Breakthrough on anti-cancer drug

SCIENTISTS in the US have made a synthetic version of Taxol, a powerful anti-cancer drug previously collected from the bark of the rare Pacific yew tree.

Rival drug companies have been racing to produce a synthetic version of the drug. Finding a way to do so opens up the possibility of making Taxol still more potent, of reducing side effects and of creating other similar anti-cancer drugs.

Taxol has been hailed as one of the most significant advances in cancer treatment, but its development has been fraught with difficulties. The main problem has been its scarcity, which has hampered clinical trials.

Its collection is controversial because the Pacific yew is rare and slow growing. Harvesting the bark kills the tree, and one 100-year-old tree yields sufficient Taxol for just one single dose.

Taxol can be partially synthesised, using leaves from the English yew tree, which is more abundant.

The natural Taxol molecule is extremely complex, and some researchers had given up hope of every creating a full laboratory-made version. However, two rival US teams have announced success in the past week.

One, from the Scripps Research Institute in La Jolla, California, reports its work in a paper in today's issue of the science journal Nature. The rival group, from Florida State University, will publish its full results later this month.

Taxol holds particular promise for treatment of ovarian and breast cancers. Trials in Britain are testing the drug on these, as well as lung, head and neck cancers.

Two pharmaceutical companies are keen to develop the competing processes, but the scientists say it will be many years before the drug is fully refined and suitable for human trials.

Latest figures for cancers in England and Wales show a 4 per cent rise in 1988 following a 5 per cent increase in 1987. Richard Doll, consultant to the Imperial Cancer Research Fund, said one explanation was the increasing numbers of elderly in the population.