Pig organs

darted back to the security of mom. Next door, older siblings laid down for a nap or checked out balls and other toys.

“It is luxury for a pig,” Ayares said. “But these are very valuable animals. They’re very smart animals. I’ve watched piglets play with balls together like soccer.”

About 300 pigs of different ages live on this farm, nestled in rolling hills, its exact location undisclosed for security reasons. Tags on their ears identify their genetics.

“There are certain ones I say hi to,” said Suyapa Ball, Revivicor’s head of porcine technology and farm operations, as she rubbed one pig’s back. “You have to give them a good life. They’re giving their lives for us.”

A subset of pigs used for the most critical experiments—those early attempts with people and the FDA-required baboon studies—are housed in more restricted, even cleaner barns.

But in neighboring Christiansburg is the clearest signal that xenotransplantation is entering a new phase— the sheer size of United Therapeutics’ new pathogen-free facility. Inside the 77,000-square-foot building, the company expects to produce about 125 pig organs a year, likely enough to supply clinical trials.

Company video shows piglets running around behind the protective barrier, chewing on toys and nosing balls back and forth.

They were born in sort of a porcine birthing center connected to the facility, weaned a day or two later and moved into their super-clean pens to be handraised. In addition to the onsite shower, their caretakers must put on a new protective suit and mask before entering each suite of pig pens— another precaution against germs.

The pig zone is surrounded on all sides by security and mechanical systems that shield the animals. Outside air enters through multiple filtration systems. Giant vats hold backup supplies of drinking water. Standing over the pig rooms, VonEsch showed how pipes and vents were placed to allow maintenance and repair without any animal contact.

It will take years of clinical trials to prove whether xenotransplantation really could work. But if it succeeds, United Therapeutics’ plan is for even larger facilities, capable of producing up to 2,000 organs a year, in several places around the country.

The field is at a point where multiple kinds of studies “are telling us that there’s no train wrecks, that there’s no immediate rejection,” Ayares said. “The next two or three years are going to be super exciting.”