A randomized study of intensified antiretroviral treatment monitoring versus standard-of-care for prevention of drug resistance and antiretroviral treatment switch

Introduction:
Standard-of-care antiretroviral treatment (ART) monitoring in low and middle-income countries consists of annual determination of HIV-RNA viral load with confirmatory viral load testing in case of viral rebound. We evaluated an intensified monitoring strategy of three-monthly viral load testing with additional drug exposure and drug resistance testing in case of viral rebound.

Methods:
We performed an open-label randomized controlled trial (RCT) at a rural South African healthcare clinic, enrolling adults already receiving or newly initiating first-line ART. During 96 weeks follow-up, intervention participants received three-monthly viral load testing and sequential point-of-care drug exposure testing and DBS-based drug resistance testing in case of rebound above 1000 copies/ml. Control participants received standard-of-care monitoring according to the WHO guidelines.

Results:
Five hundred one participants were included, of whom 416 (83.0%) were randomized at 24 weeks. Four hundred one participants were available for intention-to-treat analysis. Viral rebound occurred in 9.0% (18/199) of intervention participants and in 11.9% (24/202) of controls (P = 0.445). Time to detection of rebound was 375 days [interquartile range (IQR): 348-515] in intervention participants and 360 days [IQR: 338-464] in controls [hazard ratio: 0.88 (95% confidence interval (95% CI): 0.46-1.66]; P = 0.683]. Duration of viral rebound was 87 days [IQR: 70-110] in intervention participants and 101 days [IQR: 78-213] in controls (P = 0.423). In the control arm, three patients with confirmed failure were switched to second-line ART. In the intervention arm, of three patients with confirmed failure, switch could initially be avoided in two cases.

Conclusion:
Three-monthly viral load testing did not significantly reduce the duration of viraemia when compared with standard-of-care annual viral load testing, providing randomized trial evidence in support of annual viral load monitoring.