Introgen's vaccine works in lung cancer

CHICAGO, June 4 (UPI) -- U.S. firm Introgen said Monday its potential cancer vaccine INGN 225 shows promise for patients with small-cell lung cancer.

In a phase 2 study, 43 patients evaluable for survival after being vaccinated with INGN 225 had longer survival compared to standard treatment, with five patients remaining progression-free from 378 to 894 days.

In fact, the experimental vaccine induced an anti-tumor immune response in 42 percent of evaluable patients, and of those who had an immune response, 79 percent responded to chemotherapy, compared with just 33 percent of those patients with no immune response, Introgen said.

Researchers also noted that the tumor response rate in patients with a platinum-resistant form of the disease who were first vaccinated, then got chemotherapy, had a tumor response rate of 45 percent, up greatly from the usual rate of less than 15 percent in these patients.

Introgen's investigational cancer vaccine uses an adenovector -- a virus that has been stripped of its RNA, then implanted with a therapeutic gene -- that delivers the p53 gene to a patient's immune cells, stimulating the anti-tumor immune response.

"We are particularly encouraged by the response rate in patients with platinum-resistant disease who have very few effective treatment options," said Robert Sobol, Introgen's senior vice president of medical and scientific affairs.

The data were presented at the American Society of Clinical Oncology meeting in Chicago.