The first person to receive a heart transplant from a pig has died two months after undergoing the groundbreaking surgery, it has been confirmed.
Doctors at the University of Maryland Medical Center announced that David Bennett, 57, had passed away on Tuesday, though no exact cause of death was given.
His condition began to deteriorate several days ago - but he was able to speak with his family during his final hours, the hospital said.
Mr Bennett's son, David Jr, praised the doctors for the last-ditch experiment to save his father, who had been bedridden and on life-support, facing an otherwise certain death as he was ineligible for a human heart transplant.
"We are grateful for every innovative moment, every crazy dream, every sleepless night that went into this historic effort," Mr Bennett Jr said in a statement released by the University of Maryland School of Medicine.
He added: "We hope this story can be the beginning of hope and not the end."
After the operation in January, doctors said the transplant showed a heart from a genetically modified animal can function in the human body without immediate rejection, marking a step in a decades-long quest to use animal organs for life-saving transplants.
Mr Bennett Jr said at the time his father knew there was no guarantee the operation would work, with prior attempts at such transplants having failed largely because patients' bodies rapidly rejected the animal organ.
Baby Fae, a dying California infant, lived only 21 days with a baboon's heart in 1984.
This time, the surgeons had used a heart from a gene-edited pig that had been modified to remove genes that trigger the hyper-fast organ rejection.
At first the pig heart was functioning, and Bennett seemed to be slowly recovering, - last month, the hospital released a video of him watching the Super Bowl from his hospital bed.