High-level cross-resistance to didanosine observed in South African children failing an abacavir- or stavudine-based 1st-line regimen

Resistance is common in paediatric patients failing ART in South Africa

BACKGROUND

Minimal data exist on HIV drug resistance patterns and prevalence among paediatric patients failing ART in resource-limited settings. We assessed levels of HIV drug resistance in children with virological failure.

METHODS

This cross-sectional study, performed from March 2017 to March 2019 in South Africa, enrolled HIV-positive children aged ≤19 years, receiving ART through public health facilities with recent evidence suggestive of virological failure (at least one viral load ≥1000 copies/mL), across 45 randomly selected high-volume clinics from all nine provinces. Resistance genotyping was performed using next-generation sequencing technologies. Descriptive analysis taking into account survey design was used to determine outcomes.

RESULTS

Among 899 participants enrolled, the adjusted proportion of HIV drug resistance among children with virological failure was 87.5% (95% CI 83.0%-90.9%). Resistance to NNRTIs was detected in 77.4% (95% CI 72.5%-81.7%) of participants, and resistance to NRTIs in 69.5% (95% CI 62.9%-75.4%) of participants. Overall, resistance to PIs was detected in 7.7% (95% CI 4.4%-13.0%) of children.

CONCLUSIONS

HIV drug resistance was highly prevalent in paediatric patients failing ART in South Africa, with 9 in 10 patients harbouring resistance to NNRTIs and/or NRTIs. PI-based regimens are predicted to be highly efficacious in achieving virological suppression amongst patients failing NNRTI-based regimens. Scaling up resistance testing amongst patients would facilitate access to second- and third-line regimens in South Africa.

Drug Resistance Mutations Among South African Children Living With HIV on WHO-recommended ART Regimens

BACKGROUND

Children living with human immunodeficiency virus (HIV) (CLHIV) receiving antiretroviral therapy (ART) in resource-limited settings are susceptible to high rates of acquired HIV drug resistance (HIVDR), but few studies include children initiating age-appropriate World Health Organization (WHO)-recommended first-line regimens. We report data from a cohort of ART-naive South African children who initiated first-line ART.

METHODS

ART-eligible CLHIV aged 0-12 years were enrolled from 2012 to 2014 at 5 public South African facilities and were followed for up to 24 months. Enrolled CLHIV received standard-of-care WHO-recommended first-line ART. At the final study visit, a dried blood spot sample was obtained for viral load and genotypic resistance testing.

RESULTS

Among 72 successfully genotyped CLHIV, 49 (68.1%) received ABC/3TC/LPV/r, and 23 (31.9%) received ABC/3TC/EFV. All but 2 children on ABC/3TC/LPV/r were <3 years, and all CLHIV on ABC/3TC/EFV were ≥3 years. Overall, 80.6% (58/72) had at least one drug resistance mutation (DRM). DRMs to nonnucleoside reverse transcriptase inhibitors (NNRTIs) and nucleoside reverse transcriptase inhibitors (NRTIs) were found among 65% and 51% of all CLHIV, respectively, with no statistical difference by ART regimen. More CLHIV on ABC/3TC/EFV, 47.8% (11/23), were found to have 0 or only 1 effective antiretroviral drug remaining in their current regimen compared to 8.2% (4/49) on ABC/3TC/LPV/r.

CONCLUSIONS

High levels of NNRTI and NRTI DRMs among CLHIV receiving ABC/3TC/LPV/r suggests a lasting impact of failed mother-to-child transmission interventions on DRMs. However, drug susceptibility analysis reveals that CLHIV with detectable viremia on ABC/3TC/LPV/r are more likely to have maintained at least 2 effective agents on their current HIV regimen than those on ABC/3TC/EFV.

Antiretroviral agents in pre-exposure prophylaxis: emerging and advanced trends in HIV prevention

OBJECTIVES

Antiretroviral agents (ARVs) have been the most promising line of therapy in the management of human immunodeficiency virus (HIV) infections. Some of these ARVs are used in the pre-exposure prophylaxis (PrEP) to suppress the transmission of HIV. Prophylaxis is primarily used in uninfected people, before exposure, to effectively prevent HIV infection. Several studies have shown that ART PrEP prevents HIV acquisition from sexual, blood and mother-to-child transmissions. However, there are also several challenges and limitations to PrEP. This review focuses on the current antiretroviral therapies used in PrEP.

KEY FINDINGS

Among ARVs, the most common drugs employed from the class of entry inhibitors are maraviroc (MVC), which is a CCR5 receptor antagonist. Other entry inhibitors like emtricitabine (FTC) and tenofovir (TFV) are also used. Rilpivirine (RPV) and dapivirine (DPV) are the most common drugs employed from the Non-nucleoside reverse transcriptase inhibitor (NNRTIs) class, whereas, tenofovir disoproxil fumarate (TDF) is primarily used in the Nucleoside Reverse Transcriptase Inhibitor (NRTIs) class. Cabotegravir (CAB) is an analog of dolutegravir, and it is an integrase inhibitor. Some of these drugs are also used in combination with other drugs from the same class.

SUMMARY

Some of the most common pre-exposure prophylactic strategies employed currently are the use of inhibitors, namely entry inhibitors, non-nucleoside reverse transcriptase inhibitors, nucleoside reverse transcriptase inhibitors, integrase and protease inhibitors. In addition, we have also discussed on the adverse effects caused by ART in PrEP, pharmacoeconomics factors and the use of antiretroviral prophylaxis in serodiscordant couples.

High Prevalence of Abacavir-associated L74V/I Mutations in Kenyan Children Failing Antiretroviral Therapy

A survey of 461 HIV-infected Kenyan children receiving antiretroviral therapy found 143 (31%) failing virologically. Drug resistance mutations were found in 121; 37 had L74V/I mutations, with 95% receiving abacavir (ABC)-containing regimens. L74V/I was associated with current ABC usage (P = 0.0001). L74V/I may be more prevalent than previously realized in children failing ABC-containing regimens, even when time on treatment has been short. Ongoing rigorous pediatric drug resistance surveillance is needed.

A farewell to didanosine: harm reduction and cost savings by eliminating use of didanosine

Didanosine (ddI) is a nucleoside reverse transcriptase inhibitor associated with adverse events and public health concerns which have diminished its place in HIV clinical practice, particularly in resource-rich settings. While international guidelines do not contain ddI-containing regimens in preferred first- or second-line antiretroviral therapy (ART), there is no guidance for management of patients currently on ddI. In 2012 at least 20 countries purchased a total of $1-2 million of ddI. Drug purchase data in that year show 3.2-10.3 times higher costs for ddI compared to lamivudine (3TC). Given issues of multiple toxicities, monitoring, drug interactions, inconvenience, and virologic efficacy, as well as cost and formulary concerns, national (including resource-limited setting) ART programmes should consider complete phase-out of ddI.

Short Communication: In Vitro Accumulation of Drug Resistance Mutations in Chimeric Infectious Clones Containing Subtype B or C Reverse Transcriptase and Selected with Tenofovir or Didanosine

Highly active antiretroviral therapy (HAART) contributed to the improvement in the life expectancy of HIV-infected patients. However, the emergence of drug-resistant mutations (DRM) is a major viral factor impacting therapeutic failure. Differences in DRM can occur among HIV-1 subtypes. We evaluate the kinetics of the selection of resistance mutations in vitro analyzing two chimeric clones that contain the reverse transcriptases of subtypes B or C (RTB' and RTC') in cells treated with increasing concentrations of tenofovir disoproxil fumarate (TDF) and didanosine (ddI). The mutation K65R is selected more quickly in RTC' than in RTB' viruses with TDF and ddI, and additional mutations (positions 45, 62, and 68) were selected after K65R fixation. Other primary mutations (M184V and Q151M) were selected with ddI treatment in conjunction with K65R only in RTC' viruses. Both patterns, M184V+K65R and Q151M+K65R, have a significant impact on NRTI resistance. Our data suggest that selection of TDF and ddI DRMs can occur earlier in subtype C HIV in patients when compared to subtype B.