A 17-year-old male with retroperitoneal choriocarcinoma metastatic disease in the lungs has had shrinking of pulmonary metastases and primary tumor with four treatment courses of DMP 840. β-HCG appeared normal prior to resection of the necrotic primary tumor and a single remaining pulmonary metastasis, which was also necrotic. The patient remains free of tumor recurrence of 8 months following surgery. Further evaluation of DMP 840 in patients with germ cell tumors is indicated.