The health regulator in the USA is considering whether clinical trials of mitochondrial replacement (MR) techniques should go ahead.
The Food and Drug Administration (FDA) received a request to conduct trials from Dr Shoukhrat Mitalipov of Oregon Health and Science University, who used a MR technique last year to create early human embryos (reported in BioNews 679) and in 2009 to create rhesus monkeys (reported in BioNews 523). The FDA began to regulate the techniques in 2001 as a form of gene therapy, reports Nature News, but had not until now received a request to conduct trials because of safety concerns, it said.
Dr Mitalipov now wants to conduct clinical trials of the techniques in humans and suggests that if the trial is not permitted, his team could continue the research outside the USA.
About one in 4,000 children in the USA will develop mitochondrial disease by the age of 10. In many cases, there is no cure or treatment and the disease can be fatal. But the techniques being developed to prevent the transmission of mitochondrial disease have also raised a variety of ethical and safety concerns (see BioNews 661).
When Dr Mitalipov used a MR technique last year to create early human embryos, genetic abnormalities were detected in half of them, Nature reported - although 20 percent of the eggs produced embryos that would have been suitable for transplantation, if permitted. Other safety concerns have been raised since then (reported in BioNews 723).
'If mistakes are made, if that child [is a girl and] has children down the line, those children will inherit the mitochondria from that child, and we'll have introduced new genetic diseases into the human population', said Professor Ronald Green, a bioethicist at Dartmouth College in New Hampshire.
However, Dr Mitalipov said last year that although the MR technique used needs further refinement, it is ready for the clinic. 'You can expect the first healthy child to be born [using this method] within three years', Nature reported him as saying at the time. He also points out that the rhesus monkeys are doing well, reported The Scientist.
The FDA was due to meet on 22 October to discuss these issues and to decide whether to permit the initial clinical trials, but the meeting has been postponed because of the recent government shutdown. The FDA published draft guidance on the design of early-phase clinical trials of cellular and gene therapy products in July this year, which it is scheduled to consider.
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