High-Level Cross-Resistance to Didanosine Observed in South African Children Failing an Abacavir- or Stavudine-Based 1st-Line Regimen

Background

The knowledge-base of emerging drug resistance profiles in children exposed to abacavir-based antiretroviral regimens in South Africa is very limited. This study investigated the suitability of didanosine-based 2^nd-line regimens for children in the context of antiretroviral drug resistance patterns emerging after 1^st-line virologic failure.

Methods

A retrospective dataset of 354 antiretroviral drug resistant genotypes from children failing either abacavir (n = 81) or stavudine (n = 273) based 1^st-line regimens, was analysed. Samples were sent to the HIV genotyping laboratory at Charlotte Maxeke Johannesburg Academic Hospital, for routine testing. Pol sequences were submitted to the Stanford HIV drug resistance database for genotypic predictions.

Results

Children were exposed to abacavir or stavudine-based 1^st-line regimens for an average of 21 and 36 months, respectively. The frequency of reduced susceptibility to didanosine was substantial in the abacavir-exposed group (69.1%).This reduced susceptibility was commonly attributed to L74V/I (n = 44) and to a lesser extent K65R (n = 10) mutations. Didanosine resistance was observed in 43.2% of patients exposed to stavudine-based regimens. In contrast, most children remained susceptible to stavudine regardless of exposure to abacavir (77.8%) or stavudine (74.7%). At least 80% of children remained susceptible to zidovudine irrespective of stavudine or abacavir-exposure. The presence of the K65R mutation was more common after abacavir pressure (12.3% vs 1.8%).

Conclusion

Analysis revealed that didanosine-based 2^nd-line regimens have limitations for South African children, given the high frequency of mutations that confer cross-resistance to didanosine; especially after abacavir-exposure. This data has influenced South African paediatric treatment guidelines, which now recommend zidovudine-based 2^nd-line regimens.     

Prevalence and impact of minority variant drug resistance mutations in primary HIV-1 infection

Objective

To evaluate minority variant drug resistance mutations detected by the oligonucleotide ligation assay (OLA) but not consensus sequencing among subjects with primary HIV-1 infection.

Design/Methods

Observational, longitudinal cohort study. Consensus sequencing and OLA were performed on the first available specimens from 99 subjects enrolled after 1996. Survival analyses, adjusted for HIV-1 RNA levels at the start of antiretroviral (ARV) therapy, evaluated the time to virologic suppression (HIV-1 RNA<50 copies/mL) among subjects with minority variants conferring intermediate or high-level resistance.

Results

Consensus sequencing and OLA detected resistance mutations in 5% and 27% of subjects, respectively, in specimens obtained a median of 30 days after infection. Median time to virologic suppression was 110 (IQR 62–147) days for 63 treated subjects without detectable mutations, 84 (IQR 56–109) days for ten subjects with minority variant mutations treated with ≥3 active ARVs, and 104 (IQR 60–162) days for nine subjects with minority variant mutations treated with <3 active ARVs (p = .9). Compared to subjects without mutations, time to virologic suppression was similar for subjects with minority variant mutations treated with ≥3 active ARVs (aHR 1.2, 95% CI 0.6–2.4, p = .6) and subjects with minority variant mutations treated with <3 active ARVs (aHR 1.0, 95% CI 0.4–2.4, p = .9). Two subjects with drug resistance and two subjects without detectable resistance experienced virologic failure.

Conclusions

Consensus sequencing significantly underestimated the prevalence of drug resistance mutations in ARV-naïve subjects with primary HIV-1 infection. Minority variants were not associated with impaired ARV response, possibly due to the small sample size. It is also possible that, with highly-potent ARVs, minority variant mutations may be relevant only at certain critical codons.     

Traditional but Not HIV-Related Factors Are Associated with Nonalcoholic Fatty Liver Disease in Asian Patients with HIV-1 Infection

Background

The prevalence and factors associated with nonalcoholic fatty liver disease (NAFLD) are largely unknown in HIV-1 monoinfected patients.

Methods

The present study elucidated the prevalence and factors associated with NAFLD among Asian patients with HIV-1 infection who underwent abdominal ultrasonography between January 2004 and March 2013. Diagnosis of NAFLD was based on the liver to kidney contrast and diffusion in hepatic echogenicity. Uni- and multi-variate logistic regression analyses were applied to estimate factors associated with NAFLD.

Results

435 Asian patients free of chronic hepatitis B or C virus infection and without excessive alcohol intake were analyzed. NAFLD was diagnosed in 135 (31%) patients. Obesity (BMI >30 kg/m²) was evident in 18 (4.1%) patients, and BMI was >25 kg/m² in 103 (24%). Multivariate analysis identified higher BMI (per 1 kg/m² increment, adjusted OR = 1.198; 95% CI, 1.112–1.290; p<0.001), dyslipidemia (adjusted OR = 2.045; 95% CI, 1.183–3.538; p = 0.010), and higher ALT to AST ratio (per 1 increment, adjusted OR = 3.557; 95% CI, 2.129–5.941; p<0.001) as significant factors associated with NAFLD. No HIV-specific variables, including treatment with dideoxynucleoside analogues (didanosine, stavudine, and zalcitabine) and cumulative duration of antiretroviral therapy (ART), were associated with NAFLD.

Conclusions

The incidence of NALFD among Asian patients with HIV-1 infection is similar to that in Western countries. NAFLD was associated with high BMI, dyslipidemia, and high ALT/AST ratio, but not with HIV-related factors. The results highlight the importance of early recognition and management of NAFLD and traditional factors associated with NAFLD for Asian patients with HIV-1 infection.