Cervical and anal HPV infection: cytological and histological abnormalities in HIV-infected women in Thailand

BACKGROUND

Women infected with human immunodeficiency virus (HIV) have higher rates of persistent infection with high-risk human papillomavirus (hr-HPV) and cervical and anal dysplasia. We describe the epidemiology of hr-HPV, and cervical and anal intra-epithelial abnormalities in HIV-infected women in Thailand.

METHODS

HIV-infected women aged 18-49 years, either HAART-naïve or -experienced, were enrolled in Bangkok, Thailand. A demographic and sexual-risk behaviour questionnaire was administered and a pelvic examination with colposcopy was performed on every woman. Cervical and anal samples were tested for cytology and HPV genotyping.

RESULTS

A total of 256 women were enrolled with a median [interquartile range (IQR)] age of 35 (32-40) years. Ninety (35.2%) had detectable cervical hr-HPV. Being post-menopausal was associated with increased risk for cervical hr-HPV, while years since HIV diagnosis and plasma HIV RNA <40 copies/mL were significantly associated with decreased risk in multivariable regression analyses. Abnormal cervical cytology was detected in 6.3%. Cervical biopsies that were taken from 99 women (39.3%) owing to abnormalities seen during colposcopy showed cervical intra-epithelial neoplasia (CIN) in 22.6%. The sensitivity of cervical cytology to detect CIN2+ was 10.0%. Among 102 women enrolled in the anal substudy, 18.8% had anal HPV infection and 11.1% had anal hr-HPV. Two women had abnormal anal cytology.

CONCLUSION

We found cervical and anal hr-HPV in 35.2% and 11.1% of Thai HIV-infected women, respectively. Moreover, the observed poor agreement between cervical cytology and histology results could indicate current cervical cancer screening programs for HIV-infected women might not be optimal for the detection of pre-neoplastic lesions.

Relationships between Drug Exposure, Changes in Metabolic Parameters and Body Fat in HIV-Infected Patients Switched to a Nucleoside Sparing Regimen

Background

The pathogenesis of metabolic disturbances in treated HIV infection is incompletely understood.

Methods

Relationships between fasted metabolic parameters, body composition, and drug plasma concentrations were investigated in 59 patients who switched from failed nucleoside analogue treatment to ritonavir-boosted indinavir and efavirenz therapy. Metabolic parameters, peripheral fat, visceral adipose tissue (VAT) and drug plasma concentrations were measured prospectively.

Results

Ritonavir exposure was found to be negatively correlated with high-density lipoprotein cholesterol (HDL-c) changes, with a 2.4% decrease in HDL-c for each unit increase in ritonavir concentration ratio. Significant associations between indinavir or efavirenz concentrations and metabolic disturbances were not observed. Total cholesterol (TC) correlated positively with high body mass index (BMI) and negatively with baseline limb fat mass: each unit increase in BMI and each kilogram reduction in baseline limb fat corresponded with a TC increase of 2.4% and 4.1%, respectively. Baseline triglyceride levels were lower in those patients with relatively greater limb fat mass: each kilogram reduction of total limb fat mass was associated with a 15.7% increase in triglyceride concentration. Changes in VAT were positively correlated with TC: for every unit TC increase a 0.3% VAT increase was observed (over 48 weeks).

Conclusions

Reduced limb fat mass at the start of the study treatment, increases in VAT mass, and higher plasma concentrations of ritonavir on study treatment were each - to varying degrees - associated with various metabolic disturbances.

A Phase I/IIa Study with Succinylated Human Serum Albumin (Suc-HSA), a candidate HIV-1 Fusion Inhibitor

Background

Succinylated human serum albumin (Suc-HAS) is a negatively charged neo-glycoprotein that binds to the positively charged V3–loop of HIV-1 gp120, acting as HIV-1-fusion inhibitor in vitro (IC50: 0.5–5.0 μg/ml). Suc-HSA was safe in rats and monkeys, and showed antiretroviral effect in a human-to-mouse model. We evaluated safety and pharmacokinetics of single and multiple doses of Suc-HSA in HIV-1-infected individuals.

Methods

First, six untreated, chronically HIV-1-infected patients were randomized to a single dose of 1 or 10 mg/kg Suc-HSA intravenously. Second, five consecutive daily doses (10 mg/kg, based on the results of the single dose study) were given to four patients. Safety laboratory assessments, Suc-HSA plasma levels, plasma HIV-1 RNA (pVL), and CD4+ T-cell counts were determined.

Results

Increase of liver transaminases (grade 1/2) occurred in one of six patients in the single-dose phase and in three of four patients in the multiple-dosing phase. Suc-HSA plasma levels were undetectable 4 h after a single dose of 1 mg/kg. After a dose of 10 mg/kg, plasma levels were more sustained, but declined under the target plasma concentration (10 μg/ml) 12–24 h post-dosing. After multiple dosing, plasma levels reached peak values 2h post-dosing as predicted by our kinetic model. However, trough levels were below the target concentrations. There was no change in pVL or CD4+ T-cell count in either the single- or multiple-dosing phase.

Conclusions

At the chosen dosing regimens, adequate antiviral plasma levels were not maintained, probably because the hepatic clearance was more rapid than expected. This may partially explain the lack of effect on pVL and CD4+ T-cell count. The observed liver transaminase increases prohibit further dose escalation.

[The use of the non-nucleoside reverse transcriptase inhibitors nevirapine and efavirenz in the treatment of patients with a chronic HIV-I infection]

The non-nucleoside reverse transcriptase inhibitors (NNRTIs) are an important group ofantiretroviral drugs in the treatment of a chronic HIV-I infection. The risk of viral resistance to NNRTIs is strongly diminished when they are used as part of a highly active antiretroviral combination therapy (HAART). Randomised trials have shown that nevirapine and efavirenz have a comparable antiretroviral efficacy. While rash and hepatotoxicity are associated with the use of nevirapine, the use of efavirenz is associated with neuropsychiatric abnormalities. The increase in HDL-cholesterol, which may be associated with a lower risk of cardiovascular disease, is greater with nevirapine than with efavirenz. The choice between the two drugs can be tailored to the needs of the patient. The rapid selection ofNNRTI-resistant HIV-I strains during the sub-optimal use of nevirapine and efavirenz demands the development of new NNRTIs.

Adequacy of peritoneal dialysis and the importance of preserving residual renal function

The well-being and survival of dialysis patients not only depend on the removal of waste products and excess fluid, but also on the prevention of cardiovascular complications by maintaining normovolaemia and adequate blood pressure and avoidance of ectopic calcification. Also, the maintenance of nutritional status and adequate removal of middle molecules are amongst the most important issues in long-term renal replacement therapy. In this review, attention is given to optimal peritoneal small solute clearance and Kt/V and to the evidence concerning the role of residual renal function. In addition, factors that can influence this residual function are also discussed.

Boosted versus Unboosted Indinavir with Zidovudine and Lamivudine in Nucleoside Pre-Treated Patients: A Randomized, Open-Label Trial with 112 Weeks of Follow-Up (HIV-Nat 005)

Introduction

The use of HIV protease inhibitors (PIs) in a ritonavir (RTV)-boosted form is now common. However, randomized data comparing boosted with unboosted PI strategies are scarce.

Methods

This randomized, open-label trial compared indinavir (IDV) 800 mg three times daily with IDV/RTV 800/100 mg twice daily, both given with zidovudine (AZT)/lamivudine (3TC) twice daily in individuals with at least 3 months previous AZT experience. The primary endpoint was the time-weighted average change in HIV RNA from baseline. Designed as a 48-week study, follow-up continued until week 112. Primary analysis is by intention to treat.

Results

One hundred and three patients commenced therapy and are included in the analysis. Patients had a median of 29 months past nucleoside reverse transcriptase inhibitor (NRTI) exposure. Baseline median (interquartile range) log10 HIV RNA was 4.0 (3.3–4.5) and CD4+T-cell count 166 (40–323) cells/μl. After 112-weeks of study there was no significant difference observed between arms in the mean (sd) change in time-weighted average HIV RNA from baseline (-1.6 [1.1] HIV RNA copies/week/ml three times daily arm; -1.4 [1.1] HIV RNA copies/week/ml twice daily arm; P=0.3). Both arms were associated with substantial toxicity expressed as serious adverse events and study drug interruptions. The twice daily arm experienced greater dyslipidaemia. Mean (sd) changes in time-weighted CD4+ T-cell count from baseline were similar [88 (84) cells/week/μl three times daily arm; 70 [109] cells/week/μl twice daily arm; P=0.3).

Conclusions

RTV-boosted IDV 800/100 mg twice daily demonstrated comparable efficacy to unboosted IDV 800mg three times daily dosing. Both regimens were associated with substantial toxicity. Use of lower doses of RTV-boosted IDV may result in better tolerability without loss of efficacy and warrant further research.

Long-Term Highly Active Antiretroviral Therapy in Chronic HIV-1 Infection: Evidence for Reconstitution of Antiviral Immunity

In this study we investigated the long-term effect of highly active antiretroviral therapy (HAART) on HIV-specific CD4+ T-cell responses in comparison with virus-specific CD4+ T-cell responses against the persistent herpes viruses cytomegalovirus (CMV) and Epstein-Barr virus (EBV). To this end, HIV- and herpes virus-specific cellular immune responses were measured longitudinally in 10 seroconverters with long-term follow-up including 55 months of successful suppression of viral load by HAART. HIV- and CMV-specific CD4+ T cells producing interferon-γ (IFNγ) or interleukin-2 (IL-2) were analysed as well as proliferative capacity. EBV-specific CD4+ T cells were determined using a 12-day ex vivo assay. Initiation of HAART resulted in a transient increase of HIV-specific IL-2+IFNγ+CD4+ T cells and, to a lesser extent, IL-2+CD4+ T cells. Long-term HAART resulted in an increase in HIV-, CMV- and EBV-specific CD4+ T-cell proliferative capacity. The increase in HIV- and herpes-virus-specific CD4+ T-cell proliferative capacity after 55 months of HAART suggests that the improved proliferative response is not specific for HIV, but reflects a more general improvement of antiviral immune responses, which is induced by HAART.

Nevirapine Plasma Concentrations and Concomitant Use of Rifampin in Patients Coinfected with HIV-1 and Tuberculosis

Objectives

In countries with high numbers of HIV/tuberculosis coinfection nevirapine and rifampin are used extensively. However, limited data are available about whether or not nevirapine and rifampin can be safely coadministered without the plasma concentration of nevirapine falling below therapeutic levels.

Methods

Blood samples for determination of nevirapine plasma concentrations were collected from patients using nevirapine 200 mg twice daily with or without concomitant rifampin. Bivariate and multivariate linear regression models were used to investigate factors possibly related to nevirapine concentrations.

Results

We received 74 blood samples from patients using nevirapine plus rifampin, and collected blood samples from an equal number of controls using nevirapine only. Groups were similar for age, gender, weight, height and body mass index (BMI). In the rifampin group the mean nevirapine concentration was 5.47 ±2.66mg/l, whereas in the control group the mean nevirapine concentration was 8.72 ±3.98 mg/l. In the rifampin group seven nevirapine trough concentrations were low (<3.1 mg/l), while in the control group two patients had low nevirapine trough concentrations ( P=0.164). In the multivariate linear regression analysis, corrected for time after drug intake, the use of rifampin was significantly ( P<0.001) associated with lower nevirapine plasma concentrations, whereas higher BMI reached borderline significance ( P=0.065).

Conclusion

Although nevirapine plasma concentrations were 3.3 mg/l lower when co-administered with rifampin, still more than 86% of these patients had nevirapine plasma concentrations >3.1 mg/l. Our results suggest that from a pharmacological point of view the majority of Thai coinfected patients, who have low BMIs, reach nevirapine plasma concentrations that are adequate for treatment of HIV. However this can only be undertaken if nevirapine plasma concentration monitoring is available and can be closely followed.

Are Adverse Events of Nevirapine and Efavirenz Related to Plasma Concentrations?

Objective

The relationships between adverse events (AEs) and plasma concentrations of nevirapine (NVP) and efavirenz (EFV) were investigated as part of the large, international, randomized 2NN study.

Methods

Treatment-naive, HIV-1-infected patients received NVP (once or twice daily), EFV or their combination, each in combination with lamivudine and stavudine. Blood samples were collected on day 3 and weeks 1, 2, 4, 24 and 48. Concentrations of NVP and EFV were quantitatively assessed by a validated HPLC assay. Individual Bayesian estimates of the area under the plasma concentration–time curve over 24 h (AUC24h), and minimum and maximum plasma concentrations (Cmin and Cmax) as measures for drug exposure of NVP and EFV, were generated using a previously developed population pharmacokinetic model. Pharmacokinetic parameters were compared for patients with and without central nervous system (CNS) and psychiatric AEs, hepatic events, liver enzyme elevations (LEEs) and rash. Furthermore, it was investigated whether a clear cut-off for a pharmacokinetic parameter could be identified above which the incidence of AEs was clearly increased. AEs were also related to demographic parameters and baseline characteristics.

Results

In total, from 1077 patients, NVP (3024 samples) and EFV (1694 samples) plasma concentrations and AE data (825 observations) were available. For all patients Cmin, Cmax and AUC24h were determined. When corrected for known covariates of gender, CD4 cell count at baseline, region, hepatitis coinfection and possible interactions between these factors, no significant associations between AEs and any tested exposure parameter of NVP was observed. Also, no target Cmin value, above which patients were at increased risk for AEs, could be established. On the other hand, geographical region, hepatitis coinfection, CD4 cell count and gender were found to be significantly related with the incidence of CNS and psychiatric AEs, hepatic events, LEEs and rash during the treatment with NVP. The occurrence of elevated liver enzymes during the first 6 weeks in the EFV-containing arm was significantly ( P=0.036) correlated to the exposure of EFV (Cmin). Only hepatitis coinfection impacted on LEEs during the first 6 weeks of treatment. With an EFV Cmin above 2.18 mg/l during the induction phase, patients were 4.4 (range 1.3–15.5) times more at risk for elevated liver enzymes. No other correlations between AEs and EFV pharmacokinetics or patient characteristics could be identified.

Conclusions

Pharmacokinetic parameters of NVP did not have a relationship to AEs in the 2NN trial when corrected for known covariates. The value of periodical drug monitoring of NVP as a way to prevent toxicity is therefore limited. Treating physicians should instead focus on factors that are more predictive of AEs (gender, CD4 count and hepatitis coinfection). High EFV Cmin levels resulted in elevated liver enzyme values during the first 6 weeks of treatment. Regular measurement of EFV levels and liver enzymes at the start of therapy may therefore be advised.

Nevirapine and Efavirenz Pharmacokinetics and Covariate Analysis in the 2Nn Study

Objective

The aim of this 2NN pharmacokinetic substudy was to investigate the population pharmacokinetics of nevirapine and efavirenz.

Methods

Treatment-naive, HIV-1-infected patients received nevirapine (once or twice daily), efavirenz or a combination with lamivudine and stavudine. Blood samples were collected on day 3 and weeks 1, 2, 4, 24 and 48. Using non-linear mixed effects modelling, pharmacokinetics of nevirapine and efavirenz and factors involved in the inter-individual variability were investigated.

Results

Clearance of nevirapine in the induction phase (<14 days) and at steady state (>28 days) were 2.02 l/h and 2.81 l/h, respectively. Volume of distribution and absorption rate constant were 77.0 l and 1.66 h-1, respectively. Clearance of nevirapine was lower in females (13.8%) and in patients with hepatitis B (19.5%). Patients from South America and Western countries had higher clearance of nevirapine compared with Thai and South African patients. The clearances of efavirenz in the induction phase and at steady state were 7.95 l/h and 8.82 l/h, respectively. The volume of distribution and absorption rate constant were 418 l and 0.287 h-1, respectively. Concomitant use of nevirapine increased clearance of efavirenz (43%). Patients from Thailand had lower clearance than the rest of the population.

Conclusions

The population pharmacokinetics of nevirapine and efavirenz were assessed in the 2NN trial. For both drugs, an induction phase was distinguished from the steady-state phase. Gender, hepatitis B and geographical region were involved in the variability of the pharmacokinetics of nevirapine. Region and concomitantly used nevirapine were determinants of the pharmacokinetics of efavirenz.

Quality of Life in Patients Treated with First-Line Antiretroviral Therapy Containing Nevirapine And/Or Efavirenz

Objective

To assess whether differences in safety profiles between nevirapine (NVP) and efavirenz (EFV), as observed in the 2NN study, translated into differences in ‘health related quality of life’ (HRQoL).

Design

A sub-study of the 2NN study, with antiretro-viral-naive patients randomly allocated to NVP (once or twice daily), EFV or NVP+EFV, in addition to stavudine and lamivudine.

Methods

Comparing differences in changes of HRQoL over 48 weeks as measured with the Medical Outcomes Study HIV Health Survey (MOS-HIV) questionnaire, using analysis of variance.

Results

The 2NN study enrolled 1216 patients. No validated questionnaires were available for 244 patients, and 55 patients had no HRQoL data at all, leaving 917 patients eligible for this sub-study. A total of 471 (51%) had HRQoL measurements both at baseline and week 48. The majority (69%) of patients without HRQoL measurements did, however, complete the study. The change in the physical health score (PHS) was 3.9 for NVP, 3.4 for EFV and 2.4 for NVP+EFV ( P=0.712). For the mental health score (MHS) these values were 6.1, 7.0 and 3.9, respectively ( P=0.098). A baseline plasma HIV-1 RNA concentration (pVL) ≥100 000 copies/ml and a decline in pVL (per log10) were independently associated with an increase of PHS. An increase of MHS was only associated with pVL decline. Patients experiencing an adverse event during follow-up had a comparable change in PHS but a significantly smaller change in MHS, compared with those without an adverse event.

Conclusions

First-line ART containing NVP and/or EFV leads to an improvement in HRQoL. The gain in HRQoL was similar for NVP and EFV, but slightly lower for the combination of these drugs.

[Coinfection with hepatitis C virus and HIV]

The life expectancy of patients with an HIV infection has improved dramatically since the introduction of highly active anti-retroviral therapy (HAART). Retrospective studies have shown that since then, hospital admissions and mortality caused by a co-infection with hepatitis C virus (HCV) have increased. Patients with an HIV-HCV co-infection exhibit on average a more rapid progression to liver cirrhosis and liver failure than patients with an HCV monoinfection. It is expected that a co-infection with HCV will lead to serious complications among some of the HIV-infected population. It is therefore recommended that all HIV-infected patients be screened for a co-infection with HCV. The treatment of an HCV co-infection needs to be considered. The first choice therapy will probably be a combination of peginterferon and ribavirin, although final conclusions about the safety and efficacy are still awaited. A combination of ribavirin with zidovudine or didanosine is best avoided. Developments being made with new classes of drugs, such as HCV-specific protease inhibitors and polymerase inhibitors, seem promising.

Triple Nucleoside Combination Zidovudine/Lamivudine/Abacavir versus Zidovudine/Lamivudine/Nelfinavir as First-Line Therapy in HIV-1-Infected Adults: A Randomized Trial

Objective

To compare the efficacy and safety of a triple nucleoside combination to a protease inhibitor-containing triple regimen as first-line antiretroviral therapy (ART) in HIV-1-infected patients.

Design

Open-label study in HIV-1-infected ART-naive adults, randomized to receive either Combivir® (lamivudine 150 mg/zidovudine 300 mg twice daily) + abacavir (300 mg twice daily), or Combivir® + nelfinavir (750 mg every 8 h) for 48 weeks. Plasma HIV-1 RNA, CD4 cell count and adverse events were assessed at baseline and weeks 4, 8, 16, 24, 32, 40 and 48.

Results

195 subjects (131 men, 64 women), median age 34 years, were randomized: 98 received combivir/abacavir and 97 combivir/nelfinavir. Baseline median plasma HIV-1 RNA was 4.2 log10 copies/ml [Interquartile range (IQR): 3.7-4.5.2] and 4.1 log10 copies/ml (IQR: 3.8–4.6), respectively. Baseline median CD4 cell count was 387 cells/mm3 (IQR: 194–501) and 449 cells/mm3 (IQR: 334–605), respectively. Nine patients (3 vs 6, respectively) did not start treatment or did not have any available efficacy data. At week 48, using the intent to treat analysis (switch/missing equals failure), plasma HIV-1 RNA was <50 copies/ml in 54/95 (57%) and 53/91 (58%) of subjects, respectively. Median CD4 increase was +110 and +120 cells/mm3, respectively. Possible hypersensitivity reactions to abacavir were reported in four subjects (4%).

Conclusion

The triple nucleoside combination combivir/abacavir is well tolerated as a first-line ART regimen in HIV-1-infected adults, with comparable antiviral activity to a nelfinavir-containing regimen at week 48.

Dynamics of the Pool of Infected Resting Cd4 Hla-Dr- T Lymphocytes in Patients Who Started a Triple Class Five-Drug Antiretroviral Regimen During Primary HIV-1 Infection

Starting standard antiretroviral therapy within 10 days after the onset of a primary HIV-1 infection cannot prevent the establishment of a reservoir of HIV-1-infected memory CD4 T cells. Here we studied the reservoir of HIV-1-infected memory CD4 T cells in four patients who started a triple class, five-drug regimen during primary HIV-1 infection. There was a strong correlation between the proportion of productively infected CD4 HLA-DR- T lymphocytes and plasma HIV-1 RNA levels (r=0.852; P<0.001) during the first 24 weeks of therapy. Within 45 weeks of treatment, in three of the four patients the proportion of productively infected CD4 HLA-DR- T lymphocytes was reduced below the level of quantification. In the fourth patient the cellular reservoir remained quantifiable. In two patients who stopped therapy 44 weeks after initiation an immediate rebound of the plasma HIV-1 RNA level and the proportion of productively infected CD4 HLA-DR– T lymphocytes occurred.

In conclusion, initiation of a potent five-drug, triple class regimen during primary HIV-1 infection does not result in virus-specific immune control upon discontinuation of therapy after 44 weeks. Therefore, longer or even stronger suppression of viral replication might be necessary to achieve this goal in primary HIV-1 infection.

Low versus High CD4 Cell Count as Starting Point for Introduction of Antiretroviral Treatment in Resource-Poor Settings: A Scenario-Based Analysis

Objective

To evaluate CD4 cell count-driven strategies for the initiation of highly active antiretroviral therapy (HAART) in terms of the reduction of the incidence of AIDS-defining events in resource-poor settings.

Methods

Data from the Amsterdam Cohort Study on HIV infection and AIDS were used to estimate the hazard of AIDS in untreated HIV-1 infection and after initiation of HAART, respectively, conditional on CD4 cell count. Different strategies for initiating therapy were compared by calculating the expected HAART administration rate and 1-year cumulative AIDS incidence in three different population settings, varying in the stage of HIV-1 infection at the time of presentation.

Results

Among 695 HIV-1-infected cohort participants, the 1-year AIDS incidence density (ID) ranged from 3.2 per 100 person-years for CD4 cell counts 600–700 cells/mm3, to 31.9 per 100 person-years for CD4 cell counts 100–200 cells/mm3 and 77.9 per 100 person-years for CD4 cell counts below 100 cells/mm3. Upon initiation of HAART, the ID in the lowest CD4 strata declined to 13.3 and 16.3 per 100 person-years, respectively. Extrapolated to developing countries, supply of HAART to patients presenting with HIV-1 infection below 200 CD4 cells/mm3 is expected to give an administration rate of 67%, while the AIDS incidence will drop from over 30% to almost 10%.

Conclusions

Introduction of HAART in populations with advanced HIV-1 infection can accomplish a threefold reduction of the AIDS incidence when HAART is administered to patients with CD4 cell counts below 200 cells/mm3. In a hospital-based setting in resource-poor environments this ensures an efficient treatment allocation.

Persistence of Viral HLA-DR- CD4 T-Cell Reservoir during Prolonged Treatment of HIV-1 Infection with a Five-Drug Regimen

During sustained suppression of plasma viraemia using a standard triple-drug regimen, replication-competent HIV-1 can still be recovered from resting memory CD4 T cells. In an attempt to accelerate the clearance of this pool of infected CD4 T cells, eight antiretroviral therapy-naive HIV-1-infected patients were treated with a five-drug regimen. While plasma HIV-1 RNA levels generally remained below the level of detection (<5 copies/ml), replication competent HIV-1 was isolated from HLA-DR- CD4 T cells from all patients on multiple occasions throughout treatment. Decay slopes of infected CD4 T cells ranged from -0.061/week (half-life=2.6 months) to +0.003/week (half-life=infinite). Virus was still detectable at the last time point analysed (80–173 weeks) in all patients. Although more intensive treatment results in improved suppression of plasma viraemia compared with standard drug regimens, it does not result in clearance of the viral reservoir in this timeframe. Strategies other than treatment with a combination of five of the currently available drugs need to be pursued in order to achieve eradication of HIV-1 from this cellular reservoir.

Prednisolone does not prevent hypersensitivity reactions in antiretroviral drug regimens containing abacavir with or without nevirapine

OBJECTIVES

To determine the effect of adjuvant prednisolone use on the development of abacavir (ABC)- and nevirapine (NVP)-associated hypersensitivity reactions (HSR).

METHODS

Randomized open-label study in antiretroviral-naive adult HIV-1 infected patients using a factorial design in which NVP and/or hydroxyurea (HU) and/or prednisolone are added to a regimen of ABC, zidovudine and lamivudine. Prednisolone (40 mg once daily) was added for the first 2 weeks of treatment. As it was difficult to distinguish ABC-associated HSR from NVP-associated HSR, these events were treated as a composite endpoint. The odds ratio (OR) of developing HSR for prednisolone-use was calculated with and without stratification by NVP and/or HU. Logistic regression was performed to identify risk factors for developing HSR.

RESULTS

Of the 229 patients 115 were randomized to prednisolone and 114 to no-prednisolone; 19 (17%) and 11 (10%) patients, respectively, developed HSR. The expected prevention of HSR by prednisolone use was not observed. In fact use of prednisolone showed an increased risk for HSR although this did not reach statistical significance [OR, 1.82; 95% confidence interval (CI), 0.82-4.03]. There was a higher incidence of HSR in the NVP group than in the non-NVP group (20% versus 6%; P = 0.002). An additional risk factor identified in a multivariate logistic model was a high baseline CD4 cell count (OR, 1.26 per 100 x 10(6) cells/l increase; 95% CI, 1.06-1.51).

CONCLUSIONS

The simultaneous start of ABC and NVP in first-line antiretroviral regimens should be avoided because of a high (20%) incidence of HSR. Short-term therapy with prednisolone did not prevent HSR in patients using ABC with or without NVP.

Combination of protease inhibitors for the treatment of HIV-1-infected patients: a review of pharmacokinetics and clinical experience

The use of highly active antiretroviral therapy, the combination of at least three different antiretroviral drugs for the treatment of HIV-1 infection, has greatly improved the prognosis for HIV-1-infected patients. The efficacy of a combination of a protease inhibitor (PI) plus two nucleoside analogue reverse transcriptase inhibitors has been well established over a period of up to 3 years. However, virological treatment failure has been reported in 40-60% of unselected patients within 1 year after initiation of a PI-containing regimen. This observation may, at least in part, be attributed to the poor pharmacokinetic characteristics of the PIs. Given as a single agent the PIs have several pharmacokinetic limitations; relatively short plasma-elimination half-lives and a modest and variable oral bioavailability, which is, for some of the PIs, influenced by food. To overcome these suboptimal pharmacokinetics, high doses (requiring large numbers of pills) must be ingested, often with food restrictions, which complicates patient adherence to the prescribed regimen. Positive drug-drug interactions increase the exposure to the PIs, allowing administration of lower doses at reduced dosing frequencies with less dietary restrictions. In addition to increasing the potency of an antiretroviral regimen, combinations of PIs may enhance patient adherence, both of which will contribute to a more durable suppression of viral replication. The favourable pharmacokinetics of PIs in combination are a result of interactions through cytochrome P450 3A4 (CYP3A4) isoenzymes and, possibly, the multi-drug transporting P-glycoprotein (P-gp). Antiretroviral synergy between PIs and non-overlapping primary resistance patterns in the HIV-1 protease genome may further enhance the antiretroviral potency and durability of combinations of PIs. Many combinations contain ritonavir because this PI has the most pronounced inhibiting effects on CYP3A4. The combination of saquinavir and ritonavir, both in a dose of 400 mg twice-a-day, is the most studied double PI combination, with clinical experience extending over 3 years. Combination of a PI with a low dose of ritonavir (< or = 400 mg/day), only to boost its pharmacokinetic properties, seems an attractive option for patients who cannot tolerate higher doses of ritonavir. A recently introduced PI, lopinavir, has been co-formulated with low-dose ritonavir, which allows for a convenient three-capsules, twice-a-day dosing regimen. In an attempt to prolong suppression of viral replication combinations of PIs are becoming increasingly popular. However, further clinical studies are needed to identify the optimal combinations for treatment of antiretroviral naive and experienced HIV-1-infected patients. This review covers combinations of saquinavir, indinavir, nelfinavir, amprenavir and lopinavir with different doses of ritonavir, as well as the combinations of saquinavir and indinavir with nelfinavir.

Limited sampling strategies for the estimation of the systemic exposure to the HIV-1 nonnucleoside reverse transcriptase inhibitor nevirapine

The objective of this study was to develop and validate a limited sampling strategy (LSS) that allows accurate and precise estimation of the area under the plasma concentration versus time curve (AUC) of nevirapine, when used in the licensed dosage of 200 mg twice daily. Because nevirapine has a long plasma elimination half-life and the plasma concentration shows little variation within the 12-hour dosing interval, the authors also wanted to explore whether a time frame exists for which a single-sample LSS can be applied. Twenty HIV-1-infected individuals receiving steady-state treatment with nevirapine (200 mg twice daily) were enrolled. For the development of the LSS, 10 patients were randomly selected from the study population (index set). The pharmacokinetic results from the other 10 patients (validation set) were used for prospective validation of the proposed LSS. Blood samples were obtained before and 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 8, 10, and 12 hours after ingestion. The relationship between the nevirapine concentration at each of the designated time points and the AUC 12h was evaluated by univariate and multivariate linear regression analysis. At each of the sampling times, a strong correlation was observed between the nevirapine concentration and the corresponding AUC 12h (r > 0.97). This allows for a single-sample LSS, using any time point during the dosing interval. When a single equation is preferred, the concentration of nevirapine in a random sample drawn 2 to 4 hours after ingestion of nevirapine (C 2-4h; in microg/mL) can be used for accurate estimation of the AUC 12h (in h x microg/mL) by using the equation AUC 12h (h x microg/mL) = 11.699 (h) x C 2-4h (microg/mL) - 4.381 (h x microg/mL). Validation of this equation resulted in a predicted AUC 12h that was nonbiased and very precise. These data show that the nevirapine concentration at each time point during the dosing interval can be used for accurate estimation of the AUC 12h. Even more practical, a sample obtained at any time between 2 and 4 hours after ingestion of nevirapine can be used. The authors therefore conclude that less intensive sampling (i.e., a single sample) can readily be used to assess the AUC 12h of nevirapine when used in a dosage of 200 mg twice daily.

Pharmacokinetics of stavudine and didanosine coadministered with nelfinavir in human immunodeficiency virus-exposed neonates

We evaluated the pharmacokinetics of stavudine (d4T) and didanosine (ddI) in neonates. Eight neonates born to human immunodeficiency virus-infected mothers were enrolled to receive 1 mg of d4T per kg of body weight twice daily and 100 mg of ddI per m(2) once daily in combination with nelfinavir for 4 weeks after birth. Pharmacokinetic evaluations were performed at 14 and 28 days of age. For d4T, on days 14 and 28, the median areas under the concentration-time curves from 0 to 12 h (AUC(0-12)s) were 1,866 and 1,603, ng x h/ml, respectively, and the median peak concentrations (C(max)s) were 463 and 507 ng/ml, respectively. For ddI, on days 14 and 28, the median AUC(0-10)s were 1,573 and 1,562 h x ng/ml, respectively, and the median C(max)s were 627 and 687 ng/ml, respectively. Systemic levels of exposure to d4T were comparable to those seen in children, suggesting that the pediatric dose of 1 mg/kg twice daily is appropriate for neonates at 2 to 4 weeks of age. Levels of exposure to ddI were modestly higher than those seen in children. Whether this observation warrants a reduction of the ddI dose in neonates is unclear.

Carrier rate of zidovudine-resistant HIV-1: the impact of failing therapy on transmission of resistant strains

OBJECTIVE

Because maintenance of treatment success in HIV-1 infection requires viruses to remain therapy sensitive in drug-naive seropositive persons, we looked at the primary infections caused by drug-resistant HIV-1 over time. Furthermore, to study the coverage rate of therapy and therapy failure in relation to the transmission of resistant viruses a mathematical model was developed.

DESIGN

The reverse transcriptase and protease genes of viruses were analysed in newly infected people in the period 1990-1998 in the Amsterdam Cohort Study on HIV infection and AIDS in homosexual men.

METHODS

The mathematical model was based on the coverage of drug regimens selecting zidovudine (ZDV) resistance, the lag time in which resistance is gained or lost, the death rate of people infected with resistant virus, and the replacement of resistance-selecting regimens by more potent treatments that substantially reduce viral load and mortality.

RESULTS

Of 43 individuals with a primary HIV-infection, three (7%) harboured ZDV-resistant viruses. The first of the ZDV-resistant strains was transmitted in 1995, the last two in 1996. The build-up of ZDV resistance was described by the mathematical model indicating that the equilibrium level of resistance due to treatment depends only on the treatment rate and the outflow rate of patients with resistance virus.

CONCLUSIONS

Our model indicates that the frequency of viral resistance in a population is determined largely by the number of individuals on insufficient or failing therapy and is influenced only modestly by secondary transmission of ZDV-resistant strains.

Therapeutic immune reconstitution in HIV-1-infected children is independent of their age and pretreatment immune status

OBJECTIVE

To evaluate long-term immune reconstitution of children treated with highly active antiretroviral therapy (HAART).

METHODS

The long-term immunological response to HAART was studied in 71 HIV-1-infected children (aged 1 month to 18 years) in two prospective, open, uncontrolled national multicentre studies. Blood samples were taken before and after HAART was initiated, with a follow-up of 96 weeks, and peripheral CD4 and CD8 T cells plus naive and memory subsets were identified in whole blood samples. Relative cell counts were calculated in relation to the median of the age-specific reference.

RESULTS

The absolute CD4 cell count and percentage and the CD4 cell count as a percentage of normal increased significantly (P < 0.001) to medians of 939 x 106 cells/l (range, 10-3520), 32% (range, 1-50) and 84% (range, 1-161), respectively, after 48 weeks. This increase was predominantly owing to naive CD4 T cells. There was a correlation between the increase of absolute naive CD4 T cell counts and age. However, when CD4 T cell restoration was studied as percentage of normal values, the inverse correlation between the increase of naive CD4 T cell count and age was not observed. In addition, no difference in immunological reconstitution was observed at any time point between virological responders and non-responders.

CONCLUSIONS

Normalization of the CD4 cell counts in children treated with HAART is independent of age, indicating that children of all age groups can meet their CD4 T cell production demands. In general, it appears that children restore their CD4 T cell counts better and more rapidly than adults, even in a late stage of HIV-1 infection.

Lipodystrophy in HIV-1-positive patients is associated with insulin resistance in multiple metabolic pathways

BACKGROUND

Treatment for HIV-1 infection is complicated by fat redistribution (lipodystrophy). This is associated with insulin resistance concerning glucose uptake. Our aim was to characterize glucose metabolism more comprehensively in HIV-1-infected patients with lipodystrophy. We assessed glucose disposal and its pathways, glucose production, plasma free fatty acid (FFA) levels, and the degree to which these parameters could be suppressed by insulin.

METHODS

Six HIV-1-infected men on protease inhibitor-based HAART with lipodystrophy (HIV+LD) were studied. The results were compared with those in six matched healthy male volunteers. Insulin sensitivity was quantified by hyperinsulinemic euglycaemic clamp. Glucose production and uptake were assessed by tracer dilution employing 6,6D(2)-glucose.

RESULTS

At post-absorptive insulin concentrations, glucose production was 47% higher in HIV+LD than controls (P = 0.025). During clamp, glucose production was suppressed by 53% in HIV+LD, but by 85% in controls (P = 0.004). Glucose disposal increased in both groups, but by only 27% in HIV+LD versus 201% in controls (P = 0.004). Consequently, insulin-stimulated total glucose disposal was lower in HIV+LD patients (P = 0.006). Non-oxidative glucose disposal as percentage of total disposal did not differ significantly between groups (63% in HIV+LD and 62% in controls). Baseline plasma FFA concentrations were higher (0.60 versus 0.35 mmol/l; P = 0.024), whereas FFA decline during hyperinsulinemia was less (65 versus 85%; P = 0.01) in HIV+LD versus controls.

CONCLUSIONS

Post-absorptive glucose production is increased in HIV-1-infected patients with lipodystrophy. Moreover, both the ability of insulin to suppress endogenous glucose production and lipolysis, and to stimulate peripheral glucose uptake and its metabolic pathways is reduced, indicating severe resistance concerning multiple effects of insulin.

Long-term quality of life outcomes in three antiretroviral treatment strategies for HIV-1 infection

OBJECTIVE

To compare changes in quality of life (QoL) over 96 weeks in patients enrolled in a triple-therapy protocol, a treatment-intensification protocol, or an induction-maintenance therapy protocol, and to compare QoL between patients who continued and discontinued their antiretroviral regimen.

PATIENTS

Naive patients enrolled in a triple-therapy protocol (zidovudine/lamivudine or stavudine/didanosine or stavudine/lamivudine supplemented with protease inhibitor therapy of choice) (n = 35), a protocol of treatment intensification (ritonavir/saquinavir or ritonavir/saquinavir/stavudine) (n = 74) in which therapy was intensified with nucleoside analogue(s) in cases of insufficient viral suppression, and a protocol of induction (saquinavir/nelfinavir/lamivudine/ stavudine) maintenance (saquinavir/nelfinavir or stavudine/nelfinavir) therapy (n = 50).

MAIN OUTCOME MEASURE

Changes from baseline in QoL assessed by the Medical Outcomes Study HIV Health Survey at weeks 0, 12, 24, 36, 48, 72 and 96.

RESULTS

Patients in the triple-therapy and treatment-intensification protocols showed more favourable changes in physical function, social function, mental health, energy/fatigue, health distress and overall QoL compared to patients in the induction-maintenance protocol, with patients in the first two protocols showing improvements in QoL and those in the induction-maintenance protocol showing declining or unchanged QoL. Patients who discontinued study medication due to insufficient efficacy, toxicities or at their own request showed less favourable changes in QoL compared with patients who continued their regimen. The highest proportion of discontinuations was within the induction-maintenance protocol.

CONCLUSION

Antiretroviral treatment strategies that are effective and tolerable have the potential to improve patients' QoL over 96 weeks.

Penetration of the nucleoside analogue abacavir into the genital tract of men infected with human immunodeficiency virus type 1

The male genital tract is considered an anatomical reservoir during therapy for human immunodeficiency virus infection, because the blood-testis barrier may prevent antiretroviral drugs (e.g., the protease inhibitors ritonavir, saquinavir and nelfinavir) from entering the male genital tract. To our knowledge, there are currently no available data on the penetration of the nucleoside analogue abacavir into the male genital tract. Our report shows that abacavir has good penetration into the male genital tract.

Pharmacokinetic profiles of nevirapine and indinavir in various fractions of seminal plasma

Limited data are available on antiretroviral drug concentrations in seminal plasma during a dosing interval. Further, since human ejaculate is composed of fluids originating from the testes, the seminal vesicles, and the prostate, all having different physiological characteristics, drug concentrations in total seminal plasma do not necessarily reflect concentrations in the separate compartments. Five human immunodeficiency virus type 1-infected patients on nevirapine (NVP; 200 mg twice a day [b.i.d.]) and/or indinavir (IDV; 800 mg b.i.d. with ritonavir, 100 mg b.i.d.) regimens used a split ejaculate technique to separate seminal plasma in two fractions, representing fluids from the testes and prostate (first fraction) and fluids from the seminal vesicles (second fraction). Split-ejaculate samples were provided at 0, 2, 5, and 8 h after drug ingestion, on separate days after 3 days of sexual abstinence. NVP and IDV showed time-dependent concentrations in seminal plasma, with peak concentrations in both fractions at 2 and 2 to 5 h, respectively, after drug ingestion. The NVP concentrations were not significantly different between the first and second fractions of the ejaculate at all time points measured and were in the therapeutic range, except for the predose concentration in two patients. The median (range) predose IDV concentrations in the first and second fractions of the ejaculate were 448 (353 to 1,015) ng/ml and 527 (240 to 849) ng/ml, respectively (P = 0.7). In conclusion, NVP and IDV concentrations in seminal plasma are dependent on the time after drug ingestion. Furthermore, our data suggest that NVP and IDV achieve therapeutic concentrations in both the testes and prostate and the seminal vesicles throughout the dosing interval.

Limited patient adherence to highly active antiretroviral therapy for HIV-1 infection in an observational cohort study

BACKGROUND

Adherence to highly active antiretroviral therapy (HAART) for human immunodeficiency syndrome type 1 (HIV-1) infection is essential to sustain viral suppression and prevent drug resistance. We investigated adherence to HAART among patients in a clinical cohort study.

METHODS

Patients receiving HAART had their plasma concentrations of protease inhibitors or nevirapine measured and completed a questionnaire on adherence. We determined the percentage of patients who reported taking all antiretroviral medication on time and according to dietary instructions in the past week. Drug exposure was compared between patients reporting deviation from their regimen and fully adherent patients. Among patients who received HAART for at least 24 weeks, we assessed the association between adherence and virologic outcome.

RESULTS

A total of 224 of 261 eligible patients completed a questionnaire. Forty-seven percent reported taking all antiretroviral medication on time and according to dietary instructions. Patients who reported deviation from their regimen showed lower drug exposure compared with fully adherent patients (median concentration ratio, 0.81 vs 1.07; P =.001). Among those receiving HAART for at least 24 weeks, patients reporting deviation from their regimen were less likely to have plasma HIV-1 RNA levels below 500 copies/mL (adjusted odds ratio, 4.0; 95% confidence interval, 1.4-11.6) compared with fully adherent patients.

CONCLUSIONS

Only half of the patients took all antiretroviral medication in accordance with time and dietary instructions in the preceding week. Deviation from the antiretroviral regimen was associated with decreased drug exposure and a decreased likelihood of having suppressed plasma HIV-1 RNA loads. Patient adherence should remain a prime concern in the management of HIV-1 infection.

[HIV-1 therapy in the Netherlands; virological and immunological response to antiretroviral therapy]

OBJECTIVE

To evaluate the effect of treatment of HIV-1 infection with combination therapy consisting of since 1996 in the Netherlands available protease and reverse transcriptase inhibitors.

DESIGN

Prospective cohort study.

METHODS

In an observational clinical cohort of HIV-1-infected individuals, the short-term successful treatment end point of antiviral therapy including at least one antiretroviral drug licensed in the Netherlands since July 1, 1996 (protease inhibitors and reverse transcriptase inhibitors), was HIV-1 RNA plasma levels < or = 500 copies/ml (virological success). Cox proportional hazard models were used to identify prognostic markers for therapy success. The study included 2,148 infected individuals with a median follow-up of 135 weeks of treatment; 1,049 had been pre-treated with antiretroviral drugs before starting their new regimen and 1,099 were treatment naive.

RESULTS

Plasma HIV-1 RNA levels < or = 500 copies/ml at 24 weeks of treatment were seen in 61% of all patients. The chance of therapy success for naive patients was twice that for pre-treated patients (relative risk: 1.8; p < or = 0.001). Following the first 24 weeks, the chance of virological success was higher in the naive group (78% versus 63%; p < or = 0.001), and the number of naive patients failing therapy after initial success was smaller compared to pre-treated patients (22% versus 45%; p < or = 0.001). In the naive group, the CD4+ T-cell number increased from 239 to 440 (x 10(6) cells/l) in case of success, and decreased from 150 to 320 in case of treatment failure. HIV-1 related morbidity declined from 0.26 to 0.05 and mortality dropped from 0.07 to 0.03 per person-year of follow-up. Regimens were changed at least once in 76% of patients. Toxicity and therapy failure were the main reasons for regimen changes in naive and pre-treated patients, respectively.

CONCLUSION

A combination of antiretroviral drugs, including at least one of the drugs licensed since 1996, led to a drop in HIV-1 plasma concentrations. Morbidity and mortality also decreased. The chance of a better immunological and virological response to the new drug regimens was greatest in therapy-naive patients.

[CBO guidelines 'Antiretroviral therapy in the Netherlands']

In collaboration with the Dutch Institute for Health Care Improvement (CBO) and on the basis of recent developments, new guidelines have been developed for the diagnosis and treatment of HIV-infected patients. The most important recommendations are: Treatment of adult patients is indicated if HIV load > 30,000 RNA copies/ml, or when CD4+ cell count is < 350 x 10(6) cells/l. Treatment of children is indicated if HIV load > 5,000 copies/ml, even when CD4+ cell count is > 500 x 10(6) cells/l. Optimal antiretroviral treatment consists of a combination of two nucleoside reverse transcriptase inhibitors (NRTIs) and one protease inhibitor, or a combination of two NRTIs and one non-nucleoside reverse transcriptase inhibitor. Patients on antiretroviral treatment should be monitored every 3 months. Undetectable HIV load should be the target of first- or second-line antiretroviral treatment. In order to prevent HIV transmission from mother to child, prescription of antiretroviral drugs after the first three months of pregnancy is indicated in pregnant women with a detectable HIV load. Prophylaxis of opportunistic infections can be discontinued if CD4+ cell count recovers above 200 x 10(6)/l. In case of exposure to HIV due to a needle or other occupational accident or unsafe sexual contact, post-exposure prophylaxis should be offered after careful risk evaluation. Preferably, vaccination to prevent pneumococci infections, influenza, hepatitis A or hepatitis B should be given when CD4+ cell count is > 200 x 10(6)/l.

Steady-state pharmacokinetics of twice-daily dosing of saquinavir plus ritonavir in HIV-1-infected individuals

OBJECTIVE

To compare the steady state plasma pharmacokinetics of 1000 mg of saquinavir (SQV) in a soft-gel capsule (SGC) formulation in combination with 100 mg of ritonavir (RTV) (capsules) in a twice-daily dosing regimen in HIV-1-infected individuals with historical controls who used 400 mg of SQV in a hard-gel capsule (HGC) formulation in combination with 400 mg of RTV and to investigate the plasma pharmacokinetics of the 1000 mg/100 mg regimen after normal and high-fat breakfasts.

DESIGN

Open-label, crossover, steady-state pharmacokinetic study.

METHODS

Six HIV-1-infected individuals who used either 1200 mg of SQV (SGC or HGC) three times daily or 400 mg twice daily in combination with 400 mg of RTV twice daily were included. Each patient was switched to 1000 mg of SQV SGC twice daily in combination with 100 mg of RTV twice daily. After 14 days, the patients came to the hospital for assessment of a pharmacokinetic profile during 12 hours. Patients were randomized to receive a high-fat (+/-45 g of fat) or normal (+/-20 g of fat) breakfast. After 7 days, a second pharmacokinetic profile was assessed after ingestion of the drugs with the alternate breakfast. A noncompartmental pharmacokinetic method was used to calculate the area under the plasma concentration versus time curve (AUC0-12h), the maximum plasma concentration (Cmax), the plasma trough concentration (C12h), and the elimination half-life in plasma (t1/2). The obtained pharmacokinetic parameters were compared with those of 12 patients using SQV HGC (400 mg twice daily) in combination with RTV (400 mg twice daily).

RESULTS

The median values of the pharmacokinetic parameters for SQV SGC (1000 mg twice daily, normal breakfast) were: AUC0-12h, 18.84 h*mg/L; Cmax, 3.66 mg/L; C12h, 0.40 mg/L; and t1/2, 3.0 hours. The median values of the pharmacokinetic parameters for SQV HGC (400 mg twice daily, normal breakfast) were: AUC0-12h, 6.99 h*mg/L; Cmax, 1.28 mg/L; C12h, 0.23 mg/L; and t1/2, 3.9 hours. The exposure to SQV in the dosing regimen of 1000 mg twice daily in combination with 100 mg of RTV twice daily was significantly higher than the exposure to SQV in a dosing regimen of 400 mg twice daily in combination with 400 mg of RTV twice daily. The pharmacokinetic parameters of SQV SGC in the dosing regimen of 1000 mg twice daily in combination with 100 mg of RTV twice daily were not significantly different after ingestion of a high-fat or normal breakfast (p >.35).

CONCLUSIONS

The combination of 1000 mg of SQV SGC twice daily and 100 mg of RTV twice daily resulted in a higher exposure to SQV compared with the exposure to SQV obtained when SQV is used in the 400 mg/400 mg twice-daily combination with RTV. In this small number of patients, no significant differences in exposure were seen after ingestion of either a normal or high-fat breakfast. From a pharmacokinetic perspective, the combination of 1000 mg of SQV SGC twice daily and 100 mg of RTV twice daily seems to be a good option for further clinical evaluation.

Development of drug resistance in patients receiving combinations of zidovudine, didanosine and nevirapine

OBJECTIVE

To evaluate the development of phenotypic and genotypic resistance to zidovudine, didanosine and nevirapine as a function of the virologic response to therapy in a group of drug-naive individuals receiving various combinations of these agents.

DESIGN

All patients were enrolled in a double-blind controlled randomized trial (the INCAS study) and were selected for detailed resistance studies based on specimen availability and virologic response.

METHODS

Within the three study groups (zidovudine/nevirapine, zidovudine/didanosine or zidovudine/nevirapine/didanosine), 16, 19 and 24 patients, respectively, had evaluable baseline isolates and remained in the study > 24 weeks. Phenotypic resistance to all three drugs was evaluated using the VIRCO recombinant virus assay. Genotypic sequencing was done on selected specimens from patients receiving zidovudine/nevirapine/didanosine.

RESULTS

After 24 weeks, all available isolates taken from patients receiving nevirapine were resistant to this agent, while 18/21 (86%) patients receiving triple therapy carried such isolates at 30--60 weeks. At 24 weeks, zidovudine resistance developed in 4/40 isolates but was more frequent after 30--60 weeks, especially in patients on two drugs. The degree of zidovudine resistance (rise in concentration required for 50% inhibition) appeared lower in the triple therapy group compared with zidovudine/didanosine (P = 0.0004). All nevirapine-resistant isolates that were sequenced carried at least one mutation associated with resistance, most often K103N and/or Y181C.

CONCLUSION

The use of highly active drug therapies may be associated with a beneficial effect on the development of antiretroviral drug resistance. The characteristics of virologic suppression that must be maintained to avoid resistance are currently being studied in hypothesis-driven clinical trials.

The steady-state pharmacokinetics of efavirenz and nevirapine when used in combination in human immunodeficiency virus type 1-infected persons

The steady-state pharmacokinetics of efavirenz and nevirapine, when used in combination to treat human immunodeficiency virus type 1 (HIV-1)-infected subjects, were investigated. HIV-1-infected persons who had used efavirenz (600 mg once daily) for > or =2 weeks were eligible for study inclusion. The plasma pharmacokinetics of efavirenz were determined over 24 h. Subsequently, nevirapine (400 mg once daily) was added to the regimen. After 4 weeks, the pharmacokinetics of efavirenz and nevirapine were assessed over 24 h. The differences between the pharmacokinetic parameters of efavirenz with and without nevirapine were analyzed, and the pharmacokinetics of nevirapine were compared with those in historical control patients. The exposure to efavirenz when combined with nevirapine was significantly decreased by 22% (area under the plasma concentration vs. time curve), 36% (minimum plasma concentration), and 17% (maximum plasma concentration). Nevirapine pharmacokinetics appear to be unaffected by coadministration of efavirenz, compared with data from historical control patients.

T cell expansions in lymph nodes and peripheral blood in HIV-1-infected individuals: effect of antiretroviral therapy

OBJECTIVE

To evaluate dynamics in CD8 T cell expansions during highly active antiretroviral therapy (HAART).

DESIGN

Various T cell subsets were isolated from blood and lymph nodes and analysed for T cell receptor (TCR) diversity.

METHODS

TCR complementarity determining region 3 (CDR3) spectratyping and single-strand conformation polymorphism (SSCP) analyses were performed in combination with sequencing to assess clonality of the subsets.

RESULTS

Strongly skewed CDR3 patterns in total CD8 cells and the CD8 subsets CD45RO+CD27+ and CD45RO-CD27+ showed substantial dynamics in dominant CDR3 sizes, resulting in relative improvement of CDR3 size diversity in the first months of therapy. During sustained treatment, TCR diversity changed only moderately. SSCP profiles confirmed oligoclonality of TCR CDR3 perturbations. Various dominant CDR3 sizes for CD4 and CD8 T cells present in lymph nodes, but not in peripheral blood mononuclear cells, before the start of therapy emerged in peripheral blood early during therapy.

CONCLUSIONS

HAART induces substantial changes in CD8 TCR diversity, eventually resulting in improvement of the repertoire. Clonal expansions observed in lymph nodes before therapy were observed in peripheral blood after therapy, suggesting that recirculation of CD4 and CD8 T cells from lymph nodes contributes to the early T cell repopulation. Decreased immune activation and possibly naive T cell regeneration subsequently decreased clonal expansions and perturbations in the CD8 TCR repertoire.

High exposure to nevirapine in plasma is associated with an improved virological response in HIV-1-infected individuals

OBJECTIVE

To explore relationships between exposure to nevirapine and the virological response in HIV-1-infected individuals participating in the INCAS trial.

METHODS

The elimination rate constant of plasma HIV-1 RNA (k) was calculated during the first 2 weeks of treatment with nevirapine, zidovudine and didanosine in 51 antiretroviral-naive HIV-1-infected patients. The relationships between the value of k, the time to reach an undetectable HIV-1 RNA concentration in plasma (< 20 copies/ml) and the success of therapy after 52 weeks of treatment as dependent variables and the exposure to nevirapine, baseline HIV-1 RNA and baseline CD4 cell count as independent variables, were explored using linear regression analyses, proportional hazard models and logistic analyses, respectively.

RESULTS

The value of k for HIV-1 RNA in plasma was positively and significantly associated with the mean plasma nevirapine concentration during the first 2 weeks of therapy (P = 0.011) and the baseline HIV-1 RNA (P = 0.008). Patients with a higher exposure to nevirapine reached undetectable levels of HIV-1 RNA in plasma more rapidly (P = 0.03). From 12 weeks on, the median nevirapine plasma concentration was significantly correlated with success of therapy after 52 weeks (P < 0.02).

CONCLUSIONS

A high exposure to nevirapine (in a twice daily regimen) is significantly associated with improved virological response in the short as well as in the long term. These findings suggest that optimization of nevirapine concentration might be used as a tool to improve virological outcome in (antiretroviral-naive) patients treated with nevirapine.

Saliva as an Alternative Body Fluid for Therapeutic Drug Monitoring of the Nonnucleoside Reverse Transcription Inhibitor Nevirapine

The objective of this study was to evaluate the applicability of saliva as an alternative body fluid for therapeutic drug monitoring of nevirapine. The pharmacokinetics of nevirapine in plasma and saliva during a dosing interval was assessed in HIV-1-infected patients taking nevirapine (200 mg twice daily) to explore the relation between the concentration of nevirapine in plasma and saliva. To validate the anticipated relationship prospectively, single, paired plasma and saliva samples were obtained from nevirapine-treated HIV-1-infected outpatients. The plasma nevirapine concentration was strongly correlated with the salivary concentration. The mean saliva/plasma concentration ratio was 0.51 and was independent of the time after ingestion. Salivary nevirapine concentrations were used to estimate the corresponding plasma concentrations for 31 outpatients. Compared with the true plasma concentrations, the estimated concentrations were biased by -4.2%, with a precision of 13.3%. These data show a strong correlation between the salivary and plasma concentrations of nevirapine at a dosage of 200 mg twice daily. This relation has been validated prospectively, and the prediction of plasma concentrations was accurate and precise. Therefore, the authors conclude that saliva can be a useful body fluid for therapeutic drug monitoring of nevirapine.

A randomized, open-label, comparative trial of zidovudine plus lamivudine versus zidovudine plus lamivudine plus didanosine in antiretroviral-naive HIV-1-infected Thai patients

OBJECTIVE

To assess the efficacy and tolerability of a triple nucleoside reverse transcriptase inhibitor combination of zidovudine, lamivudine, and didanosine therapy.

DESIGN

A randomized open-label trial.

PATIENTS

Antiretroviral-naive HIV-infected patients with CD4+ cell counts of 100 to 500 cells/microl.

METHODS

A total of 106 patients were randomly assigned to 300 mg of zidovudine (200 mg for body weight <60 kg) twice daily plus 150 mg of lamivudine twice daily plus 200 mg of didanosine (125 mg for body weight <60 kg) twice daily (n = 53) or to zidovudine plus lamivudine (n = 53) for 48 weeks.

MAIN OUTCOME MEASURES

Degree and duration of reduction of HIV-1 RNA load and increase in CD4+ cell counts from baseline and development of drug-related toxicities.

RESULTS

At 48 weeks, triple drug therapy showed greater declines in plasma HIV-RNA levels from the beginning of treatment than double drug therapy (1.86 vs. 1.15 log10 copies/ml, respectively; p <.001). The proportions of patients with HIV-RNA <50 copies/ml in an intention-to-treat analysis were 54.7% (29 of 53 patients) and 11.3% (6 of 53 patients) in the triple and double drug therapy, respectively (p =.001). There was no significant difference in increase of CD4 count.

CONCLUSION

Triple drug therapy with zidovudine, lamivudine, and didanosine was significantly more effective in inducing sustained immunologic and virologic responses than the double combination of zidovudine and lamivudine.

OKT3 and IL-2 treatment for purging of the latent HIV-1 reservoir in vivo results in selective long-lasting CD4+ T cell depletion

Activation of resting T cells has been proposed to purge the reservoir of HIV-1-infected resting CD4+ T cells. We therefore treated three HIV-1-infected patients on antiretroviral therapy with OKT3, a CD3 monoclonal antibody, and recombinant human IL-2. Here we report the profound and partially long-lasting host responses induced by the OKT3 and IL-2 treatment. OKT3/IL-2 induced a strong but transient release of plasma cytokines and chemokines. The percentage CD4+ and CD8+ cells in the blood expressing the activation marker CD38 transiently increased to almost 100%, and in lymph nodes we "observed" a 10-fold increase in the number of dividing Ki67+ cells and increased numbers of apoptotic cells. Following OKT3/IL-2 treatment, a long-lasting depletion of CD4+ cells in the peripheral blood and lymph nodes occurred, suggesting the physical deletion of these cells. Increases in CD4+T cell numbers during the two year followup period were due mainly to increased memory cell numbers. CD8+ cells were also depleted in the blood, but less severely in lymph nodes, and returned to baseline levels within several weeks.

Concentrations of human immunodeficiency virus type 1 (HIV-1) RNA in cerebrospinal fluid after antiretroviral treatment initiated during primary HIV-1 infection

In 6 patients with primary human immunodeficiency virus type 1 (HIV-1) infection, concentrations of HIV-1 RNA and beta(2)-microglobulin were monitored in cerebrospinal fluid (CSF) and in plasma during antiretroviral therapy. Four patients had neurological symptoms. At baseline, the CSF of 5 patients had detectable levels of HIV-1 RNA (median, 3.68 log(10) copies/mL; range, <2.60-5.67 log(10) copies/mL), and the CSF of 3 patients had elevated levels of beta(2)-microglobulin. After 8 weeks of treatment, the median concentrations of HIV-1 RNA in CSF had decreased to <2.60 log(10) copies/mL (range, <1.60-3.00 log(10) copies/mL; P=.04) and in plasma to 3.07 log(10) copies/mL (range, 2.57-3.79 log(10) copies/mL; P=.03). Median concentration of beta(2)-microglobulin in CSF had decreased to 1.2 mg/L (range, 0.9-1.7 mg/L; P=.06) and, in plasma, to 1.7 mg/L (range, 1.1-2.2 mg/L; P=.03). After 48 weeks, HIV-1 RNA concentrations in 1 patient were still 1.97 log(10) copies/mL in CSF and 1.51 log(10) copies/mL in plasma, although beta(2)-microglobulin concentrations in CSF and plasma had normalized after 8 weeks.

A retrospective, cohort-based survey of patients using twice-daily indinavir + ritonavir combinations: pharmacokinetics, safety, and efficacy

OBJECTIVE

To describe the pharmacokinetics, safety, and efficacy of twice-daily indinavir + ritonavir regimens

DESIGN

A cohort-based survey of HIV-infected patients who either used indinavir 800 mg + ritonavir 100 mg twice daily or indinavir 400 mg + ritonavir 400 mg twice daily.

METHODS

Data were extracted from a database of samples sent to our laboratory for measurement of indinavir + ritonavir plasma concentrations. Patient characteristics, safety, and efficacy measurements were collected by retrospective chart review.

RESULTS

100 Patients using 800-mg indinavir + 100-mg ritonavir twice daily and 32 patients using 400-mg indinavir + 400-mg ritonavir twice daily were eligible. Median peak and trough concentrations of indinavir were 6.8 and 0.77 mg/L in the 800/100 group and 2.6 and 0.45 mg/L in the 400/400 group. The most frequently found side effects were nausea and vomiting, which occurred in 22.1% and 34.9% of the patients in the 800/100 and the 400/400 groups, respectively. Viral load data were analyzed for patients who switched from 800-mg indinavir three times daily to one of the indinavir + ritonavir twice daily regimens. At the time of switch 63% (800/100 group) and 60% (400/400 group) had an undetectable viral load and this increased to 77% and 70%, respectively, during follow-up. Patients who switched to the 400/400 group discontinued treatment more frequently than patients who switched to the 800/100 group (70% vs. 26%, p =.008).

CONCLUSIONS

Indinavir + ritonavir regimens show improved pharmacokinetic properties, allowing twice-daily dosing with food. Clinical data suggest that safety and efficacy is at least as good as with indinavir three-times-daily regimens without ritonavir. Prospective, comparative trials are needed to properly assess the role in HIV therapy of these twice-daily indinavir + ritonavir regimens.

Durable HIV-1 suppression with indinavir after failing lamivudine-containing double nucleoside therapy: a randomized controlled trial

OBJECTIVE

To assess the durability of the antiretroviral effect in plasma and cerebrospinal fluid (CSF) of antiviral therapy intensification, produced by the addition of indinavir from week 12 onwards to the original regimen of zidovudine/lamivudine or stavudine/lamivudine, after 72 weeks of follow-up using an ultrasensitive HIV-1 RNA assay. To assess CSF concentrations of indinavir at week 48.

DESIGN

In a prospectively, randomized, open, single-centre study, antiretroviral-naive patients (CD4 cell count > or =200 cells/microl and a plasma HIV-1 RNA level 10,000 copies/ml) were assigned to a combination of zidovudine/lamivudine or stavudine/lamivudine. Indinavir could be added to the double nucleoside analogue regimen from week 12 or thereafter in case the plasma HIV RNA level was insufficiently suppressed (>500 copies/ml).

RESULTS

Forty-seven patients were enrolled (23 stavudine/lamivudine and 24 zidovudine/lamivudine), of whom 33 completed a follow-up of 72 weeks. Indinavir was added in 89% (42/47) of the patients. Only one discontinuation occurred due to virological failure. At week 72, the median plasma HIV-1 RNA levels in the zidovudine/lamivudine group had decreased from 4.80 log10 copies/ml to <500 copies/ml in 100% of patients and <50 copies/ml in 86.6% of the patients. In the stavudine/lamivudine group the plasma HIV-1 RNA decreased from 4.98 log10 copies/ml at baseline to <500 copies/ml in 100% of patients and <50 copies/ml in 66.7% of the patients. On an intent-to-treat basis these figures were 54.2 and 52.2% for zidovudine/lamivudine and stavudine/lamivudine, respectively, for the 50 copies/ml assay. The median CD4 cell count increased from 315 cells/microl, with 150 cells/microl in the zidovudine/lamivudine arm, and from 290 cells/microl, with 310 cells/microl in the stavudine/lamivudine arm (P=0.0001). However, the percentage of CD4 cells did not differ in each group. In the zidovudine/lamivudine group 9/10 and 5/5, and in the stavudine/lamivudine group 11/11 and 6/6 had a CSF HIV-1 RNA level <50 copies/ml at week 12 and 48, respectively. The CSF indinavir concentration ranged from 50 to 170 ng/ml.

CONCLUSION

The long-term HIV-1 suppression observed in this study is remarkable, as adding a single antiretroviral agent to a failing regimen goes against current notions of adequate therapy.

Durable HIV-1 Suppression with Indinavir after Failing Lamivudine-Containing Double Nucleoside Therapy: A Randomized Controlled Trial

Objective

To assess the durability of the antiretroviral effect in plasma and cerebrospinal fluid (CSF) of antiviral therapy intensification, produced by the addition of indinavir from week 12 onwards to the original regimen of zidovudine/lamivudine or stavudine/lamivudine, after 72 weeks of follow-up using an ultrasensitive HIV-1 RNA assay. To assess CSF concentrations of indinavir at week 48.

Design

In a prospectively, randomized, open, single-centre study, antiretroviral-naive patients (CD4 cell count ≥200 cells/μl and a plasma HIV-1 RNA level ≥10000 copies/ml) were assigned to a combination of zidovudine/lamivudine or stavudine/lamivudine. Indinavir could be added to the double nucleoside analogue regimen from week 12 or thereafter in case the plasma HIV RNA level was insufficiently suppressed (>500 copies/ml).

Results

Forty-seven patients were enrolled (23 stavudine/lamivudine and 24 zidovudine/lamivudine), of whom 33 completed a follow-up of 72 weeks. Indinavir was added in 89% (42/47) of the patients. Only one discontinuation occurred due to virological failure. At week 72, the median plasma HIV-1 RNA levels in the zidovudine/lamivudine group had decreased from 4.80 log10 copies/ml to <500 copies/ml in 100% of patients and <50 copies/ml in 86.6% of the patients. In the stavudine/lamivudine group the plasma HIV-1 RNA decreased from 4.98 log10 copies/ml at baseline to <500 copies/ml in 100% of patients and <50 copies/ml in 66.7% of the patients. On an intent-to-treat basis these figures were 54.2 and 52.2% for zidovudine/lamivudine and stavudine/lamivudine, respectively, for the 50 copies/ml assay. The median CD4 cell count increased from 315 cells/μl, with 150 cells/μl in the zidovudine/lamivudine arm, and from 290 cells/μl, with 310 cells/μl in the stavudine/lamivudine arm ( P=0.0001). However, the percentage of CD4 cells did not differ in each group. In the zidovudine/lamivudine group 9/10 and 5/5, and in the stavudine/lamivudine group 11/11 and 6/6 had a CSF HIV-1 RNA level <50 copies/ml at week 12 and 48, respectively. The CSF indinavir concentration ranged from 50 to 170 ng/ml.

Conclusion

The long-term HIV-1 suppression observed in this study is remarkable, as adding a single antiretroviral agent to a failing regimen goes against current notions of adequate therapy.

Hepatitis B and C virus co-infection and the risk for hepatotoxicity of highly active antiretroviral therapy in HIV-1 infection

OBJECTIVE

To investigate the risk of hepatotoxicity after initiation of protease inhibitor-containing highly active antiretroviral therapy (HAART) for HIV-1 infected patients with chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) co-infection.

DESIGN

Retrospective study with 394 HIV-1-infected patients initiating HAART at a single university clinic.

METHODS

Liver enzyme elevation (LEE) was defined as alanine aminotransferase or aspartate aminotransferase at least five times the upper limit of normal and an absolute increase of > 100 U/l. Relative risks for time to LEE were estimated using Cox proportional hazards models.

RESULTS

Of 394 patients 7% were hepatitis B surface antigen (HBsAg)-positive and 14% were anti-HCV-positive. Patients with chronic hepatitis had a higher risk for LEE compared with patients without co-infection: 37% versus 12% respectively. After adjustment for higher baseline transaminases, the presence of HBsAg or anti-HCV remained associated with an increased risk of LEE - relative risk 2.78 (95% confidence interval, 1.50-5.16) and 2.46 (95% confidence interval, 1.43-4.24) respectively. In patients with LEE, transaminases declined whether HAART was continued or modified. Of patients with chronic HBV infection 38% lost HBeAg or developed anti-HBe after initiation of HAART, and one seroconverted from HBsAg-positive to anti-HBs-positive. However, there was no clear relationship with LEE.

CONCLUSIONS

HIV-1-infected patients co-infected with HBV or HCV were at considerably higher risk of developing LEE when HAART was initiated compared with patients without co-infection, but it is usually not necessary to modify antiretroviral therapy.

Slower decline of plasma HIV-1 RNA following highly suppressive antiretroviral therapy in primary compared with chronic infection

OBJECTIVES

To study the effect of highly suppressive antiretroviral therapy on the slopes of HIV-1 RNA decline in primary compared with chronic HIV-1 infection.

METHODS

Slopes of HIV-1 RNA decline in plasma were compared before and after the start of highly suppressive antiretroviral therapy from five acutely infected patients who started treatment 2 to 5 weeks following the onset of clinical symptoms. Slopes of decline after the initiation of therapy were also compared with those found in 12 chronically infected individuals on the same therapy. Numbers and percentages of activated CD4 and CD8 T cells at baseline were compared as well.

RESULTS

The pre-treatment slopes of HIV-1 RNA decline in the acutely infected individuals increased significantly (P = 0.0001) after the start of anti-retroviral therapy. However, these post-treatment slopes were lower than those found in the chronically infected individuals (P= 0.012). Slopes were inversely correlated (P= 0.012) with baseline HIV-1 RNA. Although the number of CD38+HLA-DR+ CD4 cells was higher in primary infection (P= 0.02), the percentage did not differ between primary and chronic infection.

CONCLUSIONS

These findings indicate that antiretroviral therapy contributes significantly to the clearance of HIV-1 during primary infection. Based on the mathematical model the less steep RNA slope following the start of treatment in primary infection can be predicted to be the result of lower clearance of productively infected cells and higher burst size per cell per unit time. This may indicate a growing immune response to HIV-1 in this very early stage of infection.

Increasing cerebrospinal fluid chemokine concentrations despite undetectable cerebrospinal fluid HIV RNA in HIV-1-infected patients receiving antiretroviral therapy

Only limited data on cerebrospinal fluid (CSF) HIV-1 RNA responses and markers of local inflammation in CSF during antiretroviral therapy are available. HIV-RNA, soluble tumor necrosis factor (TNF)-receptor (sTNFr)-II, monocyte chemoattractant protein (MCP)-1, and interferon-gamma-inducible protein (IP)-10 were measured in the peripheral blood and CSF of 26 antiretroviral-naive HIV-1-positive patients, who were treated with ritonavir (RTV)/saquinavir (SQV) (n = 5), RTV/SQV/stavudine (d4T; n = 8) or zidovudine (AZT)/lamivudine (3TC)/abacavir/nevirapine/indinavir (n = 13). After 8 to 12 weeks of treatment, CSF HIV-RNA dropped to <400 copies/ml in 1 of 5 patients in the RTV/SQV group, 8 of 8 patients in the RTV/SQV/d4T group, and 9 of 10 patients in the five-drug group. CSF sTNFr-II and IP-10 levels increased in patients with detectable CSF HIV-RNA. However, increases in CSF chemokine and sTNFr-II concentrations were also observed in some patients with good CSF HIV-RNA responses. Moreover, CSF MCP-1 concentrations increased in the whole population after 2 months of treatment. Ongoing residual HIV replication in the central nervous system, which cannot be detected with CSF HIV-RNA measurements, may account for this phenomenon.