Australian researchers today presented the first evidence of a drug that attacks a key part of cancer cells, thought to be fundamental to the survival of most cancer cells in humans.

The drug is phenoxodiol, an anti-cancer drug currently being tested in humans with a broad range of cancers. Phenoxodiol is being developed by Australian pharmaceutical company, Novogen Limited.

The announcement was made by Professor Mathew Vadas, at the Federation of American Societies for Experimental Biology conference in Tucson, Arizona.

Professor Vadas works from the Division of Human Immunology, Hanson Centre for Cancer Research, in Adelaide.

Professor Vadas presented data from studies conducted by his group showing that phenoxodiol is a potent inhibitor of the enzyme, sphingosine kinase (SK). SK is a recent discovery that is being hailed as a potentially important breakthrough in understanding why cancer cells survive indefinitely.

SK appears to be a key player in programmed cell death (apoptosis), with normal cells switching off this enzyme in order to die naturally. Cancer cells appear to over-express this enzyme, and this now is thought to be an important reason why human cancer cells stop dying naturally and accumulate in the body.

Developing drugs to knock out SK has become an important new direction within the pharmaceutical industry in the race to develop drugs that have broad anti-cancer action but limited adverse effects on healthy cells.

The Australia-based group, led by Professors Vadas and Jennifer Gamble, achieved prominence by defining the role of SK in inflammation and cancer and by cloning the first human SK gene, a crucial step in helping to develop drugs that target this important enzyme.

Professor Vadas said the experimental anti-cancer drug, phenoxodiol, had proven to be a potent inhibitor of SK.

“The importance of this is that we now have a means of inhibiting this enzyme, which we believe is a major contributor to the cancer process in humans.

“We are not sure yet whether just inhibition of sphingosine kinase alone will be enough to stop cancer growth, but the early evidence suggests that it would make a significant contribution,” Professor Vadas said.

Professor Gamble, also of the Hanson Centre for Cancer Research, added that phenoxodiol was a very interesting anti-cancer drug, because it was already known that it possessed a number of other anti-cancer effects such as its ability to stop cancer cells dividing through its inhibition of the topoisomerase 2 enzyme and its ability to inhibit signal transduction mechanisms mediated by protein tyrosine kinase enzymes.

“To be able to add inhibition of sphingosine kinase to this list means that phenoxodiol appears to be active against multiple targets in cancer cells, and that considerably increases the likelihood of having an anti-cancer effect,” Professor Gamble added.

Phenoxodiol currently is in Phase Ib/2a clinical trials in Australia and is about to commence a Phase Ib trial at the Taussig Cancer Center at the Cleveland Clinic Foundation, in Cleveland, Ohio, in patients with solid tumours.

The Cleveland Clinic Taussig Cancer Center, is one of North America’s largest cancer clinics.

Phenoxodiol, was granted Investigational New Drug (IND) status by the US Food and Drug Administration (FDA), on 29 January 2001.

Under US law, a new drug cannot be marketed until it has been investigated in clinical trials, after which a company may submit a secondary application to the FDA and the FDA may then approve the drug for marketing.

Phenoxodiol program director at Novogen, Dr Graham Kelly, said that the announcement by Professor Vadas provided an important key to explain why phenoxodiol in the laboratory displayed such broad-ranging anti-cancer effects across many types of human cancer without apparent effect on normal cells.

Based in Sydney, Novogen is developing a range of drugs in the areas of oncology, cardiovascular diseases, inflammatory diseases and osteoporosis.

ISSUED FOR : NOVOGEN LIMITED

LISTINGS : ASX (CODE NRT) NASDAQ (CODE NVGN).

FOR FURTHER INFORMATION : PROFESSOR ALAN HUSBAND, RESEARCH DIRECTOR, NOVOGEN LIMITED OR DR GRAHAM KELLY, PHENOXODIOL PROGRAM DIRECTOR TEL (02) 9878 0088 http://www.novogen.com

ISSUED BY :WESTBROOK COMMUNICATIONS CONTACT: DAVID REID TEL (02) 9231 0922 OR 0417 217 157

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