Kiwi researchers are hopeful that goats will become cheap sources of costly cancer drugs.
The high cost of lifesaving cancer drugs has been in the news lately. But as Pharmac prepares to fund one of the latest, there is news that some already widely used medicines may soon be significantly cheaper thanks to milk from New Zealand goats.
Until a drug comes off patent – generally 20 years after its invention – Pharmac often has to negotiate the price with the pharmaceutical company that developed it, which understandably wants to offset its costs and turn a profit. Once it’s off patent, anyone can produce the drug, but typically this is expensive.
Now AgResearch and a University of Auckland team led by Professor Peter Shepherd have joined forces in a bid to produce cheaper, effective anti-cancer drugs from an antibody in the milk of transgenic dairy goats.
New Zealand is well positioned for this kind of work, says Shepherd. “We have such fantastic ability in animal reproductive technology and we’re free of harmful animal diseases that are endemic in other parts of the world. Plus we’re very good at processing milk.”
The drug that researchers are focusing on initially is Cetuximab, which treats a wide range of metastatic cancers, including breast and lung. This is one of a class of drugs, delivered intravenously or by injection, that use mono-clonal antibodies to fight cancer in several ways. They work by preventing growth signals getting through to cancer cells, making them more visible to the immune system and slowing the delivery of oxygen and nutrients to them. They can also be used to deliver radiation and drugs to cancer cells.
In a biotech process developed by AgResearch, goats are primed to produce these monoclonal antibodies. The antibody is inserted into the animal’s DNA at the embryo stage so the goat develops with that gene and produces the drug as a milk protein when it matures and lactates.
The university researchers are looking at the best methods of extracting and purifying the drug as well as testing its efficacy compared with the version produced by traditional methods.
“Most of the rest of the world grows human cells in a dish and genetically engineers them to make the antibody. It’s expensive and time-consuming,” says Shepherd. “It’s possible that the goat’s milk antibody may be more effective because of the way it’s produced – we don’t know yet.”
Other drugs in their sights include breast cancer treatment Herceptin and Rituximab, which is used to treat non-Hodgkin’s lymphoma. Another potential candidate, when it comes off patent, is the expensive melanoma drug Keytruda, which has been the cause of recent controversy over Pharmac’s refusal to fund it.
“You would only need 100 milking goats to supply the world’s demand for Cetuximab as they produce a lot of the antibody,” says Shepherd. “And then you’d go on to the next drug and need 100 milking goats for that. So since production costs would be low, it has the potential to significantly lower the price of the drugs. The aim is to eventually build an industry based on this in New Zealand.”
Progress is expected to be relatively fast. “The drug is there in the goats already,” says Shepherd. “We’d hope to have the antibody out and purified in a way we can test it on cancer cells this year.”
This project is part of a bigger push to identify skills in agricultural technologies that can be exploited to improve human health. “We’re looking at how we can benefit from each other’s knowledge,” says Shepherd. “One problem in this country is that we’re not blessed with huge levels of scientific funding. If we’re going to make progress, we have to find ways to work together and make the most of our limited resources.”