Author(s): Thamm DH, Kurzman ID, King I, Li Z, Sznol M, Dubielzig RR, Vail DM, MacEwen EG. Systemic administration of an attenuated, tumor-targeting Salmonella typhimurium to dogs with spontaneous neoplasia: phase I evaluation. Clin Cancer Res. 2005 Jul 1;11(13):4827-34. PMID 16000580
Journal: Clinical Cancer Research : An Official Journal Of The American Association For Cancer Research, Volume 11, Issue 13, Jul 2005
PURPOSE Genetically modified bacteria are a potentially powerful anticancer therapy due to their tumor targeting capacity, inherent antitumor activity, and ability to serve as efficient vectors for gene delivery. This study sought to characterize the acute and short-term toxicities and tumor colonization rates of a genetically modified Salmonella typhimurium (VNP20009) in dogs with spontaneous tumors, in the context of a phase I dose escalation trial.
EXPERIMENTAL DESIGN Forty-one pet dogs with a variety of malignant tumors received weekly or biweekly i.v. infusions of VNP20009, at doses ranging from 1.5 x 10(5) to 1 x 10(8) cfu/kg. Vital signs and clinicopathologic variables were monitored regularly. Incisional biopsies were obtained before and 1 week following the first infusion for histopathology and bacterial culture.
RESULTS The nominal maximum tolerated dose was 3 x 10(7) cfu/kg, with refractory fever and vomiting being the dose-limiting toxicities. One treatment-related acute death occurred. Bacteria were cultured from tumor tissue in 42% of cases. Thirty-five patients were evaluable for antitumor response. Major antitumor responses were seen in 15% (4 complete response and 2 partial response), and disease stabilization for at least 6 weeks in 10%.
CONCLUSIONS Administration of VNP20009 at doses with acceptable toxicity results in detectable bacterial colonization of tumor tissue and significant antitumor activity in tumor-bearing dogs.