African Plant Drug
Starves Cancer Tumours
By Nigel Hawkes
Science Editor
The (London) Times
The first trial of a cancer drug designed to starve tumours into submission has shown that it may work.
Seventeen cancer patients at the Mount Vernon and Hammersmith Hospitals in West London were given the drug, Combretastatin, originally isolated from an African plant, the bush willow. The treatment curtailed blood flow to the tumours, suggesting that in combination with radiation or another drug, it could form an effective therapy.
Dr Gordon Rustin, of Mount Vernon Hopsital, said yesterday: "This study is very exciting because it is the first time in cancer research that a drug has been shown to reduce blood flow to patients' tumours. This proves that the theory of starving someone's tumour of oxygen can work in practice and it has opened the door for new cancer treatments in future."
The results are also a timely boost for a type of therapy that has proved controversial in America. In May last year, Dr Judah Folkman of Harvard Medical School in Boston reported that he had shrunk cancers in mice to microscopic sizes using two blood-starving agents, endostatin and angiostatin. Other laboratories have found reproducing the effect difficult or impossible. Despite this, patients are being recruited for a trial of endostatin in America.
The British trials, organised by the Cancer Research Campaign and carried out in conjunction with the biotech company Oxigene, based in Stockholm, did not seek to shrink the tumours but simply to see if blood flow was reduced. The results, said Björn Nordenvall, president of Oxigene, demonstrated "proof of principle".
Patients were given a ten-minute infusion of the drug into a blood vessel once a week. The main side-effect was temporary pain at the site of the tumour within two hours in some patients, probably caused by the interruption of blood flow.
Dr Rustin told the Angiogenesis '99 conference in London yesterday that such agents given alone would never lead to cures, because there would always be cancer cells on the outside of the tumours that could get their nourishment from surrounding tissue. But adding tumour-killing drugs or radiation sources to Combretastatin was producing good results in animal tests. In some experiments in mice, colon cancers appeared to have been eliminated.