With any organ transplant, doctors are trying to balance ways to prevent infection while suppressing the immune system. Without immunosuppressants, the transplanted organ will be rejected. However, giving too many of these drugs to patients can make them more susceptible to infections.
Researchers think that’s what happened in Bennett’s case. To treat the CMV infection, doctors gave Bennett a treatment called intravenous immunoglobulin, which is intended for patients with weakened immune systems, including transplant patients. The treatment, enriched with antibodies from thousands of human donors, likely contained natural antibodies that attack the pigs’ organs and damage muscle cells.
Doctors in Maryland are taking steps to ensure Fawcett’s new heart won’t be rejected. As an example, they told WIRED in December that they had developed a new, more sensitive test to detect very small amounts of swine virus DNA. Before the latest transplant, they routinely tested the donor pigs for CMV and other swine viruses, bacteria and parasites. “At this time, we have no reason to believe that this donor pig is infected with porcine PCMV, which is the virus identified in our first xenograft recipient,” a university spokesperson said in an email. told WIRED.
Doctors are treating Fawcett with traditional immunosuppressive drugs in addition to an investigational antibody therapy called Tegopulvert, developed by California biotech company Eledon Pharmaceuticals. The drug works by blocking CD154, a protein involved in immune rejection, and is administered by infusion every three weeks. Like other immunosuppressants, Fawcett will have to take it for the rest of his life to ensure his new heart doesn’t get rejected. “Blocking this receptor is very effective in preventing transplant rejection,” says Steve Perrin, president and chief scientific officer of Eledon.
When Maryland surgeons performed Bennett’s transplant in January 2022, Eledon’s drug was not available because it had not yet been tested in humans. More than 100 people are currently receiving the drug in early clinical trials. Tegopulvert has also been tested in non-human primates and has been shown to extend the lifespan of transplanted pig organs in those animals.
The next few weeks will be critical to determining whether the transplanted pig’s heart will continue to function properly. “We’re hopeful that this is the right treatment for these patients and that they can live longer with their xenografts,” said Jamie Locke, an abdominal transplant surgeon at the University of Alabama at Birmingham. Involved in a heart attack. In August, Rock’s team published research They showed that genetically modified pig kidneys functioned normally for one week in brain-dead patients.
In another xenotransplant experiment, a team from New York University Langone College announced earlier this month The brain-dead pig’s kidneys were kept functioning for two months.
The U.S. Food and Drug Administration granted emergency approval for Fawcett’s surgery earlier this month through the “compassionate use” pathway. The process, which was also used for Bennett’s transplant, is applied when an unapproved medical product, in this case a genetically modified pig heart, is the only option for a patient with a serious or life-threatening condition.
Pearson believes these individual cases of pig-to-human transplantation can help generate the evidence needed for more formal clinical trials involving multiple patients. He is optimistic that the pig’s heart will work longer in this second patient of his. “Full stop,” he says. “It may not work every time, but you will learn a lot from these one-offs.”