Predicting antiretroviral drug resistance from the latest or the cumulative genotype

Prevalence and factors associated with HIV-1 multi-drug resistance over the past two decades in the Italian ARCA database

Despite successful antiretroviral therapy (ART), patients infected with human immunodeficiency virus (HIV) can develop multi-class drug resistance (MDR). This retrospective study aimed to explore the prevalence of HIV-1 drug resistance over the past two decades by focusing on HIV-MDR and its predictors. ART-experienced patients with HIV with results from at least one plasma genotypic resistance test (GRT) from 1998 to 2018, from the Antiviral Response Cohort Analysis database, were included in this study. The temporal trend of resistance to any drug class was evaluated by considering all GRTs. Prevalence and predictors of HIV-MDR were analysed by consideration of cumulative GRTs. Among 15 628 isolates from 6802 patients, resistance to at least one drug class decreased sharply from 1998 to 2010 (1998-2001: 78%; 2008-2010: 59%; P<0.001) and then remained relatively constant at approximately 50% from 2011 to 2018, with the proportion of isolates with HIV-MDR also stable (approximately 9%). By evaluating factors associated with cumulative HIV-MDR, the following factors were found to be associated with increased risk of HIV-MDR on multi-variate analysis: male gender; sexual and vertical transmission; number of previous protease inhibitors, nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) and non-NRTIs; previous exposure to integrase strand transfer inhibitors, enfuvirtide and maraviroc; and co-infection with hepatitis B virus. In contrast, a nadir CD4 cell count ≥200 cells/mm³, starting first-line ART in 2008 or later and co-infection with hepatitis C virus were associated with lower risk of HIV-MDR. In conclusion, this study revealed that HIV-1 drug resistance has been stable since 2011 despite its dramatic decrease over the past two decades. HIV-MDR is still present, although at a lower rate, suggesting the need for continuous surveillance and accurate management of ART-experienced patients with HIV.

Utility of HIV-1 DNA genotype in determining antiretroviral resistance in patients with low or undetectable HIV RNA viral loads

Objectives

To investigate the extent to which drug resistance can be evaluated from proviral HIV-1 DNA genotype compared with RNA genotype at different timepoints.

Patients and methods

In HIV-1-infected patients routinely seen at a university hospital, who needed to change their current ART, antiretroviral drug resistance was determined from DNA genotype and was compared with past RNA genotype (group 1) or same-day RNA genotype (group 2). A 'resistance sum' was defined as the sum of agents to which resistance was present and was calculated across NRTI, NNRTI and PI. We defined 'loss of information' as when a lower resistance sum was observed in DNA than in RNA samples.

Results

Of the 74 and 26 patients included in groups 1 and 2, respectively, most had a long median duration of known HIV-1 infection (17.4 and 14.2 years) and ART (15.3 years and 13.5 years). For group 1, the median (range) resistance sums between DNA/RNA were 0 (0-6)/1 (0-6) for NRTIs, 0 (0-4)/0 (0-4) for NNRTIs and 0 (0-7)/0 (0-8) for PIs, which were comparable with group 2. Loss of information in DNA was substantial for group 1 (37.8%) and less so for group 2 (11.1%). In multivariable analysis, only longer ART duration was significantly associated with loss of information. Results were similar in patients harbouring resistance to one or more agents.

Conclusions

In a real-life setting, genotyping DNA from PBMC has some degree of concordance compared with RNA. Loss of information in DNA would appear to coincide with longer periods of ART.

High Levels of Dual-Class Drug Resistance in HIV-Infected Children Failing First-Line Antiretroviral Therapy in Southern Ethiopia

Clinical monitoring of pediatric HIV treatment remains a major challenge in settings where drug resistance genotyping is not routinely available. As a result, our understanding of drug resistance, and its impact on subsequent therapeutic regimens available in these settings, remains limited. We investigate the prevalence and correlates of HIV-1 drug resistance among 94 participants of the Ethiopia Pediatric HIV Cohort failing first-line combination antiretroviral therapy (cART) using dried blood spot-based genotyping. Overall, 81% (73/90) of successfully genotyped participants harbored resistance mutations, including 69% (62/90) who harbored resistance to both Nucleoside Reverse Transcriptase Inhibitors (NRTIs) and Non-nucleoside Reverse Transcriptase Inhibitors (NNRTIs). Strikingly, 42% of resistant participants harbored resistance to all four NRTIs recommended for second-line use in this setting, meaning that there are effectively no remaining cART options for these children. Longer cART duration and prior regimen changes were significantly associated with detection of drug resistance mutations. Replicate genotyping increased the breadth of drug resistance detected in 34% of cases, and thus is recommended for consideration when typing from blood spots. Implementation of timely drug resistance testing and access to newer antiretrovirals and drug classes are urgently needed to guide clinical decision-making and improve outcomes for HIV-infected children on first-line cART in Ethiopia.

Reporting on the prevalence of antiretroviral drug resistance in a regional HIV population over 20 years: a word of caution

BACKGROUND

Failure to achieve complete viral suppression with antiretroviral drugs (ARV) may lead to uncontrolled HIV replication, ARV resistance and negative outcomes. Monitoring and reporting of HIV resistance trends is important but problematic. We examined prevalent resistance rates in an HIV population over 20 years and document how rates may appear to vary greatly based solely on which parameters are utilized.

METHODS

We determined the annual use of genotypic antiretroviral resistance testing (GART) from 1995 to 2014 for all patients receiving HIV care in southern Alberta, Canada, and the presence of resistance mutations in those tested. The impact on prevalent resistance rates of using cumulative or latest GART was also determined.

RESULTS

Between 1995 and 2014, the number of patients with GART increased from <1% to 71%. Prevalent resistance in patients with GART decreased from a high of 52% in 2003 to 25.8% in 2014. However, if prevalence rates were reported using all active patients as denominator, including those without GART, prevalence increased from 0.7% to 18.5%. Prevalence rates were 7% to 9% higher in any given year if cumulative GART rather than latest GART results were used.

CONCLUSIONS

While prevalence resistance rates are decreasing, the precise rates being reported may vary due to increasing number of patients tested annually, using either the entire population as denominator or only patients with GART, and using either last or cumulative GART. Defining these parameters is critical if prevalence is to be compared over time or between HIV populations.

Maintaining the continuity of HIV-care records for patients transferring care between centers: challenges, workloads, needs and risks

With improved life expectancy, the medical records of HIV-infected patients are likely to be transferred repeatedly between HIV caregivers. The challenges, and risk for introducing medical error from incomplete record transfers are poorly understood. We measured number of requests for record transfer, the workload incurred, and explore, using genotypic antiretroviral resistance testing results (GART), the potential risk of incomplete records. Using retrospective database and chart review, we examined all patients followed at the Southern Alberta Clinic between 1 January 2004 and 1 January 2015, and determined how many patients transferred care into and out our program, the associated requests and the workload for record transfer. Using a complete record of all GART tests, the potential importance of absent historic records in current treatment decisions was analyzed. The annual churn rate was 22 ± 3.4%. We received requests for only 70% of patient records who had left our care. Median time for receipt of incoming medical records was 28 days; average clerical time for processing data was 2 hours/record. Of all GART results, 25% exhibited resistance. Of 111 patients with potentially misleading GART results (i.e., documented historical resistance not visible on more recent GART), 34 (30.6%) had moved in from elsewhere. Rigorous maintenance of the continuity of the HIV record is not universally practiced. Resources, costs and logistic challenges as well as a lack of appreciation of risks clearly shown by GART testing, may be relevant barriers. Addressing such issues is pressing as aging and transfers of care are increasingly common.

[Microbiological diagnosis of human immunodeficiency virus infection]

This document attempts to update the main tasks and roles of the Clinical Microbiology laboratory in HIV diagnosis and monitoring. The document is divided into three parts. The first deals with HIV diagnosis and how serological testing has changed in the last few years, aiming to improve diagnosis and to minimize missed opportunities for diagnosis. Technological improvements for HIV Viral Load are shown in the second part of the document, which also includes a detailed description of the clinical significance of low-level and very low-level viremia. Finally, the third part of the document deals with resistance to antiretroviral drugs, incorporating clinical indications for integrase and tropism testing, as well as the latest knowledge on minority variants.

Initiation of rilpivirine, tenofovir and emtricitabine (RPV/TDF/FTC) regimen in 363 patients with virological vigilance assessment in 'real life'

OBJECTIVES

To study the single-tablet regimen (STR) combination rilpivirine/tenofovir/emtricitabine (RPV/TDF/FTC) as soon as it became available. We describe a 14 month follow-up in a real clinical setting with a focus on resistance to RPV/TDF/FTC and polymorphisms associated with these drugs.

METHODS

We estimated drug resistance at STR baseline by combining all available resistance tests, resulting in a cumulative virtual genotype. Physicians were advised of current or archived resistance mutations for the three drugs. Virological response was analysed according to resistance genotype at baseline.

RESULTS

Three hundred and sixty-three patients received RPV/TDF/FTC; 79% had received previous treatment and RPV/TDF/FTC was the result of a switch of one drug to rilpivirine in two-thirds of cases. The cumulative genotype showed 4% of rilpivirine resistance mutations at baseline and 16% of polymorphisms concerning non-nucleoside reverse transcriptase inhibitors (NNRTIs). With a median duration of STR of 8 months, 78% of patients with these polymorphisms were virologically suppressed compared with 96% with wild-type genotypes. Five genotypes were determined during the follow-up, revealing three rilpivirine resistance-associated mutations: E138Q/Y181I, M230L and K101P (potentially with a K101Q intermediate).

CONCLUSIONS

This observational study reflects routine clinical practice and the relevance of virological advice. It also confirms the efficacy of this STR (RPV/TDF/FTC) for naive and virologically suppressed pretreated patients with a low prevalence of virological failure and resistance if the cumulative baseline genotype is free of resistance to NNRTIs and/or polymorphisms associated with NNRTIs.

Virologic and immunologic effectiveness of darunavir-based salvage therapy in HIV-1-infected adults in a Brazilian clinical practice setting: results of a multicenter and retrospective cohort study

Background

Darunavir has been proven efficacious for antiretroviral-experienced HIV-1-infected patients in randomized trials. However, effectiveness of darunavir-based salvage therapy is understudied in routine care in Brazil.

Methods

Retrospective cohort study of HIV-1-infected patients from three public referral centers in Belo Horizonte, who received a darunavir-based therapy between 2008 and 2010, after virologic failure. Primary endpoint was the proportion of patients with viral load < 50 copies/mL at week 48. Change in CD4 cell count was also evaluated. Outcome measures were analyzed on an intent-to-treat basis applied to observational studies. Sensitivity analysis was conducted to evaluate the impact of missing data at week 48. Predictors of virologic failure were examined using rare-event, finite sample, bias-corrected logistic regression.

Results

Among 108 patients, the median age was 44.2 years, and 72.2% were male. They had long-standing HIV-1 infection (median 11.6 years) and advanced disease (76.9% had an AIDS-defining event). All patients had previously received protease inhibitors and nucleoside reverse transcriptase inhibitors, 75% nonnucleoside reverse transcriptase inhibitors, and 4.6% enfuvirtide. The median length of protease inhibitor use was 8.9 years, and 90.8% of patients had prior exposure to unboosted protease inhibitor. Genotypic resistance profile showed a median of three primary protease inhibitor mutations and 10.2% had three or more darunavir resistance-associated mutations. Virologic success at week 48 was achieved by 78.7% (95% CI = 69.7–86%) of patients and mean CD4 cell count increase from baseline was 131.5 cells/μL (95% CI = 103.4–159.6). In multiple logistic regression analysis, higher baseline viral load (RR = 1.04 per 10,000 copies/mL increase; 95% CI = 1.01–1.09) and higher number of darunavir resistance-associated mutations (RR = 1.23 per each; 95% CI = 0.95–1.48) were independently associated with virologic failure.

Conclusion

Virologic suppression is a realistic endpoint for most treatment-experienced patients who begin a darunavir-based therapy outside the controlled conditions of a randomized trial, at routine care settings.

[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.

[Consensus document of Gesida and Spanish Secretariat for the National Plan on AIDS (SPNS) regarding combined antiretroviral treatment in adults infected by the human immunodeficiency virus (January 2012)]

This consensus document has been prepared by a panel consisting of members of the AIDS Study Group (Gesida) and the Spanish Secretariat for the National Plan on AIDS (SPNS) after reviewing the efficacy and safety results of clinical trials, cohort and pharmacokinetic studies published in medical journals, or presented in medical scientific meetings. Gesida has prepared an objective and structured method to prioritise combined antiretroviral treatment (cART) in naïve patients. Recommendations strength (A, B, C) and the evidence which supports them (I, II, III) are based on a modification of the Infectious Diseases Society of America criteria. The current antiretroviral treatment (ART) of choice for chronic HIV infection is the combination of three drugs. ART is recommended in patients with symptomatic HIV infection, in pregnancy, in serodiscordant couples with high transmission risk, hepatitis B fulfilling treatment criteria, and HIV nephropathy. Guidelines on ART treatment in patients with concurrent diagnosis of HIV infection and an opportunistic type C infection are included. In asymptomatic patients ART is recommended on the basis of CD4 lymphocyte counts, plasma viral load and patient co-morbidities, as follows: 1) therapy should be started in patients with CD4 counts <350 cells/μL; 2) when CD4 counts are between 350 and 500 cells/μL, therapy will be recommended and only delayed if patient is reluctant to take it, the CD4 are stabilised, and the plasma viral load is low; 3) therapy could be deferred when CD4 counts are above 500 cells/μL, but should be considered in cases of cirrhosis, chronic hepatitis C, high cardiovascular risk, plasma viral load >10(5) copies/mL, proportion of CD4 cells <14%, and in people aged >55 years. ART should include 2 reverse transcriptase inhibitors nucleoside analogues and a third drug (non-analogue reverse transcriptase inhibitor, ritonavir boosted protease inhibitor or integrase inhibitor). The panel has consensually selected and given priority to using the Gesida score for some drug combinations, some of them co-formulated. The objective of ART is to achieve an undetectable viral load. Adherence to therapy plays an essential role in maintaining antiviral response. Therapeutic options are limited after ART failures, but an undetectable viral load may be possible nowadays. Adverse events are a fading problem of ART. Guidelines in acute HIV infection, in women, in pregnancy, and to prevent mother-to-child transmission and pre- and post-exposition prophylaxis are commented upon. Management of hepatitis B or C co-infection, other co-morbidities, and the characteristics of ART in HIV-2 infection are included.

Mutations in the protease gene associated with virological failure to lopinavir/ritonavir-containing regimens

OBJECTIVES

To assess the most frequent resistance-associated mutations (RAMs) to lopinavir/ritonavir in a cohort of patients attended in daily practice.

METHODS

We retrospectively identified 195 multitreated subjects with virological failure. Patients were classified as follows: (i) 71 (36.4%) never received lopinavir/ritonavir (lopinavir/ritonavir naive); (ii) 75 (38.5%) had previously failed on lopinavir/ritonavir; and (iii) 49 (25.1%) were on lopinavir/ritonavir at failure. RAM patterns were assessed. Medians, IQRs, percentages, Kruskal-Wallis, χ(2) or Fisher's exact test, and multinomial logistic regression were used whenever appropriate.

RESULTS

L10I/F, K20R, L24I, L33F, M36I, M46I/L, I47V, G48V, F53L, I54V, A71V, G73S, V82A, I84V and L90M (all with P ≤ 0.037) were protease RAMs overexpressed in patients with lopinavir/ritonavir failure. L10I, M36I, M46I, I54V, L63P, A71V, V82A, I84V and L90M were the most common in lopinavir/ritonavir-naive patients. Other IAS-USA RAMs for lopinavir/ritonavir (L10R/V, K20M, V32I, I47A, I50V, I54L/A/M/T/S, A71T, L76V and V82F/T/S) were not associated with previous or current failure to lopinavir/ritonavir. Lopinavir/ritonavir failure was associated with the number of protease RAMs (OR = 1.146, 95% CI = 1.287, 1.626), higher exposure to protease inhibitors, and the presence of E44D, L33F, I54V and I84V.

CONCLUSIONS

In multitreated patients with previous or current lopinavir/ritonavir failure, some protease mutations are selected at significantly greater rates. L10I, M36I, I54V, L63P, A71V, V82A and L90M were found in >50% of cases. Thus, their presence should be expected when genotypic testing results are not available. The number of protease RAMs and higher prior exposures to protease inhibitors were significantly associated with lopinavir/ritonavir failure.