Lamivudine Monotherapy: Experience of Medium-term Outcomes in HIV-infected Children Unable to Adhere to Triple Therapy

Human Immunodeficiency Virus-1 Viral Load Is Elevated in Individuals With Reverse-Transcriptase Mutation M184V/I During Virological Failure of First-Line Antiretroviral Therapy and Is Associated With Compensatory Mutation L74I

BACKGROUND

M184V/I cause high-level lamivudine (3TC) and emtricitabine (FTC) resistance and increased tenofovir disoproxil fumarate (TDF) susceptibility. Nonetheless, 3TC and FTC (collectively referred to as XTC) appear to retain modest activity against human immunodeficiency virus-1 with these mutations possibly as a result of reduced replication capacity. In this study, we determined how M184V/I impacts virus load (VL) in patients failing therapy on a TDF/XTC plus nonnucleoside reverse-transcriptase inhibitor (NNRTI)-containing regimen.

METHODS

We compared VL in the absence and presence of M184V/I across studies using random effects meta-analysis. The effect of mutations on virus reverse-transcriptase activity and infectiousness was analyzed in vitro.

RESULTS

M184I/V was present in 817 (56.5%) of 1445 individuals with virologic failure (VF). Virus load was similar in individuals with or without M184I/V (difference in log10 VL, 0.18; 95% confidence interval, .05-.31). CD4 count was lower both at initiation of antiretroviral therapy and at VF in participants who went on to develop M184V/I. L74I was present in 10.2% of persons with M184V/I but absent in persons without M184V/I (P < .0001). In vitro, L74I compensated for defective replication of M184V-mutated virus.

CONCLUSIONS

Virus loads were similar in persons with and without M184V/I during VF on a TDF/XTC/NNRTI-containing regimen. Therefore, we did not find evidence for a benefit of XTC in the context of first-line failure on this combination.

Use and Outcomes of Antiretroviral Monotherapy and Treatment Interruption in Adolescents With Perinatal HIV Infection in Asia

PURPOSE

Antiretroviral monotherapy and treatment interruption are potential strategies for perinatally HIV-infected adolescents (PHIVA) who face challenges maintaining effective combination antiretroviral therapy (ART). We assessed the use and outcomes for adolescents receiving monotherapy or undergoing treatment interruption in a regional Asian cohort.

METHODS

Regional Asian data (2001-2016) were analyzed to describe PHIVA who experienced ≥2 weeks of lamivudine or emtricitabine monotherapy or treatment interruption and trends in CD4 count and HIV viral load during and after episodes. Survival analyses were used for World Health Organization (WHO) stage III/IV clinical and immunologic event-free survival during monotherapy or treatment interruption, and a Poisson regression to determine factors associated with monotherapy or treatment interruption.

RESULTS

Of 3,448 PHIVA, 84 (2.4%) experienced 94 monotherapy episodes, and 147 (4.3%) experienced 174 treatment interruptions. Monotherapy was associated with older age, HIV RNA >400 copies/mL, younger age at ART initiation, and exposure to ≥2 combination ART regimens. Treatment interruption was associated with CD4 count <350 cells/μL, HIV RNA ≥1,000 copies/mL, ART adverse event, and commencing ART age ≥10 years compared with age <3 years. WHO clinical stage III/IV 1-year event-free survival was 96% and 85% for monotherapy and treatment interruption cohorts, respectively. WHO immunologic stage III/IV 1-year event-free survival was 52% for both cohorts. Those who experienced monotherapy or treatment interruption for more than 6 months had worse immunologic and virologic outcomes.

CONCLUSIONS

Until challenges of treatment adherence, engagement in care, and combination ART durability/tolerability are met, monotherapy and treatment interruption will lead to poor long-term outcomes.

What Should We Do When HIV-positive Children Fail First-line Combination Antiretroviral Therapy? A Comparison of 4 ART Management Strategies

BACKGROUND

Managing virologic failure (VF) in HIV-infected children is especially difficult in resource-limited settings, given limited availability of alternative drugs, concerns around adherence, and the development of HIV resistance mutations. We aimed to evaluate 4 management strategies for children following their first episode of VF by comparing their immunologic and virologic outcomes.

METHODS

We included children (< 16 years of age) with VF from 8 International Epidemiologic Database to Evaluate AIDS Southern Africa cohorts, initiating combination antiretroviral therapy (cART) between 2004 and 2010, who followed one of the 4 management strategies: continuing on their failing regimen; switching to a second-line regimen; switching to a holding regimen (either lamivudine monotherapy or other non-cART regimen); discontinuing all ART. We compared the effect of management strategy on the 52-week change in CD4% and log10VL from VF, using inverse probability weighting of marginal structural linear models.

RESULTS

Nine hundred eighty-two patients were followed over 54,168 weeks. Relative to remaining on a failing regimen, switching to second-line showed improved immunologic and virologic responses 52 weeks after VF with gains in CD4% of 1.5% (95% confidence interval [CI], 0.2-2.8) and declines in log10VL of -1.4 copies/mL (95% CI, -2.0, -0.8), while switching to holding regimens or discontinuing treatment had worse immunologic (-5.4% (95% CI, -12.1, 1.3) and -5.6% (95% CI, -15.4, 4.1) and virologic outcomes (0.2 (95% CI, -3.6, 4.1) and 0.8 (95% CI, -0.6, 2.1), respectively.

CONCLUSIONS

The results provide useful guidance for managing children with VF. Consideration should be given to switching children failing first-line cART to second-line, given the improved virologic and immune responses when compared with other strategies.

Lamivudine monotherapy as a holding regimen for HIV-positive children

Background

In resource-limited settings holding regimens, such as lamivudine monotherapy (LM), are used to manage HIV-positive children failing combination antiretroviral therapy (cART) to mitigate the risk of drug resistance developing, whilst adherence barriers are addressed or when access to second- or third-line regimens is restricted. We aimed to investigate characteristics of children placed on LM and their outcomes.

Methods

We describe the characteristics of children (age <16 years at cART start) from 5 IeDEA-SA cohorts with a record of LM during their treatment history. Among those on LM for >90 days we describe their immunologic outcomes on LM and their immunologic and virologic outcomes after resuming cART.

Findings

We included 228 children in our study. At LM start their median age was 12.0 years (IQR 7.3–14.6), duration on cART was 3.6 years (IQR 2.0–5.9) and median CD4 count was 605.5 cells/μL (IQR 427–901). Whilst 110 (48%) had no prior protease inhibitor (PI)-exposure, of the 69 with recorded PI-exposure, 9 (13%) patients had documented resistance to all PIs. After 6 months on LM, 70% (94/135) experienced a drop in CD4, with a predicted average CD4 decline of 46.5 cells/μL (95% CI 37.7–55.4). Whilst on LM, 46% experienced a drop in CD4 to <500 cells/μL, 18 (8%) experienced WHO stage 3 or 4 events, and 3 children died. On resumption of cART the average gain in CD4 was 15.65 cells/uL per month and 66.6% (95% CI 59.3–73.7) achieved viral suppression (viral load <1000) at 6 months after resuming cART.

Interpretation

Most patients experienced immune decline on LM. Its use should be avoided in those with low CD4 counts, but restricted use may be necessary when treatment options are limited. Managing children with virologic failure will continue to be challenging until more treatment options and better adherence strategies are available.

Decline in CD4 T lymphocytes with monotherapy bridging strategy for non-adherent adolescents living with HIV infection: Results of the IMPAACT P1094 randomized trial

INTRODUCTION

Management of persistently non-adherent youth living with HIV (YLHIV) with virologic failure (VF) on combination antiretroviral therapy (cART) remains challenging. One strategy has been using 3TC/ FTC monotherapy (3TC/FTC), which in the presence of the M184V resistance mutation, does not suppress viral replication nor select for additional drug resistance mutations, and reduces viral fitness with limited side effects. P1094 compared the immunologic outcome of continuing failing cART vs. switching to 3TC/FTC as a "bridging strategy" to subsequent suppressive cART for non-adherent YLHIV with pre-existing M184V resistance.

MATERIALS & METHODS

Participants with documented nonadherence, M184V mutation, CD4+ T cell count ≥100 cells/mm3 and VF (HIV-1 plasma RNA ≥400 copies/mL (2.6 log10 HIV-1 RNA) were enrolled and randomized to continue failing cART vs. switch to 3TC/FTC. The primary endpoint (time to ≥30% CD4+ T cell decline or development of CDC class C events) at 28-weeks were assessed by Kaplan-Meier (K-M) curves in an intent-to-treat analysis.

RESULTS

Thirty-three perinatally acquired YLHIV participants (16 continuing cART and 17 3TC/FTC) enrolled in the study. The median age, entry CD4+ T cell count, and viral load were 15 years (Inter-quartile range (IQR) 14-20), 472 cells/mm3 (IQR 384-651), and 4.0 log10HIV-1 RNA copies/ml (IQR 3.2-4.5), respectively. Five participants, all in the 3TC/FTC arm, reached the primary endpoint for absolute CD4+ T cell decline (p = 0.02, exact log-rank test comparing monotherapy to cART). The Kaplan-Meier estimate of probability of primary endpoint on 3TC/FTC at 28 weeks was 0.41 (standard error 0.14). There were no CDC class C events or deaths and no statistically significant difference in frequencies of adverse events between the arms.

CONCLUSIONS

Non-adherent participants randomized to 3TC/FTC were more likely than those maintained on failing cART to experience a confirmed decline in CD4+ count of ≥30%. Although this study suffers from limitations of small sample size and premature discontinuation, the randomized comparison to continuing failing cART indicates that 3TC/FTC provides inferior protection from immunologic deterioration for non-adherent youth with M184V resistance. Better alternatives to 3TC/FTC such as ART with higher barriers to resistance and novel adherence and treatment strategies for nonadherent youth are urgently needed.

TRIAL REGISTRATION

Clinical Trials.gov NCT01338025.