First pill for dengue shows promise in human challenge trial

A pill for dengue fever developed by Johnson & Johnson appeared to protect against a form of the virus in a handful of patients in a small human challenge trial in the United States, according to data presented by the company on Friday.

There are currently no specific treatments for dengue, a growing disease threat, the company said ahead of presentation of the data at the American Society of Tropical Medicine and Hygiene Annual Meeting in Chicago.

In human challenge trials, researchers intentionally expose healthy volunteers to a pathogen to test a vaccine or treatment, or better understand the disease they cause.

Dengue fever, while often asymptomatic, is also known as "break bone fever" for the severity of the joint pain and spasms that some patients experience.

It has long been a scourge across much of Asia and Latin America, causing millions of infections each year and tens of thousands of deaths, and is likely to spread further as climate change makes more areas hospitable for the mosquitoes that spread it, the World Health Organisation's chief scientist Jeremy Farrar said earlier this month.

In the trial done with Johns Hopkins Bloomberg School of Public Health, 10 volunteers were given a high dose of the J&J pill five days before being injected with a type of dengue. They continued to take the pill for 21 days afterwards.

Six of the 10 showed no detectable dengue virus in their blood after being exposed to the pathogen, as well as no signs that their immune system had responded to infection by the virus over 85 days of monitoring.