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Resistance profiles and adherence at primary virological failure in three different highly active antiretroviral therapy regimens: analysis of failure rates in a randomized study.

OBJECTIVES: To investigate the interplay between resistance and adherence in the virological failure of three fundamentally different highly active antiretroviral therapy (HAART) regimens. METHODS: We retrospectively identified 56 verified primary virological failures (viral load >400 HIV-1 RNA copies/mL) among 293 patients randomized to two nucleoside reverse transcriptase inhibitors (NRTIs)+ritonavir+saquinavir (RS-arm) (n=115), two NRTIs+nevirapine+nelfinavir (NN-arm) (n=118), or abacavir+stavudine+didanosine (ASD-arm) (n=60) followed up for a median of 90 weeks. Data on adherence were collected from patient files, and genotyping was performed on plasma samples collected at time of failure. RESULTS: Treatment interruption or poor adherence was mainly caused by side effects and accounted for 74% of failures, and was associated with absence of resistance mutations. In the 30 failing patients not switched from randomized treatment, we found resistance in two of 12 patients in the RS-arm (M184 V only), four of six patients in the NN-arm [all four had non-nucleoside reverse transcriptase inhibitor (NNRTI) mutations], and seven of 12 patients in the ASD-arm (NRTI mutations only). Two adherent patients on randomized treatment failed in the RS-arm, none in the NN-arm, and six in the ASD-arm. CONCLUSIONS: Primary virological failure was caused mainly by treatment interruption. No primary protease inhibitor (PI) mutations were found in patients failing on boosted saquinavir, whereas resistance to NNRTIs and NRTIs was prevalent in several patients failing on regimens based on these medications.

Adult↗

Genetic mechanisms of resistance to NRTI and NNRTI.

Resistance to nucleoside reverse transcriptase inhibitors (NRTIs) seems to develop following three different pathways. Discriminatory mutations favor the binding of physiologic nucleosides over that of drugs. The newly so-called nucleoside-associated mutations (NAMs) enhance the removal of chain terminators (pyrophosphorolysis) from the cDNA in formation. Finally, some inserts at the p6 region within the gag gene (i.e., PTAP duplications) may favor virus escape from NRTI through a greater accumulation of RT molecules per virion. In respect to nonnucleoside reverse transcriptase inhibitors (NNRTIs), resistance often results from single mutations (K103N is the most frequently found) located at or near the drug pocket binding.

Anti-HIV Agents↗

Interruption of treatment with individual therapeutic drug classes in adults with multidrug-resistant HIV-1 infection.

BACKGROUND: Many antiretroviral-treated human immunodeficiency virus (HIV)-infected patients experience sustained immunologic and virologic benefit despite the presence of multidrug-resistant HIV. We hypothesized that the use of simplified regimens could maintain treatment benefit while preventing viral evolution and reducing drug-related toxicity and costs. METHODS: We conducted a 48-week nonrandomized study of adults with multidrug-resistant HIV type 1 infection. Subjects interrupted protease inhibitor (PI) (n=18), reverse-transcriptase inhibitor (RTI) (n=6), or nonnucleoside RTI (NNRTI) (n=6) treatment. RESULTS: At study entry, subjects had a median reduction in HIV RNA levels of 1.2 log10 copies/mL relative to pretreatment levels. Interruption of PI treatment was associated with stable HIV RNA levels (mean change per week, +0.005 log10 copies/mL; P=.36). PI mutations waned and replicative capacity and HIV RNA levels increased after long-term observation. HIV RNA levels also remained stable in subjects interrupting NNRTI treatment. In contrast, all subjects who interrupted RTI treatment exhibited immediate increases in HIV RNA levels, and most exhibited a subsequent loss of the M184V mutation. CONCLUSIONS: These data indicate that nucleoside analogues often exert continued antiviral activity in the setting of drug-resistance mutations and that both nucleoside analogues and PIs can select for drug-resistance mutations that reduce viral fitness. These observations support the evaluation of treatment strategies aimed at maintaining the treatment benefit of therapy while reducing drug exposure.

Anti-Retroviral Agents↗

Inhibition of wild-type human immunodeficiency virus and reverse transcriptase inhibitor-resistant variants by Phyllanthus amarus.

Substantial progress has been made in research on natural products which effectively inhibit HIV-1 replication. Many active compounds were isolated from traditionally used medicinal plants including Phyllanthus species. This study shows that aqueous as well as alcohol-based Phyllanthus amarus extracts potently inhibit HIV-1 replication in HeLa CD4(+) cells with 50% effective concentration (EC(50)) values ranging from 0.9 to 7.6 microg/ml. A gallotannin enriched fraction showed enhanced activity (0.4 microg/ml), and the purified gallotannins geraniin and corilagin were most active (0.24 microg/ml). HIV-1 replication was also blocked in CD4(+) lymphoid cells with comparable EC(50) values. Applying a cell-based internalization assay, we could demonstrate 70-75% inhibition of virus uptake at concentrations of 2.5 microg/ml for the water/alcohol extract and geraniin. In addition, a concentration-dependent inhibition of HIV-1 reverse transcriptase (RT) could be demonstrated in vitro. The 50% inhibitory concentration (IC(50)) values varied from 1.8 to 14.6 microg/ml. The ability to inhibit replication of a variety of RT inhibitor-resistant HIV-1 strains points to the potential of P. amarus extracts, as natural products, in the chemotherapy of HIV infections.

CD4 Antigens↗

Incidence and predictors of virologic failure of antiretroviral triple-drug therapy in a community-based cohort.

Highly active antiretroviral therapy fails to reach its recommended goal of sustained suppression of viral replication in a substantial proportion of patients. We analyzed incidence and predictors of virologic failure of the first regimen of a triple-drug combination therapy, including a protease inhibitor and two nucleoside analog reverse transcriptase inhibitors (NRTIs), in 274 HIV-infected patients. Long-term virologic response to combination therapy including salvage regimens was assessed 2.5 years after treatment initiation. During an initial observation period of up to 1.8 years (median, 0.8 years) 152 patients (55%) experienced sustained suppression of HIV-1 RNA to <500 copies/ml. Failure to reduce viral load to <500 copies/ml within 6 months (initial failure) was observed in 51 patients (19%). Independent risk factors for initial failure included higher baseline viral load; addition of a protease inhibitor to an unchanged NRTI regimen; use of saquinavir hard-gel capsules; and longer duration of prior NRTI treatment. Within a median of 7 months viral load rebound above 500 copies/ml occurred in 71 of 223 patients (32%) whose viral load had initially decreased below this threshold. In proportional hazard analysis none of the potential risk factors was significantly associated with viral load rebound. However, in 40 patients (56%) with viral load rebound, incomplete adherence to therapy or treatment interruptions preceded the rebound. Virologic outcome after 2.5 years correlated with initial response to the first regimen: viral load was <500 copies/ml in 88, 55, and 21% of patients with sustained suppression, viral load rebound, and initial failure, respectively.

Adult↗

Genotypic and phenotypic resistance patterns at virological failure in a simplification trial with nevirapine, efavirenz or abacavir.

BACKGROUND: The NEFA Study was a randomized study comparing nevirapine (NVP), efavirenz (EFV) or abacavir (ABC) as substitutes for protease inhibitors in a large group of HIV-1-infected patients successfully treated with antiretroviral regimens containing protease inhibitors. OBJECTIVE: To evaluate genotype and phenotype resistance patterns among patients who have experienced virological failure under one of the three study arms. METHODS: Patients with virological failure, defined as two consecutive determinations of HIV-1 RNA > 200 copies/ml, were analysed for phenotypic susceptibility and HIV-1 mutations. RESULTS: Of the 460 patients included in the study, 51 (11%) experienced virological failure after 24 months of follow-up while on assigned study medication. A higher proportion of patients in the ABC [25 (17%)] than in the NVP [14 (9%)] or EFV [12 (8%)] arms selected resistance to the study drug (P = 0.04). Moreover, a much higher number of resistance mutations to one or more of the backbone nucleoside reverse transcriptase inhibitor drugs contained in the failing regimen were observed in the ABC than in the EFV or NVP arms. In general, there was a good concordance among genotype and phenotype resistance testing, except for ABC, stavudine and didanosine, where phenotypic resistance testing added valuable information (fold change in the median inhibitory concentration). CONCLUSIONS: Cross-resistance involving nucleoside reverse transcriptase inhibitor drugs might explain the higher risk of virological failure in patients switched to ABC-containing antiretroviral therapy. Phenotypic resistance testing may be helpful in interpreting unclear genotypic results.

Adult↗

Efficacy of a nelfinavir- and nevirapine-containing salvage regimen.

PURPOSE: In this study, our purpose was to assess the efficacy of nelfinavir- and nevirapine-containing salvage regimens in nonnucleoside reverse transcriptase inhibitor (NNRTI)-naive patients virologically failing a protease inhibitor (PI)-based combination. METHOD: A retrospective case note review of all patients virologically failing their PI-based combination who were switched to a regimen containing both nelfinavir (1 g t.d.s.) and nevirapine (200 mg b.d.). CD4 cell counts and viral loads were monitored. Genotypic analysis was performed using RT-PCR sequencing. RESULTS: Nineteen patients commenced a salvage regimen containing nelfinavir and nevirapine. Five patients also changed at least one nucleoside reverse transcriptase inhibitor (NRTI), although in one case this represented recycling. Thirty-eight percent (6/16) of patients achieved a viral load below the level of detection (BLD; <200 copies/mL; complete responders [CR]), 3 achieved <20 copies/mL. Five patients achieved > or =1 log drop (partial responders [PR]) that was not sustained over follow-up, and five failed to respond to therapy (nonresponders [NR]). CRs tended to have wild-type NNRTI and PI sequences relative to PRs and NRs. CONCLUSION: In heavily pretreated patients, a nelfinavir-and nevirapine-containing salvage regimen resulted in a virological response in 38% of patients that was sustained in 31% over 63 weeks.

Adult↗

Decrease of HIV-1 RNA levels in lymphoid tissue and peripheral blood during treatment with ritonavir, lamivudine and zidovudine. Ritonavir/3TC/ZDV Study Group.

OBJECTIVES: Triple combination treatment of HIV-1 infection using two reverse transcriptase inhibitors and a protease inhibitor can result in significant and sustained decreases in the quantity of viral RNA in peripheral blood. Lymphoid tissue, however, constitutes the major reservoir of HIV in infected patients. Study of the viral burden in these tissues has provided additional insight in the efficacy of antiretroviral treatment. DESIGN: Patients were randomized into two groups in order to study differences in the development of resistance to reverse transcriptase inhibitors. Group I started treatment with all three drugs simultaneously. Group II started with ritonavir monotherapy, aiming at initial reduction in virus production before the addition of lamivudine and zidovudine 3 weeks later. METHODS: Changes in the amount of HIV in plasma and tonsillar lymphoid tissue during 24 weeks of treatment with ritonavir, lamivudine and zidovudine were studied by reverse transcriptase polymerase chain reaction. RESULTS: Thirty-three antiretroviral-naive HIV-infected patients were included for analysis. After 24 weeks, median CD4+ cell count increased by 152 x 10(6)/l and median plasma viral RNA levels decreased by at least 2.87 log10 copies/ml. In 88% of the patients remaining on treatment, plasma RNA levels were below the quantification limit of the assay used (mean, 2.4 log10 copies/ml). The lymphoid tissue viral burden, ranging from 9.16 to 8.52 log10 copies/g at baseline, was markedly reduced with at least 2.1 log10 copies/g by week 24 in the five patients analysed. Eight patients (24%) withdrew because of side-effects. In one patient in group II, ritonavir and lamivudine resistance-associated mutations developed. CONCLUSIONS: Treatment with this triple antiretroviral drug combination produced a durable and strong decrease of HIV-1 RNA burden in both plasma and lymphoid tissue.

Adult↗

Tenofovir-related nephrotoxicity: case report and review of the literature.

Tenofovir is a nucleotide reverse transcriptase inhibitor for treatment of human immunodeficiency virus (HIV) infection. Several cases of renal failure associated with tenofovir therapy recently have been reported. A 54-year-old man with HIV experienced decreasing renal function and Fanconi's syndrome secondary to tenofovir therapy. His condition gradually improved after discontinuation of the drug. The available medical literature for reported cases of tenofovir-related nephrotoxicity indicates that this complication is apparently rare. However, our case report and literature review underscore the importance of monitoring renal function when treating patients with any nucleotide reverse transcriptase inhibitor.

Acquired Immunodeficiency Syndrome↗

A multicentre study to determine the efficacy and tolerability of a combination of nelfinavir (VIRACEPT), zalcitabine (HIVID) and zidovudine in the treatment of HIV infected Nigerian patients.

Summary Forty (40) HIV positive patients with CD4 cell counts between 100 - 500 cellh/mm3 were recruited from 8 different centres in Nigeria including a research centre and specialist and teaching hospitaLs They were enrolled into an open, non-comparative study of a triple combination regimen containing the Protease Inhibitor (PI), Nelfinavir and two Reverse Transcriptase Inhibitors (RTIs), Zakitabine (Hivid) and Zidovudine for a period of 24 weeks. Thirty-one (31) patients completed the study. Nine (9) patients withdrew from the study. Two of these because of Adverse Events (AE), 2 others because they developed tuberculosis and had to withdraw because of rifampicin therapy. The remaining five (5), withdrew voluntarily. Efficacy of the PI containing triple regimen was evaluated using viral load and absolute CD4 changes, weight gain and clinical response during the course of the triaL Twenty-two (22) patients had plasma viral loads measured at the beginning and at the end of the trial (24 weeks). Seventeen (17) out of the 22 patients (77%), experienced a significant reduction in their plasma viral loads (p<0.05 There was 1 log reduction in plasma viral load in 6 patients (25%), 2 log in 4 patients (17%). In 2 patients (8%), plasma viral load was reduced below the level of detection. The viral load increased over the treatment period in five patients (21%). Similarly 22 out of the 26 patients (85%) experienced increase in the level of their CD4 lymphocyte counts at the end of the study. The average CD4 counts of all 26 patients rose from 272.94 +/- 137.71/dl to 414 +/- 243.71/ul over 24 weeks (p<0.05). There was monthly rise of 27 CD4 cells/microl. Four (4) patients (15%) had a fall in their CD4 lymphocyte counts. Twenty (20) out of the 26 patients (77%), who completed the study were observed to have weight gains ranging from 1.5 to 31 kilograms over the 24 week study period. In 4 patients, there was no weight gain during the study period. Two patients (5%) were withdrawn due to adverse events from the viracept combination. One of these was because of life threatening diarrhoea while the other patient had severe peripheral neuropathy and severe weakness in the lower limbs. Eight (8) other patients had diarrhoea but not severe enough to stop them from continuing with the triaL Other adverse events seen include anaemia (1 patient), pancytopenia (1 patient), and transient elevation of serum urea and creatinine (1 patient). None of these adverse events was severe enough to warrant withdrawal from therapy. The study has therefore demonstrated the significant efficacy and tolerability of (Nelfinavir/Zalcitabine/ Zidovudine combination in suppressing viral replication, increasing the CD4 cell counts and improving the quality of life in Nigeria patients with HIV.

Anti-HIV Agents↗

Cost effectiveness of combination HIV therapy: 3 years later.

Since 1997, expert panel guidelines for HIV care have recommended the use of combination antiretroviral therapy with at least 3 antiretroviral drugs. Several studies have examined the cost effectiveness of 3-drug combination antiretroviral regimens for the treatment of HIV infection. Analyses comparing a 3-drug protease inhibitor-containing regimen with a 1- or 2-drug non-nucleoside reverse transcriptase inhibitor regimen have consistently yielded incremental direct cost estimates ranging from $US10,000 to just over $US13,000 per year of life saved. In Western societies, such an incremental cost per year of life saved compares favourably with chronic therapy for other diseases and argues for the adoption of these drugs by payors and policy makers. The reason for this favourable cost-effectiveness ratio appears to be the decrease in opportunistic complications and hospitalisation associated with the effective use of combination antiretroviral therapy. Whether this initial benefit will be maintained is not yet known. Other comorbid illnesses such as hepatitis C or renal failure may subsequently increase the cost of HIV care, and some analyses suggest that resistance may develop to these drugs over the long term. In addition, studies are needed to assess the cost effectiveness of these therapies in developing countries where the expense of these drugs appears to put them out of reach. The collection and analysis of economic data will continue to be needed as newer HIV therapies become available and the HIV healthcare environment evolves. Quantifying medical care costs and calculating cost effectiveness involve assessing a moving target. Economic analyses of HIV infection must evolve in tandem with therapeutic changes to continue to be relevant to policy makers, payors of care, and those who provide and receive HIV care.

Antiviral Agents↗

Neurologic, neurocognitive, and brain growth outcomes in human immunodeficiency virus-infected children receiving different nucleoside antiretroviral regimens. Pediatric AIDS Clinical Trials Group 152 Study Team.

OBJECTIVES: To compare the impact of three different nucleoside reverse transcriptase inhibitor regimens, zidovudine (ZDV) monotherapy, didanosine (ddI) monotherapy, and ZDV plus ddI combination therapy, on central nervous system (CNS) outcomes in symptomatic human immunodeficiency virus (HIV)-infected children. METHODS: Serial neurologic examinations, neurocognitive tests, and brain growth assessments (head circumference measurements and head computed tomography or magnetic resonance imaging studies) were performed in 831 infants and children who participated in a randomized double-blind clinical trial of nucleoside reverse transcriptase inhibitors. The Pediatric AIDS Clinical Trials Group study 152 conducted between 1991 and 1995 enrolled antiretroviral therapy-naive children. Subjects were stratified by age (3 to <30 months of age or 30 months to 18 years of age) and randomized in equal proportions to the three treatment groups. RESULTS: Combination ZDV and ddI therapy was superior to either ZDV or ddI monotherapy for most of the CNS outcomes evaluated. Treatment differences were observed within both age strata. ZDV monotherapy showed a modest statistically significant improvement in cognitive performance compared with ddI monotherapy during the initial 24 weeks, but for subsequent protection against CNS deterioration no clear difference was observed between the two monotherapy arms. CONCLUSIONS: Combination therapy with ZDV and ddI was more effective than either of the two monotherapies against CNS manifestations of human immunodeficiency virus disease. The results of this study did not indicate a long-term beneficial effect for ZDV monotherapy compared with ddI monotherapy.

Adolescent↗

Emtricitabine: a review of its use in the management of HIV infection.

Emtricitabine (Emtriva) is an orally administered nucleoside reverse transcriptase inhibitor (NRTI) that is indicated in combination with other antiretroviral agents in the treatment of HIV infection in adults. As a component of antiretroviral therapy (ART), emtricitabine effectively reduces and/or maintains suppression of viral load in ART-naive adults or ART-experienced adults switching from stable combination regimens, and is generally well tolerated. Emtricitabine is a component of preferred initial HIV combination therapy regimens; it can be used in place of lamivudine as part of the dual NRTI backbone in non-nucleoside reverse transcriptase inhibitor (NNRTI)- and protease inhibitor (PI)-based regimens. Moreover, preliminary data from a randomised, open-label study suggest that emtricitabine plus tenofovir DF, a preferred dual-NRTI combination, is better tolerated than co-formulated lamivudine/zidovudine, another preferred dual-NRTI combination, resulting in a higher persistent virological response rate, as analysed using the US FDA time to loss of virological response (TLOVR) algorithm. With the convenience of once-daily (single pill) administration, no dietary restrictions and a favourable drug interaction and tolerability profile, emtricitabine should facilitate patient adherence to treatment, which, in turn, is central to the success of antiretroviral therapy. Similarly, emtricitabine is attractive as an option for ART-experienced stable adults requiring regimen simplification.

Adult↗

Cutaneous side effects induced by indinavir.

HIV-protease inhibitors demonstrated such high efficacy in short-term studies that they have been approved by the FDA, even though possible toxicity still needs further investigation. In the period between January 1997 and August 1998, 101 patients, staying at San Patrignano Medical Centre (Italy), received an HIV protease inhibitor (indinavir) plus two nucleoside reverse transcriptase inhibitors (NRTI's) selected from the following: AZT, didanosine, zalcitabine, lamivudine or stavudine. Seventy-three patients were male, 28 female and their ages ranged from 25 to 60 years, with an average of 34. At the end of the study, 84 patients were suitable for evaluation, as the other 17 dropped out for various reasons. Forty-eight patients (57.1%) developed cheilitis, 34 (40.5%) experienced diffuse cutaneous dryness and pruritus, 10 (11.9%) developed asteatotic dermatitis on the trunk, arms and thighs and another 10 (11.9%) complained of scalp defluvium. A severe alopecia was observed in only 1 patient (1.2%), while 6 reported that their body hair had become fairer, thinner and shed considerably. Multiple pyogenic granulomas were observed in the toenails of 5 patients (5. 9%). Softening of the nail plate was noted in 5 subjects as well. A peripheral lipodystrophy syndrome was noted in 12 patients (14.3%). Among these, one patient only developed a "buffalo hump" and another had diffused lipomatosis. The temporal relationship between the taking of indinavir and the onset of such cutaneous effects was striking. This was confirmed by the regression of symptoms in those patients who later discontinued indinavir. The emerging side effects of protease inhibitors require a multidisciplinary team for adequate diagnosis and treatment. Cutaneous toxicity involving the patient's own body image has a peculiar influence on compliance to the treatment and the patient's quality of life.

Adult↗

Virological suppression at 6 months is related to choice of initial regimen in antiretroviral-naive patients: a cohort study.

BACKGROUND: Guidelines recommend both protease inhibitor (PI)- and non-nucleoside reverse transcriptase inhibitor (NNRTI)-containing regimens for initial therapy in HIV-positive individuals whilst clinical trial data comparing treatment options remain limited. OBJECTIVE: To assess whether drug selection (PI versus NNRTI) in antiretroviral-naive patients is related to virological response at 6 months within a clinical cohort. DESIGN: Databases from two large clinics were used to identify all treatment-naive patients initiating highly active antiretroviral therapy (PI/ two PI or NNRTI). Statistical models determined the likelihood of suppressing HIV viral load < 500 copies/ml, the risk of treatment failure by 6 months, and factors associated with treatment success. RESULTS: Of 1109 potentially eligible patients 888 met study criteria and were included; 484 were prescribed a PI (40% indinavir, 41% nelfinavir) and 404 were prescribed NNRTI (40% efavirenz, 60% nevirapine). Three treatment arms were compared: efavirenz versus nevirapine versus PI. After stratification by year and centre and adjustment for baseline variables, only treatment group and baseline viral load remained significantly associated with virological suppression at 6 months. Patients on efavirenz were significantly more likely to achieve an undetectable viral load than those on PI or nevirapine. The relative hazard for nevirapine was 0.77 (95% confidence interval, 0.61-0.96, P = 0.02) and that for PI was 0.74 (95% confidence interval, 0.58-0.94, P = 0.01). Efavirenz also performed better in the analysis of treatment failure at 6 months. CONCLUSION: Although observational cohort data may be susceptible to significant bias, this study suggests a better initial virological response for efavirenz compared to either nevirapine or the PI. Clinical trial data is required to confirm these findings.

Adult↗

Variations in the care of HIV-infected adults in the United States: results from the HIV Cost and Services Utilization Study.

CONTEXT: Studies of selected populations suggest that not all persons infected with human immunodeficiency virus (HIV) receive adequate care. OBJECTIVE: To examine variations in the care received by a national sample representative of the adult US population infected with HIV. DESIGN: Cohort study that consisted of 3 interviews from January 1996 to January 1998 conducted by the HIV Cost and Services Utilization Consortium. PATIENTS AND SETTING: Multistage probability sample of 2864 respondents (68% of those targeted for sampling), who represent the 231400 persons at least 18 years old, with known HIV infection receiving medical care in the 48 contiguous United States in early 1996 in facilities other than emergency departments, the military, or prisons. The first follow-up consisted of 2466 respondents and the second had 2267 (65% of all surviving sampled subjects). MAIN OUTCOME MEASURES: Service utilization (<2 ambulatory visits, at least 1 emergency department visit that did not lead to hospitalization, at least 1 hospitalization) and medication utilization (receipt of antiretroviral therapy and prophylaxis against Pneumocystis carinii pneumonia). RESULTS: Inadequate HIV care was commonly reported at the time of interviews conducted from early 1996 to early 1997 but declined to varying degrees by late 1997. Twenty-three percent of patients initially and 15% of patients subsequently had emergency department visits that did not lead to hospitalization, 30% initially and 26% subsequently of those who had CD4 cell counts below 0.20 x 10(9)/L did not receive P carinii pneumonia prophylaxis, and 41% initially and 15% subsequently of those who had CD4 cell counts below 0.50 x 10(9)/L did not receive antiretroviral therapy (protease inhibitor or nonnucleoside reverse transcriptase inhibitor). Inferior patterns of care were seen for many of these measures in blacks and Latinos compared with whites, the uninsured and Medicaid-insured compared with the privately insured, women compared with men, and other risk and/or exposure groups compared with men who had sex with men even after CD4 cell count adjustment. With multivariate adjustment, many differences remained statistically significant. Even by early 1998, fewer blacks, women, and uninsured and Medicaid-insured persons had started taking antiretroviral medication (CD4 cell count adjusted P values <.001 to <.005). CONCLUSIONS: Access to care improved from 1996 to 1998 but remained suboptimal. Blacks, Latinos, women, the uninsured, and Medicaid-insured all had less desirable patterns of care. Strategies to ensure optimal care for patients with HIV requires identifying the causes of deficiency and addressing these important shortcomings in care.

Adult↗

HIV-associated lipodystrophy: description, pathogenesis, and molecular pathways.

HIV-infected individuals taking antiretroviral medications may experience changes in body shape and metabolism, commonly known as HIV-associated lipodystrophy (HIVLD). In vitro and in vivo research have revealed numerous effects of both protease inhibitors and nucleoside reverse transcriptase inhibitors on the function of various organs--most importantly adipose tissue, liver, and muscle. The metabolic abnormalities could result in an increased risk of cardiovascular disease in this vulnerable and relatively young population. Treatment strategies, normally successful in the general population, have generally been less effective in this group of people, in which the detrimental effects of the antiretroviral medications are ongoing.

Adipocytes↗

The impact of host pharmacogenetics on antiretroviral drug disposition.

The ability to predict efficacy and toxicity during antiretroviral therapy for HIV would be of obvious advantage. The substantial variability between patients in terms of bioavailability and distribution of current regimens is likely driven by genetic and environmental factors. Protease inhibitors and nucleoside/nucleotide reverse transcriptase inhibitors are metabolized by cytochrome P450 enzymes. Their bioavailability and excretion may also be affected by variability in drug transporters of the ABC and SLC families. In pharmacokinetics and efficacy studies, issues are complicated by multiple loci effects (driven by the large number of proteins contributing to disposition) and heterogeneity in both study populations and the virus (ie, the target). Some of these issues are now being tackled, but studies need to be sufficiently powered and the phenotype carefully characterized. This review aims to summarize the current understanding of pharmacogenetic determinants of antiretroviral disposition.

Journal Article↗