Merck abandons HIV vaccine trials

In trials, the vaccine failed to prevent HIV infections among volunteers who were at risk of catching the virus, including gay men and sex workers.

Merck had previously expressed high hopes for the drug, which it spent 10 years developing.

'Headed for failure'

Merck's international trial, called Step, began in 2004 and involved 3,000 HIV-negative volunteers from diverse backgrounds, between the ages of 18 and 45.

Merck said that 24 of 741 volunteers who got the vaccine became infected with HIV, the virus that causes Aids.

Out of a group of 762 volunteers who were given a dummy version of the jab, 21 became infected with HIV.

An independent monitoring panel recommended discontinuing the vaccination of volunteers, saying the trail was headed for failure.