washington

A US advocacy group that opposes xenotransplantation threatened last week to sue the Department of Health and Human Services (DHHS) for failing to respond to a legal petition demanding a ban on the practice because of its potential health risks.

The New York-based Campaign for Responsible Transplantation (CRT) filed a petition in December asking the DHHS to ban animal-to-human transplants of cells, tissues and organs.

The legal deadline for the department's response was 10 June. If the DHHS does not respond by 17 August, says CRT, the group will sue for breach of the Administrative Procedures Act. This law allows courts to compel government agencies to take action when this has been “unreasonably delayed”.

Lorrie McHugh, a DHHS spokeswoman, says, “We want to be as responsive as possible to the campaign”. She says that the DHHS is preparing an interagency response to the group's “very complicated legal document”. The respondents include the Food and Drug Administration and the National Institutes of Health.

CRT says that xenotransplantation poses unacceptable risks because of the danger of the transfer of deadly animal viruses to humans. In April, the Food and Drug Administration announced a de facto ban on xenotransplants from non-human primates, but left the way open for the development of transplants from pigs (see Nature 398, 549; 1999).