H. pylori Vaccine Approved as an Investigational New Drug

January 28, 2003

Medscape Staff Report

Jan. 28, 2003 -- The U.S. Food and Drug Administration (FDA) has approved the investigational new drug application (INDA) for Helivax, an inactivated, multivalent, whole-cell vaccine designed to prevent and treat infections caused by Helicobacter pylori.

The approval paves the way for patient enrollment in two phase II clinical trials scheduled for the first half of 2003, according to a press release from the vaccine's manufacturer, Antex Biologics Inc.

The Helivax INDA outlines the company's approach to the two clinical trials, one to assess the vaccine's efficacy as a prophylactic and the other to assess the vaccine's therapeutic capabilities. The two trials will focus on mucosal immune responses as correlates of protection, as well as assess the vaccine's ability to reduce the H. pylori bioburden of infected subjects. Both trials will be conducted in a randomized, open-label manner, and will include a total of 80 patients in multiple sites throughout the United States.

In preclinical trials, Helivax achieved 100% protection against infection in prophylactic animal models and statistically significant reduction of bioburden in therapeutic animal models.

In phase I safety and immunogenicity trials, the vaccine caused no serious adverse events, and it generated anticipated immune responses to H. pylori in both uninfected and asymptomatic H. pylori--infected individuals. The vaccine induced the generation of Helicobacter-specific antibody secreting cells within the gastric antrum and intestinal duodenum, the site of Helicobacter infections, and vaccination did not exacerbate H. pylori infection in the asymptomatic volunteers.

H. pylori is the most common global human pathogen; two-thirds of the world's population is infected with this bacterium, including approximately 50% of Americans. It is recognized as the predominant cause of ulcers and is associated with stomach cancers and cardiac disease. H. pylori is the only bacteria classified by the World Health Organization as a type I carcinogen; the American Cancer Society estimates there are more than 25,000 new cases of stomach cancer and more than 13,000 deaths per year.

Reviewed by Gary D. Vogin, MD


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