VB4-845 is a novel recombinant fusion protein that targets the epithelial cellular adhesion molecule (EpCAM). This initial clinical trial was conducted to determine the maximum tolerated dose of intratumoral injections in patients with advanced squamous cell carcinoma of the head and neck and to assess pharmacokinetics and immunogenicity. Twenty-four patients with advanced, recurrent squamous cell carcinoma of the head and neck received two cycles of five daily intratumoral VB4-845 injections of 20, 40, 80, 130, 200, or 280 microg. The maximum tolerated dose was established to be 280 microg administered daily for 5 days. Common adverse events were pain due to intratumoral injection and reversibly elevated liver enzymes. Of the 24 patients, 15 had detectable blood levels with a mean drug half-life of 4.0 +/- 0.3 h. VB4-845 reduced or stabilized tumors in 71.4% of epithelial cell adhesion molecule-positive patients. VB4-845 intratumoral injection therapy was well tolerated and feasible.