrier.
These concerns are not theoretical. Xenotransplantation researchers have to consider the possibility of pathogens moving from animals to humans, as well as the long-term consequences of exposing patients to genetically modified organs and powerful immunosuppressive drugs.
India Today has reached out to the government for its status on the guidelines. This copy will be updated when its reply is received. (I plan to write to the ministry for its formal response)
FROM EXPERIMENT TO CLINICAL TRIALS
Internationally, however, the field is moving closer to formal clinical trials.
In the US, eGenesis has received FDA clearance for clinical trial of its genetically engineered pig kidney, EGEN-2784, in patients with end-stage kidney disease.
As of September 2026, five patients had already received the kidney under an expanded-access programme since March 2024, with three reported to have maintained kidney function for more than eight months without dialysis. The company expects its formal trial to begin in the first quarter of 2027.
That does not mean the technology has been established as a routine alternative to human transplantation. It remains experimental, and questions around durability, rejection, infection, immunosuppression, manufacturing, cost and long-term safety remain unresolved.
The big promise of the potential applications extend beyond kidneys.
Genetically modified pig hearts are being studied because of their broadly suitable size, while pig livers and other organs are being investigated for possible use in organ failure. Genetically modified cells could eventually have applications in conditions such as type 1 diabetes, which typically start in childhood or during adolescence and make patients dependent on insulin for life.
But for India, the kidney may represent the most immediate area of interest because the demand is so much larger.
Dr Sumesh Kaistha, director of liver transplant and gastrointestinal surgeries at Paras Health in Panchkula, said the technology could be particularly relevant in the Indian context because it may reduce prolonged waiting periods and the deterioration some patients experience while waiting for a suitable donor.
Meanwhile, some other doctors raise another interesting dimension: the eventual economics may be as important as science.
Dr Vikrant Panwar, gastroenterologist and hepatologist at Shalby International Hospital in Gurugram, said the country’s growing burden of chronic liver and kidney disease and metabolic disorders associated with diabetes, obesity and metabolic dysfunction-associated steatohepatitis are adding to the pool of patients who may eventually require advanced organ care, but making the cutting – edge treatment affordable is also important
“Against this background, if these genetically modified pig breeding lines, including CRISPR knockout lines, can be indigenised by domestic biotech instead of importing them, then the cost can potentially be made affordable,” Dr Panwar said.
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