TRIALS OF a new drug which has the potential to treat the most virulent forms of lung, breast, bowel and skin cancer have begun at a Cambridge hospital, scientists said yesterday.
The Cancer Research Campaign (CRC), which has signed a pounds 1m deal with a drug company to develop the compound, dismissed criticisms that it was raising false hopes by announcing details now. It also denied that it was under commercial pressure.
A spokeswoman for the CRC said last night: 'We have seen remarkable results in laboratory tests at low doses, which is why we have decided to make the announcement. It could help people for whom conventional treatment has failed, particularly lung cancer.'
She said that each year 40,000 people died of lung cancer and there were 40,000 new cases. The survival rate after five years is about 7 per cent.
However, a leading cancer specialist, who asked not to be named, said that high-profile announcement was 'premature in the extreme'. He added: 'We are talking up test-tube results here. Lots of chemicals kill cancer cells in a test tube but that is a long way from treating patients.'
Xenova Group plc, a Slough- based biotechnology company which has obtained commercial rights to the drug from the CRC, last month floated its shares on the second tier of the New York Stock Exchange. Louis Nisbet, chief executive of the company, said that Xenova was 'considering, among other options' flotation on the London stock exchange.
The drug, known as Daca, was discovered by New Zealand cancer researchers some years ago, but was not developed or its full potential realised. CRC scientists found that it had a 'unique' ability to knock out two vital enzymes, known as topo-1 and topo-2, which are needed for tumour growth, and the uncontrolled replication of cancer cells.
Dr Paul Bevan, research director of Xenova, which has formed a partnership with CRCT, the technology transfer arm of the charity, said: 'No other compound has this dual action. It stops the tumour dead in its tracks and shrinks it.'
Other drugs can block one or other of the enzymes, but blocking both appears to have a synergistic effect, Dr Bevan added. 'Hitting them both at the same time is better than hitting one and then the other.'
In addition, Daca is effective against tumours which are resistant to existing drug therapy. Some tumours can 'pump out' drugs before they have any effect, but Daca seems to overcome this. It also has potential for treating brain tumours, notoriously difficult to treat with drugs, because it penetrates the blood-brain barrier.
A trial involving about 30 terminally-ill cancer patients who have tried all conventional forms of therapy began six weeks ago at Addenbrooke's Hospital in Cambridge. Another trial in New Zealand is planned, and both will focus on the toxicity of the drug and side-effects.
Healthy human cells also produce topo-1 and topo-2 which are needed for replication. But because healthy cells do not proliferate at the same rate as cancer cells, Daca is expected to have a minimal effect on them.
Dr Sue Foden, managing director of CRCT, and the scientists who discovered the drug 'languishing' on the laboratory shelves of the Auckland Cancer Society, said: 'This really makes Daca a very promising candidate for second-line treatment where earlier drugs have failed, or for combination therapy with other known agents.'
Even if Daca does live up to expectations it is unlikely to be on the market before the end of the decade.
XENOVA, the biotechnology company, was last month floated on the Nasdaq stock market in New York, and not on the New York Stock Exchange in our story about a new drug for cancer.Reuse content