Pharmacokinetic and pharmacodynamic study of intratumoral injection of an adenovirus encoding endostatin in patients with advanced tumors.

Angiogenesis plays a pivotal role in tumor growth, tissue invasion and metastasis. Endostatin is an angiogenesis inhibitor and has been shown to reduce tumor growth in animal models. However, therapy with recombinant endostatin protein was hampered by its short half-life and very-low yield of bioactive protein. We performed a phase I dose-escalation clinical trial using intratumoral injection of an adenovirus containing human endostatin gene (Ad-rhE; E10A; 10(10)-10(12) virus particles (vp)) in 15 patients with advanced solid tumors. We observed intratumoral injections of E10A without dose-limiting toxicity. Most frequently reported E10A-related adverse events were transient fever and local response. Distribution studies revealed that the vector was detected in the blood, throat and injection site, but rarely in the urine and stool. An increased endostatin expression was detected using enzyme immunoassay in serum in 13 of 14 treated patients throughout the period of treatment despite the presence of neutralizing antiadenovirus antibody. Median serum basic fibroblast growth factor levels decreased from 32.4 pg ml(-1) at baseline to 24.9 pg ml(-1) after 28 days of first treatment. Thus, direct intratumoral injection of up to 10(12) vp of E10A to patients is well tolerated and further studies are necessary to define and increase clinical efficacy.