DNA and hepatitis B virus vaccine evaluated in colorectal cancer patients.(Brief Article)

2002 OCT 9 - (NewsRx.com & NewsRx.net) -- by Sonia Nichols, senior medical writer - The jury is still out on whether or not DNA vaccines are effective cancer fighters.

"Despite an abundance of preclinical data, relatively little is known regarding the efficacy of DNA vaccination in humans," the authors of a recent University of Alabama at Birmingham vaccine trial pointed out.

Patients given a plasmid-encoded vaccine combining hepatitis B surface antigen (HBsAg) and carcinoembryonic antigen (CEA) responded well to the vaccine's viral antigen, but showed little clinical response to the cancer antigen, according to Robert M. Conry and coauthors, who are investigators in the Divisions of Hematology/Oncology and Gene Therapy at the University of Alabama's Comprehensive Cancer Center.

"CEA was selected as a prototypic tumor-associated self-antigen, and the HBsAg cDNA was included as a positive control for immune response to the DNA vaccine without relying upon breaking tolerance to a self-antigen," the investigators explained.

Divided into three groups, the 17 trial participants, all diagnosed with metastatic colorectal carcinoma, either received a single dose of vaccine (n=9), low doses of vaccine repeated every 3 weeks (n=6), or a higher dose of vaccine repeated every 3 weeks (n=2).

Side effects were limited, with only a few patients experiencing injection site tenderness, fatigue, and elevated levels of creatinine kinase.

Among the eight trial participants who received repeated doses of ...