- A 64-week study conducted in West Africa suggests that the lack of access to resistance testing should not be an obstacle to the prescription of third-line antiretroviral therapy (ART, darunavir plus raltegravir).
- Genotypic resistance tests, performed at the end of the study, showed that the decision to switch from second-line ART to third-line ART at 16 weeks, based on viral load measurement after 12 weeks of intensive adherence interventions, was appropriate in 75% of patients.
- Poor adherence appears as a manageable problem since intensive adherence interventions result in viral suppression in most HIV-infected people on second-line ART.
According to a 64-week study, the decision to switch to third-line ART in patients on second-line ART with virological failure is possible also when genotypic resistance tests are not available. In this setting, a standardised algorithm, based on intensive adherence interventions followed by a viral load measurement, is an efficient strategy.
The study enrolled 197 HIV-1 infected individuals on second-line ART from 4 West African countries (2013-2015), applying adherence reinforcement interventions (pill organiser, weekly phone calls and daily alarm reminders are the most popular).
Based on plasma HIV-1 RNA measurement at week 12, 63 (33%) of whom did not reach successful resuppression, switched to third-line ART at week 16, whereas 130 (67%) continued with second-line ART. This result suggests that poor adherence, the most common cause of ART failure since it can leads to drug resistance via suboptimal viral suppression, can be a manageable problem.
Genotypic resistance tests performed on baseline plasma samples, after the end of the study, showed that in 166 patients with a calculable genotypic susceptibility score, the decision taken was appropriate in 145 (75%) patients. At week 64, among patients remaining in the study, 101 (52%) had a viral load less than 50 copies per mL.
This study provides the first data on third-line therapy based on darunavir plus raltegravir in West Africa and suggests that in this setting, lack of access to resistance testing should not be an obstacle to its prescription.
Limitations: The schedule of visits and viral load testing is not feasible in remote areas.