The VNP20009 strain of Salmonella typhimurium can be safely administered to patients, and at the highest tolerated dose, some tumor colonization was observed. No antitumor effects were seen, and additional studies are required to reduce dose-related toxicity and improve tumor localization.

Purpose-A strain of Salmonella typhimurium (VNP20009), attenuated by chromosomal deletion of the purI and msbB genes, was found to target to tumor and inhibit tumor growth in mice. These findings led to the present phase I study of the intravenous infusion of VNP20009 to patients with metastatic cancer.Patients and Methods-In cohorts consisting of three to six patients, 24 patients with metastatic melanoma and one patient with metastatic renal cell carcinoma received 30-minute intravenous bolus infusions containing 10 6 to 10 9 cfu/m² of VNP20009. Patients were evaluated for dose-related toxicities, selective replication within tumors, and antitumor effects.