Concept sheet - Second line treatment, TasP

An estimated quarter of all HIV infected individuals treated with antiretroviral therapy (ART) are failing treatment on first line non-nucleoside reverse transcriptase inhibitor (NNRTI) based treatment and qualify for protease inhibitor based (bPI) second line treatment. It has been observed that up to 32% of those on second line bPI treatment do not suppress the virus, , . This has implications for third line therapy in resource limited settings.

Although the published studies are limited, there is a suggestion that the prevalence of PI drug resistance mutation at second line failure in South Africa is very low, up to 7% whereas drug resistance in other drug classes remain high, up to 78% i, v, , . All but one of these studies measured the contribution of non-adherence to second line failure. The contribution of non-adherence, drug toxicity, pharmacokinetics eg concomitant rifampicin use and pharmacodynamics eg lack of refrigerator for soft gel lopinavir tablets to second line failure have been insufficiently studied.

This study aims to estimate the incidence rate of second line failure, the prevalence of antiretroviral drug resistance and to investigate factors associated with second line failure including but not limited to non-adherence, the duration on failing first line regimen, retention in care, drug tolerance, concomitant rifampicin use and lack of refrigeration of lopinavir amongst the TasP second line failing HIV-1 patients.