David Bennett, the world’s first human to receive a genetically modified pig heart, has died just two months following the historic transplantation. Doctors at the University of Maryland Medical Center, where the surgery was performed, announced his passing Wednesday morning. At this time, the cause of death is reportedly unclear.
Bennett, 57, received the heart on January 7, which was announced by the University of Maryland three days later. He had been diagnosed with a terminal heart condition and bedridden for months, but his severe arrhythmia (an irregular heartbeat that can predispose people to heart attack or other cardiac illness) made him unsuitable for conventional treatments like a heart pump or heart transplant.
In recent months, other research teams have started to perform experimental transplants of organs obtained from genetically engineered pigs designed to be compatible with humans—in theory overcoming the hurdles that have long made animal-to-human transplants unsafe and unsuccessful. These experiments had only involved humans who were brain dead, though, and the transplants were not intended to save or prolong their lives. Similarly, transplanting a modified pig heart into Bennett, which was not expected to significantly extend his life, remains a success as it proves that the procedure is possible.
Several years earlier, researchers at the University of Maryland Medical Center had begun their own cardiac xenotransplantation program. And on New Year’s Eve, they obtained special permission from the Food and Drug Administration to perform a transplant on Bennett as a last-resort treatment, effectively making him the first living human to receive one of these engineered organs. These pigs and their organs have so far all been produced by the company Revivicor.
The surgery appeared to go well, without any major short-term complications, such as signs of acute rejection, though Bennett continued to need hospital care. In mid-February, his doctors reported that the new heart still looked healthy, and he had recovered enough to enjoy the Super Bowl. Unfortunately, his health had severely worsened in recent days, and the decision was made to offer him palliative care. On Tuesday afternoon, March 8, Bennett died, though he was reportedly communicative enough to speak with his family during his final hours.
“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. We extend our sincerest condolences to his family,” said Bartley Griffith, the lead surgeon on Bennett’s transplant, in a statement from the university.
A hospital spokesperson told USA Today Wednesday that there was no immediately clear cause of Bennett’s death, though his doctors do plan to review the case and publish all their findings in a peer-reviewed journal. It’s expected that much will be gleaned from Bennett’s experience, despite the tragic end.
“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 Mohiuddin, another of Bennett’s doctors, in a statement. “We remain optimistic and plan on continuing our work in future clinical trials.”
Even prior to the transplant, Bennett appeared to fully acknowledge the risks and limitations of the surgery, stating, “I know it’s a shot in the dark, but it’s my last choice.”