Saved by the Animals?
As examples, Fano cites the current AIDS epidemic and the swine flu epidemic of 1918, which killed about 20 million people worldwide.
"The promise of xenotransplantation has been clearly exaggerated," Fano says. "There is no question that this process is largely being driven by an irresponsible desire for money."
Still, others maintain that this research should still be pursued despite the questionable motives that have helped fuel the rapid growth of xenotransplantation research.
The immediate promise was exaggerated, agrees Daniel Salomon, MD, a transplant surgeon and associate professor of molecular medicine at the Scripps Research Institute in La Jolla, Calif. But the eventual benefits could still easily outweigh the risks, especially when considering that people already face the risk of contracting an animal virus almost everyday, Salmon says.
"The problem is that we won't know that for sure until we conduct further research," says Salomon, who also serves on two government committees charged with advising federal regulators on how to regulate xenotransplantation. "If you are not doing transplants in humans, it's all talk."
Salomon also points out that other countries are now pursuing xenotransplantation research, meaning that these risks already are being taken without any follow-up to determine whether transplanting animal organs into humans will increase the risk of transferring an animal virus.
"The research is going forward," he tells WebMD. "The fact is researchers in places like Russia or Tijuana don't care what's happening in the U.S. or Europe."
In the U.S. and Europe, health concerns have limited human xenotransplantation research to devices, such as the one currently being developed and tested by Excorp Medical. Because the devices would be used outside the body, the animal cells and the human cells do not come into contact; therefore, these type of devices have not provoked the same level of concern.
Though xenotransplantation trials also have been proposed for the treatment of Parkinson's disease, Huntington's disease, and type 1 diabetes, the chance that federal regulators will allow for mass research into animal-to-human organ transplantation in the near future appears to be ebbing.
"It seems, therefore, that the likelihood of whole-organ xenotransplantation ... being available within a clinically worthwhile time frame may be starting to recede," the advisory committee concluded in a recent report.
Still, it is worth a shot, Salomon tells WebMD.
"[M]y point of view as a transplant surgeon is that we should pursue all venues," he says. "There are always people competing for resources, but until you have met someone waiting for a transplant -- you just can't realize how tragic this organ shortage really is."