In developing a chemotherapeutic program for children with disseminated neuroblastoma, we established three human neuroblastoma lines in cell culture to study the effects of dibutyryl cyclic AMP, papaverine, 5-trifluoromethyl-2'-deoxyuridine, and cyclophosphamide on cell growth, biochemical behavior, and morphology. Based upon our studies, a clinical treatment program was designed. We have treated 15 patients with disseminated neuroblastoma and have established the optimum dose range and sequence of these drugs. Early results were promising; plans for continuation of clinical and experimental studies were discussed.