Isoniazid has early and unexpected benefit in reducing childhood mortality

A South African oral late breaker presented by Martin Cotton evaluated the impact of isoniazid (INH) on mortality in a group of young HIV positive children.

This prospective double blind study conducted at two centres in Cape Town compared INH to placebo given in addition to co-trimoxazole (TMP-SMX) – either daily or three times a week – to a group of 278 HIV positive children with a median age of 23.5 months (range 3 to 123 months). Children in Cape Town have a 4% chance of developing active TB. The study was powered to look at the effect of isoniazid primarily on mortality and secondly on developing active TB.

The children received the INH in accordance with the TMP-SMX schedule. The majority (80%) of the children where symptomatic with HIV and 7% of the children receiving INH and 6% of children receiving placebo were receiving HAART.

Between the initiation of the study – which began enrolment in January 2003 – until May of this year, the investigators reported a total of 32 deaths: 20 in the placebo and 12 in the INH groups – an overall reduction of 53% in the INH groups.

They also noted that the survival benefit appeared early – within 50 days and occurred in all CDC disease stages and age groups although mortality risk was greatest in children less than 8 months old.

Although there was a higher instance of active TB in the children that received placebo -14 cases in placebo and 5 in the INX groups – this was not statistically significant.

Considering these findings the data safety monitoring board discontinued the placebo arm of the study. The study will continue to compare the daily and three times a week TB interventions.

Zar H, Cotton M, Lambard C et al. Early and unexpected benefit of isoniazid in reducing mortality in HIV-infected children in an area of high tuberculosis presence. XV Intl AIDS Conference, Bangkok. Abstract LbOrB12.