Lopinavir/ritonavir monotherapy after virologic failure of first-line antiretroviral therapy in resource-limited settings

We should not stop considering HIV drug resistance testing at failure of first-line antiretroviral therapy

HIV drug resistance is a major global hurdle to successful and sustained antiretroviral therapy. Global guidelines recommend testing for antiretroviral drug resistance and results are used to inform treatment regimen design for patients at different stages of therapy. Several clinical trials investigated optimal regimens after failure of first-line antiretroviral therapy, yielding data that advanced knowledge and informed care. However, further interpretation of data from these studies questioned the benefit of antiretroviral drug resistance testing for cases in which first-line treatment is not effective and, furthermore, that relying on the results of antiretroviral drug resistance testing could be misleading and unnecessary. In this Viewpoint, which is largely focused on high-income settings, we review these data, reflect on the potential problems with their interpretation, and call for caution in their extrapolation. Without negating the importance of the data, and recognising the varied circumstances related to HIV drug resistance testing in different global settings, we advise caution before changing current practice and recommendations. We believe that we should not universally stop considering HIV drug resistance testing at failure of first-line antiretroviral therapy.

Protease inhibitor-based antiretroviral therapy in pregnancy: effects on hormones, placenta, and decidua

The use of antiretroviral therapy (ART) in pregnancy is important for maternal health, and has been successful in reducing vertical transmission rates to almost zero in those taking effective ART regimens with good adherence. However, there are reports of higher rates of low birthweight and preterm births in women with HIV, which can be further exacerbated by ART usage in pregnancy. Protease inhibitors, and ritonavir-boosted lopinavir in particular, might directly contribute to placental and uteroplacental pathology in part by altering plasma concentrations of the essential steroid hormones of pregnancy, progesterone and oestradiol. In this Review, we collate the increasing evidence of dysregulated maternal endocrinology, reproductive physiology, and placental compromise associated with protease inhibitors. Based on findings of placental and decidual effects, we recommend that ritonavir-boosted lopinavir should be avoided in pregnancy, in line with US and European guidelines. Long-term follow-up of children exposed to protease inhibitors in utero is also recommended.

Drug resistance in HIV-infected children living in rural South Africa: Implications of an antiretroviral therapy initiated during the first year of life

INTRODUCTION

Management of antiretroviral-drug resistance in HIV-infected children is a global health concern. We compared the long-term virological outcomes of two cohorts of children living in a rural setting of South Africa. The first cohort initiated treatment before one year and the second after two years of age. The aim of this study was to describe the long-term consequences of early treatment initiation in terms of viral load and drug-resistance.

METHODS

This retrospective study was conducted at the Edendale Hospital located in a peri-urban area of KwaZulu-Natal. Children were included during their planned appointment. Drug resistance was assessed genotypically on proviral DNA.

RESULTS

From the 161 children included in this study, 93 samples were successfully genotyped. Both cohorts had comparable viral loads, but children treated early more often presented NRTI or NNRTI mutations, while there was no difference for PI mutations rates.

CONCLUSIONS

Treatment was highly effective when comparing virological outcomes in both early- and late-treated cohorts. The persistence of NNRTI mutations could lead to treatment failures in children older than 3 years initiating their therapy with a NNRTI, or for those switching from a PI to NNRTI based regimen. The accumulation of NRTI mutations may lead to a functional PI monotherapy and consequently to viral escape. To promote access to HIV genotyping in resource-limited settings is challenging but essential to avoid inappropriate therapy switches in case of virological failure, and to adapt national treatment guidelines in line with the epidemiology of resistance.

HIV Viral Dynamics of Lopinavir/Ritonavir Monotherapy as Second-Line Treatment: A Prospective, Single-Arm Trial

Background:

Characterizing viral response to lopinavir/ritonavir (LPV/r) monotherapy as second-line treatment may guide recommendations for resource-limited settings (RLS).

Methods:

We conducted a 48-week prospective, single-arm study of LPV/r monotherapy in patients failing first-line therapy in Nigeria. The primary outcome was sustained HIV-1 viral load (VL) <400 copies/mL at 48 weeks.

Results:

Of 30 enrolled patients, 28 (93%) achieved viral suppression on LPV/r, while 29 (96%) experienced low-level viremia. At 48 weeks, 9 (30%) met the primary outcome of sustained viral suppression; 14 (47%) patients were suppressed on LPV/r in a snapshot analysis. Detectable VLs at 12 and 24 weeks were strongly associated with treatment failure at 48 weeks. New resistance mutations were not detected. The trial was stopped early due to treatment failure.

Conclusion:

In this study, the rate of virologic failure among patients on a second-line lopinavir monotherapy regimen was relatively high and predicted by early detectable viremia. However, no LPV/r-associated resistance mutations were detected despite fluctuating low-level viremia, demonstrating the high genetic barrier to resistance of the protease inhibitor class which could be useful in RLS.

Antiretroviral drug resistance mutations among patients failing first-line treatment in Hanoi, Vietnam

Objectives: To study the prevalence of drug resistance and genotype testing for HIV drug resistance on HIV/AIDS patients with first-line antiretroviral treatment failure at Dong Da Hospital, Hanoi, Vietnam.

Patients and methods: Forty-seven patients in Dong Da Hospital, Hanoi, with confirmation of first-line antiretroviral therapy (ART) failure were enrolled in this study from June 2006 to December 2016. Both the protease and reverse transcriptase genes were amplified and sequenced using Trugene^® HIV-1 Genotyping Kit and OpenGene^® DNA system at the biomolecular laboratory of the National Institute of Hygiene and Epidemiology, Vietnam. The Stanford HIV database algorithm was used for interpretation of resistance data and genotyping.

Results: Drug resistance mutations were 90.7% in patients with first-line treatment failure. Amongst patients with drug resistance mutation, 97.7% resisted to non-nucleoside reverse transcriptase inhibitors (NNRTIs), followed by nucleoside reverse transcriptase inhibitors (NRTIs, 95.3%) and protease inhibitors (PIs, 11.6%). Amongst the genetic mutations resistant to NNRTIs, G190S mutation was the highest (51.2%), K101HQ mutation was 39.5% and Y181I mutation was 34.9%. In genetic mutations to NRTIs, M184V mutation was 88.4%. In thymidine analogue mutations, K70R mutation was the most common (37.2%), followed by D67N, T215F and T69N mutations (27.9%, 27.9% and 25.6%, respectively). In genetic mutations in PIs, M36I and K20R mutations made up 9.3%. In NNRTIs, the prevalence of nevirapine resistance was 55.8%, and that of efavirenz resistance was 4.7%. In NRTIs, the ratio of lamivudine resistance was 93.0%, and that of zidovudine resistance was 9.3%. No lopinavir/ritonavir resistance was recorded.

Conclusions: Drug resistance mutations in patients with first-line ART failure had a high prevalence of NNRTI and NRTI resistance but still susceptible to PIs.

High rate of HIV-1 drug resistance in treatment failure patients in Taiwan, 2009-2014

Background

Drug resistance to nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), and protease inhibitors (PIs) has been associated with loss of viral suppression measured by a rise in HIV-1 RNA levels, a decline in CD4 cell counts, persistence on a failing treatment regimen, and lack of adherence to combination antiretroviral therapy.

Objectives

This study aimed to monitor the prevalence and risk factors associated with drug resistance in Taiwan after failure of first-line therapy.

Materials and methods

Data from the Veterans General Hospital Surveillance and Monitor Network for the period 2009–2014 were analyzed. Plasma samples from patients diagnosed with virologic failure and an HIV-1 RNA viral load >1000 copies/mL were analyzed by the ViroSeq^™ HIV-1 genotyping system for drug susceptibility. Hazard ratios (HRs) for drug resistance were calculated using a Cox proportional hazard model.

Results

From 2009 to 2014, 359 patients were tested for resistance. The median CD4 count and viral load (log) were 214 cells/μL (interquartile range [IQR]: 71–367) and 4.5 (IQR: 3.9–5.0), respectively. Subtype B HIV-1 strains were found in 90% of individuals. The resistance rate to any of the three classes of antiretroviral drugs (NRTI, NNRTI, and PI) was 75.5%. The percentage of NRTI, NNRTI, and PI resistance was 58.6%, 61.4%, and 11.4%, respectively. The risk factors for any class of drug resistance included age ≤35 years (adjusted HR: 2.30, CI: 1.48–3.56; p<0.0001), initial NNRTI-based antiretroviral regimens (adjusted HR: 1.70, CI: 1.10–2.63; p=0.018), and current NNRTI-based antiretroviral regimens when treatment failure occurs (odds ratio: 4.04, CI: 2.47–6.59; p<0.001). There was no association between HIV-1 subtype, viral load, and resistance.

Conclusion

This study demonstrated a high level of resistance to NRTI and NNRTI in patients with virologic failure to first-line antiretroviral therapy despite routine viral load monitoring. Educating younger men who have sex with men to maintain good adherence is crucial, as PI use is associated with lower possibility of drug resistance.

Assessment of non-standard HIV antiretroviral therapy regimens at Lighthouse Trust in Lilongwe, Malawi

AIM

Lighthouse Trust in Lilongwe, Malawi serves approximately 25,000 patients with HIV antiretroviral therapy (ART) regimens standardized according to national treatment guidelines. However, as a referral centre for complex cases, Lighthouse Trust occasionally treats patients with non-standard ART regimens (NS-ART) that deviate from the treatment guidelines. We evaluated factors contributing to the use of NS-ART and whether patients could transition to standard regimens.

METHODS

This was a cross-sectional study of all adult patients at Lighthouse Trust being treated with NS-ART as of February 2012. Patients were identified using the electronic data system. Medical charts were reviewed and descriptive statistics were obtained.

RESULTS

One hundred six patients were initially found being treated with NS-ART, and 92 adult patients were confirmed to be on NS-ART after review. Mean patient age was 42.4 ± 10.3 years, and 52 (57%) were female. Mean duration of treatment with the NS-ART being used at the time of data collection was 2.1 ± 1.5 years. Eight patients (9%) were on modified first-line NS-ART and 84 (91%) were on modified second-line NS-ART, with 90 patients (98%) having multiple factors contributing to NS-ART use. Severe toxicity from one medication contributed in 28 cases (30%) and toxicity from multiple medications contributed in 46 cases (50%), while 22 patients (24%) were transitioned to NS-ART following a stockout of their original medication. Following clinical review, 84 patients (91%) were transitioned to standard regimens, and eight (9%) were maintained on NS-ART because of incompatibility of their clinical features with the latest national guidelines.

CONCLUSIONS

Primary factors contributing to NS-ART use were medication toxicities and medication stockouts. Most patients were transitioned to standard regimens, although the need for NS-ART remains.

Hyperlipidaemia in HIV-infected patients on lopinavir/ritonavir monotherapy in resource-limited settings

BACKGROUND

Cardiovascular disease (CVD) is an emerging concern for HIV-infected patients. Hyperlipidaemia is a risk factor for CVD and a complication of protease-inhibitor-based antiretroviral therapy, but little is known about its incidence and risk factors in treated patients in resource-limited settings (RLS).

METHODS

We conducted a secondary analysis of ACTG A5230 trial in which HIV-infected adults from India, Malawi, Tanzania, Thailand and South Africa, with virological relapse on first-line therapy were initiated on lopinavir/ritonavir (LPV/r) monotherapy. Hyperlipidaemia was a grade 2+ elevated fasting total cholesterol (FTC≥240 mg/dl) or fasting triglycerides (FTG≥500 mg/dl) or calculated low-density lipoprotein cholesterol (LDL≥160 mg/dl) based on measurements at weeks 12, 24, 48, 68 and 104. We evaluated factors potentially associated with quantitative lipid changes from baseline to week 12. These were age, sex, race, site and baseline body mass index, CD4⁺ T-cell count, HIV-1 RNA level and lipids.

RESULTS

106 participants without hyperlipidaemia at baseline started LPV/r; median age 39 years, 68% Black African, 55% female. The cumulative incidence of hyperlipidaemia at week 104 was 48% (95% CI 36, 58%). At week 12, there were significant mean increases from baseline in FTC (17 mg/dl, P<0.001) and FTG (104 mg/dl, P<0.001). In multivariable analysis, higher baseline FTC (P=0.044), FTG (P=0.025), Thai (P<0.001) or Indian sites (P=0.020) versus African sites were associated with increased risk of hyperlipidaemia.

CONCLUSIONS

In HIV-infected adults in RLS initiating LPV/r, hyperlipidaemia was common. Baseline lipid measurements and routine monitoring should be recommended in individuals starting LPV/r-based treatments with borderline high lipids.

HIV-1 drug resistance and resistance testing

The global scale-up of antiretroviral (ARV) therapy (ART) has led to dramatic reductions in HIV-1 mortality and incidence. However, HIV drug resistance (HIVDR) poses a potential threat to the long-term success of ART and is emerging as a threat to the elimination of AIDS as a public health problem by 2030. In this review we describe the genetic mechanisms, epidemiology, and management of HIVDR at both individual and population levels across diverse economic and geographic settings. To describe the genetic mechanisms of HIVDR, we review the genetic barriers to resistance for the most commonly used ARVs and describe the extent of cross-resistance between them. To describe the epidemiology of HIVDR, we summarize the prevalence and patterns of transmitted drug resistance (TDR) and acquired drug resistance (ADR) in both high-income and low- and middle-income countries (LMICs). We also review to two categories of HIVDR with important public health relevance: (i) pre-treatment drug resistance (PDR), a World Health Organization-recommended HIVDR surveillance metric and (ii) and pre-exposure prophylaxis (PrEP)-related drug resistance, a type of ADR that can impact clinical outcomes if present at the time of treatment initiation. To summarize the implications of HIVDR for patient management, we review the role of genotypic resistance testing and treatment practices in both high-income and LMIC settings. In high-income countries where drug resistance testing is part of routine care, such an understanding can help clinicians prevent virological failure and accumulation of further HIVDR on an individual level by selecting the most efficacious regimens for their patients. Although there is reduced access to diagnostic testing and to many ARVs in LMIC, understanding the scientific basis and clinical implications of HIVDR is useful in all regions in order to shape appropriate surveillance, inform treatment algorithms, and manage difficult cases.

Challenges of Maintaining Good Clinical Laboratory Practices in Low-Resource Settings: A Health Program Evaluation Framework Case Study From East Africa

OBJECTIVES

Using a clinical research laboratory as a case study, we sought to characterize barriers to maintaining Good Clinical Laboratory Practice (GCLP) services in a developing world setting.

METHODS

Using a US Centers for Disease Control and Prevention framework for program evaluation in public health, we performed an evaluation of the Kilimanjaro Christian Medical Centre-Duke University Health Collaboration clinical research laboratory sections of the Kilimanjaro Clinical Research Institute in Moshi, Tanzania. Laboratory records from November 2012 through October 2014 were reviewed for this analysis.

RESULTS

During the 2-year period of study, seven instrument malfunctions suspended testing required for open clinical trials. A median (range) of 9 (1-55) days elapsed between instrument malfunction and biomedical engineer service. Sixteen (76.1%) of 21 suppliers of reagents, controls, and consumables were based outside Tanzania. Test throughput among laboratory sections used a median (range) of 0.6% (0.2%-2.7%) of instrument capacity. Five (55.6%) of nine laboratory technologists left their posts over 2 years.

CONCLUSIONS

These findings demonstrate that GCLP laboratory service provision in this setting is hampered by delays in biomedical engineer support, delays and extra costs in commodity procurement, low testing throughput, and high personnel turnover.

Evidence for Reduced Drug Susceptibility without Emergence of Major Protease Mutations following Protease Inhibitor Monotherapy Failure in the SARA Trial

Background

Major protease mutations are rarely observed following failure with protease inhibitors (PI), and other viral determinants of failure to PI are poorly understood. We therefore characterized Gag-Protease phenotypic susceptibility in subtype A and D viruses circulating in East Africa following viral rebound on PIs.

Methods

Samples from baseline and treatment failure in patients enrolled in the second line LPV/r trial SARA underwent phenotypic susceptibility testing. Data were expressed as fold-change in susceptibility relative to a LPV-susceptible reference strain.

Results

We cloned 48 Gag-Protease containing sequences from seven individuals and performed drug resistance phenotyping from pre-PI and treatment failure timepoints in seven patients. For the six patients where major protease inhibitor resistance mutations did not emerge, mean fold-change EC₅₀ to LPV was 4.07 fold (95% CI, 2.08–6.07) at the pre-PI timepoint. Following viral failure the mean fold-change in EC₅₀ to LPV was 4.25 fold (95% CI, 1.39–7.11, p = 0.91). All viruses remained susceptible to DRV. In our assay system, the major PI resistance mutation I84V, which emerged in one individual, conferred a 10.5-fold reduction in LPV susceptibility. One of the six patients exhibited a significant reduction in susceptibility between pre-PI and failure timepoints (from 4.7 fold to 9.6 fold) in the absence of known major mutations in protease, but associated with changes in Gag: V7I, G49D, R69Q, A120D, Q127K, N375S and I462S. Phylogenetic analysis provided evidence of the emergence of genetically distinct viruses at the time of treatment failure, indicating ongoing viral evolution in Gag-protease under PI pressure.

Conclusions

Here we observe in one patient the development of significantly reduced susceptibility conferred by changes in Gag which may have contributed to treatment failure on a protease inhibitor containing regimen. Further phenotype-genotype studies are required to elucidate genetic determinants of protease inhibitor failure in those who fail without traditional resistance mutations whilst PI use is being scaled up globally.

Lopinavir/Ritonavir Monotherapy as Second-line Antiretroviral Treatment in Resource-Limited Settings: Week 104 Analysis of AIDS Clinical Trials Group (ACTG) A5230

BACKGROUND

The AIDS Clinical Trials Group (ACTG) A5230 study evaluated lopinavir/ritonavir (LPV/r) monotherapy following virologic failure (VF) on first-line human immunodeficiency virus (HIV) regimens in Africa and Asia.

METHODS

Eligible subjects had received first-line regimens for at least 6 months and had plasma HIV-1 RNA levels 1000-200 000 copies/mL. All subjects received LPV/r 400/100 mg twice daily. VF was defined as failure to suppress to <400 copies/mL by week 24, or confirmed rebound to >400 copies/mL at or after week 16 following confirmed suppression. Subjects with VF added emtricitabine 200 mg/tenofovir 300 mg (FTC/TDF) once daily. The probability of continued HIV-1 RNA <400 copies/mL on LPV/r monotherapy through week 104 was estimated with a 95% confidence interval (CI); predictors of treatment success were evaluated with Cox proportional hazards models.

RESULTS

One hundred twenty-three subjects were enrolled. Four subjects died and 2 discontinued prematurely; 117 of 123 (95%) completed 104 weeks. Through week 104, 49 subjects met the primary endpoint; 47 had VF, and 2 intensified treatment without VF. Of the 47 subjects with VF, 41 (33%) intensified treatment, and 39 of 41 subsequently achieved levels <400 copies/mL. The probability of continued suppression <400 copies/mL over 104 weeks on LPV/r monotherapy was 60% (95% CI, 50%-68%); 80%-85% maintained levels <400 copies/mL with FTC/TDF intensification as needed. Ultrasensitive assays on specimens with HIV-1 RNA level <400 copies/mL at weeks 24, 48, and 104 revealed that 61%, 62%, and 65% were suppressed to <40 copies/mL, respectively.

CONCLUSIONS

LPV/r monotherapy after first-line VF with FTC/TDF intensification when needed provides durable suppression of HIV-1 RNA over 104 weeks.

CLINICAL TRIALS REGISTRATION

NCT00357552.

Efficacy of second-line antiretroviral therapy among people living with HIV/AIDS in Asia: results from the TREAT Asia HIV observational database

BACKGROUND

Roughly 4% of the 1.25 million patients on antiretroviral therapy (ART) in Asia are using second-line therapy. To maximize patient benefit and regional resources, it is important to optimize the timing of second-line ART initiation and use the most effective compounds available.

METHODS

HIV-positive patients enrolled in the TREAT Asia HIV Observational Database who had used second-line ART for ≥6 months were included. ART use and rates and predictors of second-line treatment failure were evaluated.

RESULTS

There were 302 eligible patients. Most were male (76.5%) and exposed to HIV via heterosexual contact (71.5%). Median age at second-line initiation was 39.2 years, median CD4 cell count was 146 cells per cubic millimeter, and median HIV viral load was 16,224 copies per milliliter. Patients started second-line ART before 2007 (n = 105), 2007-2010 (n = 147) and after 2010 (n = 50). Ritonavir-boosted lopinavir and atazanavir accounted for the majority of protease inhibitor use after 2006. Median follow-up time on second-line therapy was 2.3 years. The rates of treatment failure and mortality per 100 patient/years were 8.8 (95% confidence interval: 7.1 to 10.9) and 1.1 (95% confidence interval: 0.6 to 1.9), respectively. Older age, high baseline viral load, and use of a protease inhibitor other than lopinavir or atazanavir were associated with a significantly shorter time to second-line failure.

CONCLUSIONS

Increased access to viral load monitoring to facilitate early detection of first-line ART failure and subsequent treatment switch is important for maximizing the durability of second-line therapy in Asia. Although second-line ART is highly effective in the region, the reported rate of failure emphasizes the need for third-line ART in a small portion of patients.

Ritonavir-boosted lopinavir as maintenance monotherapy in HIV-infected patients who achieved viral suppression during a second-line protease inhibitor-based regimen: a pilot randomized trial (BIDI-MONO)

Eligibility criteria were (I) having previously failed first-line nonnucleoside reverse transcriptase inhibitor-based regimens and (2) having achieved virologic suppression >6 months while receiving a protease inhibitor (PI)-based regimen as second-line treatment. Eligible participants were randomized to receive either (I) ritonavir-boosted lopinavir (LPV/r) monotherapy (n = 29) or (2) LPV/r with optimized background regimens (OBRs; n = 31). Median duration of viral suppression before randomization was 45 months. At week 48, viral suppression during LPV/r monotherapy was 86.2% and did not differ from the suppression achieved with LPV/r with OBRs (87.1%, P = 1.000). However, persistent viremia during LPV/r monotherapy tended to be higher than during LPV/r with OBRs (10.3% versus 3.2%, P = .346). History of viral blip during virologic suppression with second-line PI-based regimen is a predictor of achieving viral suppression at all visits (adjusted relative risk 0.255 [95% confidence interval 0.080-0.821], P = .022). Use of LPV/r monotherapy as maintenance regimen in this study produced persistent viremia that tended to be higher than LPV/r monotherapy with OBRs.

Long-term outcome of second-line antiretroviral therapy in resource-limited settings

There is limited information on efficacy and durability of second-line antiretroviral therapy (2NL) beyond 12 months in resource-limited settings. A total of 73 patients were enrolled into a prospective 2NL observational cohort in Nigeria. Second-line antiretroviral therapy consisted of lopinavir/ritonavir plus nucleoside reverse transcriptase inhibitors. Time on 2NL ranged from 15 to 31 months. Genotypes were retrospectively done and not available to guide second-line regimen choice. At enrollment, median CD4 count was 121 cells/mm3, and median time on first-line antiretroviral therapy (ISL) was 24 months. At 6 to 9 months on 2NL, 72.6% (intention to treat [ITT]) and 88.3% (on treatment [OT]) had an undetectable viral load (UDVL). At 12 months, 65.8% (ITT) and 90.57% (OT) had UDVL. At >12 to 24 months and at >24 months, 57.5% (ITT) and 91.3% (OT) had UDVL. No statistically significant association was observed between CD4 at 2NL start, sex, genotypic sensitivity score of 2NL, or tenofovir (TDF) use in ISL and viral suppression. Two patients developed major protease inhibitor mutations while on 2NL. We observed a high degree of viral suppression at 12 months and little loss of viral suppression thereafter.

Durability of antiretroviral therapy and predictors of virologic failure among perinatally HIV-infected children in Tanzania: a four-year follow-up

BACKGROUND

In Tanzania, HIV-1 RNA testing is rarely available and not standard of care. Determining virologic failure is challenging and resistance mutations accumulate, thereby compromising second-line therapy. We evaluated durability of antiretroviral therapy (ART) and predictors of virologic failure among a pediatric cohort at four-year follow-up.

METHODS

This was a prospective cross-sectional study with retrospective chart review evaluating a perinatally HIV-infected Tanzanian cohort enrolled in 2008-09 with repeat HIV-1 RNA in 2012-13. Demographic, clinical, and laboratory data were extracted from charts, resistance mutations from 2008-9 were analyzed, and prospective HIV RNA was obtained.

RESULTS

161 (78%) participants of the original cohort consented to repeat HIV RNA. The average age was 12.2 years (55% adolescents ≥12 years). Average time on ART was 6.4 years with 41% receiving second-line (protease inhibitor based) therapy. Among those originally suppressed on a first-line (non-nucleoside reverse transcriptase based regimen) 76% remained suppressed. Of those originally failing first-line, 88% were switched to second-line and 72% have suppressed virus. Increased level of viremia and duration of ART trended with an increased number of thymidine analogue mutations (TAMs). Increased TAMs increased the odds of virologic failure (p = 0.18), as did adolescent age (p < 0.01).

CONCLUSIONS

After viral load testing in 2008-09 many participants switched to second-line therapy. The majority achieved virologic suppression despite multiple resistance mutations. Though virologic testing would likely hasten the switch to second-line among those failing, methods to improve adherence is critical to maximize durability of ART and improve virologic outcomes among youth in resource-limited settings.

HIV-1 subtype influences susceptibility and response to monotherapy with the protease inhibitor lopinavir/ritonavir

OBJECTIVE

PI susceptibility results from a complex interplay between protease and Gag proteins, with Gag showing wide variation across HIV-1 subtypes. We explored the impact of pre-treatment susceptibility on the outcome of lopinavir/ritonavir monotherapy.

METHODS

Treatment-naive individuals who experienced lopinavir/ritonavir monotherapy failure from the MONARK study were matched (by subtype, viral load and baseline CD4 count) with those who achieved virological response ('successes'). Successes were defined by viral load <400 copies/mL after week 24 and <50 copies/mL from week 48 to week 96. Full-length Gag-protease was amplified from patient samples for in vitro phenotypic susceptibility testing, with susceptibility expressed as fold change (FC) relative to a subtype B reference strain.

RESULTS

Baseline lopinavir susceptibility was lower in viral failures compared with viral successes, but the differences were not statistically significant (median lopinavir susceptibility: 4.4 versus 8.5, respectively, P = 0.17). Among CRF02_AG/G patients, there was a significant difference in lopinavir susceptibility between the two groups (7.1 versus 10.4, P = 0.047), while in subtype B the difference was not significant (2.7 versus 3.4, P = 0.13). Subtype CRF02_AG/G viruses had a median lopinavir FC of 8.7 compared with 3.1 for subtype B (P = 0.001).

CONCLUSIONS

We report an association between reduced PI susceptibility (using full-length Gag-protease sequences) at baseline and subsequent virological failure on lopinavir/ritonavir monotherapy in antiretroviral-naive patients harbouring subtype CRF02_AG/G viruses. We speculate that this may be important in the context of suboptimal adherence in determining viral failure.

Phenotypic characterization of virological failure following lopinavir/ritonavir monotherapy using full-length Gag-protease genes

Objectives

Major protease mutations are rarely observed following first-line failure with PIs and interpretation of genotyping results in this context may be difficult. We performed extensive phenotyping of viruses from five patients failing lopinavir/ritonavir monotherapy in the MONARK study without major PI mutations by standard genotyping.

Methods

Phenotypic susceptibility testing and viral infectivity assessments were performed using a single-cycle assay and fold changes (FC) relative to a lopinavir-susceptible reference strain were calculated.

Results

>10-fold reduced baseline susceptibility to lopinavir occurred in two of five patients and >5-fold in another two. Four of five patients exhibited phylogenetic evidence of a limited viral evolution between baseline and failure, with amino acid changes at drug resistance-associated positions in one: T81A emerged in Gag with M36I in the protease gene, correlating with a reduction in lopinavir susceptibility from FC 7 (95% CI 6–8.35) to FC 13 (95% CI 8.11–17.8). Reductions in darunavir susceptibility (>5 FC) occurred in three individuals.

Discussion

This study suggests both baseline reduced susceptibility and evolution of resistance could be contributing factors to PI failure, despite the absence of classical PI resistance mutations by standard testing methods. Use of phenotyping also reveals lower darunavir susceptibility, warranting further study as this agent is commonly used following lopinavir failure.

Assessment of second-line antiretroviral regimens for HIV therapy in Africa

BACKGROUND

The efficacy and toxic effects of nucleoside reverse-transcriptase inhibitors (NRTIs) are uncertain when these agents are used with a protease inhibitor in second-line therapy for human immunodeficiency virus (HIV) infection in resource-limited settings. Removing the NRTIs or replacing them with raltegravir may provide a benefit.

METHODS

In this open-label trial in sub-Saharan Africa, we randomly assigned 1277 adults and adolescents with HIV infection and first-line treatment failure to receive a ritonavir-boosted protease inhibitor (lopinavir-ritonavir) plus clinician-selected NRTIs (NRTI group, 426 patients), a protease inhibitor plus raltegravir in a superiority comparison (raltegravir group, 433 patients), or protease-inhibitor monotherapy after 12 weeks of induction therapy with raltegravir in a noninferiority comparison (monotherapy group, 418 patients). The primary composite end point, good HIV disease control, was defined as survival with no new World Health Organization stage 4 events, a CD4+ count of more than 250 cells per cubic millimeter, and a viral load of less than 10,000 copies per milliliter or 10,000 copies or more with no protease resistance mutations at week 96 and was analyzed with the use of imputation of data (≤4%).

RESULTS

Good HIV disease control was achieved in 60% of the patients (mean, 255 patients) in the NRTI group, 64% of the patients (mean, 277) in the raltegravir group (P=0.21 for the comparison with the NRTI group; superiority of raltegravir not shown), and 55% of the patients (mean, 232) in the monotherapy group (noninferiority of monotherapy not shown, based on a 10-percentage-point margin). There was no significant difference in rates of grade 3 or 4 adverse events among the three groups (P=0.82). The viral load was less than 400 copies per milliliter in 86% of patients in the NRTI group, 86% in the raltegravir group (P=0.97), and 61% in the monotherapy group (P<0.001).

CONCLUSIONS

When given with a protease inhibitor in second-line therapy, NRTIs retained substantial virologic activity without evidence of increased toxicity, and there was no advantage to replacing them with raltegravir. Virologic control was inferior with protease-inhibitor monotherapy. (Funded by European and Developing Countries Clinical Trials Partnership and others; EARNEST Current Controlled Trials number, ISRCTN37737787, and ClinicalTrials.gov number, NCT00988039.).

HIV-1 drug resistance and associated factors among adults failing first-line highly active antiretroviral therapy in Ho Chi Minh City, Vietnam

BACKGROUND & OBJECTIVES

Little is known about HIV-1 drug resistance (HIVDR) in people failing first-line highly active antiretroviral therapy (HAART) in Vietnam. The aim of this study was to investigate the frequency of HIV-1 drug resistance mutations (DRMs) and determine correlates of acquiring genotypic HIVDR among Vietnamese adults (age ≥ 18) who met the immunological or clinical criteria of first-line HAART failure according to the guidelines of the World Health Organization (WHO).

METHODS

A total of 138 individuals participated in a descriptive study in Ho Chi Minh City between 2006 and 2009. Blood samples were collected for performing HIV-1 viral load (VL) and genotyping for specimens with VL ≥ 1,000 copies/mL. Stanford algorithm was used to interpret DRMs and multivariate analyses were performed to investigate predictors of HIVDR acquisition.

RESULTS

Of the study population, most participants failed either stavudine/lamivudine/nevirapine or stavudine/lamivudine/efavirenz (116 individuals). Up to 51 people obtained a VL <1,000 copies/mL. Among 87 participating individuals with VL ≥1,000 copies/mL, 11 people still harbored a wild-type strain, while 76 participants harbored a HIV-1 drug-resistant strain (2 of which were against protease inhibitors); common DRMs were M184I/V (74%), Y181I/C/V (39%), G190A/S (32%), T215Y/F (32%), and K103N (31%). The proportions of K65R, Q151M, and T69 insertion were 13%, 11%, and 5%, respectively. Being antiretroviral-exposed before initiating first-line HAART in a public and free-of-charge outpatient clinic, having nonadherence to first-line HAART, per 12-month increase of duration on first-line HAART, and having clinical failure criteria were significantly associated with a genotypic HIVDR acquisition.

CONCLUSIONS

In the absence of VL for the population with WHO immunological/ clinical treatment failure criteria, a large proportion of people still achieved a VL <1,000 copies/mL, while a high prevalence of HIVDR was observed in those with VL ≥1,000 copies/mL. Thus, VL monitoring should be implemented now for the HAART-treated population in Vietnam.

Drug susceptibility and resistance mutations after first-line failure in resource limited settings

BACKGROUND

The development of drug resistance to nucleoside reverse transcriptase inhibitors (NRTIs) and nonnucleoside reverse transcriptase inhibitors (NNRTIs) has been associated with baseline human immunodeficiency virus (HIV)-1 RNA level (VL), CD4 cell counts (CD4), subtype, and treatment failure duration. This study describes drug resistance and levels of susceptibility after first-line virologic failure in individuals from Thailand, South Africa, India, Malawi, Tanzania.

METHODS

CD4 and VL were captured at AIDs Clinical Trial Group (ACTG) A5230 study entry, a study of lopinavir/ritonavir (LPV/r) monotherapy after first-line virologic failure on an NNRTI regimen. HIV drug-resistance mutation associations with subtype, site, study entry VL, and CD4 were evaluated using Fisher exact and Kruskall-Wallis tests.

RESULTS

Of the 207 individuals who were screened for A5230, sequence data were available for 148 individuals. Subtypes observed: subtype C (n = 97, 66%) AE (n = 27, 18%), A1 (n = 12, 8%), and D (n = 10, 7%). Of the 148 individuals, 93% (n = 138) and 96% (n = 142) had at least 1 reverse transcriptase (RT) mutation associated with NRTI and NNRTI resistance, respectively. The number of NRTI mutations was significantly associated with a higher study screening VL and lower study screening CD4 (P < .001). Differences in drug-resistance patterns in both NRTI and NNRTI were observed by site.

CONCLUSIONS

The degree of NNRTI and NRTI resistance after first-line virologic failure was associated with higher VL at study entry. Thirty-two percent of individuals remained fully susceptible to etravirine and rilpivirine, protease inhibitor resistance was rare. Some level of susceptibility to NRTI remained; however, VL monitoring and earlier virologic failure detection may result in lower NRTI resistance.

Generic antiretroviral drugs in developing countries: friends or foes?

Although second-line generic antiretroviral drugs are of great value in developing countries, there are concerns regarding their quality. We studied a generic Lopinavir/ritonavir (200/50  mg; Arga-L, India) marketed in the Republic of Congo but not prequalified by WHO. Despite adequate quantitative and qualitative drug content, Arga-L had a bio-availablility of 10% compared with Kaletra. To avoid selection of drug-resistant HIV, rigorous pharmacological monitoring of generic drugs not prequalified by WHO must be a priority.

[Consensus Statement by GeSIDA/National AIDS Plan Secretariat on antiretroviral treatment in adults infected by the human immunodeficiency virus (Updated January 2013)]

OBJECTIVE

This consensus document is an update of combined antiretroviral therapy (cART) guidelines for HIV-1 infected adult patients.

METHODS

To formulate these recommendations a panel composed of members of the GeSIDA/National AIDS Plan Secretariat (Grupo de Estudio de Sida and the Secretaría del Plan Nacional sobre el Sida) reviewed the efficacy and safety advances in clinical trials, cohort and pharmacokinetic studies published in medical journals (PubMed and Embase) or presented in medical scientific meetings. The strength of the recommendations and the evidence which support them are based on a modification of the criteria of Infectious Diseases Society of America.

RESULTS

cART is recommended in patients with symptoms of HIV infection, in pregnant women, in serodiscordant couples with high risk of transmission, in hepatitisB co-infection requiring treatment, and in HIV nephropathy. cART is recommended in asymptomatic patients if CD4 is <500cells/μl. If CD4 are >500cells/μl cART should be considered in the case of chronic hepatitisC, cirrhosis, high cardiovascular risk, plasma viral load >100.000 copies/ml, proportion of CD4 cells <14%, neurocognitive deficits, and in people aged >55years. The objective of cART is to achieve an undetectable viral load. The first cART should include 2 reverse transcriptase inhibitors (RTI) nucleoside analogs and a third drug (a non-analog RTI, a ritonavir boosted protease inhibitor, or an integrase inhibitor). The panel has consensually selected some drug combinations, for the first cART and specific criteria for cART in acute HIV infection, in tuberculosis and other HIV related opportunistic infections, for the women and in pregnancy, in hepatitisB or C co-infection, in HIV-2 infection, and in post-exposure prophylaxis.

CONCLUSIONS

These new guidelines update previous recommendations related to first cART (when to begin and what drugs should be used), how to monitor, and what to do in case of viral failure or adverse drug reactions. cART specific criteria in comorbid patients and special situations are similarly updated.

Emergence of HIV drug resistance during first- and second-line antiretroviral therapy in resource-limited settings

INTRODUCTION

Antiretroviral therapy (ART) in resource-limited settings has expanded in the last decade, reaching >8 million individuals and reducing AIDS mortality and morbidity. Continued success of ART programs will require understanding the emergence of HIV drug resistance patterns among individuals in whom treatment has failed and managing ART from both an individual and public health perspective. We review data on the emergence of HIV drug resistance among individuals in whom first-line therapy has failed and clinical and resistance outcomes of those receiving second-line therapy in resource-limited settings.

RESULTS

Resistance surveys among patients initiating first-line nonnucleoside reverse-transcriptase inhibitor (NNRTI)-based therapy suggest that 76%-90% of living patients achieve HIV RNA suppression by 12 months after ART initiation. Among patients with detectable HIV RNA at 12 months, HIV drug resistance, primarily due to M184V and NNRTI mutations, has been identified in 60%-72%, although the antiretroviral activity of proposed second-line regimens has been preserved. Complex mutation patterns, including thymidine-analog mutations, K65R, and multinucleoside mutations, are prevalent among cases of treatment failure identified by clinical or immunologic methods. Approximately 22% of patients receiving second-line therapy do not achieve HIV RNA suppression by 6 months, with poor adherence, rather than HIV drug resistance, driving most failures. Major protease inhibitor resistance at the time of second-line failure ranges from 0% to 50%, but studies are limited.

CONCLUSIONS

Resistance of HIV to first-line therapy is predictable at 12 months when evaluated by means of HIV RNA monitoring and, when detected, largely preserves second-line therapy options. Optimizing adherence, performing resistance surveillance, and improving treatment monitoring are critical for long-term prevention of drug resistance.

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.

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).

Ritonavir-boosted lopinavir plus nucleoside or nucleotide reverse transcriptase inhibitors versus ritonavir-boosted lopinavir plus raltegravir for treatment of HIV-1 infection in adults with virological failure of a standard first-line ART regimen (SECOND-LINE): a randomised, open-label, non-inferiority study

BACKGROUND

Uncertainty exists about the best treatment for people with HIV-1 who have virological failure with first-line combination antiretroviral therapy of a non-nucleoside analogue (NNRTI) plus two nucleoside or nucleotide analogue reverse transcriptase inhibitors (NtRTI). We compared a second-line regimen combining two new classes of drug with a WHO-recommended regimen.

METHODS

We did this 96-week, phase 3b/4, randomised, open-label non-inferiority trial at 37 sites worldwide. Adults with HIV-1 who had confirmed virological failure (plasma viral load >500 copies per mL) after 24 weeks or more of first-line treatment were randomly assigned (1:1) to receive ritonavir-boosted lopinavir plus two or three NtRTIs (control group) or ritonavir-boosted lopinavir plus raltegravir (raltegravir group). The randomisation sequence was computer generated with block randomisation (block size four). Neither participants nor investigators were masked to allocation. The primary endpoint was the proportion of participants with plasma viral load less than 200 copies per mL at 48 weeks in the modified intention-to-treat population, with a non-inferiority margin of 12%. This study is registered with ClinicalTrials.gov, number NCT00931463.

FINDINGS

We enrolled 558 patients, of whom 541 (271 in the control group, 270 in the raltegravir group) were included in the primary analysis. At 48 weeks, 219 (81%) patients in the control group compared with 223 (83%) in the raltegravir group met the primary endpoint (difference 1·8%, 95% CI -4·7 to 8·3), fulfilling the criterion for non-inferiority. 993 adverse events occurred in 271 participants in the control group versus 895 in 270 participants in the raltegravir group, the most common being gastrointestinal.

INTERPRETATION

The raltegravir regimen was no less efficacious than the standard of care and was safe and well tolerated. This simple NtRTI-free treatment strategy might extend the successful public health approach to management of HIV by providing simple, easy to administer, effective, safe, and tolerable second-line combination antiretroviral therapy.

FUNDING

University of New South Wales, Merck, AbbVie, the Foundation for AIDS Research.

Evaluation of WHO immunologic criteria for treatment failure: implications for detection of virologic failure, evolution of drug resistance and choice of second-line therapy in India

Introduction

Routine HIV viral load (VL) testing is not available in India. We compared test performance characteristics of immunologic failure (IF) against the gold standard of virologic failure (VF), examined evolution of drug resistance among those who stayed on a failing regimen because they did not meet criteria for IF and assessed implications for second-line therapy.

Methods

Participants on first-line highly active antiretroviral therapy (HAART) in Bangalore, India, were monitored for 24 months at six-month intervals, with CD4 count, VL and genotype, if VL>1000 copies/ml. Standard WHO criteria were used to define IF; VF was defined as having two consecutive VL>1000 copies/ml or one VL>10,000 copies/ml. Resistance was assessed using standard International AIDS Society-USA (IAS-USA) recommendations.

Results

Of 522 participants (67.6% male, mean age of 37.5; 85.1% on nevirapine-based and 40.4% on d4T-containing regimens), 57 (10.9%) had VF, 38 (7.3%) had IF and 13 (2.5%) had both VF and IF. The sensitivity of immunologic criteria to detect VF was 22.8%, specificity was 94.6% and positive predictive value was 34.2%. Forty-four participants with VF only continued on their failing first-line regimen; by the end of the study period, 90.9% had M184V, 63.6% had thymidine analogue mutations (TAMs), 34.1% had resistance to tenofovir, and 63.6% had resistance to etravirine.

Conclusions

WHO IF criteria have low sensitivity for detecting VF, and the presence of IF poorly predicts VF. Relying on CD4 counts leads to unnecessary switches to second-line HAART and continuation of failing regimens, jeopardizing future therapeutic options. Universal access to VL monitoring would avoid costly switches to second-line HAART and preserve future treatment options.

Short communication: high rates of thymidine analogue mutations and dual-class resistance among HIV-infected Ugandan children failing first-line antiretroviral therapy

HIV-infected children are at high risk of acquiring drug-resistant viruses, which is of particular concern in settings where antiretroviral drug options are limited. We aimed to assess resistance patterns and predict viral drug susceptibility among children with first-line antiretroviral therapy (ART) failure in Uganda. A cross-sectional analysis of children switching ART regimens due to first-line failure was performed at three clinical sites in Uganda. HIV-RNA determination and genotypic resistance testing on all specimens with HIV-RNA >1,000 copies/ml were performed. Major drug resistance mutations were scored using the 2011 International Antiviral Society-USA list. The Stanford algorithm was used to predict drug susceptibility. At the time of switch, 44 genotypic resistance tests were available for 50 children. All children harbored virus with nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance [95% confidence interval (CI) 92-100%] and NRTI resistance was present in 98% (95% CI 88-100%). Forty-six percent (95% CI 30-61%) of children harbored ≥2 thymidine analog mutations. M184V was identified as the only NRTI mutation in 27% (95% CI 15-43%). HIV susceptibility to NRTIs, with the exception of tenofovir, was reduced in ≥60% of children. Ugandan children experiencing first-line ART failure in our study harbored high rates of dual-class and accumulated HIV drug resistance. Methods to prevent treatment failure, including adequate pediatric formulations and alternative second-line treatment options, are urgently needed.

Sustained virological response on second-line antiretroviral therapy following virological failure in HIV-infected patients in rural South Africa

Objective

This study aims to describe the virological, immunological and clinical efficacy of protease inhibitor (PI)-based second-line antiretroviral therapy (ART) in rural South Africa.

Methods

An observational cohort study was performed on 210 patients (including 39 children) who initiated PI-based second-line therapy at least 12 months prior to data collection. Biannual clinical, immunological and virological monitoring was performed. Primary endpoints were adequate virological response (plasma HIV-1 RNA<400 copies/ml), full virological suppression (plasma HIV-1 RNA<50 copies/ml) and treatment failure (virological failure (plasma HIV-1 RNA>1000 after initial virological response) or on-going viremia (plasma HIV-1 RNA never<400 copies/ml for more than six months)). Data were analyzed by an on-treatment (OT) and intention-to-treat (ITT) approach. Analyses were primarily performed on the group of patients who switched following first-line virological failure.

Results

Median duration of follow-up after switch to second-line treatment was 20 months [IQR 11–35]. 191 patients had switched to second-line ART due to first-line virological failure. 139/191 of them (72.8%, ITT) were in care and on treatment at the end of follow-up and 11/191 (5.8%, ITT) had died. After twelve months, an adequate virological response was seen in 92/128 patients (71.9%, OT), of which 78/128 (60.9%, OT) experienced full virological suppression. Virological response remained stable after 24 months. Virological efficacy was similar amongst adult and pediatric patients. As in first-line ART, we observed a lack of correlation between virological failure and WHO-defined immunological failure.

Conclusions

Good virological outcomes following first-line failure can be achieved with PI-based, second-line antiretroviral therapy in both adult and pediatric patients in rural South Africa. Retention rates were high and virological outcomes were sustainable during the two-year follow-up period, although persisting low-level viremia occurred in a subset of patients. The observed viro-immunological dissociation emphasizes the need for virological monitoring.

Are subtype differences important in HIV drug resistance?

The diversity of human immunodeficiency virus type 1 (HIV-1) has given rise to multiple subtypes and recombinant strains. The majority of research into antiretroviral agents and drug resistance has been performed on subtype B viruses, yet non-subtype B strains are responsible for 90% of global infections. Although it seems that combination antiretroviral regimens are effective against all HIV-1 subtypes, there is emerging evidence of subtype differences in drug resistance, relevant to antiretroviral strategies in different parts of the world. For this purpose, extensive sampling of HIV genetic diversity, curation and analyses are required to inform antiretroviral strategies in different parts of the world.

Lopinavir/ritonavir monotherapy after 24 weeks of second-line antiretroviral therapy in Africa: a randomized controlled trial (SARA)

BACKGROUND

Boosted protease inhibitor (bPI) monotherapy (bPImono) potentially has substantial cost, safety and operational benefits. It has never been evaluated as second-line antiretroviral therapy (ART) in Africa.

METHODS

After 24 weeks of lopinavir/ritonavir-containing second-line therapy, DART participants were randomized to remain on combination therapy (CT), or change to bPImono maintenance (SARA trial; ISRCTN53817258). Joint primary end points were CD4(+) T-cell changes 24 weeks later and serious adverse events (SAEs); retrospectively assayed viral load (VL) was a secondary end point. Analyses were intention-to-treat.

RESULTS

A total of 192 participants were randomized to CT (n=95) or bPImono (n=97) and followed for median 60 weeks (IQR 45-84). Participants received median 4.0 years (IQR 3.5-4.4) first-line ART. Median CD4(+) T-cell count at first-line failure was 86 cells/mm(3) (47-136), increasing to 245 cells/mm(3) (173-325) after 24-week induction when 77% had VL<50 copies/ml. Overall, 44 (23%) were receiving second-line therapy with bPI and nucleoside reverse transcriptase inhibitors (NRTI) only, and 148 (77%) with bPI plus non-NRTI (NNRTI) with or without NRTI. At 24 weeks after randomization to CT versus bPImono, mean CD4(+) T-cell increase was 42 (CT, n=85) versus 49 cells/mm(3) (bPImono, n=88; adjusted difference 13 [95% CI -15, 43], P=0.37; non-inferior compared with predetermined non-inferiority margin [-33]). Virological suppression was greater for CT versus bPImono (trend P=0.009): 77% (70/91) versus 60% (56/94) were <50 copies/ml, and 5% (5) versus 14% (13) were ≥1,000 copies/ml, respectively. A total of 0 (0%) versus 5 (5%) participants had major protease inhibitor mutations and 3 (3%) versus 0 (0%) new NNRTI/NRTI mutations were detected during follow-up. Two participants (1 CT and 1 bPImono) died >24 weeks after randomization, and 5 (2 CT and 3 bPImono) experienced SAEs (P=0.51).

CONCLUSIONS

bPImono following a 24-week second-line induction was associated with similar CD4(+) T-cell response, but increased low-level viraemia, generally without protease inhibitor resistance. Longer-term trials are needed to provide definitive evidence about effectiveness in Africa.