The Sunday Times September 17, 2006
'Pharm' goats give birth to new drugs
Jonathan Leake, Science Editor
BRITISH patients could soon be using the world’s first medicine derived from transgenic animals after European regulators approved a drug produced by genetically modified goats.
The pioneering drug, an anti-clotting agent for people with a rare inherited disease, is made from the milk of goats whose DNA has been modified to incorporate human genes.
The drug, ATryn, sets a precedent for using modified animal proteins, and despite protests from animal welfare campaigners that “Frankendrugs” are ethically unjustifiable, the technology is sure to take off.
Drug companies have long suspected that there is profit in turning farm animals into pharmaceutical “factories”, a process known as pharming.
In theory, pharmed animals could also be used to produce insulin for diabetics, blood-clotting factor to treat haemophiliacs and a range of other proteins.
Pharming could become integral to the drugs industry if the costs fall substantially below those for current production systems. Chickens, cows, rabbits are already undergoing trials.
However, proposals to modify pigs with human genes so their organs could be transplanted into people have largely been abandoned for fear of transmitting viruses.
ATryn was developed to treat patients with hereditary antithrombin deficiency (HAD), which makes people vulnerable to deep-vein thrombosis. Tom Newberry, a spokesman for GTC Biotherapeutics, the American company that developed the drug, said it would be available in Britain and Europe from mid-2007. “This process has the potential to revolutionise the pharmaceutical industry,” he said.
Conventional methods of creating blood proteins — such as insulin, growth hormone and antithrombin from donated blood and body tissues — are vulnerable to the risk of infection.
In one case, thousands of haemophiliacs contracted HIV when they were given clotting factors from infected donors. In the 1980s such scandals prompted the creation of a new system of “bioreactors” in which cells, usually taken from the ovaries of Chinese hamsters, were genetically modified to produce a human protein and then cultured.
This system has worked well for about two decades, but it is hard for such cells to make protein molecules, especially larger ones, with exactly the right properties. It is also expensive to produce large amounts.
GTC created the first transgenic goats 15 years ago by taking fertilised goat egg cells and injecting them with the human gene for the antithrombin protein. The gene incorporated itself into the DNA of the embryonic goats, which were then implanted in surrogate mothers.
Another biotech company, the Dutch firm Pharming, is close to bringing drugs to market. Last month it lodged an application with the European Medicines Agency, the body that approved ATryn, for a second drug derived from transgenic animals.
Its drug, Rhucin, is intended to treat hereditary angioedema, a disease characterised by the painful, and sometimes fatal, swelling of soft tissues.
Transgenic animals are a mainstay of medical research: mice and rats are already used to test the function of various genes.
Professor Steve Brown, director of the Medical Research Council’s mammalian genetics unit at Harwell, Oxfordshire, said such research was shedding light on diseases ranging from cancer to deafness in children.
“We have, for example, identified the mouse genes that cause a condition analogous to glue ear in humans,” he said. “In 10 years we will have real insight into many more conditions.”
Others are uneasy at turning animals into research tools and drug factories. Genewatch, a campaign group that tracks developments in genetic engineering, said in a report: “This represents a further step towards seeing animals purely as commodities without regard for their inherent worth as sentient beings.”
However, even the protesters might approve of research at Minos BioSystems, a British biotech company. It plans to produce drugs from insect larvae. In a business plan reminiscent of the sci-fi horror film The Fly, the company proposes creating house flies with human genes to produce human blood protein.