Goats can be genetically modified to produce a common cancer drug in their milk, which could slash its production costs.
Many of the new blockbuster drugs that are used as cancer treatments are more expensive than older medicines, because they are complex proteins called monoclonal antibodies that are complicated to make.
The bowel cancer drug cetuximab, for example, is produced by mouse cells that have been genetically engineered to make a specific monoclonal antibody. This expensive manufacturing process means the drug, which is sold under the name Erbitux, 拢3000 a month for a single patient in the UK.
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A team led by Goetz Laible at AgResearch, a government-owned research institute in New Zealand, wanted to find out if it could make cetuximab at higher volumes more cheaply 鈥� by genetically engineering goats to produce the protein in their milk.
First, the researchers inserted genes into goat embryos that carried instructions on how to make cetuximab in the mammary glands. Female goats were then impregnated with the embryos and their genetically modified offspring were born five months later.
The offspring were all female and once they began lactating, they were able to produce about 10 grams of cetuximab in each litre of their milk. Since goats produce about 800 litres of milk every year, this means that each could manufacture multiple kilograms of cetuximab in a year.
鈥淚t鈥檚 a lot more economic to make cetuximab in animals because their mammary glands can produce large amounts of proteins,鈥� says Laible. The genetic modification didn鈥檛 appear to affect the goats鈥� health, he adds.
Goats producing multiple kilograms of cetuximab in a year would represent 鈥渆xcellent productivity鈥�, says Stephen Mahler at the University of Queensland, Australia. The same process could potentially be used to manufacture other monoclonal antibody drugs, says Mahler.
However, one challenge will be ensuring that drugs derived from animal milk have the same standard and purity as those made in cells, he says.
Laible and his colleagues are now hoping to test the goat-derived cetuximab in people to confirm that it is as safe and effective as the original product. If it is approved for human use, it could make the drug cheaper and more accessible, he says. 鈥淭hat鈥檚 the main driver for our research.鈥�
搁别蹿别谤别苍肠别:听bioRxix, DOI:
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