Retaining tenofovir after the failure of first-line treatment rather than replacing it with zidovudine was associated with better retention in care, better adherence and better viral load suppression in people with HIV in Haiti, especially when combined with atazanavir/ritonavir, Aidsmap reports Dr Samuel of GHESKIO in Port au Prince reported to the 23rd International AIDS Conference (AIDS 2020: Virtual).
World Health Organisation guidelines recommend the use of tenofovir disoproxil fumarate (TDF) in first-line treatment in resource-limited settings. If first-line treatment fails, the guidelines recommend switching from tenofovir to zidovudine, but there are concerns that twice-daily dosing of zidovudine may cause adherence difficulties. The side effects of zidovudine, including nausea, anaemia and limb fat loss, also make it an unattractive option for second-line treatment.
An alternative second-line option is to recycle tenofovir as part of a new combination, based on limited evidence that recycling the drug contributes to viral suppression despite the presence of the K65R mutation.
A meta-analysis of studies of drug resistance after first-line failure showed that more than half of people taking the drug developed tenofovir resistance after failure of their first-line regimen in sub-Saharan Africa and people with subtype C HIV were at higher risk of developing resistance.
The report says resistance testing in Haiti’s GHESKIO HIV clinic shows that 30% of people on failing first-line treatment have the K65R resistance mutation associated with resistance to tenofovir.
To assess the impact of retaining tenofovir in second-line treatment, researchers carried out a retrospective review of all adults who experienced failure of a first-line regimen of tenofovir/lamivudine/efavirenz and who switched to second-line treatment containing either tenofovir/lamivudine or zidovudine/lamivudine.
Abstract
Sub-optimal outcomes with switching to zidovudine vs. recycling tenofovir in second-line treatment in Haiti. 23rd International AIDS Conference, abstract OAB0405, 2020.
Not available online
[link url="https://www.aidsmap.com/news/jul-2020/recycling-tenofovir-better-switch-second-line-zidovudine"]Full Aidsmap report[/link]