Switch to Second-line Versus WHO-guided Standard of Care for Unsuppressed Patients on First-line ART With Viremia Below 1000 Copies/mL - a Multicenter, Parallel-group, Open-label, Randomized Clinical Study in Rural Lesotho

Study background & rational:

The Joint United Nations Programme on HIV/AIDS (UNAIDS) launched the 90-90-90 targets for 2020 based on the result of newly-acquired scientific evidence that - irrespective of CD4 count - early antiretroviral treatment (ART) for HIV-positive individuals is beneficial to them and prevents HIV transmission. UNAIDS expects that the 90-90-90 targets will lead to a reduction in the yearly global HIV incidence from 2 million currently to 500,000 by 2020.

A crucial step to achieve the third pillar of the UNAIDS 90-90-90 targets - 90% viral suppression among HIV-positive individuals on treatment - and thus ensure a successful treatment outcome is the monitoring and management of first-line ART failure.

Since 2013, the WHO recommends routine viral load (rVL) measurement as the preferred monitoring strategy in resource-limited settings and defines virological failure as confirmed VL 1000 copies/mL despite good adherence. Specifically, the guidelines recommend that in case of a VL ≥ 1000 copies/mL the patient should undergo enhanced adherence support and a second VL test 3 months later. A second VL ≥ 1000 copies/mL with confirmed good adherence would trigger the switch to a second-line regimen, whereas if the VL is < 1000 copies/mL the patient should continue unaltered first-line ART. However, the optimal threshold for defining virological failure and the need for switching ART regimen has not yet been determined. In fact, people with VL levels of less than 1000 copies/mL, but not fully suppressed (usually defined as 50-100 copies/mL), are at a increased risk for drug resistance mutations (DRM) and subsequent virological failure. A recently published study from our research consortium in Lesotho indicates similar findings, demonstrating a significant accumulation of drug resistance mutations in patients with VL levels of less than 1000 copies/mL.

The VL threshold of 1000 copies/mL recommended by the WHO and the Lesotho national guidelines for the switch to second-line ART is likely to miss a substantial number of patients on first-line ART with persisting virus replication below 1000 copies/mL with DRM. In resource-limited settings where VL monitoring is not as frequent as in high-income countries, this could have serious implications: after a VL below 1000 copies/mL the patient may not receive a follow-up VL for up to a year, and thus may continue on a failing regimen for a long period of time. In conclusion, such patients are at increased risk for DRM, accumulation of further resistance mutations, drug-resistant virus transmission, and subsequent virological failure.