Circadian Technologies' VGX-100 drug inhibits tumour growth

Circadian Technologies (ASX: CIR) has released data demonstrating that its lead anticancer therapeutic, VGX-100, significantly inhibits tumour growth in a variety of different animal models (tumour xenografts) of human cancer.

These data indicate that, if clinically validated, VGX-100 has the potential to be a useful new treatment for some types of cancer.

VGX-100 is a fully human monoclonal antibody targeting the VEGF-C growth factor. VGX-100 inhibits the development of blood vessels that are required for tumour growth. Additionally, VGX-100 may inhibit cancer spread (metastasis) by suppressing the development of lymphatic vessels.

“This is the first substantial data to directly demonstrate that blocking the VEGF-C pathway by VGX-100 can inhibit tumour growth in mouse models of cancer," commented Dr. Megan Baldwin, Head of Preclinical Research and Development and senior author.

"Moreover, our data indicate that VGX-100 can act either by itself or in combination with approved drugs to significantly slow the growth of several different tumour types including prostate, pancreatic, and glioblastoma,” Baldwin added.

Highlights of the data are as follows:

- In a mouse model of human prostate cancer, treatment of animals with a triple combination of VGX-100, Avastin and docetaxel inhibited tumour growth by 83.4%, as compared to only 35.8% in animals treated with Avastin plus docetaxel alone.

In the same study, animals treated with the triple combination were four times as likely to survive until the end of the study as animals treated with docetaxel alone. Survival was increased 2.7 times over animals treated with docetaxel plus Avastin.

40% of animals treated with the triple combination were tumour-free at the conclusion of the study (tumours had been eradicated). This compares to none (0%) that were tumour free among the animals treated with docetaxel plus Avastin and 20% among animals treated with docetaxel alone.

- In a glioblastoma animal model, VGX-100 added to Avastin achieved a statistically significant improvement in tumour growth inhibition compared to untreated animals. The tumours in animals treated with VGX-100 plus Avastin were on average 42% smaller than untreated control animals.

- In a pancreatic cancer model, treatment with VGX-100 inhibited tumour growth similar to
that achieved in animals treated with the drug Avastin.

The data will be presented at the upcoming American Association for Cancer Research Annual
Meeting on 19 April 2010.

Robert Klupacs, CEO of Circadian stated that “we believe that the data we’ve obtained presents a strong case for clinical evaluation of VGX-100 and its possible future use as a new cancer treatment option."

"These data suggest that there may be some cancer indications for which VGX-100 is superior to Avastin – one of the world’s leading anti-cancer drugs - or may be effective where Avastin isn’t."

"It also suggests that there may be cases where adding VGX-100 to Avastin may significantly improve existing therapies,” he added.

Circadian controls exclusive worldwide rights to an extensive intellectual property portfolio enabling it to develop antibodies targeting VEGF-C.

Circadian intends to file an Investigational New Drug (IND) application with the US FDA in the first half of 2011 in order to begin human clinical trials of VGX-100.

This is subject to successfully completing the VGX-100 animal toxicology studies which evaluate whether VGX-100 is safe to be studied in humans.