It causes 20- to 50-fold resistance to the most available NNRTIs, which is sufficient to cause virological BGB324 failure [24,25]. It was not surprising to find a high

frequency of the K103N mutation because of the common use of NNRTIs in Honduras and the ability of the virus to develop NNRTI resistance mutations during monotherapy and during incomplete viral suppression [25]. Some limitations of our analysis should be mentioned. The patients were classified as failing their current cART based on virological, immunological, and/or clinical data; but some patients may incorrectly have been classified as failing their current regimen because access to laboratory monitoring is limited in Honduras. Furthermore, for logistical reasons (i.e. safe transport of high-quality samples to Sweden), only 42 resistance tests were performed using plasma samples and the remaining sequences were obtained from PBMCs. We compared the mutational resistance patterns in plasma and PBMCs for these 42 patients and observed a high concordance. Similar results have been shown

in other studies [26–28]. hypoxia-inducible factor pathway Thus, we feel that it is unlikely that our findings have been significantly affected by the fact that most resistance tests were carried out on PBMC DNA. Another potential limitation of our study is that it is difficult to precisely estimate the representativeness of our study population with regard DOK2 to all patients failing ART in Honduras because there is no reliable information about how many patients have successful vs. failing first- or second-line therapy. In conclusion, we have documented a high prevalence of resistance to antiretroviral drugs in this sample of antiretroviral-treated adult and paediatric HIV-infected patients in Honduras. Most of the treatment failures observed in these patients can be attributed to the previous use of mono and dual therapy and to limited and interrupted access to antiretroviral drugs in this country. Irregular access to CD4

and VL testing is an additional problem. Similarly, there is a need to establish access to routine resistance testing in Honduras, and this is one of the overall aims of the bilateral collaboration between Honduras and Sweden. In our study, virological failure was the strongest predictor of resistance. This suggests that plasma HIV RNA quantification may be clinically beneficial and cost effective through preventing unnecessary treatment changes. Thus, the management of these heavily treatment-experienced HIV-infected patients represents a considerable challenge for HIV clinicians in Honduras. There is an urgent need for improved and sustainable access to antiretroviral drugs, including boosted PIs, newly introduced NNRTIs, and entry and integrase inhibitors, as well as VL, CD4 and resistance testing. We thank all collaborators in this study.