A phase 2, randomised, placebo-controlled study to evaluate once-daily oral Travelan for the prevention of Travellers’ diarrhoea

This study evaluated once-daily oral dosing of Travelan (IMM-124E), a bovine polyclonal antibody product, for prevention of Enterotoxigenic Escherichia coli (ETEC)-induced diarrhoea. In this randomised, double-blind, placebo-controlled trial using an ETEC-controlled human infection model, 60 healthy subjects received 1200mg Travelan or placebo once-daily for 7 days. Two days after dosing commenced, subjects were challenged with ETEC strain H10407 and monitored for diarrhoeal symptoms. Travelan was well-tolerated with a significant 50% reduction in ETEC challenge-related adverse events ( P = 0.0001). Efficacy outcomes did not reach statistical significance, largely due to a lower-than-expected placebo attack rate (33% vs 70% anticipated); however a strong trend consistently favoured Travelan, including a 40% reduction in moderate-to-severe diarrhoea (primary endpoint), a 50% reduction in severe diarrhoea, a 44% reduction in all diarrhoea, and a 71% reduction in early antibiotic use. These findings were supported by significant reductions in intestinal inflammation markers (faecal myeloperoxidase and calprotectin) 4 days post-challenge. Significantly lower O78 lipopolysaccharide IgA and IgG titers were observed but over 80% of subjects in each group seroconverted by day 15–29, indicating Travelan did not hinder immunity to ETEC. Although underpowered and limiting definitive interpretation, these findings suggest a potential protective effect of once-daily Travelan, warranting further investigation in a larger adequately powered trial.