In January, doctors at the University of Maryland School of Medicine made history by successfully transplanting a pig's heart into a human. The 57-year-old patient may have died two months later due to complications from the experimental procedure, but the case has inspired scientists throughout the medical field to call on the FDA to expand the scope and scale of human-porcine transplantation research. During a two-day conference in late June, policy advisors to the FDA and medical professionals discussed the future of xenotransplantation and "most attendees agreed that human trials are needed to help answer the most pressing research questions," according to Nature.
We've been stuffing pig organs into sick people since the early 19th century, but the technology has made rapid strides in recent decades thanks in part to the advent of CRISPR technology and more potent immunosuppressives. In 2017, researchers created the first human-pig hybrid embryo as well as devised a solution to potential inter-species viral infections. As of January, 2022, were implanting genetically modified pig kidneys into brain-dead donor recipients with great success.
“Our goal is not to have a one-off, but to advance the field to help our patients,” Dr. Jayme Locke, lead surgeon of the kidney study and director of UAB’s Incompatible Kidney Transplant Program, told the NYT. “What a wonderful day it will be when I can walk into clinic and know I have a kidney for everyone waiting to see me.”
Humans have also conducted numerous experimental pig-organ transplants into primates like baboons. But in order to safely and consistently do it with humans, researchers will have to test the techniques on humans, Caroline Zeiss, a veterinary specialist at Yale School of Medicine, told Nature. For example, doctors found traces of porcine cytomegalovirus (PCMV) in the heart transplant patient who died earlier this year and believe that it may have played a role in his demise, but they won't know for sure without further tests that a primate model — ones that can't be replicated in primates.
Researchers are only looking at “small, focused” clinical trials with “appropriately selected patients,” Allan Kirk, a transplant surgeon at the Duke University School of Medicine, told Nature. Researchers will have to answer a number of fundamental questions before the technology can be widely utilized, as well as determine the right mix of breeding and genetic tinkering needed to ensure that recipients' bodies won't reject them.
And while the decisions made during last week's meeting may not have an immediate impact on the agency's current stance on xenotransplantation, changes are reportedly afoot. The WSJ spoke to a "person familiar with the matter" at the end of June who asserts the FDA is planning to launch pig-organ transplantation trials in an effort ease the shortage of transplantable human organs (*angrily shakes fist at seatbelts*). There's no word on when such trials would launch as they are being handled on a case-by-case basis, the source said.