Genotypic resistance at viral rebound among patients who received lopinavir/ritonavir-based or efavirenz-based first antiretroviral therapy in South Africa

Six-Year Immunologic Recovery and Virological Suppression of HIV Patients on LPV/r-Based Second-Line Antiretroviral Treatment: A Multi-Center Real-World Cohort Study in China

The World Health Organization guidelines recommend lopinavir/ritonavir (LPV/r) as a second-line antiretroviral therapy (ART) for HIV-infected adults in middle-income and low-income countries as a protease inhibitor boost based on clinical trials; however, the real-world safety and efficacy remain unknown. Therefore, we conducted a large-scale, multicenter retrospective cohort study to evaluate the efficacy and safety of LPV/r-based ART among HIV-infected adults in China in whom first-line therapy failed. The data were obtained from a national database covering 17 clinics in China for six years of follow-up from 2009 to 2016. Failure of first-line treatment was determined according to a viral load at least 400 copies/ml at week 48, non-completers at week 48 for any reason, and those who switched ART before week 48 for any reason such as side effects. Treatment effectiveness was assessed by the rate of CD4⁺T cell recovery, defined as >500 cells/mm³, and the proportion of patients achieving viral suppression, defined as <400 or <50 copies/ml according to the methods used during treatment. Safety was assessed by rates of LPV/r-related adverse events (AEs), including lipid disorder, severe abnormal liver function, myelosuppression, and renal function. Between 2009 and 2016, 1196 participants (median, 36 years old; IQR, 30–43 years) were ultimately enrolled. All patients had been on LPV/r-based second-line ART treatment for more than one year after failure of any first-line ART regimen. Overall CD4⁺T cell counts increased from 138 cells/mm³ to 475 cells/mm³ and 37.2% of all participants reached CD4 recovery. Viral suppression rates dramatically increased at the end of the first year (<400 copies/ml, 88.8%; <50 copies/ml, 76.7%) and gradually increased during follow-up (<400 copies/ml, 95.8%; <50 copies/ml, 94.4%). The most frequently reported AEs were LPV/r-induced lipid disorders with no obvious increase on LDL-C at follow-up visits. This is the first real-world LPV/r-based second-line treatment study to cover such a large population in China. These results provide strong clinical evidence that LPV/r-based second-line ART is effective in increasing CD4⁺T cell counts and viral suppression rates with tolerable side effects in HIV-infected adults in China in whom first-line treatment had failed.

Low Frequency of Protease Inhibitor Resistance Mutations and Insertions in HIV-1 Subtype C Protease Inhibitor-Naïve Sequences

Human immunodeficiency virus-1 (HIV-1) protease sequences from 2,225 protease inhibitor (PI)-naïve HIV-1 subtype C-infected individuals collected over a 14-year period were analyzed for polymorphisms. Over 50% of sequences differed from an HIV-1 subtype B consensus sequence at 8 of the 99 amino acids at residues 12, 15, 19, 36, 41, 69, 89, and 93, but not in the functionally important regions. The frequency of primary resistance and accessory mutations occurred in <1% of the sequences. Of note, 11 sequences (0.5%) harbored amino acid insertions between residues 36 and 39, located in the elbow of the flap region. The insertions were found throughout the 13-year period. Occurrence of insertions in subtype C viruses is rare and viruses remain sensitive to currently used PIs (lopinavir/r, atazanavir/r, and darunavir/r). However, ongoing characterization of isolates is required to identify changes that may impact PI treatment since PIs are part of standard SA regimens.

Brief Report: Assessing the Association Between Changing NRTIs When Initiating Second-Line ART and Treatment Outcomes

BACKGROUND

After first-line antiretroviral therapy failure, the importance of change in nucleoside reverse transcriptase inhibitor (NRTI) in second line is uncertain due to the high potency of protease inhibitors used in second line.

SETTING

We used clinical data from 6290 adult patients in South Africa and Zambia from the International Epidemiologic Databases to Evaluate AIDS (IeDEA) Southern Africa cohort.

METHODS

We included patients who initiated on standard first-line antiretroviral therapy and had evidence of first-line failure. We used propensity score-adjusted Cox proportional-hazards models to evaluate the impact of change in NRTI on second-line failure compared with remaining on the same NRTI in second line. In South Africa, where viral load monitoring was available, treatment failure was defined as 2 consecutive viral loads >1000 copies/mL. In Zambia, it was defined as 2 consecutive CD4 counts <100 cells/mm.

RESULTS

Among patients in South Africa initiated on zidovudine (AZT), the adjusted hazard ratio for second-line virologic failure was 0.25 (95% confidence interval: 0.11 to 0.57) for those switching to tenofovir (TDF) vs. remaining on AZT. Among patients in South Africa initiated on TDF, switching to AZT in second line was associated with reduced second-line failure (adjusted hazard ratio = 0.35 [95% confidence interval: 0.13 to 0.96]). In Zambia, where viral load monitoring was not available, results were less conclusive.

CONCLUSIONS

Changing NRTI in second line was associated with better clinical outcomes in South Africa. Additional clinical trial research regarding second-line NRTI choices for patients initiated on TDF or with contraindications to specific NRTIs is needed.

HIV-1 antiretroviral drug resistance patterns in patients failing NNRTI-based treatment: results from a national survey in South Africa

BACKGROUND

Routine HIV-1 antiretroviral drug resistance testing for patients failing NNRTI-based regimens is not recommended in resource-limited settings. Therefore, surveys are required to monitor resistance profiles in patients failing ART.

METHODS

A cross-sectional survey was conducted amongst patients failing NNRTI-based regimens in the public sector throughout South Africa. Virological failure was defined as two consecutive HIV-1 viral load results >1000 RNA copies/mL. Pol sequences were obtained using RT-PCR and Sanger sequencing and submitted to Stanford HIVdb v7.0.1.

RESULTS

A total of 788 sequences were available for analysis. Most patients failed a tenofovir-based NRTI backbone (74.4%) in combination with efavirenz (82.1%) after median treatment duration of 36 months. K103N (48.9%) and V106M (34.9%) were the most common NNRTI mutations. Only one-third of patients retained full susceptibility to second-generation NNRTIs such as etravirine (36.5%) and rilpivirine (27.3%). After M184V/I (82.7%), K65R was the most common NRTI mutation (45.8%). The prevalence of K65R increased to 57.5% in patients failing a tenofovir regimen without prior stavudine exposure. Cross-resistance to NRTIs was often observed, but did not seem to affect the predicted activity of zidovudine as 82.9% of patients remained fully susceptible to this drug.

CONCLUSIONS

The introduction of tenofovir-based first-line regimens has dramatically increased the prevalence of K65R mutations in the HIV-1-infected South African population. However, most patients failing tenofovir-based regimens remained fully susceptible to zidovudine. Based on these data, there is currently no need to change either the recommended first- or second-line ART regimens in South Africa.

Induction with lopinavir-based treatment followed by switch to nevirapine-based regimen versus non-nucleoside reverse transcriptase inhibitors-based treatment for first line antiretroviral therapy in HIV infected children three years and older

BACKGROUND

The World Health Organization recommends non-nucleoside reverse transcriptase inhibitors (NNRTIs)-based antiretroviral therapy (ART) for children three years and older. In younger children, starting ART with lopinavir boosted with ritonavir (LPVr) results in lower risk of virological failure, but data in children three years and older are scarce, and long-term ART with LPVr is problematic in resource-poor settings.

METHODOLOGY

Retrospective cohort of children three years and older who started triple ART including LPVr or a NNRTI between 2007 and 2013 in a rural setting in India. Children who started LPVr were switched to nevirapine-based ART after virological suppression. We analysed two outcomes, virological suppression (HIV-RNA <400 copies/ml) within one year of ART using logistic regression, and time to virological failure (HIV-RNA >1000 copies/ml) after virological suppression using Cox proportional hazard regression. A sensitivity analysis was performed using inverse probability of treatment weighting (IPTW) based of propensity score methods.

FINDINGS

Of 325 children having a viral load during the first year of ART, 74/83 (89.2%) in the LPVr group achieved virological suppression versus 185/242 (76.5%) in the NNRTI group. In a multivariable analysis, the use of LPVr-based ART was associated with higher probability of virological suppression (adjusted odds ratio 3.19, 95% confidence interval [CI] 1.11-9.13). After IPTW, the estimated risk difference was 12.2% (95% CI, 2.9-21.5). In a multivariable analysis including 292 children who had virological suppression and available viral loads after one year of ART, children switched from LPVr to nevirapine did not have significant higher risk of virological failure (adjusted hazard ratio 1.18, 95% CI 0.36-3.81).

CONCLUSIONS

In a cohort of HIV infected children three years and older in a resource-limited setting, an LPVr induction- nevirapine maintenance strategy resulted in more initial virological suppression and similar incidence of virological failure after initial virological suppression than NNRTI-based regimens.

First-line antiretroviral therapy with nevirapine versus lopinavir-ritonavir based regimens in a resource-limited setting

Objective:

To compare WHO first-line antiretroviral therapy (ART) with nonnucleoside reverse transcriptase inhibitors (NNRTI)-based regimen with a boosted protease inhibitor (bPI) regimen in a resource-limited setting regarding treatment outcome and emergence of drug resistance mutations (DRMs).

Methods:

Treatment-naive adults were randomized to nevirapine (NVP) or ritonavir-boosted lopinavir (LPV/r) regimens each in combination with tenofovir (TDF)/emtricitabine (FTC) or zidovudine (ZDV)/lamivudine (3TC). Primary endpoint was the incidence of therapeutical (clinical and/or virologic) failure at week 48 with follow-up till week 96.

Results:

Four hundred and twenty-five patients (120 men; 305 women) received at least one dose of the study drug. mITT analysis showed no difference in proportion of therapeutical failure between treatment arms [67/209 (32%) in NVP vs. 63/216 (29%) LPV/r at week 48 (P = 0.53); 88/209 (42%) in NVP vs. 83/216 (38%) in LPV/r at week 96 (P = 0.49)]. Per-protocol analysis demonstrated significantly more virologic failure with NVP than with LPV/r regimens [at week 48: 19/167 (11%) vs. 7/166 (4%), P = 0.014; at week 96: 27/158 (17%) vs. 13/159 (8%), P =  0.019)]. Drug resistance mutations to NNRTI were detected in 19 out of 22 (86.3%) and dual-class resistance to nucleoside reverse transcriptase inhibitor (NRTI) and NNRTI in 15 out of 27 (68.2%) of NVP failing patients. K65R mutation was present in seven out of 14 patients failing NVP-TDF/FTC regimen. No major protease inhibitor-DRM was detected among LPV/r failing patients. Discontinuation for adverse events was similar between treatment groups.

Conclusion:

In resource-limited settings, first-line NNRTI-NRTI regimen as compared with bPI-based regimen provides similar outcome but is associated with a significantly higher number of virologic failure and resistance mutations in both classes that jeopardize future options for second-line therapy.

Antiretroviral treatment sequencing strategies to overcome HIV type 1 drug resistance in adolescents and adults in low-middle-income countries

Antiretroviral treatment (ART) is expanding to human immunodeficiency virus type 1 (HIV-1)-infected persons in low-middle income countries, thanks to a public health approach. With 3 available drug classes, 2 ART sequencing lines are programmatically foreseen. The emergence and transmission of viral drug resistance represents a challenge to the efficacy of ART. Knowledge of HIV-1 drug resistance selection associated with specific drugs and regimens and the consequent activity of residual drug options are essential in programming ART sequencing options aimed at preserving ART efficacy for as long as possible. This article determines optimal ART sequencing options for overcoming HIV-1 drug resistance in resource-limited settings, using currently available drugs and treatment monitoring opportunities. From the perspective of drug resistance and on the basis of limited virologic monitoring data, optimal sequencing seems to involve use of a tenofovir-containing nonnucleoside reverse-transcriptase inhibitor-based first-line regimen, followed by a zidovudine-containing, protease inhibitor (PI)-based second-line regimen. Other options and their consequences are explored by considering within-class and between-class sequencing opportunities, including boosted PI monotherapies and future options with integrase inhibitors. Nucleoside reverse-transcriptase inhibitor resistance pathways in HIV-1 subtype C suggest an additional reason for accelerating stavudine phase out. Viral load monitoring avoids the accumulation of resistance mutations that significantly reduce the activity of next-line options. Rational use of resources, including broader access to viral load monitoring, will help ensure 3 lines of fully active treatment options, thereby increasing the duration of ART success.

Resistance at virological failure using boosted protease inhibitors versus nonnucleoside reverse transcriptase inhibitors as first-line antiretroviral therapy--implications for sustained efficacy of ART in resource-limited settings

BACKGROUND

Increases in the prevalence of resistance to nonnucleoside reverse transcriptase inhibitors (NNRTIs) have been observed among previously untreated individuals in all areas of sub-Saharan Africa. We aimed to examine whether first-line use of 2 NRTIs plus a boosted protease inhibitor (bPI) could protect against emergence of NRTI resistance mutations, compared to the use of 2 NRTIs plus 1 NNRTI.

METHODS

We carried out a weighted meta-analysis of randomized clinical trials comparing bPI- with NNRTI-based first-line antiretroviral therapy regimens using random effects modeling.

RESULTS

In intention to treat analyses, there was no difference in the risk of viral failure at week 48 between NNRTI and bPI (P = .19). At week 48, the overall difference between NNRTI- and PI-based regimens in selection of any major NRTI resistance mutation (crude unweighted prevalence 3.3% vs 1.6%) was 1.7% (95% confidence interval [CI], .4-3.0; P = .00927). There was a statistically significant difference in prevalence of K65R when comparing NNRTI (1.3%) with PI (0.67%); absolute weighted difference 1.0% (95% CI, .3-1.7; P = .00447). There was also a significant difference in prevalence of M184V/I between NNRTI and PI (crude unweighted prevalence 3.2% vs 1.4%); difference 1.6% (95% CI 0.1-3.1; P = .0368).

CONCLUSIONS

Despite the equivalent efficacy and more favorable resistance implications of PI- versus NNRTI-based first line therapy, widespread use of PI-based first-line therapy is not warranted at this time, due to resource limitations and predicted increased risk of resistance-related failure of NNRTI/NRTI second-line regimens. PI-based first-line therapy could be reconsidered when antiretroviral agents from other classes become available for second-line regimens in resource-limited settings.

Short communication: high natural polymorphism in the gag gene cleavage sites of non-B HIV type 1 isolates from Gabon

The main goal of the present study was to determine the frequency of substitutions in the cleavage sites (CS) of gag gene among non-B HIV-1 isolates from Gabon. Fifty plasma specimens, collected in 2010-2011, from HIV-1-infected patients failing first-line antiretroviral (ARV) regimens (constituted of two nucleoside reverse transcriptase inhibitors+one nonnucleoside reverse transcriptase inhibitor) (n=38) and from HIV-1-infected individuals untreated with ARV (n=12) were analyzed in the gag and gag-pol cleavage sites. Compared to HXB2 reference sequence, the total median number of substitutions in gag and gag-pol CS was 10 (range, 5-18). The cleavage site p2/NC was the most variable of the four gag CS with 100% (50/50) isolates carrying at least 1 substitution (range, 1-9). The two gag-pol TFP/p6pol and p6pol/PR CS sites were also highly variable (at least one substitution, 50/50, 100% in both cases). Substitutions at position G381 (p2/NC), L449 (p1/p6gag), and K444 (TFP/p6pol) were significantly more frequent in CRF02_AG strains, compared to other non-B strains (30.4% vs. 3.7%, p=0.03; 87.0% vs. 59.3%, p=0.03; and 91.3% vs. 59.3%, p=0.01, respectively). Other non-B subtypes were significantly more likely to harbor substitutions at position N487 (p6pol) (70.4%) than CRF02_AG (39.1%) (p=0.02). In Gabon, gag and gag-pol cleavage sites were highly polymorphic in protease inhibitor-naive patients harboring non-B HIV-1 strains. In sub-Saharan Africa, further studies are definitively required to better understand the impact of gag mutations among subjects receiving second-line LPV/r-containing regimens (monotherapy or triple combinations).

Virological failure rates and HIV-1 drug resistance patterns in patients on first-line antiretroviral treatment in semirural and rural Gabon

Introduction

As antiretroviral treatment (ART) continues to expand in resource-limited countries, the emergence of HIV drug resistance mutations (DRMs) is challenging in these settings. In Gabon (central Africa), no study has yet reported the virological effectiveness of initial ART given through routine HIV care.

Methods

Following the World Health Organization (WHO) recommendations, a cross-sectional study with a one-time HIV-1 RNA viral load (VL) measurement was conducted in Gabon to assess virological failure (VF) defined by a VL result ≥1000 copies/ml and DRMs among adult patients living with non-B HIV-1 strains and receiving first-line non-nucleoside reverse transcriptase inhibitor (NNRTI)-based antiretroviral therapy for at least 12 months. Risk factors associated with VF and DRMs were assessed.

Results

Between March 2010 and March 2011, a total of 375 patients were consecutively enrolled from two decentralized (one semirural and one rural) HIV care centres. Median time on ART was 33.6 months (range, 12–107). Overall, the rate of VF was 41.3% (36.4–46.4). Among viremic patients, 56.7% (80/141) had at least one DRM and 37.6% had dual-class resistance to nucleoside reverse transcriptase inhibitors (NRTIs) and NNRTIs. The most frequent DRMs were K103N/S (46.1%) and M184V/I (37.6%). Thymidine analogue mutations were found in 10.6%. Independent risk factors associated with VF were being followed up at the semirural centre (P=0.033), having experienced unstructured treatment interruptions (P=0.0044), and having low CD4⁺ counts at enrolment (P<0.0001). A longer time on ART (P=0.0008) and being followed up at the rural centre (P=0.021) were risk factors for DRMs.

Conclusions

This is the first study conducted in Gabon providing VF rates and DRM patterns in adult patients receiving first-line ART. In sub-Saharan Africa, where NNRTI-based regimens are recommended as the standard for first-line ART, strengthening virological monitoring together with preventing unplanned treatment interruptions are a global public health priority.