The emergence of drug resistant HIV variants at virological failure of HAART combinations containing efavirenz, tenofovir and lamivudine or emtricitabine within the UK Collaborative HIV Cohort

Design, synthesis and biological evaluation of indole-2-carboxylic acid derivatives as novel HIV-1 integrase strand transfer inhibitors

Integrase plays an important role in the life cycle of HIV-1, and integrase strand transfer inhibitors (INSTIs) can effectively impair the viral replication. However, drug resistance mutations have been confirmed to decrease the efficacy of INSTI during the antiviral therapy. Herein, indole-2-carboxylic acid (1) was found to inhibit the strand transfer of integrase, and the indole nucleus of compound 1 was observed to chelate with two Mg2+ ions within the active site of integrase. Through optimization of compound 1, a series of indole-2-carboxylic acid derivatives were designed and synthesized, and compound 17a was proved to markedly inhibit the effect of integrase, with IC50 value of 3.11 μM. Binding mode analysis of 17a demonstrated that the introduced C6 halogenated benzene ring could effectively bind with the viral DNA (dC20) through π-π stacking interaction. These results indicated that indole-2-carboxylic acid is a promising scaffold for the development of integrase inhibitors.

HIV-1 Transcription Inhibition Using Small RNA-Binding Molecules

The HIV-1 transactivator protein Tat interacts with the transactivation response element (TAR) at the three-nucleotide UCU bulge to facilitate the recruitment of transcription elongation factor-b (P-TEFb) and induce the transcription of the integrated proviral genome. Therefore, the Tat-TAR interaction, unique to the virus, is a promising target for developing antiviral therapeutics. Currently, there are no FDA-approved drugs against HIV-1 transcription, suggesting the need to develop novel inhibitors that specifically target HIV-1 transcription. We have identified potential candidates that effectively inhibit viral transcription in myeloid and T cells without apparent toxicity. Among these candidates, two molecules showed inhibition of viral protein expression. A molecular docking and simulation approach was used to determine the binding dynamics of these small molecules on TAR RNA in the presence of the P-TEFb complex, which was further validated by a biotinylated RNA pulldown assay. Furthermore, we examined the effect of these molecules on transcription factors, including the SWI/SNF complex (BAF or PBAF), which plays an important role in chromatin remodeling near the transcription start site and hence regulates virus transcription. The top candidates showed significant viral transcription inhibition in primary cells infected with HIV-1 (98.6). Collectively, our study identified potential transcription inhibitors that can potentially complement existing cART drugs to address the current therapeutic gap in current regimens. Additionally, shifting of the TAR RNA loop towards Cyclin T1 upon molecule binding during molecular simulation studies suggested that targeting the TAR loop and Tat-binding UCU bulge together should be an essential feature of TAR-binding molecules/inhibitors to achieve complete viral transcription inhibition.

Enhanced Antiviral Ability by a Combination of Zidovudine and Short Hairpin RNA Targeting Avian Leukosis Virus

Avian leukosis virus (ALV) causes tumor diseases in poultry and is circulating all over the world, leading to significant economic losses. In addition, mixed infection of ALV with other viruses is very common and is often reported to contaminate live vaccines. At present, there is no effective method to suppress the replication of ALV in vitro, so it is very difficult to remove it in mixed infection. As a retrovirus, the replication of ALV can be limited by reverse transcriptase (RT) inhibitors like zidovudine (AZT), but it also causes nontargeted cytotoxicity. To find the optimal solution in cytotoxicity and inhibition efficiency in vitro culture system, we firstly designed a combination therapy of AZT and short hairpin RNA (shRNA) targeting ALV and then verified its efficiency by multiple biological methods. Results showed that shRNA can effectively inhibit the expression of RT and then limit the replication of ALV. The combination of AZT and shRNA can significantly improve the antiviral efficiency in viral replication, shedding, and provirus assembly under the condition of low cytotoxicity. Overall, in this study, the combination therapy of AZT and shRNA targeting ALV showed excellent antiviral performance against ALV in vitro culture system. This method can be applied to multiple scenarios, such as the removal of ALV in mixed infection or the purification of contaminated vaccine strains.

The Estimation of Transmitted Drug Resistance Mutation Strains Probability in the Treatment of HIV Using the Beta-Binomial Model

The human immunodeficiency virus (HIV) is a viral infection that destroys the human immune system resulting in acquired immunodeficiency syndrome (AIDS). The Zambia HIV prevalence rate (11.3%) remains among the highest in the sub-Saharan Africa. In the treatment of HIV-naive patients, a problem that relates to the transmitted drug resistance mutation strains (TDRMs) occurs in the administration of antiretroviral (ARV) drugs. To address this problem, we propose the use of transition probabilities when prescribing a switch from the first-line to the second-line or to the third-line regimen on the ARV drugs combination. We formulate a statistical technique to determine an optimal ARV drugs combination. To compute a transition probability matrix chart on ARV drugs combinations of the first-line and second-line regimens, we apply a beta-binomial hierarchical model on HIV data. The transition probability matrices corresponding to the ARV drugs combinations TDF+ETC+NVP, TDF+FTC+EFV, AZT+3TC+NVP, AZT+3TC+EFV, D4T+3TC+NVP, and D4T+3TC+EFV provide an upper triangular matrix of probabilities. We observe a higher probability of remaining in the same regimen state than moving to another state. A transition probability chart provides information on the most effective combination to prescribe to a patient in the presence of transmitted drug resistance mutation (TDRM) test results. The transmission probabilities play a major role in aiding the physicians make an informed decision to prescribe an optimal ARV drugs combination. We suggest a TDRM test to be carried out to all newly diagnosed HIV individuals before prescribing any of the ARV drugs combination.

Switching to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide in Adults With HIV and M184V/I Mutation

BACKGROUND

The ability of elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide (E/C/F/TAF) to maintain virologic suppression in participants with M184V and/or M184I resistance mutations from historical genotypic reports when switching from a tenofovir disoproxil fumarate-based or abacavir (ABC)-based regimen was investigated.

SETTING

Phase IIIb, 48-week, open-label, single-arm, multicenter, clinical trial (NCT02616029).

METHODS

Virologically suppressed adults with HIV and documented M184V/I on historical genotypic records switched to E/C/F/TAF from a tenofovir disoproxil fumarate-based or ABC-based regimen. The primary end point was HIV-1 RNA of <50 copies per milliliter at week 12 using pure virologic response (PVR). Secondary end points included HIV-1 RNA of <50 copies per milliliter at weeks 24/48 (PVR) and at weeks 12, 24, and 48 (Food and Drug Administration snapshot algorithm), and change in CD4+ count at weeks 12, 24, and 48.

RESULTS

M184V alone was reported in 82.8% of 64 participants; 9.4% and 7.8% had M184I and M184V/I, respectively, and 43.8% had archived M184V/I (baseline DNA). All (62/62 with available data, 100%, 95% confidence interval 94.2% to 100%) participants maintained PVR at weeks 12, 24, and 48. By Food and Drug Administration snapshot algorithm, one participant had HIV-1 RNA of ≥50 copies per milliliter (week 12); confirmatory HIV-1 RNA was <50 copies per milliliter. No significant changes were observed in CD4+ cell count. Drug-related adverse events (AEs) were reported by 10 (15.6%) participants. Six (9.4%) and 5 (7.8%) participants had grade 3-4 AEs or serious AEs, respectively (none drug related).

CONCLUSIONS

The presence of the resistance mutations M184V/I did not jeopardize the efficacy of switching to E/C/F/TAF in virologically suppressed adults. High rates of virologic suppression were maintained throughout 48 weeks of therapy and treatment was well tolerated.

The evidence for using tenofovir disoproxil fumarate plus lamivudine as a nucleoside analogue backbone for the treatment of HIV

This article evaluates the evidence supporting use of the tenofovir disoproxil fumarate (TDF) plus lamivudine (3 ​TC) combination as a dual nucleoside backbone within a triple drug antiretroviral regimen. Key trials that assess the relative efficacy, safety and resistance profile of 3 ​TC and emtricitabine (FTC) are discussed. Clinical use of 3 ​TC and FTC with two tenofovir prodrugs –TDF and tenofovir alafenamide (TAF) – is presented. Recommendations from various international guidelines for the construction of triple and emerging dual regimens are summarised. In conclusion, data suggest the therapeutic equivalence of 3 ​TC and FTC, especially when 3 ​TC is combined with TDF.

Identification of Modulators of HIV-1 Proviral Transcription from a Library of FDA-Approved Pharmaceuticals

Human immunodeficiency virus 1 (HIV-1) is the most prevalent human retrovirus. Recent data show that 34 million people are living with HIV-1 worldwide. HIV-1 infections can lead to AIDS which still causes nearly 20,000 deaths annually in the USA alone. As this retrovirus leads to high morbidity and mortality conditions, more effective therapeutic regimens must be developed to treat these viral infections. A key target for intervention for which there are no current FDA-approved modulators is at the point of proviral transcription. One successful method for identifying novel therapeutics for treating infectious diseases is the repurposing of pharmaceuticals that are approved by the FDA for alternate indications. Major benefits of using FDA-approved drugs include the fact that the compounds have well established toxicity profiles, approved manufacturing processes, and immediate commercial availability to the patients. Here, we demonstrate that pharmaceuticals previously approved for other indications can be utilized to either activate or inhibit HIV-1 proviral transcription. Specifically, we found febuxostat, eltrombopag, and resveratrol to be activators of HIV-1 transcription, while mycophenolate was our lead inhibitor of HIV-1 transcription. Additionally, we observed that the infected cells of lymphoid and myeloid lineage responded differently to our lead transcriptional modulators. Finally, we demonstrated that the use of a multi-dose regimen allowed for enhanced activation with our transcriptional activators.

Epidemiologic and viral predictors of antiretroviral drug resistance among persons living with HIV in a large treatment program in Nigeria

BACKGROUND

Expanded access to combination antiretroviral therapy (cART) throughout sub-Saharan Africa over the last decade has remarkably improved the prognosis of persons living with HIV (PLWH). However, some PLWH experience virologic rebound after a period of viral suppression, usually followed by selection of drug resistant virus. Determining factors associated with drug resistance can inform patient management and healthcare policies, particularly in resource-limited settings where drug resistance testing is not routine.

METHODS

A case-control study was conducted using data captured from an electronic medical record in a large treatment program in Nigeria. Cases PLWH receiving cART who developed acquired drug resistance (ADR) and controls were those without ADR between 2004 and 2011. Each case was matched to up to 2 controls by sex, age, and education. Logistic regression was used estimate odds ratios (ORs) and 95% confidence intervals (CIs) for factors associated with ADR.

RESULTS

We evaluated 159 cases with ADR and 299 controls without ADR. In a multivariate model, factors associated with ADR included older age (OR = 2.35 [age 30-40 years 95% CI 1.29, 4.27], age 41 + years OR = 2.31 [95% CI 1.11, 4.84], compared to age 17-30), higher education level (secondary OR 2.14 [95% CI 1.1.11-4.13]), compared to primary and tertiary), non-adherence to care (OR = 2.48 [95% CI 1.50-4.00]), longer treatment duration (OR = 1.80 [95% CI 1.37-2.35]), lower CD4 count((OR = 0.95 [95% CI 0.95-0.97]) and higher viral load (OR = 1.97 [95% CI 1.44-2.54]).

CONCLUSIONS

Understanding these predictors may guide programs in developing interventions to identify patients at risk of developing ADR and implementing prevention strategies.

An association between K65R and HIV-1 subtype C viruses in patients treated with multiple NRTIs

Objectives: HIV-1 subtype C might have a greater propensity to develop K65R mutations in patients with virological failure compared with other subtypes. However, the strong association between viral subtype and confounding factors such as exposure groups and ethnicity affects the calculation of this propensity. We exploited the diversity of viral subtypes within the UK to undertake a direct comparative analysis.

Patients and methods: We analysed only sequences with major IAS-defined mutations from patients with virological failure. Prevalence of K65R was related to subtype and exposure to the NRTIs that primarily select for this mutation (tenofovir, abacavir, didanosine and stavudine). A multivariate logistic regression model quantified the effect of subtype on the prevalence of K65R, adjusting for previous and current exposure to all four specified drugs.

Results: Subtype B patients (n = 3410) were mostly MSM (78%) and those with subtype C (n = 810) were mostly heterosexual (82%). K65R was detected in 7.8% of subtype B patients compared with 14.2% of subtype C patients. The subtype difference in K65R prevalence was observed irrespective of NRTI exposure and K65R was frequently selected by abacavir, didanosine and stavudine in patients with no previous exposure to tenofovir. Multivariate logistic regression confirmed that K65R was significantly more common in subtype C viruses (adjusted OR = 2.02, 95% CI = 1.55–2.62, P < 0.001).

Conclusions: Patients with subtype C HIV-1 have approximately double the frequency of K65R in our database compared with other subtypes. The exact clinical implications of this finding need to be further elucidated.

Candidates for inclusion in a universal antiretroviral regimen: are lamivudine and emtricitabine interchangeable?

PURPOSE OF REVIEW

Lamivudine (3TC) and emtricitabine (FTC) are the most widely used antiretroviral medications worldwide and are considered by the WHO to be interchangeable. This article reviews evidence supporting interchangeability of 3TC and FTC and considerations for future use.

RECENT FINDINGS

Three randomized trials have directly compared the safety and efficacy of 3TC and FTC against identical backbone regimens. Each of these trials reported a nonsignificant difference in virological suppression, and when results were pooled the overall difference was nonsignificant (relative risk 1.03, 95% confidence interval 0.96-1.10). These findings of equivalence are further supported by indirect evidence from nine randomized trials comparing 3TC and FTC against a similar backbone regimen of two different nucleoside reverse transcriptase inhibitors (relative risk of virological suppression 0.99, 95% confidence interval 0.96-1.01). Data from observational studies is mixed. Overall, reported differences between 3TC and FTC in observational studies are often associated with differences in the baseline characteristics of the treatment groups, notably with respect to immunological and virological status, comorbidity, substance misuse, and pill burden.

SUMMARY

The totality of evidence to date, from pharmacological data to observational studies to direct and indirect comparisons in randomized trials, suggests that 3TC and FTC can be considered to be therapeutically interchangeable and that if there are any differences, these are likely to be very small and not of major clinical importance.

Durability of Second Antiretroviral Regimens in the Italian Cohort Naive Antiretrovirals Foundation Study and Factors Associated with Discontinuation

The study was designed to investigate the median duration of second antiretroviral regimens and factors associated with early discontinuation in HIV patients who switched with an undetectable viral load. We conducted a retrospective analysis of the Italian Cohort Naive Antiretrovirals Foundation Study (ICONA), which collects data throughout the country. Patients who started first antiretroviral therapy (ART) after January 1, 2008 in any center involved in this cohort and then switched to a second regimen were included in the study. Second ART failure was described as two HIV-RNA >200 copies/mL or the discontinuation of any drug. Statistical analysis was performed utilizing Kaplan-Meier curves and Cox regression model. The study population included 835 patients and the median duration of first ART regimens was 16 months with HIV-RNA undetectable for 13 months. The main causes of switch to second ART regimens were toxicity (42.5%) and simplification (37.5%). The switch mostly involved the third drug (63.5%) and almost one third of the population received a single-tablet regimen (STR) as second treatment (30.6%). The median duration of second ART regimens was 9.2 months and the probabilities of treatment discontinuation at 12, 24, and 36 months were 21%, 35%, and 48.2%, respectively. STR formulations had a protective effect against second ART discontinuation. Almost half of our population needed a third regimen within 3 years, but STR could improve second ART durability.

N-hydroxy-substituted 2-aryl acetamide analogs: A novel class of HIV-1 integrase inhibitors

An in silico method has been used to discover N-hydroxy-substituted 2-aryl acetamide analogs as a new class of HIV-1 integrase inhibitors. Based on the molecular requirements of the binding pocket of catalytic active site, two molecules (compounds 2 and 4b) were designed as fragments. These were further synthesized and biologically evaluated. In vitro potency along with docking studies highlighted compound 4b as an active fragment which was further used to synthesize new leads as HIV-1 integrase inhibitors. Finally, six promising compounds (compounds 5b, 5c, 5e, 6-2c, 6-3b, and 6-5b) were identified by integrase inhibition assay (>50% inhibition). Based on in vitro anti-HIV-1 activity in a reporter gene-based cell assay system, compounds 5d, 6s, and 6k were found as novel HIV-1 integrase inhibitors due to its better selectivity index. Additionally, docking study revealed the importance of H-bond as well as hydrophobic interactions with Asn155, Lys156, and Lys159 which were required for their anti-HIV-1 activity.

Development of a Qualitative Quantitative Polymerase Chain Reaction Test to Identify Patients Failing First-Line Therapy to Non-Nucleotide Reverse Transcriptase Inhibitor

Antiretroviral therapy (ART) can be compromised by selection of drug resistance strains, which can be promoted by lack of adherence during therapy and drug tolerance, and some of these drug-resistant strains can persist for years as minority populations. The K103N drug resistance mutation is selected by the use of non-nucleotide reverse transcriptase inhibitors, including nevirapine or efavirenz (EFV), used in low-income countries. Here we describe the use of a less expensive qualitative point mutation polymerase chain reaction (PMqPCR_K103N) targeting K103N mutation. To validate the use of this methodology, we tested previously sequenced samples from patients treated with highly active ART with viral loads above 2,000 copies/ml and compared the results of our assay with Illumina deep sequencing. Due to its low cost and high specificity, this test is particularly suitable for low-income countries to screen for pretreatment resistance in patients either initiating ART or failing first-line regimens containing EFV.

An analysis of drug resistance among people living with HIV/AIDS in Shanghai, China

BACKGROUND

Understanding the mechanisms of drug resistance can facilitate better management of antiretroviral therapy, helping to prevent transmission and decrease the morbidity and mortality of people living with HIV/AIDS. However, there is little data about transmitted drug resistance and acquired drug resistance for HIV/AIDS patients in Shanghai.

METHODS

A retrospective cohort study of HIV-infected patients who visited the Department of Infectious Disease from June 2008 to June 2015 was conducted in Shanghai, China. Logistic regression analysis was performed to analyze risk factors for drug resistance among HIV-infected people with virological failure. The related collected factors included patient age, gender, marital status, infection route, baseline CD4 count, antiretroviral therapy regimens, time between HIV diagnosis and initiating antiretroviral therapy. Factors with p<0.1 in the univariate logistic regression test were analyzed by multivariate logistic regression test.

RESULTS

There were 575 subjects selected for this study and 369 participated in this research. For the antiretroviral therapy drugs, the rates of transmitted drug resistance and acquired drug resistance were significantly different. The non-nucleoside reverse transcriptase inhibitor (NNRTI) had the highest drug resistance rate (transmitted drug resistance, 10.9%; acquired drug resistance, 53.3%) and protease inhibitors (PIs) had the lowest drug resistance rate (transmitted drug resistance, 1.7%; acquired drug resistance, 2.7%). Logistic regression analysis found no factors that were related to drug resistance except marital status (married status for tenofovir: odds ratio = 6.345, 95% confidence interval = 1.553-25.921, P = 0.010) and the time span between HIV diagnosis and initiating antiretroviral therapy (≤6M for stavudine: odds ratio = 0.271, 95% confidence interval = 0.086-0.850, P = 0.025; ≤6M for didanosine: odds ratio = 0.284, 95% confidence interval = 0.096-0.842, P = 0.023; ≤6M for tenofovir: odds ratio = 0.079, 95% confidence interval = 0.018-0.350,P<0.001).

CONCLUSION

NNRTI had a higher DR rate compared with nucleoside reverse transcriptase inhibitor (NRTI) and PIs, consequently, LPV/r was a reasonable choice for patients with NNRTI drugs resistance in China. Only married status and a time span≤6 month between the HIV confirmed date and the time initiating antiretroviral therapy were risk factors for TDF drug resistance. Both baseline HIV-RNA load and resistance test is crucial for TDR diagnosis, and frequent monitoring of HIV-RNA load is crucial for ADR identification and intervention. Treatment adherence still plays a positive role on the outcome of ART.

Rapid In Vitro Evaluation of Antiretroviral Barrier to Resistance at Therapeutic Drug Levels

Failure of combination antiretroviral (ARV) therapy in HIV-infected patients is often associated with the emergence of drug resistance-associated mutations (RAMs). To facilitate analysis of the barrier to resistance at therapeutically relevant ARV concentrations, we performed fixed-dose in vitro HIV-1 drug resistance selection assays using the immortalized MT-2 T-cell line and primary human CD4⁺ T cells with a panel of FDA-approved ARVs, each at their respective cell culture equivalent clinical trough concentration (CCE C_min). At high multiples of its CCE C_min, emtricitabine (FTC) selected for the rapid emergence of M184I/V, a result consistent with resistance emergence in vivo. While the rate of viral breakthrough in the presence of rilpivirine or efavirenz was delayed relative to FTC, both inhibitors selected for virus with known clinically relevant RAMs. No viral breakthrough was observed for the protease inhibitor atazanavir even at subtherapeutic drug concentrations, which is consistent with its previously characterized high in vivo barrier to resistance. Depending on assay conditions, treatment with integrase inhibitors elvitegravir and raltegravir resulted in breakthrough of both resistant and wild-type virus. The RAMs observed in drug selections were not detected above a 2% threshold by deep sequencing in the in vitro virus inoculum, and only rarely in isolates from treatment-naive HIV+ patients. These new viral breakthrough assays facilitate the analysis of multiple experimental replicates and conditions in parallel and provide a rapid quantitative means to evaluate drug resistance emergence at therapeutically relevant drug concentrations, which should facilitate the identification of new ARVs with a high barrier to resistance.

Pre-treatment minority HIV-1 drug resistance mutations and long term virological outcomes: is prediction possible?

Background

Although the use of highly active antiretroviral therapy in HIV positive individuals has proved to be effective in suppressing the virus to below detection limits of commonly used assays, virological failure associated with drug resistance is still a major challenge in some settings. The prevalence and effect of pre-treatment resistance associated variants on virological outcomes may also be underestimated because of reliance on conventional population sequencing data which excludes minority species. We investigated long term virological outcomes and the prevalence and pattern of pre-treatment minority drug resistance mutations in individuals initiating HAART at a local HIV clinic.

Methods

Patient’s records of viral load results and CD4 cell counts from routine treatment monitoring were used and additional pre-treatment blood samples for Sanger sequencing were obtained. A selection of pre-treatment samples from individuals who experienced virological failure were evaluated for minority resistance associated mutations to 1 % prevalence and compared to individuals who achieved viral suppression.

Results

At least one viral load result after 6 months or more of treatment was available for 65 out of 78 individuals followed for up to 33 months. Twenty (30.8 %) of the 65 individuals had detectable viremia and eight (12.3 %) of them had virological failure (viral load > 1000 RNA copies/ml) after at least 6 months of HAART. Viral suppression, achieved by month 8 to month 13, was followed by low level viremia in 10.8 % of patients and virological failure in one patient after month 20. There was potentially reduced activity to Emtricitabine or Tenofovir in three out of the eight cases in which minority drug resistance associated variants were investigated but detectable viremia occurred in one of these cases while the activity of Efavirenz was generally reduced in all the eight cases.

Conclusions

Early viral suppression was followed by low level viremia for some patients which may be an indication of failure to sustain viral suppression over time. The low level viremia may also be representing early stages of resistance development. The mutation patterns detected in the minority variants showed potential reduced drug sensitivity which highlights their potential to dominate after treatment initiation.

Trial registration

Not applicable.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-016-0628-x) contains supplementary material, which is available to authorized users.

The Experience of Antiretroviral Treatment for Black West African Women who are HIV Positive and Living in London: An Interpretative Phenomenological Analysis

Antiretroviral therapy (ART) offers a powerful intervention in HIV but effectiveness can be compromised by inadequate adherence. This paper is a detailed examination of the experience of medication in a purposively selected group of people living with HIV. In-depth interviews were conducted with 10 HIV positive, West African women of black heritage living in London, UK. This group was of interest since it is the second largest group affected by HIV in the UK. Interviews were subjected to interpretative phenomenological analysis, an idiographic, experiential, qualitative approach. The paper details the women's negative experience of treatment. ART can be considered difficult and unrelenting and may be disconnected from the women's sense of health or illness. Participants' social context often exacerbated the difficulties. Some reported an improvement in their feelings about the medication over time. These findings point to some intrinsic and social motivators which could act as spurs to adherence.

Global epidemiology of drug resistance after failure of WHO recommended first-line regimens for adult HIV-1 infection: a multicentre retrospective cohort study

Background

Antiretroviral therapy (ART) is crucial for controlling HIV-1 infection through wide-scale treatment as prevention and pre-exposure prophylaxis (PrEP). Potent tenofovir disoproxil fumarate-containing regimens are increasingly used to treat and prevent HIV, although few data exist for frequency and risk factors of acquired drug resistance in regions hardest hit by the HIV pandemic. We aimed to do a global assessment of drug resistance after virological failure with first-line tenofovir-containing ART.

Methods

The TenoRes collaboration comprises adult HIV treatment cohorts and clinical trials of HIV drug resistance testing in Europe, Latin and North America, sub-Saharan Africa, and Asia. We extracted and harmonised data for patients undergoing genotypic resistance testing after virological failure with a first-line regimen containing tenofovir plus a cytosine analogue (lamivudine or emtricitabine) plus a non-nucleotide reverse-transcriptase inhibitor (NNRTI; efavirenz or nevirapine). We used an individual participant-level meta-analysis and multiple logistic regression to identify covariates associated with drug resistance. Our primary outcome was tenofovir resistance, defined as presence of K65R/N or K70E/G/Q mutations in the reverse transcriptase (RT) gene.

Findings

We included 1926 patients from 36 countries with treatment failure between 1998 and 2015. Prevalence of tenofovir resistance was highest in sub-Saharan Africa (370/654 [57%]). Pre-ART CD4 cell count was the covariate most strongly associated with the development of tenofovir resistance (odds ratio [OR] 1·50, 95% CI 1·27–1·77 for CD4 cell count <100 cells per μL). Use of lamivudine versus emtricitabine increased the risk of tenofovir resistance across regions (OR 1·48, 95% CI 1·20–1·82). Of 700 individuals with tenofovir resistance, 578 (83%) had cytosine analogue resistance (M184V/I mutation), 543 (78%) had major NNRTI resistance, and 457 (65%) had both. The mean plasma viral load at virological failure was similar in individuals with and without tenofovir resistance (145 700 copies per mL [SE 12 480] versus 133 900 copies per mL [SE 16 650; p=0·626]).

Interpretation

We recorded drug resistance in a high proportion of patients after virological failure on a tenofovir-containing first-line regimen across low-income and middle-income regions. Effective surveillance for transmission of drug resistance is crucial.

Funding

The Wellcome Trust.

Design of boronic acid-attributed carbon dots on inhibits HIV-1 entry

The development of gp120 targeted human immunodeficiency virus (HIV) drug has improved antiretroviral therapies owing to its effects on attachment to target cells.

Efficacy of tenofovir and efavirenz in combination with lamivudine or emtricitabine in antiretroviral-naive patients in Europe

BACKGROUND

The combination of tenofovir and efavirenz with either lamivudine or emtricitabine (TELE) has proved to be highly effective in clinical trials for first-line treatment of HIV-1 infection. However, limited data are available on its efficacy in routine clinical practice.

METHODS

A multicentre cohort study was performed in therapy-naive patients initiating ART with TELE before July 2009. Efficacy was studied using ITT (missing or switch = failure) and on-treatment (OT) analyses. Genotypic susceptibility scores (GSSs) were determined using the Stanford HIVdb algorithm.

RESULTS

Efficacy analysis of 1608 patients showed virological suppression to <50 copies/mL at 48 weeks in 91.5% (OT) and 70.6% (ITT). Almost a quarter of all patients (22.9%) had discontinued TELE at week 48, mainly due to CNS toxicity. Virological failure within 48 weeks was rarely observed (3.3%, n = 53). In multilevel, multivariate analysis, infection with subtype B (P = 0.011), baseline CD4 count <200 cells/mm³ (P < 0.001), GSS <3 (P = 0.002) and use of lamivudine (P < 0.001) were associated with a higher risk of virological failure. After exclusion of patients using co-formulated compounds, virological failure was still more often observed with lamivudine. Following virological failure, three-quarters of patients switched to a PI-based regimen with GSS <3. After 1 year of second-line therapy, viral load was suppressed to <50 copies/mL in 73.5% (OT).

CONCLUSIONS

In clinical practice, treatment failure on TELE regimens is relatively frequent due to toxicity. Virological failure is rare and more often observed with lamivudine than with emtricitabine. Following virological failure on TELE, PI-based second-line therapy was often successful despite GSS <3.