Xenotransplant setbacks leave Korea trailing US and China, but Optipharm bets on edited pigs

Korea can breed the pigs and stitch the grafts. What it cannot do, at least not yet, is run the human-facing studies that turned xenotransplantation from a moonshot into clinical reality in the United States and a national project in China.

The choke points are simple and stubborn: a legal code that treats brain death as life except in human-to-human donation, and a primate shortage that leaves surgeons without baboons, the human-sized model needed for in-chest heart work.

The science keeps pressing forward anyway. Korean teams report monkey survival of roughly 221 days for pig kidneys and 217 days for pig hearts placed heterotopically, that is, parked in the abdomen for monitoring rather than replacing the native heart. 

“In primates we have made kidneys last about 221 days,” said Yun Ik-jin, a transplant surgeon at Konkuk University who helps lead the national xenotransplant program, in an interview with Korea Biomedical Review. 

“For hearts we are over 200 days in heterotopic models. Without orthotopic trials, hearts in the chest doing the full job, regulators will not treat it as the same thing.” Orthotopic heart work usually uses baboons, often 15 to 40 kilograms and close to human hemodynamics. Korea works mostly with macaques, seven to eight kilograms at most.

The country is not short on pigs or on know-how to edit them. Optipharm, the main private supplier of donor swine for xenografts (pig-to-human or pig-to-primate transplants), says its production herds now include pigs with eight genetic edits, four porcine genes knocked out and four human genes added, that a 10-edit line has been created, and that a 12-edit animal sits on next year’s roadmap. 

The company also says it has “DPF” herds, designated pathogen free, a human-grade biosecurity standard that goes beyond farm “SPF” by excluding dozens of agents of concern for recipients. “Purely on the pig side we are ready,” said Kim Hyun-il, Optipharm’s chief executive, in an interview.

He pointed to a balance sheet that leans on vaccines and bacteriophage products, roughly 20 billion won ($14.3 million) in annual sales, and said about 5 billion won a year goes back into xenotransplant work while the business keeps growing.

Edit counts are not a performance metric by themselves, cautioned Kim Sung-joo, now a surgeon at Sungkyunkwan University and formerly the head of GenNBio, the other Kosdaq-listed xenotransplant player before it unraveled.

“What matters is stability and function,” he said in an interview, meaning fertility and faithful transmission of the edits, graft performance in primates, and peer-reviewed publication. GenNBio built a 60 billion won ($43 million) facility in Pyeongtaek, ran nonhuman primate studies and then ran out of runway. “It was financial,” he said. “An investor promised funding and did not follow through. We had enough to build and run studies, not enough to cross into clinical stages.” Kim declined to offer specifics in our interview, saying he did not wish to elaborate.

Korea has crossed harder gaps before. Its transplant program dates to 1969, when a living-donor kidney was implanted at Seoul St. Mary's Hospital, and the first deceased-donor kidney followed in 1979. Today, five- and ten-year survival after human-to-human kidney, heart and liver transplants at major centers such as Asan and Samsung Medical Center rivals U.S. leaders. The friction sits in the verification layer between edited pigs and patients.

That layer is where the United States changed the field. Academic teams placed pig kidneys and hearts into brain-dead human donors on ventilators, building days to weeks of human-physiology data before attempting living recipients. 

Law and logistics

Korea’s Organ Transplantation Act recognizes brain death as legal death only in the context of donation to another human. Research use is outside the law and, under Korean rules, organs cannot be procured without a designated human recipient. 

“Unlike the U.S. and China, we have not conducted brain-dead donor trials, so we do not know how results differ between primates and humans,” Optipharm’s Kim said. “If we could conduct even 10 cases, we would learn how the human body responds. Priority one is allowing transplants in brain-dead donors.”

He said his team has met with staff from the Ministry of Health and Welfare (MOHW) about a narrow exception that could authorize a small number of donor cases in the national interest. Officials are listening, he said, without a timeline.

While that grinds, researchers are steering first toward tissues and cells. Surgeons say corneal xenografts have stayed clear in primates for about 15 months using mostly approved immunosuppressants, which they argue is enough to start in people after one more case. 

Islet cells for type 1 diabetes (pancreatic islets, the insulin-secreting clusters) look closer to clinical viability after improvements in isolation methods. Kidney remains the most practical solid-organ candidate in Korea. If a graft falters, surgeons can remove it and the patient can return to dialysis. “That safety net is the reason kidneys go first,” Yun said.

Liver is the outlier, in Korea and everywhere else, because of coagulation traps and a pig-to-human physiology mismatch. Both Kims said months-long survival in a human liver recipient, which some groups abroad have hinted at, would be a genuine milestone and a bridge to human donation. Kim Sung-joo put it this way: if five months is real and gets published, it matters even before true long-term function because it buys time.

The animal gap is not only biology. It is logistics and law. Airlines have largely stopped carrying research primates after activist pressure. China halted exports during Covid-19 and never fully reopened them, which drove prices for macaques to peaks above twenty thousand dollars before easing. 

Baboons are CITES-controlled and rarely exported for research in practice. Even when U.S. institutions signal willingness to help, Korea lacks mirrored quarantine and certification pathways to accept baboons. “The U.S. side even offered exports,” Kim Sung-joo recalled, “but the policy framework to receive them was not there.”

Pathogens remain the field’s shadow. Several swine pathogens cause human disease, including hepatitis E virus, influenza A and Streptococcus suis. After the first U.S. pig-heart transplant in 2022, a porcine roseolovirus, often labeled PCMV or PRV, was detected in the organ postmortem and is thought to have contributed to the patient’s death, although whether it infects human cells directly is still debated. That is what DPF herds are designed to screen out, along with a long list of bacteria and parasites.

A Korean review that aligns with the Ministry of Food and Drug Safety guidance counts roughly 148 pathogens on the exclusion roster. The deeper fear, porcine endogenous retroviruses embedded in pig genomes, has not shown clinical transmission. 

Researchers have even used CRISPR to inactivate all PERV copies and bred live pigs from those cells, which functionally removes that risk from a given line. Yun takes a working view of the unknowns. Known agents can be cataloged, blocked and managed, he said. The real danger is the pathogen no one has identified yet, which means vigilance without promising the impossible.

How Korea stacks up

Technically, Yun argues, Korea’s pig engineering is in the same neighborhood as the United States. “We currently have pigs with seven to eight genetic modifications, aiming for ten in the next one to two years,” he said, citing Optipharm and the National Institute of Animal Science. 

In the United States, two private programs dominate the push into patients. Revivicor, owned by United Therapeutics, supplies a different 10-edit genotype than eGenesis, whose kidney program used a three-knockout and seven-transgene configuration in the Massachusetts General Hospital case, along with PERV inactivation. 

Germany has been a preclinical leader, including long-surviving pig-to-baboon heart grafts reported by the Munich group, and its LMU and CiMM breeding programs are active. 

Japan has added capacity through PorMedTec, a Meiji University venture that, working with eGenesis, produced edited piglets domestically in early 2024 and began monkey kidney transplants later that year with AMED support. 

Australia built a solid regulatory framework but has not led edited-pig production. Seoul National University, for its part, has run a government-backed xenotransplant initiative for years and hosted an “Xenotransplantation Seoul Forum” series since 2005.

Korea’s nonhuman primate work is not trivial. Academic groups have reported insulin-independent control for up to about a thousand days after pig-islet transplants in monkeys. Regulators approved steps toward a human islet trial starting in 2020, and a formal protocol was published in 2024. Kidney trials are being discussed in the near term. 

The catch is volume. “Our consortium has roughly 70 to 80 researchers and about 8 billion won ($5.7 million) annually,” Yun said. A single nonhuman primate study can cost one to 200 million won, which limits teams to far fewer than 20 procedures a year. “The gap is less about making the pigs and more about proving them,” he added. “We lack evidence cycles.”

Money and law move faster elsewhere. Optipharm’s Kim describes China as the cautionary and aspirational case. He says a Chinese pig supplier he knows stood on the brink in 2022, then received cash and facility support after U.S. brain-dead donor data came out, and has since supplied dozens of brain-dead procedures with at least one reported living recipient around five months. 

Ethics in Korea are not limited to animals. The country relies heavily on living donors, especially for liver, often parent-child pairs under family pressure. “It is praised as noble, but we cannot always say it is truly voluntary,” Yun said. If xenotransplantation clears quality and safety bars, he argues, it should eventually replace, not merely supplement, human-to-human transplantation because it would reduce the burden now placed on living donors and families. 

As for identity questions, the heart as the seat of the soul and the queasy thought of a pig’s heart, he treats them as philosophical more than medical. Public acceptability, he said, tracks a simpler line. Most people accept raising pigs for food, and many will accept raising pigs to save human lives.

Optipharm is trying to outlast the stalemate. The company says it expects to turn profitable next year on vaccines and bacteriophage sales, then step up R&D in 2027.

GenNBio’s trajectory runs as a cautionary echo. Public filings show about three years of government funding for “verifying clinical applicability,” an investigational new drug (IND) pathway for porcine islets, serial convertible bonds that diluted shareholders and, by mid-2025, delisting and court auction of its Pyeongtaek real estate after a cash crunch and audit refusals. That was not a scientific failure so much as a capital structure that could not carry a long proof cycle.

The road to patients

What happens next depends less on CRISPR than on policy and infrastructure. Yun’s near-term map is clinical tissues such as cornea and islets, with an organ, most likely kidney, on a year-year horizon if the law budges.

His longer view is a network: a dedicated primate facility for xenotransplant studies, a full-time preclinical transplant team, clinical teams to validate protocols and run trials, and continued investment to push the pig platform beyond what private balance sheets can fund alone. Optipharm’s shorter ask is even simpler. “We are not talking about 20 or 30 brain-dead donors,” Kim said. “Give us even 10. Then the data can speak.”

The stakes are national. If pig organs prove viable abroad first, patients will travel and the revenue will follow them. Korea has the surgeons, the ICUs and a domestic supplier with cash flow, surgeons said.

It also has a law that still sees a brain as not quite dead, a research pipeline that needs bigger primates and a budget that buys too few experiments to convince regulators. The pigs are ready. The question is whether the system is ready to test them in humans.