24 October 1999

New treatments for liver diseases

by Kate Melville

German and Australian scientists are exploring new treatments for liver diseases using gene therapy. The research project aims to develop revolutionary new treatments for malignant diseases such as liver cancer and metabolic diseases such as Wilson's disease.

HepaVec AG, a German based liver disease therapy company last week signed an option agreement with the CSIRO, allowing HepaVec to evaluate and build on research into using a sheep adenovirus as a delivery mechanism to take genes for disease treatment into human cells.

According to says CSIRO Molecular Science Chief, Dr Annabelle Duncan, "Gene therapy offers huge potential to lead to better treatments for a number of diseases. These treatments are designed to be very specific, to go right into the diseased cells themselves and either correct the defects or destroy the cells without affecting healthy tissue. The advantages of this will be that the treatments will be safer, minimally invasive, cause less side effects, and, we hope, that in the case of cancer, it will mean less likelihood of the disease recurring."

Different viruses have different abilities to target certain cell types. Adenoviruses infect both dividing and non-dividing cells from a wide variety of tissues including liver, lung, muscle, breast, prostate and many others. HepaVec and CSIRO have recently shown that sheep adenovirus have been able to safely enter several human cell types, including liver cells and express their cargo genes.

"Adenoviruses are widespread in nature and show a high level of species specificity. Human adenoviruses are common causes of mild upper respiratory infections in humans," explains team-leader, Dr Gerry Both. "Since most people will have been infected at some stage in their life with human adenoviruses they will possess immunity that will limit the use of human viruses for delivery of therapeutic genes. Sheep adenoviruses have never been encountered by humans hence their use as gene delivery vehicles should not be limited by pre-existing immunity. All studies to date would indicate that ovine adenovirus will not cause disease in humans because whilst it can infect human cells it cannot replicate in them", says Dr Both.