“
crucial in

widening African

children’s access

to antiretrovirals

”

Bringing antiretroviral drugs to children

The CHAPAS trials have ensured that many more children with HIV have benefited
from life-saving antiretrovirals.

The challenge

HIV/AIDS is the leading cause of death of young people aged 10–24 in Africa. Between 2000 and 2015, the number of adolescents dying from AIDS-related illness tripled – the only age group in which the number of deaths rose. Young people account for 37% of all new HIV infections, and in 2016 nearly three-quarters of all new HIV infections in adolescents occurred in Africa.

These figures suggest that prevention strategies that have proven effective in other populations are not working in this age group, and alternatives are required.

The CHAPS project is evaluating a range of strategies adapted to the characteristics of adolescents. These include a modified version of pre-exposure prophylaxis (PrEP) – pre-emptive use of antiretroviral drugs to prevent infection. Although daily PrEP has been clearly shown to reduce the risk of HIV infection, it is costly, has some side effects, and adherence is less good in adolescents.

The CHAPS project aims to overcome these challenges by evaluating the impact of an alternative, less toxic drug combination (tenofovir alafenamide and emtricitabine) as well as ‘on-demand’ PrEP – use of PrEP just around the time of sexual activity.

The project is consulting with adolescents to determine attitudes to on-demand PrEP and its likely acceptability. Laboratory-based studies are being used to optimise dose levels and dosing schedules for the novel antiretroviral drug combination. The CHAPS team is also undertaking laboratory studies to explore whether the drug combination could provide protection for longer periods after exposure to HIV, allowing more flexible use of post-exposure prophylaxis.

The project

The later CHAPAS-3 trial compared the efficacy and safety of three fixed-dose combinations including two without stavudine (found to have some long-term side effects in adults, leading to a recommendation that its use be discontinued in children). The trial the first of its kind in Africa studied nearly 500 children at four sites in two African countries.

The CHAPS study is the first to undertake research into attitudes to on-demand PrEP among adolescents in sub-Saharan Africa and the first multi-country study to investigate optimal dosing for on-demand PrEP. Its findings will play a key role in shaping the design of trials of on-demand PrEP in a group where more effective prevention is urgently required.

ratios forfixed-dose combinations and on appropriatedosage according to weight. 

The CHAPAS-3 trial confirmed the effectiveness of fixed-dose combinations, providing further impetus to the rollout of antiretrovirals to children. Its evidence on abacavir informed the WHO recommendation of abacavir-containing combinations for first-line therapy in children. Trial data have also been used to support applications for regulatory approval for new scored efavirenz tablets.

Impact