Genetically engineered rabbits which could be milked to churn out a potentially lifesaving drug have been created by researchers.
And Dutch farmers are set to start commercially milking rabbits, pending authorization from European authorities.
Developed by Netherlands-based biotech firm Pharming, the rabbits have been outfitted with a human gene that produces a protein called C1 inhibitor.
A drug made from the protein can be used to treat people with hereditary angioedema.
People suffering from this condition have naturally low levels of C1 inhibitor, which can result in episodes of severe swelling, similar to an allergic reaction.
Untreated, angioedema can cause painful cramps and potentially fatal suffocation. Unlike drugs that can be made synthetically in the lab, therapeutic proteins need to be made by biological processes, making transgenic animals a popular option.
For example, a rabbit can produce an average of 120 milliliters of milk a day.
Pharming spokesperson Marjolein van Helmond said that in the modified rabbits, each litre contains 12 grams of human C1 inhibitor.
"Human C1 inhibitor can be obtained from donor blood, but our ... product can be produced in unlimited quantities from a scaleable and stable production system, and there are no safety issues in terms of [blood] viruses," National Geographic News quoted van Helmond as saying.
Pharming has been milking rabbits experimentally for years, and recently developed a drug called Rhucin from the rabbit milk-derived C1 inhibitor protein.
If the drug is approved in Europe, Pharming would start milking a herd of about a thousand rabbits, according to an email from company CEO Sijmen de Vries.
The rabbits are milked using mini pumping machines that attach to the female rabbits' teats.
Researchers then extract the protein in the lab.