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

A characterization of the HIV population with limited/exhausted treatment options: a multicenter Belgian study

OBJECTIVE

Describe the prevalence and characteristics of people living with HIV (PLWH) in Belgium with limited/exhausted treatment options.

METHODS

A cross-sectional, multicenter study involving adult treatment-experienced individuals with limited/exhausted treatment options defined as having a multi-drug resistant HIV-1 or a history of multiple treatment changes. The primary outcome was to determine the prevalence of these individuals and classify them based on their two most recent consecutive HIV-1 viral loads (VLs): suppressed (2 VLs < 50 copies/mL), intermediate (≥1 VL between 50-200 copies/mL), or unsuppressed (2 VLs > 200 copies/mL). Secondary outcome was to characterize the participants included in this analysis.

RESULTS

There were 119 individuals included (prevalence of 0.97%; 119 of 12 282 in care). The majority were aged > 50 years (88.2%), women represented 35.3%, and individuals were primarily White (54.7%). Median (IQR) CD4+ T-cell count was 635 (400-875) cells/µL and most (42%) were on a 3-drug ART regimen. Overall, 87.4% were classified as suppressed, 9.2% as intermediate, and 3.4% as unsuppressed. On multivariable analysis, CD4+ T-cell count < 200 cells/µL was associated with being classified as intermediate or unsuppressed (p = 0.004).

CONCLUSION

In this analysis of PLWH in Belgium, individuals with limited/exhausted treatment options represented a small fraction. Most were on a 3-drug ART regimen, were virologically suppressed, and had a CD4+ T-cell count within normal range. A small proportion were not virologically suppressed while others, despite being suppressed, were on ≥ 4-drug ART regimens. As such, new therapeutic options are needed to achieve and maintain virologic suppression in such individuals while decreasing their pill burden.

Fostemsavir for the treatment of HIV

Introduction: For those with heavily treatment experienced (HTE) HIV-1 and virologic failure, therapeutic options are limited. A variety of barriers such as drug resistance, side effects, past intolerance, and administration inability contribute to the need for novel drug classes in this population.Areas Covered: Herein, we review the pharmacology, clinical efficacy, and safety profile of fostemsavir, a first in its class attachment inhibitor recently FDA approved for use.Expert Opinion: Fostemsavir is a well-tolerated oral medication with relatively few drug-drug interactions. Clinical trial data demonstrates virologic and notable immunologic response in conjunction with optimal background therapy in HTE persons living with HIV. Fostemsavir exhibits no cross-resistance with other ARV classes and thus is an important advancement for patients harboring drug-resistant HIV. Further study will be needed to determine outstanding clinical questions such as the role of drug resistance testing and fostemsavir use outside of the HTE population.

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.

Substantial decline in heavily treated therapy-experienced persons with HIV with limited antiretroviral treatment options

OBJECTIVE

Historically, a high burden of resistance to antiretroviral therapy (ART) in heavily treatment-experienced (HTE) persons with HIV (PWH) resulted in limited treatment options (LTOs). We evaluated the prevalence, risk factors, and virologic control of HTE PWH with LTO throughout the modern ART era.

DESIGN

We examined all ART-experienced PWH in care between 2000 and 2017 in the Centers for AIDS Research Network of Integrated Clinical Systems cohort.

METHODS

We computed the annual prevalence of HTE PWH with LTO defined as having two or less available classes with two or less active drugs per class based on genotypic data and cumulative antiretroviral resistance. We used multivariable Cox proportional hazards models to examine risk of LTO by 3-year study entry periods adjusting for demographic and clinical characteristics.

RESULTS

Among 27 133 ART-experienced PWH, 916 were classified as having LTO. The prevalence of PWH with LTO was 5.2-7.5% in 2000-2006, decreased to 1.8% in 2007, and remained less than 1% after 2012. Persons entering the study in 2009-2011 had an 80% lower risk of LTO compared with those entering in 2006-2008 (adjusted hazard ratio 0.20; 95% confidence interval: 0.09-0.42). We found a significant increase in undetectable HIV viral loads among PWH ever classified as having LTO from less than 30% in 2001 to more than 80% in 2011, comparable with persons who never had LTO.

CONCLUSION

Results of this large multicenter study show a dramatic decline in the prevalence of PWH with LTO to less than 1% with the availability of more potent drugs and a marked increase in virologic suppression in the current ART era.

Impact of three decades of antiretroviral therapy in a longitudinal population cohort study

BACKGROUND

We have used a comprehensive HIV population to characterize antiretroviral therapy (ART), drug class selection, pill burden, drug costs and health outcomes over the entire span of the HIV epidemic.

METHODS

Antiretroviral (ARV) use (drugs, classes, formulations) and both the laboratory and clinical outcomes (HIV-1 RNA, CD4⁺ T-cell count and mortality) were determined for all patients in Southern Alberta, Canada, at each year-end between 1986 and 2017. Pill burden, cumulative drug exposure and costs were calculated for each year.

RESULTS

The number of ARV-treated patients increased from 29.6% (77/260) in 1989 to 93.4% (1,814/1,943) in 2017. Regimen selection showed continuous adjustments for toxicity, resistance, pill burden and adherence. Dramatic improvements in outcomes were seen. In 1997, 22.4% of treated patients had an undetectable viral load, this has been consistently around 90% since 2010 (92.7% in 2017). While HIV-related annual mortality rate declined from 11.0% in 1994 to 0.1% in 2017, all-cause mortality remained relatively stable from 1997 onwards. ART pill burden escalated in 1997 (12.4/day), then decreased to 2.1/day in 2016. Mean ART cost increased in 1997 (CAN$905/month/regimen in 1997, $1,223 in 2016). Mean cumulative lifetime exposure to protease inhibitors is 5.98 ±4.9 and to nucleoside reverse transcriptase inhibitors 8.8 ±6.2 years.

CONCLUSIONS

Our findings demonstrate not only the immense burden that HIV has imposed on both patients and society, but also the substantial benefit of ART on patient outcomes. They show that research, patient engagement and programme support can with time minimize the harmful long-term effects of HIV-infection.

Evaluation of A Phylogenetic Pipeline to Examine Transmission Networks in A Canadian HIV Cohort

Keywords: HIV; Canada; molecular phylogenetics; viral evolution; person-to-person transmission inference; transmission network; summary statistics.

Trends in HIV-1 Drug Resistance Mutations from a U.S. Reference Laboratory from 2006 to 2017

Trends in resistance to antiretroviral drugs for HIV-1 may inform clinical support and drug development. We evaluated drug resistance mutation (DRM) trends for nucleoside reverse transcriptase inhibitor (NRTI), non-nucleoside reverse transcriptase inhibitor (NNRTI), protease inhibitor (PI), and integrase strand transfer inhibitor (INSTI) in a large U.S. reference laboratory database. DRMs with a Stanford HIV Drug Resistance Database mutation score ≥10 from deidentified subtype B NRTI/NNRTI/PI specimens (2006-2017; >10,000/year) and INSTI specimens (2010-2017; >1,000/year) were evaluated. Sequences with NRTI, NNRTI, or PI single- or multiclass DRMs declined from 48.9% to 39.3%. High-level dual- and triple-class resistance declined from 43.3% (2006) to 17.1% (2017), while sequences with only single-class DRMs increased from 40.0% to 52.9%. The prevalence of DRMs associated with earlier treatment regimens declined, while prevalence of some DRMs associated with newer regimens increased. M184V/I decreased from 48.3% to 29.4%. K103N/S/T declined from 42.5% in 2012 to 36.4% in 2017. Rilpivirine and etravirine DRMs E138A/Q/R and E138K increased from 4.9% and 0.4% to 9.7% and 1.7%, respectively. Sequences with ≥1 darunavir DRM declined from 18.1% to 4.8% by 2017. INSTI DRM Q148H/K/R declined from 39.3% (2010) to 13.8% (2017). Prevalence of elvitegravir-associated DRMs T66A/I/K, E92Q, S147G, and the dolutegravir-associated DRM R263K increased. For a subset of patients with serial testing, 50% (2,646/5,290) of those who initially had no reportable DRM subsequently developed ≥1 DRM for NRTI/NNRTI/PI and 49.7% (159/320) for INSTI. These trends may inform the need for baseline genotypic resistance testing. The detection of treatment-emergent DRMs in serially tested patients confirms the value of genotypic testing following virologic failure.

New antiretroviral agent use affects prevalence of HIV drug resistance in clinical care populations

OBJECTIVE

To estimate the prevalence of HIV drug resistance over time and identify risk factors for multiclass resistance.

DESIGN

Prospective clinical cohort of HIV-infected patients at the University of North Carolina.

METHODS

Among antiretroviral therapy (ART)-experienced patients in care 2000-2016, we estimated annual prevalences of cumulative resistance, defined as at least one major mutation by drug class. Clinical data and multiple imputation were used when genotypic data were missing, and mutations were carried forward in time. We estimated resistance odds ratios comparing characteristics of patients in care in 2016.

RESULTS

A total of 3682 patients contributed 23 169 person-years. Prevalence of at least one major resistance mutation, irrespective of viral suppression, peaked in 2005 with 49% (95% confidence interval 46, 52) and decreased to 38% (35, 40) in 2016. Resistance to nucleoside reverse transcriptase inhibitors, protease inhibitors, and nonnucleoside reverse transcriptase inhibitors also peaked in 2005-2007 and decreased to 28 (26, 31), 14 (12, 16), and 27% (24, 29) in 2016, respectively. In 2016, prevalence of integrase strand transfer inhibitor (INSTI) resistance was 2% (1, 3) and triple-class resistance 10% (9, 12). Over the study period, cumulative resistance was frequent among patients with detectable viremia, but uncommon among patients initiating ART post-2007. Among 1553 patients in care in 2016, ART initiation at an older age, with an INSTI, and with higher CD4 cell counts were associated with resistance to fewer or no classes.

CONCLUSION

Prevalence of resistance to older ART classes has decreased in the last 10 years in this clinical cohort, whereas INSTI resistance has increased but remained very low. Patients with viremia continue to have a high burden of resistance even if they initiated ART recently.

Combating the HIV reservoirs

Impressive advances have been made in the treatment and management of HIV-1 infected individuals. Combination antiretroviral therapy (cART) has turned HIV-1 infection from an almost invariable deadly infectious disease, to a lifelong manageable infectious disease. However, a cure or vaccine has not been forthcoming. A major problem in HIV-1 infection is the persistent and latently infected cellular and tissue reservoirs. One of these reservoirs is the Gut Associated Lymphoid tissue (GALT), which has been the research focus of our group. Our group and others have shown that HIV-1 evolves differently in different parts of the gastro intestinal tract, which also appears to affect the development of antiretroviral drug resistance. The GALT is not the only reservoir. HIV-1 continues to persist and evolve in various other cell and tissue reservoirs despite intense and apparent successful antiretroviral therapy. Moreover, drug resistance mutations remain prevalent under therapy and successful viral suppression. In addition to finding a vaccine, the research on combating and eradicating the HIV-1 viral reservoirs has also been an important focus of HIV-1 cure strategies. We will discuss some of the research findings on reservoirs in the context of some of the HIV-1 cure approaches.