Implementation of raltegravir in routine clinical practice: selection criteria for choosing this drug, virologic response rates, and characteristics of failures

Effectiveness of integrase strand transfer inhibitors among treatment-experienced patients in a clinical setting

OBJECTIVE

Characterize virologic and immunologic outcomes of INSTI-based antiretroviral therapy (ART) in experienced patients with and without virologic failure.

DESIGN

Prospective clinical cohort.

METHODS

ART-experienced, INSTI-naive participants in the University of North Carolina Center for AIDS Research HIV Clinical Cohort (UCHCC) initiating an INSTI-containing regimen 2007-2016 were followed from INSTI initiation (baseline) to the earliest of: outcome of interest, loss to follow-up (LTFU, 1 year without clinical visit), or death. Outcomes of interest were virologic failure (first of two consecutive viral loads at least 200 copies/ml more than 2 weeks apart, or one viral load ≥200 before LTFU) and immune recovery (first CD4 ≥500 cells/μl). Patients with baseline viral load at least 50 copies/ml were given 24 weeks before meeting virologic failure criteria. Kaplan-Meier curves and Cox proportional hazards models compared INSTI regimens and patient characteristics.

RESULTS

Of 773 patients, 32% were women, 59% African-American, and 42% had a viral load at least 50 copies/ml at INSTI initiation. After 2 years, 5% of patients with baseline viral load less than 50 copies/ml experienced virologic failure, compared with 35% of patients with baseline viral load at least 50 copies/ml (P < 0.01). Among patients with baseline viral load less than 50 copies/ml, dolutegravir/NRTIs was associated with longer time to virologic failure [adjusted hazard ratio (aHR) 0.11, 95% confidence interval (CI) 0.01-0.80], whereas among patients with baseline viral load at least 50 copies/ml, raltegravir/NRTIs was associated with longer time to virologic failure (aHR 0.35, 95% CI 0.18-0.68), both compared with elvitegravir/NRTIs. After 5 years suppressed, irrespective of baseline viral load, 61% of patients experienced immune recovery.

CONCLUSION

In this cohort, INSTI-containing regimens led to low virologic failure rates in patients switching ART while suppressed. Viremic patients initiating INSTIs were at high risk of virologic failure during follow-up.

Long-term immunologic and virologic responses on raltegravir-containing regimens among ART-experienced participants in the HIV Outpatient Study

OBJECTIVES

Raltegravir (RAL)-containing antiretroviral therapy (ART) produced better immunologic and virologic responses than optimized background ART in clinical trials of heavily ART-experienced patients, but few data exist on long-term outcomes in routine HIV care.

METHODS

We studied ART-experienced HIV outpatient study (HOPS) participants seen at 10 US HIV-specialty clinics during 2007-2011.We identified patients who started (baseline date) either continuous ≥ 30 days of RAL-containing or RAL-sparing ART, and used propensity score (PS) matching methods to account for baseline clinical and demographic differences. We used Kaplan-Meier methods and log-rank tests for the matched subsets to evaluate probability of death, achieving HIV RNA < 50 copies/ml, and CD4 cell count (CD4) increase of ≥ 50 cells mm(- 3) during follow-up.

RESULTS

Among 784 RAL-exposed and 1062 RAL-unexposed patients, 472 from each group were matched by PS. At baseline, the 472 RAL-exposed patients (mean nadir CD4, 205 cells mm(- 3); mean baseline CD4, 460 cells mm(- 3); HIV RNA < 50 copies ml(- 1) in 61%; mean years on prescribed ART, 7.5) were similar to RAL unexposed. During a mean follow-up of over 3 years, mortality rates and immunologic and virologic trajectories did not differ between the two groups. Among patients with detectable baseline HIV RNA levels, 76% of RAL-exposed and 63% of RAL-unexposed achieved HIV RNA < 50 copies ml(- 1) (P = 0.51); 69 and 58%, respectively, achieved a CD4 increase ≥ 50 cells mm(- 3) (P = 0.70).

DISCUSSION

In our large cohort of US ART-experienced patients with a wide spectrum of clinical history, similar outcomes were observed when prescribed RAL containing versus other contemporary ART.

Origin of minority drug-resistant HIV-1 variants in primary HIV-1 infection

BACKGROUND

Drug-resistant human immunodeficiency virus type 1 (HIV-1) minority variants (MVs) are present in some antiretroviral therapy (ART)-naive patients. They may result from de novo mutagenesis or transmission. To date, the latter has not been proven.

METHODS

MVs were quantified by allele-specific polymerase chain reaction in 204 acute or recent seroconverters from the Zurich Primary HIV Infection study and 382 ART-naive, chronically infected patients. Phylogenetic analyses identified transmission clusters.

RESULTS

Three lines of evidence were observed in support of transmission of MVs. First, potential transmitters were identified for 12 of 16 acute or recent seroconverters harboring M184V MVs. These variants were also detected in plasma and/or peripheral blood mononuclear cells at the estimated time of transmission in 3 of 4 potential transmitters who experienced virological failure accompanied by the selection of the M184V mutation before transmission. Second, prevalence between MVs harboring the frequent mutation M184V and the particularly uncommon integrase mutation N155H differed highly significantly in acute or recent seroconverters (8.2% vs 0.5%; P < .001). Third, the prevalence of less-fit M184V MVs is significantly higher in acutely or recently than in chronically HIV-1-infected patients (8.2% vs 2.5%; P = .004).

CONCLUSIONS

Drug-resistant HIV-1 MVs can be transmitted. To what extent the origin-transmission vs sporadic appearance-of these variants determines their impact on ART needs to be further explored.

The prevalence of erectile dysfunction and its association with antiretroviral therapy in HIV-infected men: the Swiss HIV Cohort Study

BACKGROUND

Here, we aimed to determine the prevalence of erectile dysfunction (ED) among HIV-infected men and its association with components of antiretroviral therapy.

METHODS

Cross-sectional data on sexual dysfunction were collected in the Swiss HIV Cohort Study (SHCS) between December 2009 and November 2010. Multilevel logistic regression models were used to estimate the association between ED and exposure to 24 different antiretroviral drugs from four drug classes.

RESULTS

During the study period, 5,194 of 5,539 eligible men in the SHCS had a follow-up visit; 4,064 men answered a question on ED for the first time. Among these men, ED was experienced often by 459 (11%), sometimes by 543 (13%), rarely by 389 (10%), never by 2,526 (62%) and 147 (4%) did not know. ED was associated with older age, an earlier HIV diagnosis and depression. No association was found with any drug class; however, ED was associated with cumulative exposure to either zalcitabine (OR 1.29 per year of use; 95% CI 1.07, 1.55) or enfuvirtide (OR 1.28; 95% CI 1.08, 1.52).

CONCLUSIONS

Around 1 in 10 men in the SHCS reported often experiencing ED. We found no association between ED and any drug class, but those exposed to zalcitabine or enfurvitide (drugs no longer or rarely used) were more likely to report ED; this second association was probably not causal.

Optimizing background therapy in treatment-experienced HIV-1 patients by rules-based algorithms and bioinformatics

In HIV-1-infected patients with extensive drug resistance, the optimization of background antiretroviral therapy is essential when changing drugs after treatment failure. The genotypic sensitivity score (GSS) and phenotypic sensitivity score (PSS), determined by rules-based algorithms, are employed to predict which drugs to select in a background therapy in order to receive the best treatment response when a new drug will be used, both in investigational trials of new agents and in clinical care. However, the outcome of the GSS/PSS approach for the purpose of assessing antiretroviral efficacy in patients with multiresistance has become more problematic, despite improvements such as drug potency weighting and adding information on treatment history. Bioinformatics-based methods are more recent attractive alternatives that have demonstrated equal or better precision compared with rules-based algorithms. This review aims to discuss the usefulness of GSS/PSS and bioinformatics, respectively, for the optimization of anti-HIV background therapy in heavily treatment-experienced patients.

Antiretroviral therapy in Indian setting: when & what to start with, when & what to switch to?

With the rapid scale up of antiretroviral therapy, there is a dramatic decline in HIV related morbidity and mortality in both developed and developing countries. Several new safe antiretroviral, and newer class of drugs and monitoring assays are developed recently. As a result the treatment guideline for the management of HIV disease continue to change. This review focuses on evolving science on Indian policy - antiretroviral therapy initiation, which drugs to start with, when to change the initial regimen and what to change.

Population pharmacokinetic analysis and pharmacogenetics of raltegravir in HIV-positive and healthy individuals

The objectives of this study were to characterize raltegravir (RAL) population pharmacokinetics in HIV-positive (HIV(+)) and healthy individuals, identify influential factors, and search for new candidate genes involved in UDP glucuronosyltransferase (UGT)-mediated glucuronidation. The pharmacokinetic analysis was performed with NONMEM. Genetic association analysis was performed with PLINK using the relative bioavailability as the phenotype. Simulations were performed to compare once- and twice-daily regimens. A 2-compartment model with first-order absorption adequately described the data. Atazanavir, gender, and bilirubin levels influenced RAL relative bioavailability, which was 30% lower in HIV(+) than in healthy individuals. UGT1A9*3 was the only genetic variant possibly influencing RAL pharmacokinetics. The majority of RAL pharmacokinetic variability remains unexplained by genetic and nongenetic factors. Owing to the very large variability, trough drug levels might be very low under the standard dosing regimen, raising the question of a potential relevance of therapeutic drug monitoring of RAL in some situations.

Viral suppression rates in salvage treatment with raltegravir improved with the administration of genotypic partially active or inactive nucleoside/tide reverse transcriptase inhibitors

BACKGROUND

Nucleoside reverse transcriptase inhibitors (NRTIs) are often administered in salvage therapy even if genotypic resistance tests (GRTs) indicate high-level resistance, but little is known about the benefit of these additional NRTIs.

METHODS

The effect of <2 compared with 2 NRTIs on viral suppression (HIV-1 RNA < 50 copies/mL) at week 24 was studied in salvage patients receiving raltegravir. Intent-to-treat and per-protocol analyses were performed; last observation carried forward imputation was used to deal with missing information. Logistic regressions were weighted to create a pseudopopulation in which the probability of receiving <2 and 2 NRTIs was unrelated to baseline factors predicting treatment response.

RESULTS

One-hundred thirty patients were included, of whom 58.5% (n = 76) received <2 NRTIs. NRTIs were often replaced by other drug classes. Patients with 2 NRTIs received less additional drug classes compared with patients with <2 NRTIs [median (IQR): 1 (1-2) compared with 2 (1-2), P Wilcoxon < 0.001]. The activity of non-NRTI treatment components was lower in the 2 NRTIs group compared with the <2 NRTIs group [median (IQR) genotypic sensitivity score: 2 (1.5-2.5) compared with 2.5 (2-3), P Wilcoxon < 0.001]. The administration of <2 NRTIs was associated with a worse viral suppression rate at week 24. The odds ratios were 0.34 (95% confidence interval: 0.13 to 0.89, P = 0.027) and 0.19 (95% confidence interval: 0.05 to 0.79, P = 0.023) when performing the last observation carried forward and the per-protocol approach, respectively.

CONCLUSIONS

Our findings showed that partially active or inactive NRTIs contribute to treatment response, and thus the use of 2 NRTIs in salvage regimens that include raltegravir seems warranted.

Cell disposition of raltegravir and newer antiretrovirals in HIV-infected patients: high inter-individual variability in raltegravir cellular penetration

OBJECTIVES

The site of pharmacological activity of raltegravir is intracellular. Our aim was to determine the extent of raltegravir cellular penetration and whether raltegravir total plasma concentration (C(tot)) predicts cellular concentration (C(cell)).

METHODS

Open-label, prospective, pharmacokinetic study on HIV-infected patients on a stable raltegravir-containing regimen. Plasma and peripheral blood mononuclear cells were simultaneously collected during a 12 h dosing interval after drug intake. C(tot) and C(cell) of raltegravir, darunavir, etravirine, maraviroc and ritonavir were measured by liquid chromatography coupled to tandem mass spectrometry after protein precipitation. Longitudinal mixed effects analysis was applied to the C(cell)/C(tot) ratio.

RESULTS

Ten HIV-infected patients were included. The geometric mean (GM) raltegravir total plasma maximum concentration (C(max)), minimum concentration (C(min)) and area under the time-concentration curve from 0-12 h (AUC(0-12)) were 1068 ng/mL, 51.1 ng/mL and 4171 ng·h/mL, respectively. GM raltegravir cellular C(max), C(min) and AUC(0-12) were 27.5 ng/mL, 2.9 ng/mL and 165 ng·h/mL, respectively. Raltegravir C(cell) corresponded to 5.3% of C(tot) measured simultaneously. Both concentrations fluctuate in parallel, with C(cell)/C(tot) ratios remaining fairly constant for each patient without a significant time-related trend over the dosing interval. The AUC(cell)/AUC(tot) GM ratios for raltegravir, darunavir and etravirine were 0.039, 0.14 and 1.55, respectively.

CONCLUSIONS

Raltegravir C(cell) correlated with C(tot) (r = 0.86). Raltegravir penetration into cells is low overall (∼5% of plasma levels), with distinct raltegravir cellular penetration varying by as much as 15-fold between patients. The importance of this finding in the context of development of resistance to integrase inhibitors needs to be further investigated.

Novel integrase inhibitors for HIV

IMPORTANCE OF THE FIELD

Integrase inhibitors are the newest class of antiretroviral agents developed to treat HIV-1 infection. Raltegravir (RAL), the only integrase inhibitor (INI) currently approved for the treatment of HIV-infected patients, has proven to be a potent and well-tolerated antiretroviral (ARV) agent. It is currently approved and used for the treatment of both ARV-experienced and ARV-naive patients. Nevertheless, the relatively low genetic barrier for resistance of RAL encourages the search for new INIs with different mechanisms of actions and resistance profiles.

AREAS COVERED IN THIS REVIEW

Here we review the data available about INI that are currently being tested in clinical trials or are in preclinical development: elvitegravir (EVG), S/GSK1349572, S/GSK1265744 and LEDGINs. We focus on their clinical efficacy, pharmacokinetic, safety and resistance profiles.

WHAT THE READER WILL GAIN

Up-to-date overview on the currently available, clinically relevant INIs and promising preclinical inhibitors at all phases of development.

TAKE HOME MESSAGE

Integrase inhibitors represent the newest therapeutic class available to treat HIV-1 infection. There are a variety of compounds either available in the clinic (RAL), advancing to Phase III trials (EVG), or in earlier phases of development. Taken together, this class offers new treatment options for the HIV-infected individual.

Transmitted drug resistance in persons with acute/early HIV-1 in San Francisco, 2002-2009

Background

Transmitted HIV-1 drug resistance (TDR) is an ongoing public health problem, representing 10–20% of new HIV infections in many geographic areas. TDR usually arises from two main sources: individuals on antiretroviral therapy (ART) who are failing to achieve virologic suppression, and individuals who acquired TDR and transmit it while still ART-naïve. TDR rates can be impacted when novel antiretroviral medications are introduced that allow for greater virologic suppression of source patients. Although several new HIV medications were introduced starting in late 2007, including raltegravir, maraviroc, and etravirine, it is not known whether the prevalence of TDR was subsequently affected in 2008–2009.

Methodology/Principal Findings

We performed population sequence genotyping on individuals who were diagnosed with acute or early HIV (<6 months duration) and who enrolled in the Options Project, a prospective cohort, between 2002 and 2009. We used logistic regression to compare the odds of acquiring drug-resistant HIV before versus after the arrival of new ART (2005–2007 vs. 2008–2009). From 2003–2007, TDR rose from 7% to 24%. Prevalence of TDR was then 15% in 2008 and in 2009. While the odds of acquiring TDR were lower in 2008–2009 compared to 2005–2007, this was not statistically significant (odds ratio 0.65, 95% CI 0.31–1.38; p = 0.27).

Conclusions

Our study suggests that transmitted drug resistance rose from 2003–2007, but this upward trend did not continue in 2008 and 2009. Nevertheless, the TDR prevalence in 2008–2009 remained substantial, emphasizing that improved management strategies for drug-resistant HIV are needed if TDR is to be further reduced. Continued surveillance for TDR will be important in understanding the full impact of new antiretroviral medications.

Cohort profile: the German ClinSurv HIV project--a multicentre open clinical cohort study supplementing national HIV surveillance

BACKGROUND

New forms of HIV/AIDS therapy require new surveillance instruments to meet shifting public health demands. The Clinical Surveillance of HIV Disease (ClinSurv HIV) project was established in 1999 as a collaboration between major HIV treatment centres in Germany and the Robert Koch Institute (RKI). The project contributes to national HIV surveillance and focuses on the changing epidemiology of HIV/AIDS after the introduction of new therapies in 1995.

METHODS

ClinSurv HIV is designed as an open multicentre observational cohort study of HIV-infected patients. Anonymized data on diagnoses, treatment and laboratory parameters are collected in a standardized format. Data are currently sampled biannually via 11 centres specializing in HIV diagnosis and care within the legal framework of the German Protection against Infection Act [Infektionsschutzgesetz (IfSG)].

RESULTS

A total of 14874 patients were enrolled in the study by 30 June 2009. Of these, 10221 patients (68.7%) were enrolled after 1 January 1999 and 6006 patients (40.4%) were known to have been diagnosed as positive for HIV before 1999. Evaluation indicators, such as the number of newly enrolled patients per half-year period, loss to follow-up, completeness of data per case, availability of data per possible clinical contact, and internal quality control parameters, show a very stable evolution in the cohort, which although open, can be observed. Comparison with the national HIV surveillance data suggests a high degree of representativeness according to major demographic variables.

CONCLUSION

Bearing in mind the obvious strengths and weaknesses discussed, the German ClinSurv HIV cohort provides a broad range of research opportunities in the field of HIV/AIDS both within Germany and in international collaborative research.

Clinical, virological and immunological responses in Danish HIV patients receiving raltegravir as part of a salvage regimen

BACKGROUND

Raltegravir is the first integrase inhibitor approved for treatment of HIV-infected patients harboring multiresistant viruses.

METHODS

From a Danish population-based nationwide cohort of HIV patients we identified the individuals who initiated a salvage regimen including raltegravir and a matched cohort of HIV-infected patients initiating HAART for the first time. We compared these two cohorts for virological suppression, gain in CD4 count, and time to first change of initial regimen.

RESULTS

We identified 32 raltegravir patients and 64 HIV patients who initiated HAART for the first time in the period 1 January 2006 to 1 July 2009. The virological and immunological responses in the raltegravir patients were comparable to those seen in the control cohort. No patients in the two cohorts died and no patients terminated raltegravir treatment in the observation period. Time to first change of initial regimen was considerably shorter for HAART-naïve patients.

CONCLUSION

We conclude that salvage regimens including raltegravir have high effectiveness in the everyday clinical setting. The effectiveness of the regimens is comparable to that observed for patients initiating HAART for the first time. The risk of change in the salvage regimens after initiation of raltegravir is low.