Data describe selectivity, efficacy, lack of toxicity of oncolytic adenovirus.

2004 SEP 18 - (NewsRx.com & NewsRx.net) -- Geron Corp. (GERN) announced the publication of research demonstrating selectivity, efficacy, and lack of toxicity of an oncolytic virus containing the human telomerase promoter.

The work was published in the August 2004 issue of Cancer Gene Therapy by scientists from Genetic Therapy, Inc., (an affiliate of Novartis, AG) and Cell Genesys, Inc.

Oncolytic viruses are designed to treat cancer by employing the natural properties of lytic viruses - they invade cells, replicate inside the cell until it is destroyed, and then spread to adjacent cells where the process is repeated. In one class of oncolytic virus, the virus is engineered using a promoter that is preferentially active in tumor cells to control expression of a gene necessary for viral replication. The result is that the virus replicates in - and kills - cancer cells without damaging most other cells.

The new publication describes an oncolytic adenovirus (CG 4030) that contains 2 tumor-selective promoters, each driving a gene in the virus that is required for viral replication: the telomerase promoter (active in over 90% of all human cancers) driving the viral E4 gene, and the E2F-1 promoter (active in tumors that have a defective Rb pathway, approximately 85% of all human cancers) driving the E1A gene. In vitro assays showed the virus killed multiple human cancer cell lines while having little effect on normal cells, including cultures of primary liver cells. This virus was significantly less toxic in normal liver cells than an earlier version which did not contain the telomerase promoter.

The researchers administered the virus intravenously to mice and found it to be well-tolerated, as well as less toxic than the ...