The experimental drug that donald trump said cured him of coronavirus was tested using cells originally derived from an aborted foetus a practice his administration has tried to restrict.

The cocktail of antibodies made by the us company regeneron was tested on cells from the hek293t cell line, which was developed from stem cells first taken from aborted human tissue.

The us president on wednesday touted the treatment as a cure for coronavirus. but his administration cut funding for the kind of research that enabled the antibody treatment to be tested, a move that was praised by pro-life campaigners but widely condemned by scientific researchers.

Regeneron said on thursday: we did use the hek293t cell line to test our antibodies ability to neutralise the sars-cov-2 virus.

It added: hek293t wasnt used in any other way, and foetal tissue was not used in this research.we did not use human stem cells or human embryonic stem cells in the development of regn-cov2.

Mr trump has raved about the possibilities of regenerons treatment since leaving hospital on monday. in a video released on wednesday, he said he had given it his authorisation, even though the food and drug administration is still deciding whether to give it a green light for emergency use.

Line chart of share price, $ showing regeneron pharmaceuticals shares are up about 60% this year

The drug uses antibodies taken from a mouse and a human who recovered from coronavirus. it was tested using cells from the hek293t line, which was initially derived from stem cells first taken from the kidney of a foetus which was aborted in the netherlands in the 1970s.

Those cells were used to make a fake virus which mimicked the spike protein of the coronavirus to test the treatments ability to counteract it.

Hek293s are commonly used in drug development across the industry, but the research that made them possible has in recent years been one of the most politically sensitive elements of drug development.

Last year, the health department moved to restrict federal funding for studies using foetal tissue, saying that any such research would have to be approved by an ethics board before receiving government money.

The department said at the time: promoting the dignity of human life from conception to natural death is one of the very top priorities of president trumps administration.

Last years policy change would not have restricted any research by regeneron, as an exception was granted for work relying on cells that had been taken from foetuses in the administration official said:a product made using extant cell lines that existed before june 5 2019 would not implicate the administrations policy on the use of human foetal tissue from elective abortions.

In august, the boardrejected 13 of the 14 proposalsthat included foetal tissue, approving one where the tissue had already been acquired and no more would be needed to complete the research.