Oxford Biomedica and Viragen have announced a breakthrough in transgenic research in which scientists have successfully achieved expression of significant quantities of a human protein in hens that is a key component of the human immune system and is the active ingredient in several leading multiple sclerosis (MS) therapies.
Certain biotech drugs require post-translational modifications in order that the drug retains its full efficacy and is well tolerated when used as a human therapeutic and this latest achievement could well have implications in developing a viable, cost-effective, transgenic bio-manufacturing system.
The collaborators managed to express significant quantities of the human protein, interferon beta-1a, in the whites of eggs laid by transgenic hens using the OVA System (Avian Transgenic Biomanufacturing) that employs Oxford BioMedica's LentiVector technology.
The OVA System is the result of a project, which was designed to develop the chicken into a pharmaceutical bioreactor, one that can meet the growing need for protein-based human therapeutics.
The system is based on the creation of lines of transgenic hens, which have been engineered to produce a target protein in their eggs using the LentiVector gene delivery system licensed from Oxford BioMedica,
"This achievement positions the OVA System as a revolutionary transgenic bio-manufacturing alternative," said Karen Jervis, vice president and managing director of Viragen.
"We will continue to collect eggs from these hens and subsequent generations to confirm quality and quantity of the protein. In addition, we will be analysing the carbohydrate profile of the product, which may represent an advantage to OVA-expressed proteins," she added.
To get an idea of the potential of this discovery, it is conceivable that a small flock of a couple of hundred hens could satisfy the entire US market demand for interferon beta-1a.
These figures are preliminary, but suggest why this technology might be so desirable to a company seeking new benefits in the manufacturing of current and future products.
Oxford BioMedica's LentiVector gene delivery technology is based on lentiviruses and is available for treating a range of diseases, particularly those of the central nervous system. The lentiviral vectors are able to deliver genes in a variety of dividing and non-dividing cells, including neurons in the brain.
The technology has proved useful for production of lentiviral vector gene delivery systems of both human and non-human origin for diseases such as Parkinson's disease, retinopathy, motor neuron disease, spinal muscular atrophy and nerve repair.
"This is the second protein candidate with which we have achieved promising results, as we previously reported expression and recovery of a functional humanised antibody," said Helen Sang of Scotland's Roslin Institute and the Project's Scientific Leader.
"As we fully characterise the interferon beta that is recovered, both biochemically and by functional tests, we expect such results will confirm our progress."
The results are the first in a series of anticipated milestones demonstrating "Proof-of-Principle" with an avian-expressed version of interferon beta.
Viragen and Roslin are currently conducting avian expression studies on various protein candidates including interferon beta-1a, which is currently marketed under two competing brand names for the treatment of MS.
These MS products are Avonex, marketed by Biogen Idec, and Rebif, marketed by Serono.