Surgeons in Baltimore have transplanted the heart of a genetically altered pig into a man with terminal heart disease who had no other hope for treatment, the University of Maryland Medical Center announced on Friday.
It is the second such procedure performed by the surgeons. The first patient, David Bennett, 57, died two months after his transplant, but the pig heart functioned well and there were no signs of acute organ rejection, a major risk in such procedures.
The second patient, Lawrence Faucette, 58, a Navy veteran and married father of two in Frederick, Md., underwent the transplant surgery on Wednesday and is “recovering well and communicating with his loved ones,” the medical center said in a statement.
Mr. Faucette, who had terminal heart disease and other complicated medical conditions, was so sick that he had been rejected from all transplant programs that use human donor organs.
“At least now I have hope and I have a chance,” Mr. Faucette said before the surgery. “I will fight tooth and nail for every breath I can take.”
The transplantation was performed by Dr. Bartley Griffith, who operated on the first patient. Dr. Muhammad Mohiuddin, of the University of Maryland School of Medicine, designed the protocol.
Mr. Bennett died after multiple complications, and traces of a virus that infects pigs were found in his new heart, raising concerns that so-called xenotransplants of organs from animals to people could introduce new pathogens into the human population.
Hospital officials said they repeatedly tested the pig used in the transplant last week for both the virus, called porcine cytomegalovirus, and antibodies using a new assay that was not available at the time of Mr. Bennett’s transplant.
Before undergoing the transplant, Mr. Faucette said he recognized that it would be a miracle if he was able to leave the hospital and go home, and another miracle if he lived for months or a year longer.
“Realistically, this is in the early-stage learning process,” he said of the procedure.
In recent years, the science of xenotransplantation has taken huge strides with gene editing and cloning technologies designed to make animal organs less likely to be rejected by the human immune system.
Although the advances are still in nascent stages, they offer hope to the more than 100,000 Americans who are living with end-stage organ disease yet face an acute shortage of human donor organs. Most of those waiting for an organ need a kidney, but fewer than 25,000 kidney transplants are performed each year and thousands die on waiting lists.
Transplant surgeons at the University of Alabama at Birmingham and NYU Langone Health have transplanted kidneys from genetically modified pigs into brain-dead patients maintained on ventilators, demonstrating that the kidneys can make urine and perform other essential biological functions without being rejected.
“There is a growing need for organs and for people with end-stage organ failure who are out of options,” said Dr. Jay Fishman, a professor of medicine at Harvard and associate director of the Transplant Center at Massachusetts General Hospital.
“While decedent trials are informative, transplants in living recipients are, of course, most relevant to advancing knowledge in the field,” Dr. Fishman added. He said he was optimistic that the surgery would encourage scientists to enter the field and accelerate the path to clinical trials.
The heart transplanted into Mr. Faucette came from a pig that had received 10 genetic modifications. Scientists removed three pig genes that cause rapid rejection of pig organs by the human immune system, while inserting six human genes that allow the immune system to accept the organ.
An additional pig gene, responsible for the heart’s growth, was knocked out to prevent the organ from becoming too large.
The genetically altered pig was provided by Revivicor, a regenerative medicine company based in Blacksburg, Va., that is a subsidiary of United Therapeutics Corporation. Before the transplant, the pig was screened for viruses, bacteria and parasites.
The Food and Drug Administration granted emergency approval to the transplant last week under a “compassionate use” process that allows experimental procedures to be performed on a single patient who has a life-threatening condition.
Mr. Faucette is also receiving an experimental new antibody therapy developed by Eledon Pharmaceuticals called tegoprubart, which blocks a protein involved in the activation of the immune system. Other conventional drugs are also being used to suppress his immune system and prevent rejection of the organ.
Mr. Faucette’s wife, Ann, said the two were keeping expectations low and just hoping for some more time together. “That could be as simple as sitting on the front porch and having coffee together,” she said.