David Bennett Sr., the first person in the world to receive a genetically modified pig’s heart, died Tuesday, according to officials at the University of Maryland Medical Center.
Bennett “proved to be a brave and noble patient who fought all the way to the end,” said Bartley P. Griffith Jr., the surgeon who performed the heart transplant. “Mr. Bennett became known by millions of people around the world for his courage and steadfast will to live.”
Bennett’s death is a setback for the accelerating field of xenotransplantation — the process of implanting organs from one species into another. Recent advances, including Bennett’s surgery and kidney transplants into brain-dead humans at NYU Langone Health and the University of Alabama at Birmingham, have been made possible by new technologies. They include CRISPR, the gene-editing tool that was recognized with a Nobel Prize in chemistry in 2020. The organs are modified to make them less foreign to the human recipient, reducing the chance they will be rejected.
Doctors hope the use of organs from genetically altered animals can address the shortage of organs available for transplant.
The need is dire. More than 100,000 patients are on the national transplant waiting list. Seventeen of them die every day awaiting donor organs.
Bennett, who suffered from heart failure and an irregular heartbeat, was deemed ineligible for a conventional human heart transplant. The hospital said he consented to the experimental procedure, which came with “unknown risks and benefits.” The Food and Drug Administration granted emergency authorization for the surgery Dec. 31. It took place a week later.
Xenotransplantation, which involves breeding a genetically modified pig to provide organs that humans are less likely to reject, has raised concerns among animal rights advocates and is closely monitored by ethicists.
Some scientists, particularly in the field of public health, believe the huge investments in xenotransplantation are misplaced. They say money should be devoted instead to preventing and treating the chronic conditions and behaviors such as diabetes, hypertension, obesity and smoking that lead some people to need replacement organs.
Bennett’s surgery became controversial for another reason.
The Post reported shortly after the surgery took place that Bennett was convicted in 1988 of stabbing a man seven times, leaving him paralyzed. A jury acquitted Bennett of intent to murder but found him guilty of battery and carrying a concealed weapon. He was sentenced to 10 years in prison and served six.
The victim, Edward Schumacher, spent 19 years in a wheelchair, suffered a stroke in 2005 and died two years later at 40, The Post reported. University of Maryland Medical Center officials declined in January to say whether they knew about Bennett’s criminal past.
The hospital said Wednesday that Bennett’s heart transplant was initially successful and there were no signs of rejection. He underwent physical therapy and watched the Super Bowl. At the time, the hospital released video of a frail-looking Bennett in his hospital bed singing some of the words to “America the Beautiful” with his therapist.
Before modified pig organs can be offered widely to people through xenotransplantation, the procedure’s safety and efficacy will have to be tested in clinical trials.
With the exception of Bennett’s surgery, for which the FDA granted emergency authorization through its compassionate use provision, the recent kidney transplants have been preclinical trials, performed on brain-dead humans.
Jayme Locke, director of the University of Alabama at Birmingham’s Incompatible Kidney Transplant Program, has said she is hoping to enter phase one clinical trials this year — usually the first phase for testing safety in people. She and her team published the kidney transplantation they performed in September in the American Journal of Transplantation, giving fellow scientists as well as ethicists information that is critical if the field is to advance.
A spokesperson for the University of Maryland Medical Center said Wednesday that Bennett’s medical team is investigating the causes of his death and plans to submit its findings to a peer-reviewed journal. They also plan to pursue clinical trials in the future under the guidance of the FDA.
“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 Muhammad M. Mohiuddin, a professor of surgery and scientific director of the cardiac xenotransplantation program at the University of Maryland School of Medicine. “We remain optimistic and plan on continuing our work in future clinical trials.”