Cancer Vaccine Sensitizes Tumors to Platinum, Taxane Chemotherapies

Introgen Therapeutics has reported interim results of its Phase II trial of INGN 225, its investigational cancer vaccine, in patients with advanced small cell lung cancer (SCLC) previously treated with chemotherapy.

Following INGN 225 treatment, 67 percent of the evaluable patients in the study had objective responses (greater than 50 percent tumor reduction) to subsequent chemotherapy.

Researchers at the H. Lee Moffitt Cancer Center are conducting the study in collaboration with Introgen. INGN 225 is a therapeutic vaccine consisting of a cancer patient's dendritic cells, a type of immune cell, treated with an adenovector carrying the human p53 gene (Ad-p53).

Eight weeks following the last dose of first-line chemotherapy, dendritic cells were collected from each patient and treated in the laboratory with Ad-p53, to generate the INGN 225 vaccine. Initial results show that the vaccine was well-tolerated, with no appreciable INGN 225-related toxicity in any of the treated patients. After vaccine therapy, 18 patients with progressive disease were treated with second-line chemotherapy.

To date, 12 patients (66.7 percent) had objective responses or tumor reduction greater than 50 percent. Historically, the expected objective response rate in these patients is between 20 and 30 percent. There was a statistically significant correlation between the development of a p53 immunological response to vaccination and objective responses to second line chemotherapy.