[Characteristics of antiretroviral drugs]

As of November 2010, a total of 22 antiretroviral agents are marketed in Spain. These agents are divided into 6 classes according to their mechanism of action: 1) nucleos(t)ide reverse transcriptase inhibitors (NRTI) (abacavir, didanosine, emtricitabine, stavudine, lamivudine, zidovudine, and tenofovir), 2) non-nucleoside reverse transcriptase inhibitors (NNRTI) (efavirenz, etravirine, and nevirapine), 3) protease inhibitors (PI) (atazanavir, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, ritonavir, saquinavir, tipranavir), 4) entry inhibitors (enfuvirtide), 5) coreceptor CCR5 inhibitors (maraviroc), and 6) integrase inhibitors (raltegravir). All 22 agents are indicated for the treatment of HIV-1 infection in combination with other antiretroviral drugs. Most have also proven to be active against HIV-2 (except the NNRTIs, enfuvirtide, and maraviroc) and some are active against hepatitis B virus (lamivudine, emtricitabine, and tenofovir). The present article reviews the main characteristics of the different antiretroviral agents and classes, namely, commercial presentations, paediatric and adult dosages, dose adjustments in renal and hepatic insufficiency, pharmacokinetics and interactions, mechanism of action, treatment indications, resistance, adverse effects, and safety during pregnancy and breastfeeding. Some of the characteristics of antiretrovirals are class-specific and common to other agents of the same class, and others are individual and different from those of other drugs in the same class. Knowledge of these characteristics enables us to prepare efficacious therapeutic regimens according to the specific requirements of the patient (tolerability, simplicity, adaptability to lifestyle) and clinical setting (naive, simplification, rescue, resistance).

Late initiation of HAART among HIV-infected patients in Spain is frequent and related to a higher rate of virological failure but not to immigrant status

PURPOSE

To determine whether immigrant status is associated with late initiation of highly active antiretroviral treatment (HAART) and/or poor response to antiretrovirals.

METHODS

GESIDA 5808 is a multicenter, retrospective cohort study (inclusion period January 2005 through December 2006) of treatment-naïve patients initiating HAART that compares HIV-infected patients who are immigrants with Spanish-born patients. A late starter (LS) was defined as any patient starting HAART with a CD4+ lymphocyte count <200 cells/μL and/or diagnosis of an AIDS-defining illness before or at the start of therapy. The primary endpoint was time to treatment failure (TTF), defined as virological failure (VF), death, opportunistic infection, treatment discontinuation/switch (D/S), or missing patient. Secondary endpoints were time to treatment failure as observed data (TTO; censoring missing patients) and time to virological failure (TVF; censoring missing patients and D/S not due to VF).

RESULTS

LS accounted for 56% of the patients. Lower educational and socioeconomic level and intravenous drug use (IVDU) were associated with categorization as LS, but immigrant status was not. Cox regression analysis (hazard ratio [HR]; 95% CI) between LS and non-LS patients showed no differences in TTF (0.97; 0.78-1.20) or TTO (1.18; 0.88-1.58), although it did reveal a difference in TVF (1.97; 1.18-3.29). CD4+ lymphocyte recovery was equivalent for both LS and non-LS patients (159 vs 173).

CONCLUSIONS

In our cohort, immigrant status was not shown to be related to late initiation of HAART. Although LS patients did not have a longer TTF for any reason, TVF was significantly shorter. Despite universal free access to HAART in Spain, measures to ensure early diagnosis and treatment of HIV infection are necessary.

From old to new nucleoside reverse transcriptase inhibitors: changes in body fat composition, metabolic parameters and mitochondrial toxicity after the switch from thymidine analogs to tenofovir or abacavir

INTRODUCTION

Thymidine analogs zidovudine (AZT) and stavudine (d4T) have been widely used because of their antiviral activity against HIV, but at the expense of high toxicity, mainly related to mitochondrial damage. Many studies have been performed replacing AZT or d4T with newer nucleoside analogs reverse transcriptase inhibitors (NRTIs) with less toxicity, such as tenofovir (TDF) or abacavir (ABC), maintaining virological efficacy.

AREAS COVERED

Relevant literature was identified using a PubMed search of articles published up to June 2010. Search terms included: 'thymidine analogs', 'stavudine', 'zidovudine', 'd4T', 'AZT', 'ZDV', 'treatment switch'. Original articles in which d4T or AZT had been replaced by TDF or ABC as switch strategies (with undetectable viral load) were reviewed where information about body fat distribution, mitochondrial functionality and/or plasma lipid parameters were available. Relevant references from these articles were also considered. Only studies performed in adult patients (18 years or older) are included. The readers will gain a better understanding of the toxicity caused by thymidine analogs, the treatment alternatives and the benefits observed after treatment switch to newer NRTIs.

EXPERT OPINION

Thymidine analogs AZT and d4T yield considerable toxicity and proactive switch to newer NRTIs such as TDF or ABC is necessary in order to avoid or partially reverse such side effects.

Acute meningoencephalitis due to human immunodeficiency virus type 1 infection in 13 patients: clinical description and follow-up

The objective of this study is to describe a series of cases of severe meningitis caused by human immunodeficiency virus type 1 (HIV-1) occurring during primary infection or after antiretroviral treatment interruption. In an observational cohort study, 13 patients with clinical diagnosis of meningitis or meningoencephalitis were reviewed. Ten cases occurred during primary HIV-1 infection and 3 after antiretroviral therapy (ART) withdrawal. Demographic parameters, clinical presentation and outcome, and laboratory and cerebrospinal fluid (CSF) parameters were recorded. The risk factor for HIV-1 infection acquisition was sexual transmission in all cases. The most frequent systemic symptoms were fever (12/13) and headeache (9/13). Among neurologic symptoms, focal signs appeared in seven patients (53.8%), confusion in six (46.2%), and agitation in five (38.5%). The median CD4 cell count was 434 cells/mm3. In all cases, CSF was a clear lymphocytaire fluid with normal glucose levels. Cranial computerized tomography was performed in seven patients, with a normal result in all of them; brain magnetic resonance in eight patients was normal in five cases and showing cortical atrophy, limbic encephalitis, and leptomeningeal enhancement in one patient each. The electroencephalographs (EEG) just showed diffuse dysfunction in three cases. ART was started in 11 patients. HIV RNA load at 12 months was <50 copies/ml in all treated patients. The 13 patients recovered without neurologic sequela. Meningitis or meningoencephalitis during primary HIV-1 infection or after ART cessation are unusual but sometimes a life-threatening manifestation. Although all patients tend to recover and the necessity of ART is not well established, some data suggest its potential benefit in these patients.

Immune reconstitution in severely immunosuppressed antiretroviral-naive HIV type 1-infected patients using a nonnucleoside reverse transcriptase inhibitor-based or a boosted protease inhibitor-based antiretroviral regimen: three-year results (The Advanz Trial): a randomized, controlled trial

Late diagnosis of HIV-1 infection is quite frequent in Western countries. Very few randomized clinical trials to determine the best antiretroviral treatment in patients with advanced HIV-1 infection have been performed. To compare immune reconstitution in two groups of very immunosuppressed (less than 100 CD4(+) cells/microl), antiretroviral-naive HIV-1-infected adults, 65 patients were randomly assigned in a 1:1 ratio to receive zidovudine + lamivudine + efavirenz (group A, 34 patients) or zidovudine + lamivudine + ritonavir-boosted indinavir (group B, 31 patients). The median (interquartile range) CD4(+) cell increase after 12 and 36 months was +199 (101, 258) and +299 (170, 464) cells/microl in the efavirenz arm and +136 (57, 235) and +228 (119, 465) cells/microl in the ritonavir-boosted indinavir arm (p > 0.05 for all time points). The proportion (95% confidence interval) of patients achieving HIV-1 RNA levels under 50 copies/ml was significantly greater in the efavirenz arm at 3 years by the intention-to-treat analysis [59% (41%, 75%) vs. 23% (10%, 41%)], whereas no differences were found in the on-treatment analysis. Immune activation (CD8(+)CD38(+) and CD8(+)CD38DR(+) T cells) was significantly lower for the efavirenz arm from month 6 to month 24. Adverse events were more frequent in the ritonavir-boosted indinavir arm. Almost all cases of disease progression and death were observed in the first year of treatment, with no significant differences between the two arms (p = 0.79 by the log-rank test). At 1 and 3 years, the immune reconstitution induced by an efavirenz-based regimen in very immunosuppressed patients was at least as potent as that induced by a ritonavir-boosted protease inhibitor-based antiretroviral regimen.

The future of antiretroviral therapy: challenges and needs

The introduction of combination antiretroviral therapy (cART) has substantially modified the natural history of HIV infection. At the beginning of the cART era the objective was focused on HIV-1-associated mortality and morbidity, but as this objective was accomplished other issues emerged, including toxicity, resistance and compliance with treatment. Moreover, the participation of other disease mechanisms, such as proinflammatory activity, in the so-called non-AIDS events is becoming increasingly important. To overcome these issues, therapeutic options have dramatically expanded, which has made the management of HIV-1-infected patients increasingly complex. The intense changes seen raise the question of what will be the future of HIV infection and its treatment. A projection into the future may help to reflect on current limitations, needs and research priorities, to optimize patient care. To debate on this topic a group of 38 experts has initiated The HIV 2020 Project, with the aim of reflecting on the future of HIV infection and identifying the needs that should be the attention of research in different areas. This document summarizes the group's conclusions on the future of antiretroviral treatment, presented as 20 relevant questions. Each question includes the current status of the topic and our vision for the future.

HIV-1 infection in subjects older than 70: a multicenter cross-sectional assessment in Catalonia, Spain

We designed a multicenter cross-sectional study to describe the epidemiological characteristics of the HIV-1-infected population aged 70 years or more in our setting. 179 individuals from eight university hospitals in Barcelona, Spain, were included, representing 1.5% of HIV-1 infected subjects followed during 2008. Most subjects were male (76%) and had acquired HIV infection through sexual intercourse (87%); 69% had been diagnosed with HIV-1 after their sixties. The CD4 cell counts at HIV-1 diagnosis were < 200 cells/mm(3) in 52% of individuals, whereas this was only seen in 34% of subjects from a published cohort including younger HIV- infected adults from the same setting [1]. Most of our patients were on HAART, had undetectable HIV-1 viremia and the most recent median CD4 cell counts were >or= 350 cells/mm(3). 154 subjects had at least one comorbid condition, including dyslipidemia (54%), hypertension (36%), hyperglycemia or diabetes (30%), cardiovascular disease (23%), chronic renal failure (18%), history of neoplasia (17%) and cognitive impairment (11%). Lipodystrophy was reported in 58% of individuals. Rates of hypercholesterolemia, diabetes and cancer were higher than those reported in unselected local population (28%, 17% and 7%, respectively). The study participants were taking an average of 2.97 drugs (range 1-10) other than antiretrovirals. In conclusion, the elder population infected with HIV-1 is likely being diagnosed late and at lower CD4+ counts and is frequently affected by comorbidities and co-medication. Based on our findings, we suggest some recommendations regarding the management of this growing population.

Characteristics and outcome of HIV infection in gypsies in the Spanish VACH Cohort

OBJECTIVE

To study the characteristics of HIV infection in the gypsy (Roma) population in Spain, as compared with those of the Caucasian, non-gypsy majority.

DESIGN

Cross-sectional, historical cohort study from the Spanish VACH Cohort.

METHODS

Patients attending VACH clinics between 1 June 2004 and 30 November 2004 were classified according to their racial and ethnic origin as "gypsies", Caucasian non-gypsy Spanish natives (CNGN), and "other" (the last being excluded from this study). Their sociodemographic and clinico-epidemiological characteristics were compared, as well as the Kaplan-Meier curves of time to AIDS, or death, or disease progression (either of the 2 outcomes).

RESULTS

4819 (48%) of 10,032 cases included in the VACH database were eligible: 210 (4.2%) were gypsies and 4252 (84.8%) were CNGN. Differences were observed in age, household, academic, inmate, marital, and employment history. Injecting drug use had been the most frequent mechanism of transmission in both groups, but to a greater extent among gypsies (72% versus 50%; P<0.000). Sex distribution, CD4 cell counts, and viral loads at the first visit were similar in the 2 groups, as was the percentage of patients with previous AIDS, percentage receiving antiretrovirals, and percentage subsequently starting antiretroviral therapy. Up to 1 April 2005, 416 new AIDS cases and 85 deaths were recorded. The percentage of these outcomes did not differ between groups, but log-rank test showed a shorter time to AIDS and disease progression among gypsies.

CONCLUSIONS

The sociodemographic characteristics of gypsies, the largest minority in the VACH Cohort, show differences relative to those of CNGN. HIV-related outcomes suggest that gypsies have a poorer prognosis.

How much fat loss is needed for lipoatrophy to become clinically evident?

The objective of this study was to evaluate how much limb fat is needed to be lost for lipoatrophy to become clinically evident. Antiretroviral drug-naive patients from a randomized trial comparing stavudine or abacavir plus lamivudine and efavirenz, who had subjective assessment to detect clinically evident lipoatrophy (standardized questionnaire) and objective measurements of limb fat (dual X-ray absorptiometry) at baseline, 48 weeks, and 96 weeks were included. ROC curves were used to assess the sensitivity and specificity of several cut-off values of absolute and percent limb fat loss for diagnosing lipoatrophy. Of 54 patients included, 13 (24%) had subjective lipoatrophy at 96 weeks. After 96 weeks, median limb fat change was -2.3 kg (interquartile range: -5.2, +0.2) and 0.4 kg (interquartile range: -7.2, +3.4) in patients with and without lipoatrophy, respectively. Median percent limb fat change was -45.5% (interquartile range: -78.0, +3.7) and 5.5% (interquartile range: -62.8, +95.6), respectively. The cut-off values of absolute and percent limb fat loss showing the best sensitivity and specificity values were -1.5 kg (sensitivity, 77%; specificity, 76%) and -30% (sensitivity, 85%; specificity, 73%). At least 30% limb fat is needed to be lost in HIV-infected patients for lipoatrophy to become clinically evident.

Non-tuberculous mycobacteria in the sputum of HIV-infected patients: infection or colonization?

It can be difficult to establish the clinical significance of the isolation of non-tuberculous mycobacteria (NTM) from the sputum of HIV-infected patients. In this observational study, we have investigated factors associated with having NTM infection. During the period of the study, 10 patients had NTM infection and 14 had NTM colonization. Factors associated with having NTM infections were: CD4 lymphocyte count <50 cells/mL (odds ratio [OR] 10; 95% confidence interval [CI] 1.4-69.3), haemoglobin <11 g/dL (OR 7.2; 95% CI 1.08-47.9), weight loss (OR 9; 95% CI 1.3-63.9), duration of symptoms for more than a month (OR 54; 95% CI 4.2-692.5), the presence of acid fast bacilli (AFB) in sputum (OR 30.3; 95% CI 2.6-348.9) and repeated positive NTM cultures in other sputum samples (OR 4.3; 95% CI 1.6-11.7). In conclusion, we must suspect NTM infection in patients with long-standing symptoms, anaemia, low CD4 lymphocyte count, several positive sputum cultures and when AFB are seen.

Response-guided therapy for chronic hepatitis C virus infection in patients coinfected with HIV: a pilot trial

BACKGROUND

To study the feasibility of a response-guided therapy for chronic hepatitis C virus (HCV) infection in patients coinfected with human immunodeficiency virus (HIV) in a tertiary care hospital.

METHODS

Treatment duration was individualized on the basis of week 4 and week 12 virologic response. Sixty patients were enrolled and received pegylated interferon alfa-2b (1.5 microg/kg per week) plus weight-based ribavirin (800-1400 mg/day). Patients who achieved a rapid virologic response, defined as viral load <50 IU/mL at treatment week 4, completed 24 weeks of therapy. Patients who did not achieve a rapid virologic response were reassessed at treatment week 12. Patients with a complete early virologic response, defined as an HCV RNA level <600 IU/mL, were treated for 48 weeks. Patients with a partial response, defined as a decrease in the viral load > or = 2 log10 and an HCV RNA level > or = 600 IU/mL, who attained an undetectable viral load at week 24 were treated for 60 weeks. The primary efficacy end point was sustained virologic response, defined as HCV RNA <50 IU/mL, 24 weeks after the end of treatment.

RESULTS

Overall, 33 (55%) of 60 patients achieved a sustained virologic response: 11 (44%) of 25 patients with HCV genotype 1, 3 (27%) of 11 patients with genotype 4, and 19 (79%) of 24 patients with genotype 3. One-third of patients showed a rapid virologic response. Of patients with genotype 1, there was a rapid virologic response in 4 (16%) of 25; with genotype 4, in 1 (9%) of 11; and with genotype 3, in 14 (58%) of 24. Of the 19 patients with a rapid virologic response, 17 (89.5%) eradicated the virus after 24 weeks of therapy. The rate of sustained virologic response was significantly higher among patients with genotype 3 and low pretreatment HCV RNA levels. A high relapse rate (46%) after 48 weeks of therapy occurred among patients infected with genotypes 1 or 4 who first achieved undetectable viral load at treatment week 12.

CONCLUSION

A response-guide therapy is feasible and may be useful to optimize the individual outcome of HCV treatment in patients coinfected with HIV.

Impact of prior pneumococcal vaccination on clinical outcomes in HIV-infected adult patients hospitalized with invasive pneumococcal disease

BACKGROUND

Recent studies in hospitalized patients with community-acquired pneumonia have found a lower risk of bacteraemia and better clinical outcomes in patients who had previously received the 23-valent pneumococcal polysaccharide vaccine (PPV) in comparison with unvaccinated individuals. The aim of this study was to assess the influence of prior PPV on clinical outcomes in HIV-infected adult patients hospitalized with invasive pneumococcal disease (IPD).

METHODS

This was an observational study of all consecutive HIV-infected adults hospitalized with IPD from January 1996 to October 2007 in three hospitals in Spain. Baseline characteristics and clinical outcome-related variables were compared according to prior PPV vaccination status.

RESULTS

A total of 162 episodes of IPD were studied. In 23 of these (14.2%), patients had previously received PPV. In both vaccinated and unvaccinated patients, most of the causal serotypes were included in the 23-valent PPV (76.9% and 84.1%, respectively). Overall, 25 patients (15.4%) died during hospitalization, 21 patients (13%) required admission to an intensive care unit (ICU) and 34 patients (21%) reached the composite outcome of death and/or admission to the ICU. None of the 23 patients who had previously received PPV died or required ICU admission, in comparison with 25 (18%; P=0.026) and 21 (15.1%; P=0.046), respectively, of the unvaccinated patients. The length of hospital stay for vaccinated patients was significantly shorter (8.48 vs. 13.27 days; P=0.011).

CONCLUSIONS

Although 23-valent PPV failed to prevent IPD in some HIV-infected patients, vaccination produced beneficial effects on clinical outcomes by decreasing illness severity and mortality related to IPD.