The Pune-based vaccine manufacturer Serum Institute of India will be conducting clinical studies on eight protein drugs including EPO, GCSF, Doxorubicin, flu and pneumococcal vaccines.

These drugs have been developed using the patented polymer conjugation technology like PolyXen and ImuXen provided by the London-based Lipoxen Technologies Ltd.

Dr. Gregory Gregoriadis, Chief Scientific Officer and Founder-Director of Lipoxen Technologies, told Pharmabiz that by using the technologies like PolyXen and ImuXen, the proteins, conjugated or linked to polymers like polysalic acid (PolyXen) or lyposomes (ImuXen), which enhances the life of the protein like EPO or a vaccine, are retained in the body for a longer time, protects from degradation in blood and generates lesser antibody resistance, compared to a protein which is not conjugated. Dr Gregory spoke to Pharmabiz while his recent visit to Mumbai for a scientific discussion with Serum.

Lipoxen will transfer the technology to Serum Institute, and is currently providing the technological know how to the Serum scientists.

"Serum is expected to complete clinical trials on protein drugs like EPO, G-CSF, Doxirubicin, flu and Pneumococcal vaccines by early 2006," said Dr. Gregoriadis.

"The technology was quite promising on animals. If the trials are successful, serum will be able to market the products in India, Africa, Asia (except Japan) and Latin America. Lipoxen will control the marketing rights for Europe and the US," he said.

Generally, in PolyXen, the protein is conjugated with polysalic acid, which increases the molecular mass of the molecule. In case of ImuXen (for DNA vaccines), the DNA of the virus (which produces the antigen) and the antigen itself are entrapped within Lyposomes.

There is also technology provided by Lipoxen, which combines the two technologies. For example, a protein like Doxorubicin is entrapped in lyposome, which is further coated with polysalic acid.

The method Pegylation is similar to PolyXen or ImuXen. The EPOs and G-CSFs that are available in the market are often pegylated. In pegylation, polyethylene glycol (PEG) is attached to a protein molecule in order to extend its life.

However, according to Dr. Gregoriadis, PEG is non-biodegradable whereas polysalic acid and liposome are biodegradable. Therefore, in the long run, the body could be prone to toxic effects of PEG, if proteins like insulin and epo (which have to be taken on a life long basis) are coated with PEG, he said.