The UK’s Human Fertilisation and Embryology Authority (HFEA) has agreed in principle to the use of cytoplasmic hybrid embryos for research purposes.

The decision, which was widely expected but condemned by pro-life groups, means the HFEA can now go ahead and assess the licence applications for research projects using cytoplasmic hybrids that were submitted by teams from King’s College London and Newcastle University early this year. The Authority hopes to make a decision on both applications this November.

The tentative approval for cytoplasmic embryo research, which will be assessed on a case-by-case basis, was encouraged by the outcome of a wide-ranging consultation with scientists and the general public on whether there was a case for using hybrid embryos as a source of stem cells to compensate for the current shortage of human eggs available for research.

In the written consultation, 65% of the 810 respondents felt no research using human embryos was acceptable. Moreover, 494 individuals and 33 organisations believed the HFEA should not issue licences for research using cytoplasmic embryos – i.e, those created by replacing the nucleus of an animal egg or a cell derived from an animal embryo with a human cell or the nucleus of a human cell.

Increase in acceptance

In a public opinion poll involving interviews with a sample of 2,073 UK residents, however, there was a marked increase in acceptance of research with cytoplasmic hybrid embryos when people were given a reason for conducting the research. Specifically, only 35% of the poll agreed with scientists creating cytoplasmic human embryos purely for research purposes. but this proportion rose to 61% with the reassurance that the research might help scientists to understand some diseases, such as Parkinson’s and Motor Neurone Disease.

Having examined all of the evidence, the HFEA decided there was “no fundamental reason to prevent cytoplasmic hybrid research.” Nonetheless, it said, public opinion on the issue was “very finely divided with people generally opposed to this research unless it is tightly regulated and it is likely to lead to scientific or medical advancements.”

The decision was “not a total green light for cytoplasmic hybrid research, but recognition that this area of research can, with caution and careful scrutiny, be permitted,” the Authority stressed. “Individual research teams should be able to undertake research projects involving the creation of cytoplasmic hybrid embryos if they can demonstrate, to the satisfaction of an HFEA licence committee, that their planned research project is both necessary and desirable. They must also meet the overall standards required by the HFEA for any embryo research.”

There was also “a clear demand from people to know more about what researchers are doing and their plans for future work, highlighting a need for better communication about science and research from both the scientific community and ourselves as regulator,” the HFEA noted, adding: “In the coming months we will be looking to see how this can be delivered.”

In terms of other types of hybrid and chimera research, “it became very clear that not only did the scientific community not wish to perform such research at present but that the prospect was so distant that they could not envisage what form this research would possibly take in the future,” the Authority stated.

It would be “completely wrong” to make a decision on broader hybrid and chimera research without an adequate evidence base, the HFEA concluded. The Authority would “continue to monitor the potential for this wider research and any emerging evidence through its ‘horizon scanning’ programme.”

Major breakthroughs

Scientists and their political supporters, such as Liberal Democrat MP and House of Commons Science and Technology Committee member Dr Evan Harris, who had pressed for government concessions on hybrid embryo research, welcomed the HFEA’s announcement.

Dr Tony Calland, chairman of the British Medical Association’s Medical Ethics Committee, commented: “This kind of research could lead to major breakthroughs in treatments for Alzheimer’s, Parkinson’s and other serious diseases. We understand people’s initial resistance to the idea of hybrid embryos, but there would be very strict controls on the way they are used. The law already prevents such embryos being implanted in a woman, and they must be destroyed within 14 days. Individual research projects are highly regulated.”

In January this year, the HFEA decided not to rule on the two licence applications for research proposals using hybrid embryos until there had been a “full a proper public debate” on the issue. In April, the Science and Technology Committee criticised the HFEA for deferring judgment on the applications, in a report that called for immediate action to permit research using some forms of human-animal chimera under licence.

More recently, the Joint Committee on the government’s Human Tissues and Embryos (Draft) Bill argued that all types of interspecies embryos should be allowed research licences. The bill, which was presented in May as a sop to the opinions of the Science and Technology Committee on hybrid embryos, accepted in principle that creating interspecies embryos was necessary and acceptable for research purposes, but without a actually including language to that effect in the body of the proposed legislation.

The bill itself listed the following as exceptions to a general prohibition on interspecies embryos (“except in pursuance of a licence”): cytoplasmic hybrids, human transgenic embryos (human embryos that have been altered by the introduction of any sequence of nuclear or mitochondrial DNA of an animal) and human-animal chimera (human embryos that have been altered by the introduction of one or more animal cells). It did not, however, include ‘true’ hybrids created by mixing human and animal gametes.