Vion Pharmaceuticals Inc has initiated a new Phase 1 trial of Tapet VNP20009, its Salmonella bacteria anticancer vector, in patients with advanced solid tumors or lymphomas. The objective of the trial is to establish the safety of selectively suppressing the immune system just before and after an intravenous dose of VNP20009. After treatment, patients' tumors will be assessed for the presence of VNP20009 and for any anti-tumor effects. Enrollment of patients began at the Royal Marsden Hospital, London, England, under the direction of Dr. Kevin Harrington.

Alan Kessman, Vion's Chief Executive Officer, stated, "Initiation of this new Tapet trial with immune system modulation, in conjunction with our ongoing work on second generation Tapet vectors, is indicative of Vion's commitment to realize the potential of our Tapet technology." He added, "We continue to believe that Tapet has the promise to be groundbreaking therapy in cancer."

Preclinical studies indicate that brief selective suppression of the immune system at the time of VNP20009 administration can improve the ability of the VNP20009 bacteria to establish colonization in tumors. Colonization in tumors is necessary for VNP20009 to exert anti-tumor effects, either on its own, or as a delivery vehicle for anticancer agents.

In previous Phase 1 trials, Vion observed that VNP20009 could be administered safely to patients with advanced cancer by the intravenous route within a defined dose range. The studies also demonstrated that VNP20009 could establish colonization in tumors in some patients. Vion licenses Tapet technology from Yale University.