&NA;Batimastat is a synthetic low molecular weight (474Da) broad-spectrum collagenase and matrix metalloprotease inhibitor (MMPI) originally synthesised by British Biotech. Batimastat is the lead compound of this class which also includes another hydroxamate MMPI, BB 2516. Unlike most cancer therapies, batimastat is designed to prevent malignant cells from breaking away to form secondary tumours rather than eradicating all cells from the body. It is also designed to ‘starve’ tumours of nutrients by inhibiting the development of blood vessels. Native MMPIs also exist (TIMP-1, TIMP-2) although these are disadvantaged by lack of oral activity. Batimastat is undergoing phase II clinical trials in the UK for the treatment of pleural effusions. Pivotal phase III clinical trials of batimastat in the treatment of malignant ascites were suspended by British Biotech following unexpected adverse effects (inflammation and pain in the abdomen) among patients. However, although UK approval was granted for clinical trials to recommence with a dose-ranging study, British Biotech has since discontinued clinical development of batimastat for the treatment of malignant ascites.Batimastat is the lead synthetic broad-spectrum MMPI. It had shown promising activity in phase I studies against malignant ascites, however development was discontinued due to severe adverse effects.