Antex Biologics Inc announced that two Phase II trials for its Helivax vaccine against Helicobacter pylori, a bacterial pathogen responsible for peptic ulcers and stomach cancers, are scheduled to begin next quarter. One trial will assess the preventative properties of the vaccine while the other trial will assess the vaccine''''s therapeutic capabilities.
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. The Helivax vaccine was developed using the Company''''s patented Nutriment Signal Transduction (NST) technology. The Company has patents issued and pending claiming composition of matter and methods of using the vaccine, including for both prophylactic and therapeutic indications in humans.
The Phase II trials will focus on mucosal immune responses elicited by the vaccine as correlates of protection and on the vaccine''''s ability to reduce the H. pylori bioburden in infected subjects. Reducing the level of H. pylori bioburden in infected individuals will be used to evaluate Helivax as a therapeutic vaccine.
Antex has conducted a thorough pre-clinical evaluation of Helivax including assessing its prophylactic and therapeutic efficacy in murine infection models. Based on immune cell stimulation patterns, cytokine release profiles and antibody isotype patterns elicited among animals immunized with Helivax, the protection afforded by the vaccine appears to correlate with both Th1 (cellular) and Th2 (humoral) type immune responses. Antex has achieved statistically significant protection against infection in prophylactic models and statistically significant results in therapeutic models.
The Company has previously conducted Phase I safety and immunogenicity trials with Helivax. The first Phase I trial, consisting of forty-five patients, assessed the safety and immunogenicity of the vaccine in healthy adults. In a dose-response study, groups of subjects with and without Helicobacter pylori infection were immunized with ascending doses of the vaccine. Helicobacter pylori-infected individuals were assigned, in a double- blind manner, to receive either three doses of the vaccine or a placebo. The vaccine caused no serious adverse events and generated anticipated immune responses to Helicobacter pylori in both uninfected and asymptomatic Helicobacter pylori infected individuals. Vaccination did not exacerbate the H. pylori infection in the asymptomatic volunteers.
Helicobacter-specific serum IgG and IgA and fecal and salivary IgA antibody responses were seen following vaccination, evidencing that the vaccine induced both systemic and mucosal immune responses. The vaccine induced the generation of Helicobacter-specific antibody secreting cells within the gastric antrum and intestinal duodenum, the site of Helicobacter infections.
The second Phase I clinical trial also showed the vaccine to be safe and immunogenic. The objectives were to compare immune responses and clinical tolerance following oral administration of the vaccine formulated in different buffer solutions and with varying amounts of adjuvant. Forty-five healthy, uninfected adults participated in this Phase I trial. No serious adverse events were reported. The vaccine stimulated multi-fold increases in salivary IgA antibodies against Helicobacter pylori. No differences were observed in serum or mucosal antibody responses among the groups of subjects receiving different buffer solutions concomitant with the dose of vaccine. The laboratory analysis of the cellular immune response and fecal antibody production showed that the vaccinated volunteers were positive for immune cell proliferation, cytokine production and secretory IgA antibodies. Similar to the findings from the first Phase I trial, the vaccine stimulated mucosal antibody responses that should correlate with protection against infection and disease.
Helicobacter pylori is the most common global human pathogen; two-thirds of the world''''s population is infected with this bacterium including about 50 percent of Americans. It is also recognized as the predominant cause of ulcers and is associated with stomach cancers and cardiac disease. Helicobacter pylori is the only bacteria classified by the World Health Organization as a Type I carcinogen. The American Cancer Society estimates there are over 25,000 new cases of stomach cancer and over 13,000 deaths per year.