BACKGROUND Vascular endothelial growth factor (VEGF) is a proangiogenic molecule produced by melanoma cells. We hypothesized that administration of bevacizumab (Bev), a monoclonal antibody that neutralizes VEGF, with low-dose interferon alfa-2b (IFN-alpha2b), an inhibitor of basic fibroblast growth factor (FGF), would lead to the regression of metastatic melanoma. METHODS Patients with metastatic melanoma were randomized to receive Bev (15 mg/kg intravenously every 2 weeks) with or without low-dose IFN-alpha2b (1 MU/m2 subcutaneously daily). Patients exhibiting a clinical response or stable disease after 12 weeks were treated until disease progression. RESULTS Thirty-two patients (16 per arm) were accrued (18 male, 14 female; mean age 57.5 years). Both regimens were well tolerated. Six patients developed easily managed exacerbations of preexisting hypertension. Two patients developed grade 3 proteinuria that resolved after a treatment break. IFN-alpha2b therapy was associated with grade 1 to 2 constitutional symptoms. Arterial thromboembolic complications were observed in three patients (two mild myocardial infarctions, one transient ischemic attack), all of whom had risk factors. One patient (Bev plus IFN-alpha2b arm) had locally recurrent scalp disease that partially responded to therapy. Eight patients (five Bev, three Bev plus IFN-alpha2b) had prolonged disease stabilization (24 to 146 weeks). Plasma levels of VEGF and FGF did not correlate with any clinical parameter. The patient with the longest period of stable disease had the highest baseline VEGF and FGF. CONCLUSIONS Bev was well tolerated at this dose and prolonged disease stabilization was achieved in one-quarter of metastatic melanoma patients. Low-dose IFN-alpha2b did not augment the activity of Bev.