Current antiretroviral therapy: an overview

Quality of Life in Older Adults with HIV Disease

Quality-of-life (QOL) measures have become valuable additions to traditional morbidity and mortality outcomes in evaluating the progression of disease or the efficacy of medical interventions. With significant increases in longevity and an expanding treatment repertoire, QOL issues for people with HIV/AIDS have become increasingly important. Furthermore, as people are living longer with HIV/AIDS and the population in general ages, the number of persons older than age 50 who have HIV/AIDS is increasing. As QOL issues become more important for people with HIV/AIDS and as the population with HIV/AIDS ages, several issues related to QOL among older people arise. These include conceptual issues related to QOL and aging, as well as methodological issues of QOL assessments among older persons. This article begins with a brief discussion of why QOL is important to measure, various measurement strategies, and QOL comparisons between HIV/AIDS populations and other chronic disease groups. This is followed by a discussion of conceptual and methodological issues in measuring QOL among older persons. Finally, the authors conclude with recommendations for future research.

X-ray crystal structures of human immunodeficiency virus type 1 protease mutants complexed with atazanavir

Atazanavir, which is marketed as REYATAZ, is the first human immunodeficiency virus type 1 (HIV-1) protease inhibitor approved for once-daily administration. As previously reported, atazanavir offers improved inhibitory profiles against several common variants of HIV-1 protease over those of the other peptidomimetic inhibitors currently on the market. This work describes the X-ray crystal structures of complexes of atazanavir with two HIV-1 protease variants, namely, (i) an enzyme optimized for resistance to autolysis and oxidation, referred to as the cleavage-resistant mutant (CRM); and (ii) the M46I/V82F/I84V/L90M mutant of the CRM enzyme, which is resistant to all approved HIV-1 protease inhibitors, referred to as the inhibitor-resistant mutant. In these two complexes, atazanavir adopts distinct bound conformations in response to the V82F substitution, which may explain why this substitution, at least in isolation, has yet to be selected in vitro or in the clinic. Because of its nearly symmetrical chemical structure, atazanavir is able to make several analogous contacts with each monomer of the biological dimer.

Structure–activity and structure–metabolism relationships of HIV protease inhibitors containing the 3-hydroxy-2-methylbenzoyl-allophenylnorstatine structure

A series of peptidomimetic human immunodeficiency virus (HIV) protease inhibitors containing substituted all-phenylnorstatine [APNS: (2S,3S)-3-amino-2-hydroxy-4-phenylbutyric acid] were designed and synthesized. From the structure-metabolism relationship of this type of HIV protease inhibitors, the compounds having para substitution of the phenyl ring of Apns and/or 2,6-disubstitution of the P2' benzylamine were found to be able to avoid the P2 phenol glucuronidation that occurs with SM-319777 (formerly named JE-2147, KNI-764); one of the main metabolic pathways of SM-319777. These new analogues, such as SM-322377, had more desirable pharmacokinetic profiles and more potent antiviral activity against not only wild type HIV-1 but also the multi-drug-resistant HIV-1 than SM-319777.

A demographic and health profile of gay and bisexual men in a large Canadian urban setting

The purpose of this study was to provide both a population estimate and a socio-economic and health profile of gay and bisexual men living with HIV/AIDS in a large Canadian urban centre. A random telephone survey was used to determine the number of men in the study area over the age of 20 identifying as gay or bisexual and to characterize their health and socio-economic status. Out of a total of 1,176 completed interviews, 300 males described themselves as gay or bisexual. Projecting this figure on recent census data we estimated the number of men identifying as gay or bisexual in this region of downtown Vancouver, BC, at 5,100. Among these men we found an HIV prevalence rate of 16%, with those who reported a positive serostatus being less likely to be employed full time and more likely to earn less than $20,000 per year. In terms of clinical characteristics, HIV-positive men had a median CD4 cell count of 397 cells/mm(3) and a median viral load of less than 500 copies/ml. Eighty-three per cent of the HIV-positive respondents were on antiretroviral therapy and the median number of drugs taken by these men was three. In summary, random surveys of populations affected by this epidemic are important for policy makers, clinicians and persons caring for those with HIV/AIDS as they paint a clearer picture of who is being affected and help to identify areas where increased services are needed.

A content analysis of hiv/aids information in psychology textbooks: implications for education, training, and practice

Early in the pandemic, psychologists who engaged in HIV/AIDS research and practice or care relied more on their "general" psychological knowledge and training than on HIV/AIDS-specific information or training for combating the disease. In the past two decades much has been gained from the contributions of psychologists working in the areas of HIV/AIDS prevention and intervention. However, little is known regarding how the discipline prepares its students for a career in HIV/AIDS research and practice/care. One important venue for educating future psychologists is college-level textbooks because they are often the students' gateway to the scientific literature in psychology. Therefore, presentation of adequate and accurate information in these texts is critical. The present study involved a review and content analysis of introductory, clinical/counseling, health, human sexuality, and social/community psychology textbooks. It revealed that some level of information regarding HIV/AIDS was found in the majority of most college-level psychology texts that were reviewed. However, many books do not present a comprehensive overview or review of this problem, and do not adequately address the role psychology and behavior change can play in abating it. Implications for education, training, and practices are discussed.

Health-related quality of life and virologic outcomes in an HIV clinic

OBJECTIVE

The purpose of this study was to describe the relationship between viral load and health-related quality of life (HRQOL) in a cohort of persons with human immunodeficiency virus (HIV) infection.

DESIGN

We evaluated HRQOL measurements in a clinical cohort of HIV-positive patients recruited from a university-associated HIV primary care clinic. HRQOL instruments included the medical outcomes survey-short form-36(MOS-SF-36) from which mental and physical component summary scores (MCS and PCS) and subscale scores were calculated.

RESULTS

Significant negative associations were found between viral load and SF-36 PCS, physical functioning (PF), role-physical (RP), bodily pain (BP), general health (GH), role-emotional (RE), and vitality (VT). Similar negative associations were found between CD4 cell count and SF-36 summary and subscale scores, with the notable exception of bodily pain. Multivariate analyses controlling for the effects of CD4 cell count and other clinical variables indicated viral load as an independent predictor of SF-36 PCS, RP, BP and VT scores.

CONCLUSIONS

The relationship between viral load, a measure of HIV disease activity, and several dimensions of the SF-36, a patient-focused measure of HRQOL, appears to be strong and independent of CD4 cell count. These findings suggest that having a lower viral load positively impacts the quality of life of HIV-positive patients.

Inhibition of HIV-1 protease by a boron-modified polypeptide

Six boronated tetrapeptides with the carboxy moiety of phenylalanine replaced by dihydroxyboron were synthesized, and their activities against human immunodeficiency virus 1 (HIV-1) protease subsequently investigated. The sequences of these peptides were derived from HIV-1 protease substrates, which included the C-terminal part of the scissile bond (Phe-Pro) within the gag-pol polyprotein. Enzymatic studies showed that these compounds were competitive inhibitors of HIV-1 protease with K(i) values ranging from 5 to 18 microM when experiments were performed at high enzyme concentrations (above 5 x 10(-8) M); however, at low protease concentrations inhibition was due in part to an increase of the association constants of the protease subunits. Ac-Thr-Leu-Asn-PheB inhibited HIV-1 protease with a K(i) of 5 microM, whereas the non-boronated parental compound was inactive at concentrations up to 400 microM, which indicates the significance of boronation in enzyme inhibition. The boronated tetrapeptides were inhibitory to an HIV-1 protease variant that is resistant to several HIV-1 protease inhibitors. Finally, fluorescence analysis showed that the interactions between the boronated peptide Ac-Thr-Leu-Asn-PheB and HIV-1 protease resulted in a rapid decrease of fluorescence emission at 360 nm, which suggests the formation of a compound/enzyme complex. Boronated peptides may provide useful reagents for studying protease biochemistry and yield valuable information toward the development of protease dimerization inhibitors.

In vitro resistance profile of the human immunodeficiency virus type 1 protease inhibitor BMS-232632

BMS-232632 is an azapeptide human immunodeficiency virus (HIV) type 1 (HIV-1) protease inhibitor that displays potent anti-HIV-1 activity (50% effective concentration [EC(50)], 2.6 to 5.3 nM; EC(90), 9 to 15 nM). In vitro passage of HIV-1 RF in the presence of inhibitors showed that BMS-232632 selected for resistant variants more slowly than nelfinavir or ritonavir did. Genotypic and phenotypic analysis of three different HIV strains resistant to BMS-232632 indicated that an N88S substitution in the viral protease appeared first during the selection process in two of the three strains. An I84V change appeared to be an important substitution in the third strain used. Mutations were also observed at the protease cleavage sites following drug selection. The evolution to resistance seemed distinct for each of the three strains used, suggesting multiple pathways to resistance and the importance of the viral genetic background. A cross-resistance study involving five other protease inhibitors indicated that BMS-232632-resistant virus remained sensitive to saquinavir, while it showed various levels (0. 1- to 71-fold decrease in sensitivity)-of cross-resistance to nelfinavir, indinavir, ritonavir, and amprenavir. In reciprocal experiments, the BMS-232632 susceptibility of HIV-1 variants selected in the presence of each of the other HIV-1 protease inhibitors showed that the nelfinavir-, saquinavir-, and amprenavir-resistant strains of HIV-1 remained sensitive to BMS-232632, while indinavir- and ritonavir-resistant viruses displayed six- to ninefold changes in BMS-232632 sensitivity. Taken together, our data suggest that BMS-232632 may be a valuable protease inhibitor for use in combination therapy.

BMS-232632, a highly potent human immunodeficiency virus protease inhibitor that can be used in combination with other available antiretroviral agents

BMS-232632 is an azapeptide human immunodeficiency virus type 1 (HIV-1) protease (Prt) inhibitor that exhibits potent anti-HIV activity with a 50% effective concentration (EC(50)) of 2.6 to 5.3 nM and an EC(90) of 9 to 15 nM in cell culture. Proof-of-principle studies indicate that BMS-232632 blocks the cleavage of viral precursor proteins in HIV-infected cells, proving that it functions as an HIV Prt inhibitor. Comparative studies showed that BMS-232632 is generally more potent than the five currently approved HIV-1 Prt inhibitors. Furthermore, BMS-232632 is highly selective for HIV-1 Prt and exhibits cytotoxicity only at concentrations 6,500- to 23, 000-fold higher than that required for anti-HIV activity. To assess the potential of this inhibitor when used in combination with other antiretrovirals, BMS-232632 was evaluated for anti-HIV activity in two-drug combination studies. Combinations of BMS-232632 with either stavudine, didanosine, lamivudine, zidovudine, nelfinavir, indinavir, ritonavir, saquinavir, or amprenavir in HIV-infected peripheral blood mononuclear cells yielded additive to moderately synergistic antiviral effects. Importantly, combinations of drug pairs did not result in antagonistic anti-HIV activity or enhanced cytotoxic effects at the highest concentrations used for antiviral evaluation. Our results suggest that BMS-232632 may be an effective HIV-1 inhibitor that may be utilized in a variety of different drug combinations.

Depressive symptoms decline among persons on HIV protease inhibitors

OBJECTIVE

To ascertain whether initiation of protease inhibitors was associated with a change in depressive symptoms among persons infected with HIV.

METHODS

Study subjects included men and women who were enrolled in the HIV/AIDS Drug Treatment Program and who had completed an annual participant survey before and after initiating triple combination therapy with a protease inhibitor. Depressive symptoms were assessed using the Centre for Epidemiologic Studies-Depression scale (CES-D). Statistical analyses to determine the change in CES-D total and subscale scores before and after protease inhibitor use were conducted using parametric and multivariate methods.

RESULTS

Our analysis was restricted to 453 participants. Of these 234 (52%) were depressed at baseline (CES-D score > or = 16). Compared with nondepressed participants, depressed participants were slightly younger (p = .048), less likely to be employed (p < .001) and more likely to have an annual income less than $10,000 per annum (p < .001). After adjusting for CD4 count, employment status, income, age, and CES-D total or subscale score at baseline, we found a significant improvement in total scale score (p = .001) and depressive mood (p = .002), positive affects (p = .005), and somatic symptoms (p = .011) subscale scores at follow-up. There was no significant change in the interpersonal relations score over the study period.

CONCLUSION

Our findings indicate that in addition to conferring impressive clinical benefits, protease inhibitor use is associated with a significant improvement in HIV-positive individuals' mental health.

Impact of combination therapies on HIV risk perceptions and sexual risk among HIV-positive and HIV-negative gay and bisexual men

The availability of improved HIV treatments may prompt reduced concern about HIV and sexual risk. Gay and bisexual men (N = 554, 17% HIV-positive) completed measures of treatment attitudes, sexual risk, and assumptions regarding the infectiousness of sexual partners. A substantial minority reported reduced HIV concern related to treatment advances. Reduced HIV concern was an independent predictor of sexual risk, particularly among HIV-positive men. In response to hypothetical scenarios describing sex with an HIV-positive partner, participants rated the risk of unprotected sex to be lower if the partner was taking combination treatments and had an undetectable viral load, relative to scenarios with a seropositive partner not taking combination treatments. Prevention efforts must address attitudinal shifts prompted by recent treatment successes, stressing the continued importance of safer sex, and that an undetectable viral load does not eliminate infection risks.

Beneficial effects of protease inhibitors on body composition and energy expenditure: a comparison between HIV-infected and AIDS patients

OBJECTIVES

(i) To investigate whether protease inhibitor (PI) (nelfinavir)-containing highly active antiretroviral therapy (HAART) affects body composition differently in HIV-infected and AIDS patients without wasting syndrome. (ii) To delineate the changes in resting energy expenditure (REE) under PI therapy, and to determine whether sustained reductions in HIV RNA would decrease REE.

DESIGN

Prospective longitudinal cohort study with individually matched healthy controls.

SETTING

Tertiary care centre at a University Hospital.

METHODS

HIV-seropositive (n = 20) and AIDS patients (n = 17) with a plasma viral load of at least 10000 copies/ml and 37 healthy volunteers were enrolled. All participants were weight stable, free of acute opportunistic infections, and naive to PI therapy. Patients underwent testing of bioelectrical impedance analysis (BIA), indirect calorimetry and food intake, shortly before the initiation of HAART and 24 weeks thereafter.

RESULTS

Both patient groups gained weight, body mass index (BMI), and fat-free mass (FFM) (P < 0.05 versus baseline), whereas only AIDS patients gained fat mass. Increases were more pronounced in the AIDS group. REE was elevated compared with corresponding controls at baseline, and decreased similarly in HIV and in AIDS patients during PI therapy (P < 0.05). The reduction in the viral burden preceded the decrease in REE by several weeks.

CONCLUSION

Body composition and metabolic parameters improved during PI therapy in HIV-infected and AIDS patients without wasting. Although an early reduction in viral load as a result of HAART does not seem to influence REE directly, sustained viral load suppression may promote a decrease in energy expenditure.

Economic methods for measuring the quality of life associated with HIV infection

BACKGROUND

Quality of life is measured as utilities for cost-effectiveness analyses.

OBJECTIVE

To test the adequacy of three common utility elicitation methods for individuals with Human Immunodeficiency Virus (HIV) disease.

MEASUREMENTS

HIV-positive participants (n = 75) rated three standardized health states (symptomatic HIV infection, minor AIDS defining illness, and major AIDS defining illness) with two utility elicitation methods (Standard Gamble [SG], and Time Trade-off [TTO]) and one value method (Visual Analog [VA]). Participants also rated their own health with one utility method (Health Utilities Index [HUI]) and one conventional quality of life method (Medical Outcomes Study--HIV Health Survey [MOS-HIV]).

RESULTS

For all states, SG and TTO scores ranged from near 0.00 (equivalent to death) to 1.00 (best possible quality of life). Mean scores for symptomatic HIV were similar with the SG (0.80) and TTO (0.81) but higher than with the VA (0.70). Similar results were observed for minor AIDS defining illnesses (0.65, 0.65, 0.46 respectively) and major AIDS defining illnesses (0.42, 0.44, 0.25 respectively). Discrepant SG and TTO scores were observed in many individuals and were not explained by demographic characteristics. As expected, HUI scores of an individual's own health were related to the disease state. Four of ten MOS-HIV subscales (overall health, physical functioning, role functioning, and pain) were also related to disease state. HUI scores were correlated with the MOS-HIV score for overall health and for all MOS-HIV subscales except health transition.

CONCLUSIONS

Mean utility scores for HIV-related health states elicited by the Standard Gamble and Time Trade-off were similar but a large degree of individual variation persists. Economic methods provide imprecise estimates of the quality of life associated with HIV infection.

Adherence to combination therapy in persons living with HIV: balancing the hardships and the blessings

Evidence from clinical trials demonstrates the benefits of combination therapy in persons living with HIV (PLWHIV); however, there is little information about the patient's experience when taking a complex regimen. Thus, the primary purpose of this preliminary study was to describe the everyday experience of PLWHIV who were prescribed combination therapy in order to identify a potential intervention to enhance adherence to this regimen. The secondary purpose was to examine the association between adherence to combination therapy and quality of life. The researchers purposively sampled six PLWHIV (two women and four men) to reflect the diverse demographic characteristics of the population of PLWHIV. The themes that evolved were decision making, difficulties, problem solving, and quality of life. Clinical indicators provide only one measure of the effectiveness of combination therapy. When the informants described the outcome of this therapy as "having their life back," they spoke of having quality in their lives that they viewed as more than their physical health.

Stavudine Resistance: An Update on Susceptibility following Prolonged Therapy

The current report summarizes the available published and unpublished data from several investigators on resistance in clinical isolates following prolonged stavudine therapy. Results suggest that stavudine resistance is both modest in degree and infrequent in appearance. Phenotypic evaluation of 61 patients on stavudine therapy showed only modest changes in drug sensitivity following up to 29 months of treatment. The post-treatment isolates from 15 patients exhibited an increase in EC50 value >fourfold (level above variability of assay) when compared with the corresponding pretreatment isolates. However, the vast majority (11) of these pretreatment isolates either had unexpectedly low EC50 levels and/or had post-treatment isolates that lacked any amino acid changes within their reverse transcriptase (RT) gene to account for the observed change in sensitivity. Of the four remaining isolates, two appeared to have a multi-resistant phenotype to several nucleoside analogues and two had no detectable RT amino acid changes to account for the observed change in stavudine sensitivity. To date, clinical HIV-1 isolates displaying stavudine-specific resistance have yet to be reported. Furthermore, full or partial RT sequence analysis of 194 post-treatment isolates failed to identify any consistent amino acid changes. The strain-specific V75T mutation reported to confer stavudine resistance to the HXB2 HIV-1 strain in vitro, was found in only six isolates and did not correlate with stavudine resistance. This low incidence of stavudine resistance is in striking contrast to that observed with other nucleoside analogues and further supports the use of stavudine in first-line combination therapy for HIV patients.