A woman from New Jersey has died less than three months after becoming the second person in history to receive a genetically modified pig kidney transplant. Lisa Pisano underwent the historic procedure in April as an experimental last resort for severe illness, but had to have the porcine organ removed 47 days later.

The 54-year-old made history as the first person ever to receive both a heart pump and a kidney transplant after both organs failed. Typically, patients with heart pumps are not considered for new kidneys, although doctors decided to go ahead with the operation using a livestock organ.

At present, there are more than 100,000 people in desperate need of organ transplants in the US alone, with the greatest demand being for kidneys. Tragically, 17 people die each day while on the waiting list, which is why researchers are so keen to master the art of xenotransplantation, which refers to the use of animal organs in human patients.

The difficulty, however, lies in the fact that our bodies are primed to reject any non-human components. To overcome this hurdle, scientists have been using CRISPR gene-editing technology to tweak livestock organs so that they become more acceptable to our immune system.

For instance, pig organs have been modified to prevent them from producing a molecule called alpha-gal, which our bodies recognize as foreign before triggering an antibody response to destroy it.

After transplanting the edited kidney into Pisano’s body, doctors reported that the organ had not been rejected, indicating that their modifications had been successful. Sadly, however, the kidney failed due to insufficient blood supply as a result of the patient’s heart pump.

As a consequence, surgeons at NYU Langone Health – where the transplant was performed – decided to remove the organ after less than seven weeks, placing Pisano on dialysis. Earlier this week, it was announced that she had passed away.

“Lisa’s contributions to medicine, surgery and xenotransplantation cannot be overstated,” Dr. Robert Montgomery, director of the NYU Langone Transplant Institute, told the New York Times. “Her bravery gave hope to thousands of people living with end-stage kidney or heart failure who could soon benefit from an alternative supply of organs.”

Sadly, Pisano’s passing comes just two months after the death of the first patient to receive a modified pig kidney. Richard Slayman entered the history books in March of this year when he underwent the transplant at Mass General Brigham in Boston, and while initial signs showed that the procedure had been successful, the patient later experienced complications and died in early May.