TD Vaccines’ Oral, Dual-Action ETEC Vaccine Candidate Reduces Bacterial Infection and Diarrhoea in Phase II Challenge Study
TD Vaccines A/S announced that ACE527, its oral, dual-action, ETEC (enterotoxigenic E. coli) vaccine candidate to combat the most frequent cause of bacterial diarrhoea in travellers, has significantly decreased the level of bacterial infection and has also reduced the incidence and severity of diarrhoea in a randomised, placebo-controlled Phase II study in which volunteers were challenged with ETEC after receiving the vaccine.
ACE527 is a uniquely attractive vaccine candidate because:
- It is delivered orally: providing high acceptability and compliance.
- It has the potential to provide broad coverage: designed to generate an immune response to over 85% of ETEC strains.
- It has a dual mechanism of action: delivering strong immune responses to toxin and reducing bacterial colonization, thereby better promoting protection.
During the study, 29 subjects who had received the vaccine and 27 who had received an oral placebo were challenged with a virulent strain of enterotoxigenic E. coli. The study showed that:
- There was a reduction in the incidence and severity of diarrhoea (P = 0.04 and 0.06, respectively); vaccine recipients were more likely to be diarrhoea-free than placebo recipients after the challenge and vaccination resulted in approximately a 50% reduction in the number and amount of loose or liquid stools passed during the study period.
- The reduction in the total amount of diarrhoeal stool produced was most pronounced in the first 24 hours after the onset of symptoms (P = 0.05).
- There was a significant reduction in the level of colonization by the challenge bacteria (P = 0.001) as measured by bacterial shedding in the stool.
- The vaccine reduced the incidence of moderate-to-severe diarrhoea (P = 0.12).
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