March 17, 2006

Introgen Therapeutics has announced positive data from a Phase I/II clinical trial of Advexin in advanced esophageal cancer patients. Intratumoral administration of multiple Advexin doses was shown to be safe, feasible and clinically active. Nine of 10 patients had local tumor responses of stable disease and overall one-year survival was 60 percent. No evidence of tumor in multiple biopsies following treatment was observed in 30 percent. Advexin is an investigational cancer therapy that utilizes an adenoviral vector to deliver the p53 tumor suppressor directly to tumors.

The trial enrolled 10 patients with confirmed squamous cell carcinoma of the esophagus who were not candidates for further surgery and who had become resistant to standard chemotherapy. At the time of entry into the trial, five of the patients had tumors growing into adjacent organs. Overall responses included six patients with stable disease for more than one year. One patient who entered the trial with a tumor that prevented swallowing was able to swallow liquid and meals after two injections of Advexin. Another patient remained progression free and alive 47 months after completing Advexin therapy. As in other clinical trials, Advexin therapy was well-tolerated.