British Biotech shares slump on `complicated data'

British Biotech's shares slumped 9 per cent yesterday despite test results which the company claimed provided further confirmation of the effectiveness of its Marimastat anti-cancer treatment. The company, whose shares soared a year ago on hopes for Marimastat, said the phase two trials involving 381 cancer sufferers were the most wide-ranging yet and gave further evidence of the drug's ability to restrain the disease across a wide range of cancers. But it was rewarded with a 21.5p slump in the share price to 207.5p yesterday.

James Noble, finance director, said: "It is rather odd that the shares have gone down, because these are by far the most important results we have reported as a company." He ascribed the reaction to the fact that data was "just very, very complicated".

Many analysts, however, downplayed the significance of the results, which for the first time included information on trials with patients with gastric and colorectal cancers. One analyst said: "Our broad thinking is that the information doesn't really add substantially to what we already know." Questions remained about the dosage regime and the side-effects of the drug, which causes pains in the arm and shoulder when used over a prolonged period.

The data was presented at the European Society for Medical Oncology meeting in Vienna, which brings together cancer specialists from all round Europe. British Biotech said the tests confirmed earlier results that showed higher dosage rates of 10mg, 25mg and 50mg twice a day were more effective than lower ones. The group claimed that the outcomes confirmed there was a connection between a reduction in antigens, used as a marker to monitor the progression of cancer, and a reduction in the disease.

"It is absolutely proved that we can reduce the antigens in a group of 381 patients and where we reduce the antigens people live longer," Mr Noble said. "We obviously think it is the drug's effect, but we can't prove it as yet."

The results in 14 patients suffering from gastric cancers showed half appearing to respond or showing no further progression of the disease. Despite microscopic evidence that Marimastat was coating tumours in a fibre, as predicted, analysts said the sample size was too small to be significant. Other studies in colorectal, ovarian and pancreatic cancers had shown similar results, Mr Noble said.

Phase three trials under way on Marimastat remain the key to the drug's final approval and launch onto the market, which is unlikely before 1999 or 2000, analysts say. A treatment for pancreatic cancer is likely to be marketed first, but external sales forecasts vary widely from $100m in the first year to $1bn.

Later this month, the group will give phase three test data for its Lexipaphant treatment for acute pancreatitis.