UC San Diego

Background

Virological monitoring (VM) and drug resistance (DR) analysis are crucial for effective HIV management. Due to the high cost of commercial assays, VM and DR analysis is not performed in resource-limited-settings.

Objective

The objective of this study is to develop a pooling based algorithm for the combined identification of virologic treatment failure (VTF) by nucleic acid testing (NAT) and DR by sequencing - NAT+DR assay.

Study design

We enrolled 559 participants on first-line therapy and analyzed for VTF. The virologically suppressed participants were followed-up to see the VTF prevalence (>1000 copies/mL) and DR by the NAT+DR pooling. Each pool comprising 5 plasma samples were amplified by targeting reverse transcriptase gene, if found positive, the pool was deconvoluted and samples were individually tested for HIV RNA and DR. Assay characteristics of NAT+DR assay were calculated in comparison with commercial assay.

Results

Of 559 participants, 67 had VTF at baseline and were excluded. Of the remaining 478 participants, 325 returned for follow-up and NAT+DR assay was performed for them. Of 65 pools tested, 13 pools were positive. On deconvolution 14 individuals were found to have VTF. Sensitivity, specificity, positive predictive value and negative predictive value was 100%, relative efficiency was 59% and 87% & 85% cost was saved for identifying VTF and combined identification of VTF and DR, respectively.

Conclusions

Pooled NAT+DR assay is likely a good strategy to drastically reduce the cost and sustainability of the VM and can thereby facilitate the scale-up of successful HIV treatment programs, and reduce unnecessary switching to second-line drugs in resource-limited-settings.