Mike the Mad Biologist

A Patch for…Diarrhea?

Forget smoking cessation. This is a patch everyone can use. From the August 10 edition of ScripNews (subscription only):

Iomai’s traveller’s diarrhoea vaccine patch shows promise

Iomai’s investigational vaccine patch for traveller’s diarrhoea has shown positive Phase II results in volunteers travelling to Mexico and Guatemala. If approved, it would become the first vaccine approved in the US for traveller’s diarrhoea, says the company.

The patch is designed to treat traveller’s diarrhoea associated with enterotoxigenic Escherichia coli (ETEC), which is responsible for most cases of the illness. It uses the firm’s transcutaneous immunisation technology to deliver heat-labile toxin from ETEC into Langerhans cells of the skin through the skin. The toxin then induces an immune response in nearby lymph nodes.

Iomai said the patch is the only way to get the product into the immune system, as it cannot be injected. It added that the patch method of delivery also had the advantage of a good shelf-life and the convenience of self-application. Out of a total of 170 subjects, 59 were vaccinated twice before travelling to Mexico or Guatemala, in a randomised, double-blind, placebo-controlled field trial. The ETEC attack rate, which was the number of patients in the placebo group infected with travellers diarrhoea, was about 10%, as expected, the company said. Vaccinated travellers were found to be 75% less likely to suffer from moderate or severe diarrhoea from all causes compared with placebo patients (p < 0.01). In addition, 85% of volunteers were protected from severe diarrhoea (p < 0.05). At this time, the company said it would not disclose the numbers of patients infected in each group.

As well as being highly preventative, the vaccine was also found to lessen the symptoms in those who did become ill by markedly reducing the number of loose stools, compared with unvaccinated individuals. The vaccine gave an immune response even at a low dose and was well tolerated.

Iomai said that the trial provided sufficient incidence data for a US FDA submission, which it plans to make once it has conducted a Phase III trial next year. The company would not disclose further details of the trial. 54 million travellers this year will be at risk from traveller’s diarrhoea in high-risk areas, the company said, adding that the market for traveller’s diarrhoea vaccines is over $500 million.

Of course, this technology could also be used to vaccinate children in the developing world against diarrheagenic E. coli. But there’s no money in that