Pig heart transplants could be offered more widely to patients in the US as health chiefs consider green-lighting clinical trials of the controversial operations.
The Food and Drug Administration (FDA) is said to be drawing up plans to make it easier for researchers to study a larger number of patients.
So far there have only a handful of one-off xenotransplantations, which are seen as a potential fix for the deadly shortage of human donors.
There was excitement earlier this year