AG 3340 is an orally available, lead compound selected from a series of highly selective, nonpeptidic matrix metalloprotease inhibitors (MMPIs) developed by researchers at Agouron Pharmaceuticals, USA. The drug has also inhibited angiogenesis in animal studies. Agouron has inititated 2 North American phase II/III pivotal clinical trials for the treatment of advanced non-smallcell lung (n = 500 in combination with paclitaxel and carboplatin) and advanced prostate cancer (n = 500 in combination with mitoxantrone and prednisone). Another trial in non-small-cell lung cancer in combination with cisplatin/etoposide is planned.In September 1998, Agouron intiated a phase II trial to evaluate the efficacy and tolerablity of AG 3340 when used to treat age-related macular degeneration. The US trial will involve approximately 100 patients over the age of 50 years. Preclinical studies have shown that AG 3340 can cross the blood-retina barrier.In addition, AG 3340 is in phase I clinical development as an antirheumatic agent. Roche Bioscience has marketing rights for the indication of rheumatic disease.AG 3340 is the first in a series of MMPIs with potential in the treatment of both solid tumours and age-related macular degeneration. Its positive features include oral administration and linear kinetics. Its relative lack of potency against collegenase 1, compared with gelatinases and stromelysin 1, is expected to result in fewer serious adverse events compared with non-selective MMPIs. No serious adverse events have been seen in cancer patients to date.