BLACKSBURG, Va. — Some people who develop a weird and terrifying allergy to red meat after a bite from a lone star tick can still eat pork from a surprising source: Genetically modified pigs created for organ transplant research.
It cannot be found in grocery stores or restaurants. Revivicor, the company that bred these special pigs, shares its small supply, at no cost, with patients suffering from allergies to red meat.
“We get hundreds and hundreds of orders,” said David Ayares, who heads Revivicor, as he opened a freezer jammed with packages of ground pork patties, ham, ribs and pork chops.
The allergy is called alpha-gal syndrome, named for a sugar present in the tissues of nearly all mammals — except for people and some of our primate cousins. It can cause a serious reaction hours after eating beef, pork, red meat or certain mammalian products such as milk or gelatin.
But where does organ transplantation come into the picture? There are nowhere close to enough donated human organs to go around, so researchers are working to use organs from pigs instead — and that same alpha-gal sugar is a big barrier. It causes the human immune system to destroy a transplanted organ from an ordinary pig immediately. So, the first gene that Revivicor inactivated as it began genetically modifying pigs for animal-to-human transplants was the one that produces alpha-gal.
While xenotransplants are still in the experimental stages, Revivicor’s “GalSafe” pigs won the Food and Drug Administration approval in 2020 to be used as a food source and a potential source for human therapeutics. The FDA determined no detectable alpha-gal level across multiple generations of the pigs.
Revivicor, a subsidiary of United Therapeutics, isn’t a food company — it researches xenotransplantation. Nor has it yet found anyone in the agriculture business interested in selling GalSafe pork.
Still, “this is a research pig that FDA approved, so let’s get it to the patients,” is how Ayares describes beginning the shipments a few years ago.
Revivicor’s GalSafe herd is housed in Iowa. To keep its numbers in check, some meat is periodically processed in a slaughterhouse certified by the U.S. Agriculture Department. Revivicor then mails frozen shipments to alpha-gal syndrome patients who have filled out applications for the pork.
Thank-you letters relating the joy of eating bacon again line a bulletin board near the freezer in Revivicor’s corporate office.
Separately, pigs with various gene modifications for xenotransplant research live on a Revivicor farm in Virginia, including a GalSafe pig that was the source for a recent experimental kidney transplant at The New York University Langone Transplant Institute.
And that begs the question: Could the pig be used for meat after removing transplantable organs?
No. “The strong anesthesia used so the animals feel no pain during organ removal means they don’t meet United States Department of Agriculture rules for drug-free food,” said United Therapeutics spokesman Dewey Steadman.