Approach to salvage antiretroviral therapy in heavily antiretroviral-experienced HIV-positive adults

Prevalence and clinical characteristics of people with HIV with limited treatment options in Japan: A Japanese claims data analysis

INTRODUCTION

Long-term medication leads some people with HIV (PWH) to limited treatment options (LTO) due to multiple factors. The present study investigated the prevalence of PWH with LTO in Japan and their clinical characteristics, persistence, and adherence.

METHODS

PWH who received antiretroviral therapy (ART) between 2017 and 2022 were identified in the Medical Data Vision (MDV) Japanese claims database. PWH with LTO were defined as: 1) receiving regimens indicative for LTO or 2) having a complex treatment history (≥4 different core agents, ≥11 ART agents). Prevalence by calendar year, clinical characteristics, persistence, and adherence measured by the proportion of days covered (PDC) of ART were investigated.

RESULTS

A total of 5740 PWH were included, and 207 (3.6 %) were identified as LTO. Mean (SD) age was 50.3 (11.8) years, 148 (71.5 %) had evidence of AIDS-defining condition, and 25 (12.1 %) had hemophilia. The prevalence of PWH with LTO increased from 2.58 % in 2017 to 3.55 % in 2022. Persistence at 1 year was estimated as 70.3 % and mean PDC through 1 year was 96.7 %.

CONCLUSION

Between the years 2017-2022, 3.6 % (approximately 200) Japanese PWH were identified as having LTO. The results of this analysis found clinical characteristics of PWH with LTO as older age and higher percentages with an AIDS-defining condition and hemophilia than the general HIV population. Low persistence indicates that treatment optimization is required in this population. These results will help health care providers to understand the clinical characteristics of PWH with LTO and may contribute to the establishment of appropriate treatment strategies.

Long-term outcomes of highly experienced people with HIV undergoing salvage therapy with raltegravir

Raltegravir and other third-line drugs have shown promise in improving outcomes in treatment-experienced patients. However, the efficacy and tolerability of these agents vary. This study assessed real-life virologic success, long-term survival, and adverse events in patients receiving raltegravir or other third-line drugs as salvage regimens. This retrospective cohort study included adults who experienced treatment failure (human immunodeficiency syndrome-1 RNA plasma viral load >1000 copies/mL) and subsequently initiated raltegravir or other third-line drugs (darunavir/ritonavir, maraviroc, or etravirine). Propensity score matching methods were employed to account for differences at the time of switching from failing antiretroviral therapy regimens. The matched subset was analyzed using the Kaplan-Meier method and Generalized Wilcoxon tests to evaluate the probability of achieving virologic suppression (plasma viral load <50 copies/mL). Mortality rates, toxicity, treatment interruption, virologic failure, and loss to follow-up were determined using Poisson regression. One hundred and sixty-eight patients initiating salvage regimens were included, with 123 receiving raltegravir and 45 other third-line drugs. Propensity score matching resulted in a subset of 90 patients, 45 in each group. During the follow-up period, there were no significant differences observed between the groups in terms of virologic suppression (77.8% vs 82.2%, P = .73), mortality rates (4.04 vs 6.18 persons per 100 person-years [p-y]; P = .67), drug toxicity (0.00 vs 2.06 persons per 100 p-y; P = .49), treatment interruption (8.07 vs 0.00 persons per 100 p-y; P = .06), virologic failure (2.02 vs 4.12 persons per 100 p-y; P = .61), and loss of follow-up (6.05 vs 4.12 persons per 100 p-y; P = .70). Our findings indicate comparable survival and virological success rates between raltegravir and other drugs used in salvage regimens. Similar rates of drug toxicity, treatment interruption, virologic failure, and loss of follow-up were also observed. These results suggest that raltegravir may be a viable option for salvage therapy, demonstrating outcomes comparable to other third-line drugs in real life.

Heavily treatment-experienced people living with HIV in the OPERA® cohort: population characteristics and clinical outcomes

BACKGROUND

Multi-class resistance, intolerance, and drug-drug interactions can result in unique antiretroviral (ART) combinations for heavily treatment-experienced (HTE) people living with HIV (PLWH). We aimed to compare clinical outcomes between HTE and non-HTE PLWH.

METHODS

Eligible ART-experienced PLWH in care in the OPERA® Cohort were identified in a cross-sectional manner on December 31, 2016 and observed from the date of initiation of the ART regimen taken on December 31, 2016 until loss to follow up, death, study end (December 31, 2018), or becoming HTE (non-HTE group only). In the absence of resistance data, HTE was defined based on the ART regimens used (i.e., exposed to ≥ 3 core agent classes or regimen suggestive of HTE). Time to virologic undetectability, failure, and immunologic preservation were assessed using Kaplan-Meier methods; cumulative probabilities were compared between the two groups. Regimen changes, incident morbidities, and death were described.

RESULTS

A total of 24,183 PLWH (2277 HTE PLWH, 21,906 non-HTE) were followed for a median of 28 months (IQR 21, 38). Viremic HTE PLWH (viral load [VL] ≥ 50 copies/mL) were less likely to achieve undetectability (VL < 50 copies/mL; 24-month cumulative probability: 80% [95% Confidence Interval 77-82]) than their non-HTE counterparts (85% [84-86]). No difference was observed in the probability of maintaining VLs < 200 copies/mL over the first 48 months after achieving suppression (< 50 copies/mL). HTE PLWH were less likely than non-HTE PLWH to maintain CD4 cell counts ≥ 200 cells/µL (24-month cumulative probability: 95% HTE [91-93]; 97% non-HTE [97-97]), and more likely to change regimens (45% HTE; 41% non-HTE). Incident non-AIDS defining event (ADE) morbidities were common in both populations, though more likely among HTE PLWH (45%) than non-HTE PLWH (35%). Incident ADE morbidities and deaths were uncommon among HTE (ADEs 5%; deaths 2%) and non-HTE (ADEs 2%; deaths 1%) PLWH.

CONCLUSIONS

HTE PLWH were at greater risk of unfavorable treatment outcomes than non-HTE PLWH, suggesting additional therapeutic options are needed for this vulnerable population.

CD4-gp120 interaction interface - a gateway for HIV-1 infection in human: molecular network, modeling and docking studies

The major causative agent for Acquired Immune Deficiency Syndrome (AIDS) is Human Immunodeficiency Virus-1 (HIV-1). HIV-1 is a predominant subtype of HIV which counts on human cellular mechanism virtually in every aspect of its life cycle. Binding of viral envelope glycoprotein-gp120 with human cell surface CD4 receptor triggers the early infection stage of HIV-1. This study focuses on the interaction interface between these two proteins that play a crucial role for viral infectivity. The CD4-gp120 interaction interface has been studied through a comprehensive protein-protein interaction network (PPIN) analysis and highlighted as a useful step towards identifying potential therapeutic drug targets against HIV-1 infection. We prioritized gp41, Nef and Tat proteins of HIV-1 as valuable drug targets at early stage of viral infection. Lack of crystal structure has made it difficult to understand the biological implication of these proteins during disease progression. Here, computational protein modeling techniques and molecular dynamics simulations were performed to generate three-dimensional models of these targets. Besides, molecular docking was initiated to determine the desirability of these target proteins for already available HIV-1 specific drugs which indicates the usefulness of these protein structures to identify an effective drug combination therapy against AIDS.

Cost-effectiveness of newer antiretroviral drugs in treatment-experienced patients with multidrug-resistant HIV disease

OBJECTIVE

Newer antiretroviral drugs provide substantial benefits but are expensive. The cost-effectiveness of using antiretroviral drugs in combination for patients with multidrug-resistant HIV disease was determined.

DESIGN

A cohort state-transition model was built representing treatment-experienced patients with low CD4 counts, high viral load levels, and multidrug-resistant virus. The effectiveness of newer drugs (those approved in 2005 or later) was estimated from published randomized trials. Other parameters were estimated from a randomized trial and from the literature. The model had a lifetime time horizon and used the perspective of an ideal insurer in the United States. The interventions were combination antiretroviral therapy, consisting of 2 newer drugs and 1 conventional drug, compared with 3 conventional drugs. Outcome measures were life-years, quality-adjusted life-years (QALYs), costs, and incremental cost-effectiveness.

RESULTS

Substituting newer antiretroviral drugs increased expected survival by 3.9 years in advanced HIV disease. The incremental cost-effectiveness ratio of newer, compared with conventional, antiretroviral drugs was $75,556/QALY gained. Sensitivity analyses showed that substituting only one newer antiretroviral drug cost $54,559 to $68,732/QALY, depending on assumptions about efficacy. Substituting 3 newer drugs cost $105,956 to $117,477/QALY. Cost-effectiveness ratios were higher if conventional drugs were not discontinued.

CONCLUSIONS

In treatment-experienced patients with advanced HIV disease, use of newer antiretroviral agents can be cost-effective, given a cost-effectiveness threshold in the range of $50,000 to $75,000 per QALY gained. Newer antiretroviral agents should be used in carefully selected patients for whom less expensive options are clearly inferior.

Protease-Mediated Maturation of HIV: Inhibitors of Protease and the Maturation Process

Protease-mediated maturation of HIV-1 virus particles is essential for virus infectivity. Maturation occurs concomitant with immature virus particle release and is mediated by the viral protease (PR), which sequentially cleaves the Gag and Gag-Pol polyproteins into mature protein domains. Maturation triggers a second assembly event that generates a condensed conical capsid core. The capsid core organizes the viral RNA genome and viral proteins to facilitate viral replication in the next round of infection. The fundamental role of proteolytic maturation in the generation of mature infectious particles has made it an attractive target for therapeutic intervention. Development of small molecules that target the PR active site has been highly successful and nine protease inhibitors (PIs) have been approved for clinical use. This paper provides an overview of their development and clinical use together with a discussion of problems associated with drug resistance. The second-half of the paper discusses a novel class of antiretroviral drug termed maturation inhibitors, which target cleavage sites in Gag not PR itself. The paper focuses on bevirimat (BVM) the first-in-class maturation inhibitor: its mechanism of action and the implications of naturally occurring polymorphisms that confer reduced susceptibility to BVM in phase II clinical trials.

Virus maturation as a new HIV-1 therapeutic target

Development of novel therapeutic targets against HIV-1 is a high research priority owing to the serious clinical consequences associated with acquisition of resistance to current antiretroviral drugs. The HIV-1 structural protein Gag represents a potential new therapeutic target as it plays a central role in virus particle production yet is not targeted by any of the antiretroviral drugs approved at present. The Gag polyprotein precursor multimerizes to form immature particles that bud from the infected cell. Concomitant with virus release, the Gag precursor undergoes proteolytic processing by the viral protease to generate the mature Gag proteins, which include capsid (CA). Once liberated from the Gag polyprotein precursor, CA molecules interact to reassemble into a condensed conical core, which organizes the viral RNA genome and several viral proteins to facilitate virus replication in the next round of infection. Correct Gag proteolytic processing and core assembly are therefore essential for virus infectivity. In this review, we discuss new strategies to inhibit maturation by targeting proteolytic cleavage sites in Gag or CA-CA interactions required for core formation. The identification and development of lead maturation inhibitors are highlighted.

Novel approaches to inhibiting HIV-1 replication

Considerable success has been achieved in the treatment of HIV-1 infection, and more than two-dozen antiretroviral drugs are available targeting several distinct steps in the viral replication cycle. However, resistance to these compounds emerges readily, even in the context of combination therapy. Drug toxicity, adverse drug-drug interactions, and accompanying poor patient adherence can also lead to treatment failure. These considerations make continued development of novel antiretroviral therapeutics necessary. In this article, we highlight a number of steps in the HIV-1 replication cycle that represent promising targets for drug discovery. These include lipid raft microdomains, the RNase H activity of the viral enzyme reverse transcriptase, uncoating of the viral core, host cell machinery involved in the integration of the viral DNA into host cell chromatin, virus assembly, maturation, and budding, and the functions of several viral accessory proteins. We discuss the relevant molecular and cell biology, and describe progress to date in developing inhibitors against these novel targets. This article forms part of a special issue of Antiviral Research marking the 25th anniversary of antiretroviral drug discovery and development, Vol 85, issue 1, 2010.

Impact of previous virological treatment failures and adherence on the outcome of antiretroviral therapy in 2007

Background

Combination antiretroviral treatment (cART) has been very successful, especially among selected patients in clinical trials. The aim of this study was to describe outcomes of cART on the population level in a large national cohort.

Methods

Characteristics of participants of the Swiss HIV Cohort Study on stable cART at two semiannual visits in 2007 were analyzed with respect to era of treatment initiation, number of previous virologically failed regimens and self reported adherence. Starting ART in the mono/dual era before HIV-1 RNA assays became available was counted as one failed regimen. Logistic regression was used to identify risk factors for virological failure between the two consecutive visits.

Results

Of 4541 patients 31.2% and 68.8% had initiated therapy in the mono/dual and cART era, respectively, and been on treatment for a median of 11.7 vs. 5.7 years. At visit 1 in 2007, the mean number of previous failed regimens was 3.2 vs. 0.5 and the viral load was undetectable (<50 copies/ml) in 84.6% vs. 89.1% of the participants, respectively. Adjusted odds ratios of a detectable viral load at visit 2 for participants from the mono/dual era with a history of 2 and 3, 4, >4 previous failures compared to 1 were 0.9 (95% CI 0.4–1.7), 0.8 (0.4–1.6), 1.6 (0.8–3.2), 3.3 (1.7–6.6) respectively, and 2.3 (1.1–4.8) for >2 missed cART doses during the last month, compared to perfect adherence. From the cART era, odds ratios with a history of 1, 2 and >2 previous failures compared to none were 1.8 (95% CI 1.3–2.5), 2.8 (1.7–4.5) and 7.8 (4.5–13.5), respectively, and 2.8 (1.6–4.8) for >2 missed cART doses during the last month, compared to perfect adherence.

Conclusions

A higher number of previous virologically failed regimens, and imperfect adherence to therapy were independent predictors of imminent virological failure.

Tipranavir: a review of its use in the management of HIV infection

Tipranavir (Aptivus) is a selective nonpeptidic HIV-1 protease inhibitor (PI) that is used in the treatment of treatment-experienced adults with HIV-1 infection. Tipranavir is administered orally twice daily and must be given in combination with low-dose ritonavir, which is used to boost its bioavailability. The durable efficacy of tipranavir, in combination with low-dose ritonavir (tipranavir/ritonavir 500 mg/200 mg twice daily), has been demonstrated in well designed trials in treatment-experienced adults infected with multidrug-resistant strains of HIV-1. In treatment-experienced adults with HIV-1 infection receiving an optimized background regimen, viral suppression was greater and immunological responses were better with regimens containing tipranavir/ritonavir than with comparator ritonavir-boosted PI-containing regimens. The efficacy benefit appeared to be more marked in patients receiving two fully active drugs in the regimen, with the combination of tipranavir/ritonavir and enfuvirtide (for the first time) appearing to be the most successful. Although tipranavir is generally well tolerated, clinical hepatitis and hepatic decompensation, and intracranial haemorrhage have been associated with the drug. Tipranavir also has a complex drug-interaction profile. Thus, tipranavir, administered with ritonavir, is an effective treatment option for use in the combination therapy of adults with HIV-1 infection who have been previously treated with other antiretroviral drugs.

Current and future antiretroviral treatment options in paediatric HIV infection

Because of a lack of prevention policies or problems in implementing prevention of mother-to-child transmission (P-MTCT), most of the 1500 daily new HIV infections in children aged<15 years are caused by MTCT. Fifteen percent of all HIV-infected individuals are children, but the vast majority lack access to highly active antiretroviral therapy (HAART), which can drastically reduce morbidity and mortality. There are 22 antiretroviral drugs currently approved by the US FDA for use in the treatment of HIV-infected adults and adolescents, but only 12 of these drugs are approved for use in children. Antiretroviral drugs belong to four major classes: nucleoside and nucleotide analogue reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors and fusion inhibitors. According to international guidelines developed by organizations including WHO, the Paediatric European Network for Treatment of AIDS (PENTA) and the US National Institutes of Health (US-NIH), the treatment of choice for HIV-infected children and adults is a combination of two NRTIs (backbone treatment) plus a third potent agent from a different class, either an NNRTI or a ritonavir-boosted protease inhibitor. There are specific challenges in treating HIV-infected children, including uncertainty about the best time to start treatment, the need for more paediatric formulations, the lack of pharmacokinetic studies for new drugs, and incomplete dosing guidelines. Furthermore, the most appropriate regimen for an individual child depends on a variety of factors, including the age of the child; the availability of appropriate drug formulations; the potency, complexity and toxicity of the drug regimen; the home situation; the child and caregiver's ability to adhere to the regimen; and the child's antiretroviral treatment history. In addition, antiretroviral drugs are not licensed for all age groups and the drugs are often not affordable. This review describes NNRTI and protease inhibitors as key components of first- and second-line antiretroviral therapy (ART), focusing on the rationale for choosing an NNRTI- versus protease inhibitor-based regimen based on the results of available phase II and III studies. Some of the new agents available for children as second-line and salvage therapy both on- and off-label are also discussed. The drug regimens described in this review are relevant to clinicians in developed and developing countries. The availability of new, potent compounds with different resistance and toxicity profiles may represent an alternative option to interclass switching and could redefine ART strategy, including the option of first-line NRTI-sparing regimens.

Two cases of multidrug-resistant human immunodeficiency virus infection treated with atazanavir and lopinavir/ritonavir combination therapy

The combination of atazanavir (ATV) and lopinavir/ritonavir (LPV/RTV) with nucleoside reverse transcriptase inhibitors (NRTI) has been used as a salvage regimen for human immunodeficiency virus (HIV)-positive patients. In this paper, we discuss two cases of HIV-positive patients who had long histories of virological failure following a heavy treatment of antiretroviral drugs, but then achieved virological suppression with double-boosted protease inhibitor (PI) regimens. In patients with multiple genotypic resistance to PIs and NRTIs, virological suppression can be achieved with a combination of ATV plus LPV/RTV with an NRTI backbone. The two cases in this report suggest that a combination of ATV plus LPV/RTV could be a useful salvage regimen for the subset of HIV-positive patients with limited treatment options.

Raltegravir with optimized background therapy for resistant HIV-1 infection

BACKGROUND

Raltegravir (MK-0518) is an inhibitor of human immunodeficiency virus type 1 (HIV-1) integrase active against HIV-1 susceptible or resistant to older antiretroviral drugs.

METHODS

We conducted two identical trials in different geographic regions to evaluate the safety and efficacy of raltegravir, as compared with placebo, in combination with optimized background therapy, in patients infected with HIV-1 that has triple-class drug resistance in whom antiretroviral therapy had failed. Patients were randomly assigned to raltegravir or placebo in a 2:1 ratio.

RESULTS

In the combined studies, 699 of 703 randomized patients (462 and 237 in the raltegravir and placebo groups, respectively) received the study drug. Seventeen of the 699 patients (2.4%) discontinued the study before week 16. Discontinuation was related to the study treatment in 13 of these 17 patients: 7 of the 462 raltegravir recipients (1.5%) and 6 of the 237 placebo recipients (2.5%). The results of the two studies were consistent. At week 16, counting noncompletion as treatment failure, 355 of 458 raltegravir recipients (77.5%) had HIV-1 RNA levels below 400 copies per milliliter, as compared with 99 of 236 placebo recipients (41.9%, P<0.001). Suppression of HIV-1 RNA to a level below 50 copies per milliliter was achieved at week 16 in 61.8% of the raltegravir recipients, as compared with 34.7% of placebo recipients, and at week 48 in 62.1% as compared with 32.9% (P<0.001 for both comparisons). Without adjustment for the length of follow-up, cancers were detected in 3.5% of raltegravir recipients and in 1.7% of placebo recipients. The overall frequencies of drug-related adverse events were similar in the raltegravir and placebo groups.

CONCLUSIONS

In HIV-infected patients with limited treatment options, raltegravir plus optimized background therapy provided better viral suppression than optimized background therapy alone for at least 48 weeks. (ClinicalTrials.gov numbers, NCT00293267 and NCT00293254.)

Early changes in T-cell activation predict antiretroviral success in salvage therapy of HIV infection

OBJECTIVE

Because effective antiretroviral therapy (ART) reduces immune activation, we hypothesize that early changes in immune activation are associated with subsequent virologic response to therapy.

DESIGN

Observational cohort study.

SETTING

Institutional HIV clinic.

SUBJECTS

Thirty-four adult HIV patients with virologic failure on their current antiretroviral regimen.

INTERVENTION

Change to salvage regimen selected by patient's physician.

MAIN OUTCOME MEASURES

Measures of immune activation at baseline and at 2, 4, 8, and 24 weeks after enrollment. Data were analyzed by proportional hazards (PH) models.

RESULTS

PH models showed that reductions between baseline and week 2 in expression of CD38 (P = 0.02) or CD95 (P = 0.02) on CD4 T cells were associated with increased likelihood of achieving virologic suppression. Kaplan-Meier analysis demonstrated that patients who had reductions within the first 2 weeks of therapy in CD4 T-cell expression of CD38 (P = 0.003) or CD95 (P = 0.08) were more likely to achieve viral suppression than those who did not.

CONCLUSIONS

Reduced CD4 T-cell expression of CD38 and CD95 occurring within 2 weeks of salvage therapy is associated with subsequent viral suppression. Monitoring CD38 and CD95 may allow earlier assessment of the response to ART.

Declining Prevalence of HIV-1 Drug Resistance in Treatment-Failing Patients: A Clinical Cohort Study

Objectives

A major barrier to successful viral suppression in HIV type 1 (HIV-1)-infected individuals is the emergence of virus resistant to antiretroviral drugs. We explored the evolution of genotypic drug resistance prevalence in treatment-failing patients from 1999 to 2005 in a clinical cohort.

Patients and Methods

Prevalence of major International AIDS Society-USA HIV-1 drug resistance mutations was measured over calendar years in a population with treatment failure and undergoing resistance testing. Predictors of the presence of resistance mutations were analysed by logistic regression.

Results

Significant reductions of the prevalence of resistance to all three drug classes examined were observed. This was accompanied by a reduction in the proportion of treatment-failing patients. Independent predictors of drug resistance were the earlier calendar year, prior use of suboptimal nucleoside analogue therapy, male sex and higher CD4 levels at testing.

Conclusions

In a single clinical cohort, we observed a decrease in the prevalence of resistance to all three examined antiretroviral drug classes over time. If this finding is confirmed in multicentre cohorts it may translate into reduced transmission of drug-resistant virus from treated patients.