A pilot trial of suramin in metastatic breast cancer to assess antiangiogenic activity in individual patients

Suramin is a polysulfonated naphthylurea with multiple potential mechanisms of action against tumors, including the ability to bind growth factors kno wn to promote tumor angiogenesis, Using an established fixed dosing scheme for the administration of suramin in patients, a pilot study was conducted in patients with progressive, metastatic breast cancer, The primary objecti ve of this trial is to define the effect of suramin on the angiogenic activ ity in individual patients using in vitro laboratory assays. The secondary objective was to assess the antitumor effect of suramin in a population of metastatic breast cancer patients. No objective tumor responses were observ ed in any of the 9 patients who received treatment with suramin, however 1 patient did maintain stable disease status, The strength of angiogenic acti vity present in patient samples was assessed by testing patient plasma in t he capillary endothelial cell migration assay, Angiogenic activity followed over time was lowest in patients with the highest suramin concentrations a nd highest in patients with the lowest suramin concentrations. We conclude that it is feasible to continually monitor the activity of antiangiogenic a gents in individual patients without relying on clinical tumor response, co pyright (C) 2000 S. Karger AG, Basel.