Correction: British Biotech's Batimastat

In last week's issue of the Marketletter, an article on British Biotech's anticancer drug batimastat contained misleading statements which were wrongly attributed to the company. Marketletter apologises for any embarrassment this may have caused. To follow is an account which should clarify British Biotech's position on the matter.

The tolerability problems which led to the suspension of BB's first Phase III trial of batimastat was due to a change in the manufacturing process, which produced a product which had a slightly improved chemical impurity profile but which was more irritant, most probably due to subtly different physical properties. The dose used in the trial (1,000mg/m2) was not the cause of the intolerability, says BB, as this same dose had been used in a 40-patient Phase II study with good tolerability. However, the doses in malignant ascites had not been finally decided and a further two Phase III trials had been planned to explore lower doses of 250mg/m2 and 500mg/m2. In the event these other trials were not started.

The new ascites trial is a "cautious restart" with new material manufactured to match the previously well-tolerated material used in Phase II. The top dose used in this study was chosen as 500mg/m2 rather than 1,000mg/m2 because: - BB already has a large amount of data at the 1,000mg/m2 dose; - it is very likely that lower doses are efficacious; - the doses shown to be efficacious in the other indication of malignant pleural effusion are much lower (100-300mg/m2); and - the pleural effusion data is important because BB does not wish to have much discrepancy, if any, between the dose for malignant effusions in the chest and the abdomen.