Lack of drug-resistance testing should not stop prescription of third-line HIV treatment

02 December 2019

Two-thirds of people with second-line antiretroviral treatment failure can reach viral suppression following adherence support in West Africa.

Stop sign in Guinea Bissau

Viral load testing with subsequent adherence support is broadly sufficient in indicating whether patients should be offered third-line therapy, finds a new study from West Africa.

Treatment failure among people living with HIV in sub-Saharan Africa on second-line antiretroviral treatment (ART) remains unacceptably high. Genotypic resistance testing is considered the ‘gold standard’ in establishing whether people at this stage might still respond to second-line drugs or whether they have developed drug resistance and need to be urgently swapped to a third-line regimen.

But access to this type of testing is scarce in the region. This, coupled with the costly nature of third-line ART drugs, means many people experiencing treatment failure are not offered an alternative. As a result, there is a need to look for methods that do not rely on resistance testing to improve treatment.

This 16-month study was conducted between 2013 and 2015 involving 198 adults from cities in Burkina Faso, Côte d’Ivoire, Mali and Senegal experiencing second-line ART failure.

The study had two stages: in the first, people were offered intensive adherence support for three-months. After three months, participants underwent viral testing, and these results were used to decide who to switch to third-line ART. Adherence support continued throughout the study.

At the end of the 64 weeks, genotypic resistance testing was then carried out on frozen plasma samples, which had been collected from participants during enrolment, and the decision about whether to switch people retrospectively appraised.

Participants were able to chose as many adherence interventions as they wished from the following: support from a relative, a pill organiser, weekly phone calls with a therapist, daily alarm reminders, daily text messages, home visits, individual sessions with health-workers, a self-help group, and limiting other non-essential drugs. Pillboxes, weekly phone calls, alarm reminders, and support from a relative were the most popular interventions.

Five people died before the three-month viral load tests were conducted – underlining the importance of studies such as this. Of the remaining 193, 67% reached viral suppression and continued with second-line ART, suggesting the focus on adherence was extremely effective. The remaining participants were switched to third-line ART. The results provide the first data on the use of third-line raltegravir-boosted darunavir regimens in West Africa.

Participants were then assessed every four weeks. Those who had stayed on second-line ART were switched to third-line treatment if they had two consecutive viral loads more than 1,000 copies per mL.

At the end of the study, 2% of participants had left HIV care, 5% had died and 52% had suppressed viral loads. Third-line ART tolerance was found to be excellent. In line with numerous other findings, women were more likely than men to reach viral suppression.

The post-study resistance testing suggests the decision on whether to switch treatment regimens was correct in 75% of cases. Of the 31 patients who were inappropriately kept on second-line ART, five had been switched to third-line before week 64, 24 were still on second-line ART and 2 people had died.

The findings provide further evidence that comprehensive, patient-centred adherence support is effective for reversing multiple treatment failure. It also shows that, when drug-resistance testing is not available, repeated viral load monitoring is a reasonable strategy for enabling more people to reach viral suppression – and ultimately, better health.

Photo credit:
iStock/Tiago_Fernandez

Written by Hester Phillips

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