HIV-1 Drug Resistance and Second-Line Treatment in Children Randomized to Switch at Low Versus Higher RNA Thresholds

A Per-Protocol Analysis Using Inverse-Probability-of-Censoring Weights in a Randomized Trial of Initial Protease Inhibitor Versus Nonnucleoside Reverse Transcriptase Inhibitor Regimens in Children

Protocol adherence may influence measured treatment effectiveness in randomized controlled trials. Using data from a multicenter trial (Europe and the Americas, 2002-2009) of children with human immunodeficiency virus type 1 who had been randomized to receive initial protease inhibitor (PI) versus nonnucleoside reverse transcriptase inhibitor (NNRTI) antiretroviral therapy regimens, we generated time-to-event intention-to-treat (ITT) estimates of treatment effectiveness, applied inverse-probability-of-censoring weights to generate per-protocol efficacy estimates, and compared shifts from ITT to per-protocol estimates across and within treatment arms. In ITT analyses, 263 participants experienced 4-year treatment failure probabilities of 41.3% for PIs and 39.5% for NNRTIs (risk difference = 1.8% (95% confidence interval (CI): -10.1, 13.7); hazard ratio = 1.09 (95% CI: 0.74, 1.60)). In per-protocol analyses, failure probabilities were 35.6% for PIs and 29.2% for NNRTIs (risk difference = 6.4% (95% CI: -6.7, 19.4); hazard ratio = 1.30 (95% CI: 0.80, 2.12)). Within-arm shifts in failure probabilities from ITT to per-protocol analyses were 5.7% for PIs and 10.3% for NNRTIs. Protocol nonadherence was nondifferential across arms, suggesting that possibly better NNRTI efficacy may have been masked by differences in within-arm shifts deriving from differential regimen forgiveness, residual confounding, or chance. A per-protocol approach using inverse-probability-of-censoring weights facilitated evaluation of relationships among adherence, efficacy, and forgiveness applicable to pediatric oral antiretroviral regimens.

HIV-1 Treatment Failure, Drug Resistance, and Clinical Outcomes in Perinatally Infected Children and Adolescents Failing First-Line Antiretroviral Therapy in Western Kenya

BACKGROUND

Long-term impact of drug resistance in perinatally infected children and adolescents living with HIV (CALWH) is poorly understood. We determined drug resistance and examined its long-term impact on failure and mortality in Kenyan CALWH failing first-line non-nucleoside reverse transcriptase inhibitor-based antiretroviral therapy (ART).

SETTING

Academic Model Providing Access to Healthcare, western Kenya.

METHODS

Participants were enrolled in 2010-2013 (timepoint 1) and a subsample re-enrolled after 4-7 years (timepoint 2). Viral load (VL) was performed on timepoint 1 samples, with genotyping of those with detectable VL. Primary endpoints were treatment failure (VL >1000 copies/mL) at and death before timepoint 2. Multinomial regression analysis was used to characterize resistance effect on death, failure, and loss-to-follow-up, adjusting for key variables.

RESULTS

The initial cohort (n = 480) was 52% (n = 251) female, median age 8 years, median CD4% 31%, 79% (n = 379) on zidovudine/abacavir + lamivudine + efavirenz/nevirapine for median 2 years. Of these, 31% (n = 149) failed at timepoint 1. Genotypes at timepoint 1, available on n = 128, demonstrated 93% (n = 119) extensive resistance, affecting second line. Of 128, 22 failed at timepoint 2, 17 died, and 32 were lost to follow-up before timepoint 2. Having >5 resistance mutations at timepoint 1 was associated with higher mortality [relative risk ratio (RRR) = 8.7, confidence interval (CI) 2.1 to 36.3] and loss to follow-up (RRR = 3.2, CI 1.1 to 9.2). Switching to second line was associated with lower mortality (RRR <0.05, CI <0.05 to 0.1) and loss to follow-up (RRR = 0.1, CI <0.05 to 0.3).

CONCLUSION

Extensive resistance and limited switch to second line in perinatally infected Kenyan CALWH failing first-line ART were associated with long-term failure and mortality. Findings emphasize urgency for interventions to sustain effective, life-long ART in this vulnerable population.

Time to treatment disruption in children with HIV-1 randomized to initial antiretroviral therapy with protease inhibitors versus non-nucleoside reverse transcriptase inhibitors

BACKGROUND

Choice of initial antiretroviral therapy regimen may help children with HIV maintain optimal, continuous therapy. We assessed treatment-naïve children for differences in time to treatment disruption across randomly-assigned protease inhibitor versus non-nucleoside reverse transcriptase inhibitor-based initial antiretroviral therapy.

METHODS

We performed a secondary analysis of a multicenter phase 2/3, randomized, open-label trial in Europe, North and South America from 2002 to 2009. Children aged 31 days to <18 years, who were living with HIV-1 and treatment-naive, were randomized to antiretroviral therapy with two nucleoside reverse transcriptase inhibitors plus a protease inhibitor or non-nucleoside reverse transcriptase inhibitor. Time to first documented treatment disruption to any component of antiretroviral therapy, derived from treatment records and adherence questionnaires, was analyzed using Kaplan-Meier estimators and Cox proportional hazards models.

RESULTS

The modified intention-to-treat analysis included 263 participants. Seventy-two percent (n = 190) of participants experienced at least one treatment disruption during study. At 4 years, treatment disruption probabilities were 70% (protease inhibitor) vs. 63% (non-nucleoside reverse transcriptase inhibitor). The unadjusted hazard ratio (HR) for treatment disruptions comparing protease inhibitor vs. non-nucleoside reverse transcriptase inhibitor-based regimens was 1.19, 95% confidence interval [CI] 0.88-1.61 (adjusted HR 1.24, 95% CI 0.91-1.68). By study end, treatment disruption probabilities converged (protease inhibitor 81%, non-nucleoside reverse transcriptase inhibitor 84%) with unadjusted HR 1.11, 95% CI 0.84-1.48 (adjusted HR 1.13, 95% CI 0.84-1.50). Reported reasons for treatment disruptions suggested that participants on protease inhibitors experienced greater tolerability problems.

CONCLUSIONS

Children had similar time to treatment disruption for initial protease inhibitor and non-nucleoside reverse transcriptase inhibitor-based antiretroviral therapy, despite greater reported tolerability problems with protease inhibitor regimens. Initial pediatric antiretroviral therapy with either a protease inhibitor or non-nucleoside reverse transcriptase inhibitor may be acceptable for maintaining optimal, continuous therapy.

Incidence of switching to second-line antiretroviral therapy and associated factors in children with HIV: an international cohort collaboration

BACKGROUND

Estimates of incidence of switching to second-line antiretroviral therapy (ART) among children with HIV are necessary to inform the need for paediatric second-line formulations. We aimed to quantify the cumulative incidence of switching to second-line ART among children in an international cohort collaboration.

METHODS

In this international cohort collaboration study, we pooled individual patient-level data for children younger than 18 years who initiated ART (two or more nucleoside reverse-transcriptase inhibitors [NRTI] plus a non-NRTI [NNRTI] or boosted protease inhibitor) between 1993 and 2015 from 12 observational cohort networks in the Collaborative Initiative for Paediatric HIV Education and Research (CIPHER) Global Cohort Collaboration. Patients who were reported to be horizontally infected with HIV and those who were enrolled in trials of treatment monitoring, switching, or interruption strategies were excluded. Switch to second-line ART was defined as change of one or more NRTI plus either change in drug class (NNRTI to protease inhibitor or vice versa) or protease inhibitor change, change from single to dual protease inhibitor, or addition of a new drug class. We used cumulative incidence curves to assess time to switching, and multivariable proportional hazards models to explore patient-level and cohort-level factors associated with switching, with death and loss to follow-up as competing risks.

FINDINGS

At the data cutoff of Sept 16, 2015, 182 747 children with HIV were included in the CIPHER dataset, of whom 93 351 were eligible, with 83 984 (90·0%) from sub-Saharan Africa. At ART initiation, the median patient age was 3·9 years (IQR 1·6-6·9) and 82 885 (88·8%) patients initiated NNRTI-based and 10 466 (11·2%) initiated protease inhibitor-based regimens. Median duration of follow-up after ART initiation was 26 months (IQR 9-52). 3883 (4·2%) patients switched to second-line ART after a median of 35 months (IQR 20-57) of ART. The cumulative incidence of switching at 3 years was 3·1% (95% CI 3·0-3·2), but this estimate varied widely depending on the cohort monitoring strategy, from 6·8% (6·5-7·2) in settings with routine monitoring of CD4 (CD4% or CD4 count) and viral load to 0·8% (0·6-1·0) in settings with clinical only monitoring. In multivariable analyses, patient-level factors associated with an increased likelihood of switching were male sex, older age at ART initiation, and initial NNRTI-based regimen (p<0·0001). Cohort-level factors that increased the likelihood of switching were higher-income country (p=0·0017) and routine or targeted monitoring of CD4 and viral load (p<0·0001), which was associated with a 166% increase in likelihood of switching compared with CD4 only monitoring (subdistributional hazard ratio 2·66, 95% CI 2·22-3·19).

INTERPRETATION

Our global paediatric analysis found wide variations in the incidence of switching to second-line ART across monitoring strategies. These findings suggest the scale-up of viral load monitoring would probably increase demand for paediatric second-line ART formulations.

FUNDING

International AIDS Society-CIPHER.

Time to First-Line ART Failure and Time to Second-Line ART Switch in the IeDEA Pediatric Cohort

BACKGROUND

Globally, 49% of the estimated 1.8 million children living with HIV are accessing antiretroviral therapy (ART). There are limited data concerning long-term durability of first-line ART regimens and time to transition to second-line.

METHODS

Children initiating their first ART regimen between 2 and 14 years of age and enrolled in one of 208 sites in 30 Asia-Pacific and African countries participating in the Pediatric International Epidemiology Databases to Evaluate AIDS consortium were included in this analysis. Outcomes of interest were: first-line ART failure (clinical, immunologic, or virologic), change to second-line, and attrition (death or loss to program ). Cumulative incidence was computed for first-line failure and second-line initiation, with attrition as a competing event.

RESULTS

In 27,031 children, median age at ART initiation was 6.7 years. Median baseline CD4% for children ≤5 years of age was 13.2% and CD4 count for those >5 years was 258 cells per microliter. Almost all (94.4%) initiated a nonnucleoside reverse transcriptase inhibitor; 5.3% a protease inhibitor, and 0.3% a triple nucleoside reverse transcriptase inhibitor-based regimen. At 1 year, 7.7% had failed and 14.4% had experienced attrition; by 5 years, the cumulative incidence was 25.9% and 29.4%, respectively. At 1 year after ART failure, 13.7% had transitioned to second-line and 11.2% had experienced attrition; by 5 years, the cumulative incidence was 31.6% and 25.9%, respectively.

CONCLUSIONS

High rates of first-line failure and attrition were identified in children within 5 years after ART initiation. Of children meeting failure criteria, only one-third were transitioned to second-line ART within 5 years.

Time to Switch to Second-line Antiretroviral Therapy in Children With Human Immunodeficiency Virus in Europe and Thailand

Background

Data on durability of first-line antiretroviral therapy (ART) in children with human immunodeficiency virus (HIV) are limited. We assessed time to switch to second-line therapy in 16 European countries and Thailand.

Methods

Children aged <18 years initiating combination ART (≥2 nucleoside reverse transcriptase inhibitors [NRTIs] plus nonnucleoside reverse transcriptase inhibitor [NNRTI] or boosted protease inhibitor [PI]) were included. Switch to second-line was defined as (i) change across drug class (PI to NNRTI or vice versa) or within PI class plus change of ≥1 NRTI; (ii) change from single to dual PI; or (iii) addition of a new drug class. Cumulative incidence of switch was calculated with death and loss to follow-up as competing risks.

Results

Of 3668 children included, median age at ART initiation was 6.1 (interquartile range (IQR), 1.7-10.5) years. Initial regimens were 32% PI based, 34% nevirapine (NVP) based, and 33% efavirenz based. Median duration of follow-up was 5.4 (IQR, 2.9-8.3) years. Cumulative incidence of switch at 5 years was 21% (95% confidence interval, 20%-23%), with significant regional variations. Median time to switch was 30 (IQR, 16-58) months; two-thirds of switches were related to treatment failure. In multivariable analysis, older age, severe immunosuppression and higher viral load (VL) at ART start, and NVP-based initial regimens were associated with increased risk of switch.

Conclusions

One in 5 children switched to a second-line regimen by 5 years of ART, with two-thirds failure related. Advanced HIV, older age, and NVP-based regimens were associated with increased risk of switch.

Impact of Human Immunodeficiency Virus Drug Resistance on Treatment of Human Immunodeficiency Virus Infection in Children in Low- and Middle-Income Countries

Children living with human immunodeficiency virus (HIV) in low- and middle-income countries (LMICs) experience higher rates of virologic failure than adults. Human immunodeficiency virus drug resistance (HIVDR) plays a major role in pediatric HIV treatment failure because nonsuppressive maternal antiretroviral therapy (ART) during pregnancy and breastfeeding as well as infant antiretroviral prophylaxis lead to high rates of pretreatment drug resistance to regimens most commonly used in children living with HIV. Lack of availability of durable, potent drugs in child-friendly formulations in LMICs and adherence difficulties contribute to acquired drug resistance during treatment. Optimizing drugs available for treating children living with HIV in LMICs, providing robust adherence support, and ensuring virologic monitoring for children receiving ART are essential for reducing HIVDR and improving treatment outcomes for children living with HIV in LMICs.

Virological response and resistance among HIV-infected children receiving long-term antiretroviral therapy without virological monitoring in Uganda and Zimbabwe: Observational analyses within the randomised ARROW trial

BACKGROUND

Although WHO recommends viral load (VL) monitoring for those on antiretroviral therapy (ART), availability in low-income countries remains limited. We investigated long-term VL and resistance in HIV-infected children managed without real-time VL monitoring.

METHODS AND FINDINGS

In the ARROW factorial trial, 1,206 children initiating ART in Uganda and Zimbabwe between 15 March 2007 and 18 November 2008, aged a median 6 years old, with median CD4% of 12%, were randomised to monitoring with or without 12-weekly CD4 counts and to receive 2 nucleoside reverse transcriptase inhibitors (2NRTI, mainly abacavir+lamivudine) with a non-nucleoside reverse transcriptase inhibitor (NNRTI) or 3 NRTIs as long-term ART. All children had VL assayed retrospectively after a median of 4 years on ART; those with >1,000 copies/ml were genotyped. Three hundred and sixteen children had VL and genotypes assayed longitudinally (at least every 24 weeks). Overall, 67 (6%) switched to second-line ART and 54 (4%) died. In children randomised to WHO-recommended 2NRTI+NNRTI long-term ART, 308/378 (81%) monitored with CD4 counts versus 297/375 (79%) without had VL <1,000 copies/ml at 4 years (difference = +2.3% [95% CI -3.4% to +8.0%]; P = 0.43), with no evidence of differences in intermediate/high-level resistance to 11 drugs. Among children with longitudinal VLs, only 5% of child-time post-week 24 was spent with persistent low-level viraemia (80-5,000 copies/ml) and 10% with VL rebound ≥5,000 copies/ml. No child resuppressed <80 copies/ml after confirmed VL rebound ≥5,000 copies/ml. A median of 1.0 (IQR 0.0,1.5) additional NRTI mutation accumulated over 2 years' rebound. Nineteen out of 48 (40%) VLs 1,000-5,000 copies/ml were immediately followed by resuppression <1,000 copies/ml, but only 17/155 (11%) VLs ≥5,000 copies/ml resuppressed (P < 0.0001). Main study limitations are that analyses were exploratory and treatment initiation used 2006 criteria, without pre-ART genotypes.

CONCLUSIONS

In this study, children receiving first-line ART in sub-Saharan Africa without real-time VL monitoring had good virological and resistance outcomes over 4 years, regardless of CD4 monitoring strategy. Many children with detectable low-level viraemia spontaneously resuppressed, highlighting the importance of confirming virological failure before switching to second-line therapy. Children experiencing rebound ≥5,000 copies/ml were much less likely to resuppress, but NRTI resistance increased only slowly. These results are relevant to the increasing numbers of HIV-infected children receiving first-line ART in sub-Saharan Africa with limited access to virological monitoring.

TRIAL REGISTRATION

ISRCTN Registry, ISRCTN24791884.

Second-line HIV Treatment in Ugandan Children: Favorable Outcomes and No Protease Inhibitor Resistance

BACKGROUND

Data on pediatric second-line antiretroviral treatment (ART) outcomes are scarce, but essential to evaluate second-line and design third-line regimens.

METHODS

Children ≤12 years switching to second-line ART containing a protease inhibitor (PI) in Uganda were followed for 24 months. Viral load (VL) was determined at switch to second-line and every 6 months thereafter; genotypic resistance testing was done if VL ≥ 1000 cps/ml.

RESULTS

60 children were included in the analysis; all had ≥1 drug resistance mutations at switch. Twelve children (20.0%) experienced treatment failure; no PI mutations were detected. Sub-optimal adherence and underweight were associated with treatment failure.

CONCLUSIONS

No PI mutations occurred in children failing second-line ART, which is reassuring as pediatric third-line is not routinely available in these settings. Poor adherence rather than HIV drug resistance is likely to be the main mechanism for treatment failure and should receive close attention in children on second-line ART.