Marimastat (BB2516): current status of development.

Marimastat (BB-2516) is the first matrix metalloproteinase inhibitor to have entered clinical trials in the field of oncology. It has excellent bioavailability and has completed phase I and II trials. Phase I studies involved healthy volunteers who received short courses of marimastat; these were well tolerated. Symptoms experienced by many patients with various malignancies included severe joint and muscle pain which were debilitating in >60% of patients at doses >50 mg bid. These symptoms were reversible on discontinuation of the drug, and their incidence has been decreased by using marimastat 10 mg bid, the dose used in current studies. Phase II studies involved the use of serum tumor markers as surrogate indicators of antitumor activity. Six studies in colorectal, ovarian, and prostate cancer have been completed and pooled analysis has demonstrated a dose-dependent biological effect (as defined by the authors); 58% of patients respond at doses >50 mg bid. Effects on tumor markers were associated with increased survival. Small phase II studies have suggested potential activity in pancreatic and gastric cancer and have demonstrated the safety of combining cytotoxic chemotherapeutic agents with marimastat. Ongoing phase III studies are investigating the effects of marimastat in addition to chemotherapy in the treatment of small cell lung cancer and pancreatic and gastric carcinoma.