The first person to receive a heart transplant from a pig has died, two
months after the groundbreaking experiment, the Maryland hospital that
performed the surgery announced Wednesday.
David Bennett, 57, died Tuesday at the University of Maryland Medical
Center. Doctors didn’t give an exact cause of death, saying only that his
condition had begun deteriorating several days earlier.
Bennett’s son praised the hospital for offering the last-ditch experiment,
saying the family hoped it would help further efforts to end the organ
shortage.
“We are grateful for every innovative moment, every crazy dream, every
sleepless night that went into this historic effort,” David Bennett Jr. said
in a statement released by the University of Maryland School of Medicine.
“We hope this story can be the beginning of hope and not the end.”
Doctors for decades have sought to one day use animal organs for life-saving
transplants. Bennett, a handyman from Hagerstown, Maryland, was a candidate
for this newest attempt only because he otherwise faced certain death —
ineligible for a human heart transplant, bedridden and on life support, and
out of other options.
After the Jan. 7 operation, Bennett’s son told The Associated Press his
father knew there was no guarantee it would work.
Prior attempts at such transplants -- or xenotransplantation -- have failed
largely because patients’ bodies rapidly rejected the animal organ. This
time, the Maryland surgeons used a heart from a gene-edited pig: Scientists
had modified the animal to remove pig genes that trigger the hyper-fast
rejection and add human genes to help the body accept the organ.
At first the pig heart was functioning, and the Maryland hospital issued
periodic updates that Bennett seemed to be slowly recovering. Last month,
the hospital released video of him watching the Super Bowl from his hospital
bed while working with his physical therapist.
Bennett survived significantly longer with the gene-edited pig heart than
one of the last milestones in xenotransplantation -- when Baby Fae, a dying
California infant, lived 21 days with a baboon’s heart in 1984.
“We are devastated by the loss of Mr. Bennett. He proved to be a brave and
noble patient who fought all the way to the end,” Dr. Bartley Griffith, who
performed the surgery at the Baltimore hospital, said in a statement.
Other transplant experts praised the Maryland team’s landmark research and
said Bennett’s death shouldn’t slow the push to figure out how to use animal
organs to save human lives.
“This was a first step into uncharted territory,” said Dr. Robert Montgomery
of NYU Langone Health, a transplant surgeon who received his own heart
transplant. “A tremendous amount of information” will contribute to the next
steps as teams at several transplant centers plan the first clinical trials.
“It was an incredible feat that he was kept alive for two months and was
able to enjoy his family,” Montgomery added.
The need for another source of organs is huge. More than 41,000 transplants
were performed in the U.S. last year, a record -- including about 3,800
heart transplants. But more than 106,000 people remain on the national
waiting list, thousands die every year before getting an organ and thousands
more never even get added to the list, considered too much of a long shot.
The Food and Drug Administration had allowed the dramatic Maryland
experiment under “compassionate use” rules for emergency situations.
Bennett’s doctors said he had heart failure and an irregular heartbeat, plus
a history of not complying with medical instructions. He was deemed
ineligible for a human heart transplant that requires strict use of
immune-suppressing medicines, or the remaining alternative, an implanted
heart pump.
Organ rejection, infections and other complications are risks for any
transplant recipient. Experts hope the Maryland team quickly publishes in a
medical journal exactly how Bennett’s body responded to the pig heart.
From Bennett’s experience, “we have gained invaluable insights learning that
the genetically modified pig heart can function well within the human body
while the immune system is adequately suppressed,” said Dr. Muhammad
Mohiuddin, scientific director of the Maryland university’s animal-to-human
transplant program.
One next question is what evidence, from Bennett’s experience and some other
recent experiments with gene-edited pig organs, may persuade the FDA to
allow a clinical trial — possibly with an organ such as a kidney that isn’t
immediately fatal if it fails.
Twice last fall, Montgomery’s team at NYU got permission from the families
of deceased individuals to temporarily attach a gene-edited pig kidney to
blood vessels outside the body and watch them work before ending life
support. And surgeons at the University of Alabama at Birmingham went a step
further, transplanting a pair of gene-edited pig kidneys into a brain-dead
man in a step-by-step rehearsal for an operation they hope to try in living
patients possibly later this year.
Patients may see Bennett’s death as suggesting a short life-expectancy from
xenotransplantation, but the experience of one desperately ill person cannot
predict how well this procedure ultimately will work, said ethics expert
Karen Maschke of The Hastings Center. That will require careful studies of
multiple patients with similar medical histories.
Transplant centers should start educating their patients now about what to
expect as this science unfolds, said Maschke, who with funding from the
National Institutes of Health is developing ethics and policy
recommendations on who should be allowed in the first studies of pig kidneys
and what they need to know before volunteering.
Pigs have long been used in human medicine, including pig skin grafts and
implantation of pig heart valves. But transplanting entire organs is much
more complex than using highly processed tissue. The gene-edited pigs used
in these experiments were provided by Revivicor, a subsidiary of United
Therapeutics, one of several biotech companies in the running to develop
suitable pig organs for potential human transplant.
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