Impact Of Low-Frequency HIV-1 Drug Resistance Mutations On Antiretroviral Therapy Outcomes

BACKGROUND

The association between low-frequency HIV-1 drug resistance mutations (DRMs) and treatment failure (TF) is controversial. We explore this association using NGS methods that accurately sample low-frequency DRMs.

METHODS

We enrolled women with HIV-1 in Malawi who were either ART naïve (A), had ART failure (B), or had discontinued ART (C). At entry, A and C began an NNRTI-based regimen and B started a PI-based regimen. We used Primer ID MiSeq to identify regimen-relevant DRMs in entry and TF plasma samples, and a Cox proportional hazards model to calculate hazard ratios (HRs) for entry DRMs. Low-frequency DRMs were defined as ≤ 20%.

RESULTS

We sequenced 360 participants. Cohort B and C participants were more likely to have TF than Cohort A participants. The presence of K103N at entry significantly increased TF risk among A and C participants at both high and low frequency, with HR of 3.12 [1.58-6.18, 95% CI] and 2.38 [1.00-5.67, 95% CI] respectively. At TF, 45% of participants showed selection of DRMs while in the remaining participants there was an apparent lack of selective pressure from ART.

CONCLUSIONS

Using accurate NGS for DRM detection may benefit an additional 10% of the patients by identifying low-frequency K103N mutations.

Three-year outcomes for women newly initiated on lifelong antiretroviral therapy during pregnancy - Malawi option B

INTRODUCTION

Antiretroviral therapy (ART) is very effective in preventing vertical transmission of HIV but some women on ART experience different virologic, immunologic, and safety profiles. While most pregnant women are closely monitored for short-term effects of ART during pregnancy, few women receive similar attention beyond pregnancy. We aimed to assess retention in care and clinical and laboratory-confirmed outcomes over 3 years after starting ART under Malawi's Option B + program.

METHODS

We conducted a prospective cohort study of pregnant women newly diagnosed with HIV who started tenofovir disoproxil fumarate/emtricitabine/efavirenz (TDF/3TC/EFV) for the first time at Bwaila Hospital in Lilongwe, Malawi between May 2015 and June 2016. Participants were followed for 3 years. We summarized demographic characteristics, pregnancy outcomes, and clinical and laboratory adverse events findings using proportions. Log-binomial regression models were used to estimate the overall risk ratios (RR) and the corresponding 95% confidence interval (CI) for the association between index pregnancy (i.e. index pregnancy vs. subsequent pregnancy) and preterm birth, and index pregnancy and low birthweight.

RESULTS

Of the 299 pregnant women who were enrolled in the study, 255 (85.3%) were retained in care. There were 340 total pregnancies with known outcomes during the 36-month study period, 280 index pregnancies, and 60 subsequent pregnancies. The risks of delivering preterm (9.5% for index pregnancy and13.5% for subsequent pregnancy: RR = 0.70; 95% CI: 0.32-1.54), or low birth weight infant (9.8% for index pregnancy and 4.2% for subsequent pregnancy: RR = 2.36; 95% CI: 0.58-9.66) were similar between index and subsequent pregnancies. Perinatally acquired HIV was diagnosed in 6 (2.3%) infants from index pregnancies and none from subsequent pregnancies. A total of 50 (16.7%) women had at least one new clinical adverse event and 109 (36.5%) women had at least one incident abnormal laboratory finding. Twenty-two (7.3%) women switched to second line ART: of these 64.7% (8/17) had suppressed viral load and 54.9% (6/17) had undetectable viral load at 36 months.

CONCLUSION

Most of the women who started TDF/3TC/EFV were retained in care and few infants were diagnosed with perinatally acquired HIV. Despite switching, women who switched to second line therapy continued to have higher viral loads suggesting that additional factors beyond TDF/3TC/EFV failure may have contributed to the switch. Ongoing support during the postpartum period is necessary to ensure retention in care and prevention of vertical transmission.

Prevalence of antiretroviral therapy treatment failure among HIV-infected pregnant women at first antenatal care: PMTCT Option B+ in Malawi

BACKGROUND

In Malawi's PMTCT Option B+ program, HIV-infected pregnant women who are already receiving ART are continued on their current therapy regimen without testing for treatment failure at the first antenatal care (ANC) visit. HIV RNA screening at ANC may identify women with treatment failure and ensure that viral suppression is maintained throughout the pregnancy.

METHODS

We conducted a cross-sectional study of HIV-infected pregnant women who had been receiving ART for at least 6 months at the first ANC visit under the PMTCT Option B+ program at Bwaila Hospital in Lilongwe, Malawi from June 2015 to December 2017. Poisson regression models with robust variance were used to investigate the predictors of ART treatment failure defined as viral load ≥1000 copies/ml.

RESULTS

The median age of 864 women tested for ART failure was 31.1 years (interquartile range: 26.9-34.5). The prevalence of treatment failure was 7.6% (95% confidence interval (CI): 6.0-9.6). CD4 cell count (adjusted prevalence ratio (aPR) = 0.57; 95% CI: 0.50-0.65) was strongly associated with treatment failure.

CONCLUSION

The low prevalence of treatment failure among women presenting for their first ANC in urban Malawi demonstrates success of Option B+ in maintaining viral suppression and suggests progress towards the last 90% of the UNAIDS 90-90-90 targets. Women failing on ART should be identified early for adherence counseling and may require switching to an alternative ART regimen.