Advanced phase I/II studies of targeted gene delivery in vivo: intravenous Rexin-G for gemcitabine-resistant metastatic pancreatic cancer.

Rexin-G, a nonreplicative pathology-targeted retroviral vector bearing a cytocidal cyclin G1 construct, was tested in a phase I/II study for gemcitabine-resistant pancreatic cancer. The patients received escalating doses of Rexin-G intravenously from 1 x 10(11) colony-forming units (cfu) 2-3x a week (dose 0-1) to 2 x 10(11) cfu 3x a week (dose 2) for 4 weeks. Treatment was continued if there was less than or equal to grade 1 toxicity.