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Background: Human immunodeficiency virus type 1 (HIV-1)-specific cellular immunity contributes to the control of HIV-1 replication. HIV-1-infected volunteers who were receiving antiretroviral therapy were given a replication-defective adenovirus type 5 HIV-1 gag vaccine in a randomized, blinded therapeutic vaccination study., Methods: HIV-1-infected vaccine or placebo recipients underwent analytical treatment interruption (ATI) for 16 weeks. The log(10) HIV-1 RNA load at the ATI set point and the time-averaged area under the curve served as co-primary end points. Immune responses were measured by intracellular cytokine staining and carboxyfluorescein succinimidyl ester dye dilution., Results: Vaccine benefit trends were seen for both primary end points, but they did not reach a prespecified significance level of P < or = 25. The estimated shifts in the time-averaged area under the curve and the ATI set point were 0.24 (P=.04, unadjusted) and 0.26 (P=.07, unadjusted) log(10) copies lower, respectively, in the vaccine arm than in the placebo arm. HIV-1 gag-specific CD4(+) cells producing interferon-gamma were an immunologic correlate of viral control., Conclusion: The vaccine was generally safe and well tolerated. Despite a trend favoring viral suppression among vaccine recipients, differences in HIV-1 RNA levels did not meet the prespecified level of significance. Induction of HIV-1 gag-specific CD4 cells correlated with control of viral replication in vivo. Future immunogenicity studies should require a substantially higher immunogenicity threshold before an ATI is contemplated.

Background: The usefulness of plasma human herpesvirus 8 (HHV-8) DNA as a marker of response to treatment for acquired immunodeficiency syndrome-associated Kaposi sarcoma (AIDS-KS) in an African setting is unknown., Methods: We conducted a prospective pilot study at the Parirenyatwa Hospital Kaposi Sarcoma Clinic (Harare, Zimbabwe) to investigate the hypothesis that the clinical response of AIDS-KS is associated with suppression of HHV-8 DNA. Antiretroviral therapy (ART) was provided as coformulation of abacavir, lamivudine, and zidovudine. Clinical response was defined as survival to week 96 with either complete or partial resolution of KS disease., Results: Ninety ART-naive participants (62 men and 28 women) aged >18 years who had human immunodeficiency virus type 1 (HIV-1) infection and biopsy-confirmed KS were studied; 82% had stage T1 disease. Fifty participants received adjunctive chemotherapy. The median CD4(+) lymphocyte count increased from 124 cells/microL at baseline to 281 cells/microL, the plasma HIV-1 RNA level decreased from 4.69 to <2.60 log(10) copies/mL, the plasma HHV-8 DNA level decreased from 660 to <25 copies/mL, and HHV-8 DNA level in peripheral blood mononuclear cells decreased from 2790 to 37 copies/10(6) cells (P < .001 for each comparison). There were 14 deaths (16%) and 13 patients (15%) lost to follow-up. The most common cause of death was infection. Clinical response of KS occurred in 17 participants (19%). Pretreatment plasma HHV-8 DNA levels of <660 copies/mL were associated with greater survival (odds ratio, 2.83; 95% confidence interval, 1.07-7.53; P = .04) and a better clinical response (odds ratio, 6.38; 95% confidence interval, 1.68-24.19; P = .006)., Conclusions: AIDS-KS tumor responses after ART initiation were limited. Pretreatment plasma HHV-8 DNA level may be a surrogate for KS disease that is in need of intensive clinical management.

To detect early cases of pandemic (H1N1) 2009 infection, in 2009 we surveyed 303 persons from marginalized populations of drug users, sex workers, and homeless persons in Tijuana, Mexico. Six confirmed cases of pandemic (H1N1) 2009 were detected, and the use of rapid, mobile influenza testing was demonstrated.

Background: To our knowledge, the antiviral activity of pegylated interferon alfa-2a has not been studied in participants with untreated human immunodeficiency virus type 1 (HIV-1) infection but without chronic hepatitis C virus (HCV) infection., Methods: Untreated HIV-1-infected volunteers without HCV infection received 180 microg of pegylated interferon alfa-2a weekly for 12 weeks. Changes in plasma HIV-1 RNA load, CD4(+) T cell counts, pharmacokinetics, pharmacodynamic measurements of 2',5'-oligoadenylate synthetase (OAS) activity, and induction levels of interferon-inducible genes (IFIGs) were measured. Nonparametric statistical analysis was performed., Results: Eleven participants completed 12 weeks of therapy. The median plasma viral load decrease and change in CD4(+) T cell counts at week 12 were 0.61 log(10) copies/mL (90% confidence interval [CI], 0.20-1.18 log(10) copies/mL) and -44 cells/microL (90% CI, -95 to 85 cells/microL), respectively. There was no correlation between plasma viral load decreases and concurrent pegylated interferon plasma concentrations. However, participants with larger increases in OAS level exhibited greater decreases in plasma viral load at weeks 1 and 2 (r = -0.75 [90% CI, -0.93 to -0.28] and r = -0.61 [90% CI, -0.87 to -0.09], respectively; estimated Spearman rank correlation). Participants with higher baseline IFIG levels had smaller week 12 decreases in plasma viral load (0.66 log(10) copies/mL [90% CI, 0.06-0.91 log(10) copies/mL]), whereas those with larger IFIG induction levels exhibited larger decreases in plasma viral load (-0.74 log(10) copies/mL [90% CI, -0.93 to -0.21 log(10) copies/mL])., Conclusion: Pegylated interferon alfa-2a was well tolerated and exhibited statistically significant anti-HIV-1 activity in HIV-1-monoinfected patients. The anti-HIV-1 effect correlated with OAS protein levels (weeks 1 and 2) and IFIG induction levels (week 12) but not with pegylated interferon concentrations.

A novel strain of influenza A H1N1 emerged in the spring of 2009 and has spread rapidly throughout the world. Although vaccines have recently been developed that are expected to be protective, their availability was delayed until well into the influenza season. Although anti-influenza drugs such as neuraminidase inhibitors can be effective, resistance to these drugs has already been reported. Although human saliva was known to inhibit viral infection and may thus prevent viral transmission, the components responsible for this activity on influenza virus, in particular, influenza A swine origin influenza A virus (S-OIV), have not yet been defined. By using a proteomic approach in conjunction with beads that bind alpha-2,6-sialylated glycoprotein, we determined that an alpha-2-macroglobulin (A2M) and an A2M-like protein are essential components in salivary innate immunity against hemagglutination mediated by a clinical isolate of S-OIV (San Diego/01/09 S-OIV). A model of an A2M-based "double-edged sword" on competition of alpha-2,6-sialylated glycoprotein receptors and inactivation of host proteases is proposed. We emphasize that endogenous A2M in human innate immunity functions as a natural inhibitor against S-OIV.

Rong and colleagues have applied a mathematical model of hepatitis C virus (HCV) replication to experimental data from initial clinical investigations of HCV protease inhibitors. In this Perspective, we discuss how mathematical modeling and other modern translational research tools and approaches can be used to expedite drug development with well-designed combination clinical trials that test drugs from multiple collaborators.

Therapies for hepatitis B virus (HBV) have continued to evolve, and new therapies for hepatitis C virus (HCV) will soon be available in clinical practice. These medications for hepatitis C will mark the first time that direct antivirals that target HCV functions have been used. When such drugs are used as single agents, previously existing mutants with reduced susceptibility to them are rapidly selected. The relationship between these drug-resistant mutants and "wild-type" virus is unclear, but resistant strains likely have the potential to maintain the progression of liver disease despite successful treatment of "wild-type" virus. Resistant HBV and now HCV are already a clinical problem. The same issue was recognized very early in the development of therapy against HIV, with azidothymidine-resistant mutants detected within the first weeks of therapy. Clinical investigation and a progressive understanding of the pathogenesis of the disease overcame this challenge and led to the substantial and durable benefits of antiretroviral therapy that are evident today. To bring experts from the fields of HIV and viral hepatitis virology and therapy together for interactive discussions about how to apply the lessons from HIV to the further development of viral hepatitis therapy, the American Association for the Study of Liver Diseases held a single-topic conference entitled "Viral Hepatitis Therapy: Lessons to be Learned From HIV" on 24-26 July 2008. This article summarizes that conference.

The octadecyloxyethyl (ODE) and hexadecyloxypropyl (HDP) esters of (S)-9-[3-hydroxy-2-(phosphonomethoxy)propyl]adenine (HPMPA) are potent inhibitors of orthopoxvirus, herpesvirus, human immunodeficiency virus type 1, and hepatitis B virus replication in vitro. HDP and ODE esters of (S)-HPMPA and (R)-HPMPA were evaluated for their activity in hepatitis C virus (HCV) replicon assays using luciferase (1B and 2A replicons) or RNA (1B) quantification. The ODE ester of (S)-HPMPA [ODE-(S)-HPMPA] was the most active compound, with 50% effective concentrations (EC(50)s) in the 0.69 to 1.31 microM range. HDP and ODE esters of (R)-HPMPA were severalfold less active, while (S)-HPMPA and (R)-HPMPA were inactive. In genotype 1A and 1B replicons analyzed by HCV RNA analysis, ODE-(S)-HPMPA was the most active compound, with EC(50)s of 1.8 and 2.1 microM, respectively.

Leishmania species are obligate intracellular protozoan parasites that cause a broad spectrum of clinical diseases in mammalian hosts. The most frequently used approach to quantify parasites in murine model systems is based on thickness measurements of the footpad or ear after experimental infection. To overcome the limitations of this method, we used a Leishmania mutant episomally transfected with enhanced green fluorescent protein, enabling in vivo real-time whole-body fluorescence imaging, to follow the progression of Leishmania infection in parasitized tissues. Fluorescence correlated with the number of Leishmania parasites in the tissue and demonstrated the real-time efficacy of a therapeutic vaccine. This approach provides several substantial advantages over currently available animal model systems for the in vivo study of immunopathogenesis, prevention, and therapy of leishmaniasis. These include improvements in sensitivity and the ability to acquire real-time data on progression and spread of the infection.

After disappointing results from all efficacy trials conducted to date, the field of microbicides research now faces substantial challenges. Poor coordination among interested parties and the choice of nonvalidated scientific targets for phase III studies have hampered progress and created mistrust about the use of microbicides as a method to prevent HIV-1 sexual transmission. Although new promising strategies are available, there will need to be serious reappraisals of how decisions are made to advance the next generations of candidates into clinical trials, and the use of appropriate animal models in this process will be critical.

A DNA vaccine encoding sequence-conserved human immunodeficiency virus type 1 (HIV-1)-derived cytotoxic T-lymphocyte (CTL) epitopes from multiple HIV-1 gene products (designated EP HIV-1090) was evaluated in a placebo-controlled, dose escalation phase 1 clinical trial of HIV-1-infected subjects receiving potent combination antiretroviral therapy. Patients received four intramuscular immunizations with EP HIV-1090 over a 4-month period at one of four doses (0.5, 1.0, 2.0, or 4.0 mg) or received a placebo. The vaccine was determined to be safe and well tolerated at all doses tested. CTL responses were measured from cryopreserved peripheral blood mononuclear cells using gamma interferon enzyme-linked immunospot assays, with and without in vitro peptide stimulation (IVS). Responses to one or more vaccine epitopes were detected throughout the course of vaccination in 37.5% (12/32) and 47% (15/32) of vaccine recipients measured without and with IVS, respectively, indicating possible vaccine-induced priming of epitope-specific T cells. However, differences in rates of response to HIV-1 epitopes between vaccine and placebo recipients did not achieve statistical significance. The HIV-1 epitope-specific CTL responses measured in the peripheral blood after vaccination were often low level and short-lived, and therefore, alternative immunization schedules, routes of delivery, or vaccine formulations may be required to increase vaccine potency.

Rapid emergence of resistance to monotherapy with virus-specific inhibitors necessitates combination therapy. ACH-806 is a hepatitis C virus NS4A inhibitor with a novel mechanism of action and resistance pathway. This compound was synergistic with NS3 protease inhibitors and NS5B nucleoside and nonnucleoside polymerase inhibitors.

Small molecular inhibitors of hepatitis C virus (HCV) replication provide remarkable potency, but the rapid selection of resistance mutations will require that these agents be used in combination for clinical treatment. Using a model HCV replicon system, we have extended prior in vitro studies of double combinations of candidate small molecular inhibitors to studies evaluating the simultaneous use of 3 agents. This was done in an effort to anticipate conditions that might ultimately be required clinically. We formally demonstrate synergistic antiviral activity with 3-drug combinations in this model, further supporting the concept of clinical investigations of combination therapy for HCV infection.

To understand the extent of immune dysregulation in primary HIV infection (PHI) and the impact of antiretroviral therapy (ART) on restoring these abnormalities, we longitudinally evaluated 52 subjects (Acute-Treated (AT); Early-Treated (ET); Early Untreated (EU)) for markers of activation, proliferation, and function on T cells. ET and AT patients differed by 0.54 log viral load (VL) at baseline but did not differ thereafter by more than 0.34 log10 VL. AT subjects had higher CD8(+) T cell counts and expression of markers indicative of CD8(+) T cell activation (CD38), and proliferation (Ki67), at baseline, than ET subjects but were not different 48 weeks post-ART. Although acute PHI is marked by higher level of immune activation than early PHI, virologic and immunologic responses were similar post-ART, suggesting that the extent of immunologic recovery is not negatively impacted by a delay of treatment beyond the acute stage of disease.

Chronic hepatitis C virus (HCV) infection is a significant worldwide health problem with limited therapeutic options. A number of novel, small molecular inhibitors of HCV replication are now entering early clinical trials in humans. Resistance to small molecular inhibitors is likely to be a significant hurdle to their use in patients. A systematic assessment of combinations of interferon and/or novel anti-hepatitis C virus agents from several different mechanistic classes was performed in vitro. Combinations of inhibitors with different mechanisms of action consistently demonstrated more synergy than did compounds with similar mechanisms of action. These results suggest that combinations of inhibitors with different mechanisms of action should be prioritized for assessment in clinical trials for chronic hepatitis C virus infection.

Antiretroviral therapy success is highly dependent on the ability of the patient to fully adhere to the prescribed treatment regimen. We present the results of a cross-sectional study that evaluates the predictive value of a self-administered questionnaire of adherence to antiretroviral (ARV) therapy. Study participants were interviewed using a 36-item Patient Medication Adherence Questionnaire (PMAQ) designed to assess knowledge about ARV therapy, motivation to adhere to treatment, and behavioral skills. Plasma HIV-1 RNA levels were correlated with the results obtained from the PMAQ. Of the 182 study participants, 82 (45%) were receiving their initial ARV regimen. Of the remaining patients, 39 (21%) and 61 (34%) were on a second or additional ARV regimen, respectively. An undetectable viral load was documented in 47/62 (76%) patients on their first regimen who reported missing medication on less than 4 days in the last 3 months. The PMAQ had a higher predictive value of plasma viral suppression for patients in the initial regimen than for patients in salvage therapy. The overall predictive value of the PMAQ to identify adherence was 74%, and 59% for nonadherence, with an overall efficacy of 64%. Of the 74 patients (45%) who did not understand the concept of antiretroviral therapy, 80% were failing or had previously failed the ARV treatment. Of 35 patients with doubts about their HIV status or skeptical of the benefits of ARV therapy, 29 (84%) were nonadherent. Despite the positive predictive value of PMAQ in identifying adherence, self-reported adherence is not a sufficiently precise predictor of treatment success to substitute for viral load monitoring. On the other hand, the use of such an instrument to identify factors associated with nonadherence provides an excellent opportunity to apply early intervention designed to specifically address factors that might be contributing to the lack of adherence prior to regimen failure.

HIV-1 enters cells by membrane fusion, mediated by the trimeric viral envelope glycoprotein gp160, which is processed by a single proteolytic cleavage into stably associated gp120 and gp41. The gp120/gp41 trimer can be triggered to undergo an irreversible conformational change. Using a protein-based assay designed to mimic the gp41 conformational change, we screened for small molecules that prevent the formation of postfusion gp41. Several compounds were identified. One set of structurally related molecules inhibited formation of a postfusion-like assembly with an IC50 of approximately 5 microM. The compounds also inhibited envelope-mediated membrane fusion in both cell-cell fusion and viral infectivity assays. Thus, our screen identifies effective fusion inhibitors. Tested against a panel of envelope proteins from primary HIV-1 isolates, the compounds inhibited fusion across a broad range of clades, including both M and T tropic strains. They bind in a highly conserved, hydrophobic pocket on the inner core of the gp41 trimer, a region previously identified as a potential inhibitor site.

Recently, antiretroviral agents directed at several steps involved in viral entry have been shown to reduce viral replication in vitro and in vivo. We have demonstrated a high level of in vitro synergistic antiretroviral activity for two entry inhibitors that are directed at sequential steps in the entry process.

Hepatitis C virus (HCV) infection is common in HIV-infected individuals and is responsible for increasing morbidity in these patients. HIV infection increases HCV replication and accelerates progression of HCV disease. HCV infection increases the risk of antiretroviral treatment. HCV genotype 1 is the predominant genotype in HCV/HIV-coinfected individuals living in the United States. State-of-the-art treatment with peginterferon alfa plus ribavirin results in lower sustained HCV virologic response rates in patients with genotype 1 infection than in those infected with other genotypes. Data from studies of HCV infection treatment in coinfected patients are discussed, as are prospects for future therapy. This article summarizes a presentation on HIV/HCV coinfection by Robert T. Schooley, MD, at the International AIDS Society-USA course in San Francisco in June 2005.

The effects of hematopoietic stem cell (HSC) mobilization on Kaposi's sarcoma-associated herpesvirus (KSHV) were evaluated in three KSHV and human immunodeficiency virus type 1 co-infected subjects. KSHV DNA was not detected in purified CD34+ cell preparations from the period of filgrastim treatment. However, two of 3 subjects had transiently increased cell-free plasma KSHV DNA during filgrastim treatment. Peak plasma KSHV DNA (2,600 and 4,300 copies/mL) occurred on day 4 and declined to below the limit of detection by day 7. These findings suggest that, although CD34+ cell preparations do not have evidence of KSHV infection, HSC mobilization may stimulate KSHV replication in other cellular compartments that contribute to KSHV viremia., (2004 Wiley-Liss, Inc.)

The hypothesis that filgrastim (r-met-huG-CSF) activates replication of minor variants of human inmmunodeficiency virus type 1 (HIV-1) was tested by analysis of plasma quasi-species composition in 7 subjects in whom plasma HIV-1 RNA had increased during filgrastim treatment. Inferred phylogenetic trees of env sequences from 3 subjects during filgrastim treatment contained unique intrasubject subclusters that shared a most recent common ancestor with the baseline HIV-1 quasi species. Genotypes in the unique subclusters were not detected before filgrastim treatment, yet they composed 40%-70% of the plasma quasi species during treatment. The minority variants that appeared in 1 subject were more distantly related to plasma quasi species present 5 years before filgrastim treatment than were the majority of the pretreatment plasma quasi species. These findings provide evidence that increased HIV-1 replication during filgrastim treatment was associated with activation of HIV-1 variants that, before filgrastim treatment, were minor components of the plasma quasi species.

Context: Substantial changes in the field of human immunodeficiency virus (HIV) treatment have occurred in the last 2 years, prompting revision of the guidelines for antiretroviral management of adults with established HIV infection., Objective: To update recommendations for physicians who provide HIV care regarding when to start antiretroviral therapy, what drugs to start with, when to change drug regimens, and what drug regimens to switch to after therapy fails., Data Sources: Evidence was identified and reviewed by a 16-member noncompensated panel of physicians with expertise in HIV-related basic science and clinical research, antiretroviral therapy, and HIV patient care. The panel was designed to have broad US and international representation for areas with adequate access to antiretroviral management., Study Selection: Evidence considered included published basic science, clinical research, and epidemiological data (identified by experts in the field or extracted through MEDLINE searches using terms relevant to antiretroviral therapy) and abstracts from HIV-oriented scientific conferences between July 2002 and May 2004., Data Extraction: Data were reviewed to identify any information that might change previous guidelines. Based on panel discussion, guidelines were drafted by a writing committee and discussed by the panel until consensus was reached., Data Synthesis: Four antiretroviral drugs recently have been made available and have broadened the options for initial and subsequent regimens. New data allow more definitive recommendations for specific drugs or regimens to include or avoid, particularly with regard to initial therapy. Recommendations are rated according to 7 evidence categories, ranging from I (data from prospective randomized clinical trials) to VII (expert opinion of the panel)., Conclusion: Further insights into the roles of drug toxic effects, drug resistance, and pharmacological interactions have resulted in additional guidance for strategic approaches to antiretroviral management.

Adherence is the milestone of a successful therapy. Over the last decade several authors have addressed the importance of adherence for optimal results of antiretroviral (ARV) therapy. Many health care systems are investing substantial resources to make available contemporary antiretroviral therapy. Despite the large investment in medications, insufficient investments have been made into an integrated adherence component to maximize the impact of these medications. Adherence, unlike drug therapy, cannot be defined as a single method with a defined prescription or formula. Instead, it is the result of a complex interaction between the patient, a prescribed medication and the health system. Many reports are available analyzing each of these components. We have found that critical elements of adherence include the patient's knowledge about the disease and how medications will help achieve a longer and healthier life, together with the motivation to adapt to a new style of life. A trilogy composed of information, motivation and behavioral skills is essential to achieve the maximum desired level of adherence. We have computerized this trilogy in a software program for self-administration in which each of the three components is provided to the patient as many times as necessary to transmit an understanding of the problem and to help make a rational decision to adhere to the ARV treatment program. In this review we analyze several efforts and techniques to improve adherence to any recommended medication that may interfere with the patient's lifestyle and outline how the adherence trilogy can be best used to optimize the ability of ARV therapy to durably suppress plasma HIV RNA to undetectable levels.

Objective: New information warrants updated recommendations for the 4 central issues in antiretroviral therapy: when to start, what drugs to start with, when to change, and what to change to. These updated recommendations are intended to guide practicing physicians actively involved in human immunodeficiency virus (HIV)- and acquired immunodeficiency syndrome (AIDS)-related care., Participants: In 1995, physicians with specific expertise in HIV-related basic science and clinical research, antiretroviral therapy, and HIV patient care were invited by the International AIDS Society-USA to serve on a volunteer panel. In 1999, others were invited to broaden international representation. The 17-member panel met regularly in closed meetings between its last report in 2000 and April 2002 to review current data. The effort was sponsored and funded by the International AIDS Society-USA, a not-for-profit physician education organization., Evidence and Consensus Process: The full panel was convened in late 2000 and assigned 7 section committees. A section writer and 3 to 5 section committee members (each panel member served on numerous sections) identified relevant evidence and prepared draft recommendations. Basic science, clinical research, and epidemiologic data from the published literature and abstracts from recent (within 2 years) scientific conferences were considered by strength of evidence. Extrapolations from basic science data and expert opinion of the panel members were included as evidence. Draft sections were combined and circulated to the entire panel and discussed in a series of full-panel conference calls until consensus was reached. Final recommendations represent full consensus agreement of the panel., Conclusions: Because of increased awareness of the activity and toxicity of current drugs, the threshold for initiation of therapy has shifted to a later time in the course of HIV disease. However, the optimal time to initiate therapy remains imprecisely defined. Availability of new drugs has broadened options for therapy initiation and management of treatment failure, which remains a difficult challenge.

Objective: To evaluate the virologic responses and mutational profiles in antiretroviral-experienced patients adding tenofovir DF once-daily to their existing regimens., Design: Resistance analyses were performed for patients in a phase II placebo-controlled clinical trial of tenofovir DF., Methods: HIV-1 reverse transcriptase and protease genes from plasma samples were analyzed genotypically and phenotypically at baseline, week 24, and week 48., Results: Of 184 patients, 173 (94%) had baseline HIV-1 expressing one or more nucleoside reverse transcriptase inhibitor-associated resistance mutation. Protease inhibitor and non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance mutations were observed in 57% and 32% of patients, respectively. Compared to placebo, significant reductions in HIV-1 RNA were observed for tenofovir DF-treated patients who had thymidine analog- (TAM), lamivudine- (M184V), NNRTI- or protease inhibitor-associated mutations. Patients with phenotypic susceptibility to tenofovir within 4-fold of wild-type responded durably to tenofovir DF 300 mg therapy with a decline in plasma HIV-1 RNA of > or = 0.5 log10 copies/ml; few patients had a more than 4-fold reduced susceptibility to tenofovir at baseline. Four patients (2%) developed the K65R mutation (selected by tenofovir in vitro) and showed 3- to 4-fold reductions in tenofovir susceptibility but no evidence of rebound viremia. Thirty-four percent of patients developed additional TAMs, coincident with concurrent zidovudine or stavudine therapy, but also showed durable HIV-1 reductions. There was no evidence of novel resistance to tenofovir., Conclusions: Adding tenofovir DF 300 mg to an existing regimen in patients with ongoing viral replication and a wide range of genotypic resistance patterns resulted in significant and durable HIV-1 RNA reductions. In addition, there was a low incidence of genotypic or phenotypic resistance to tenofovir DF arising during 48 weeks of therapy.

Objective: To evaluate the safety and efficacy of once daily doses of tenofovir DF (TDF) administered in combination with other antiretroviral therapy (ART) in treatment-experienced HIV-1-infected patients with incomplete virological suppression., Design: One-hundred and eighty-nine subjects with plasma HIV-1 RNA levels between 400 and 100,000 copies/ml and stable ART (> or = 8 weeks) were randomized (2 : 2 : 2 : 1 ratio) to add TDF 75 mg, 150 mg, or 300 mg or placebo to existing ART in a double-blinded manner. After 24 weeks, patients initially randomized to placebo received blinded TDF 300 mg., Methods: Efficacy was analyzed by the mean changes HIV-1 RNA levels (log10 copies/ml plasma; DAVG(xx)) from week 0 to weeks 4, 24, and 48. Safety was analyzed by incidence of grade 3 or 4 clinical and laboratory adverse events., Results: At baseline, patients had mean 4.6 years prior ART use with 94% having HIV-1 with nucleoside-associated resistance mutations. There were statistically significant decreases in DAVG(4) and DAVG(24) for all doses of TDF compared with placebo, with the greatest effect seen with TDF 300 mg (DAVG(4), -0.62, P < 0.001; DAVG(24), -0.58; P < 0.001; DAVG(48), -0.62). The incidence of adverse events was similar among the TDF groups and placebo through week 24. Throughout the 48-week study, no significant changes in renal function were observed., Conclusions: In treatment-experienced patients with baseline nucleoside resistance mutations, TDF provided dose-related, durable reductions in HIV-1 RNA. Through 24 weeks, the safety profile of TDF was similar to that of placebo.

Human immunodeficiency virus type 1 (HIV-1)-specific memory, or precursor, cytotoxic T lymphocytes (CTL) in 14 subjects who had recently experienced seroconversion were evaluated with respect to virus set point, defined as plasma HIV-1 RNA level 6 months after seroconversion. Env-, Gag-, Pol-, and Nef-specific precursor CTL were detected in (51)Cr-release assays, using antigen-stimulated peripheral blood mononuclear cells as effectors and B cell lines infected with HIV-1-vaccinia recombinants as targets. All subjects tested had precursor CTL specific to at least 2 HIV-1 antigens. Detection of Env-specific precursor CTL was associated with a high set point (P=.0221). The number of antigens recognized tended to be greater in subjects with higher set points (rho=.45621; P=.1171). Gag-specific precursor CTL frequency correlated inversely with set point (rho=-.8478; P=.0003). Two heterozygotes for a 32-bp deletion in CCR5 had the lowest set points (P=.0220) and highest Gag precursor CTL frequencies (P=.0128). These data suggest that host factors that restrict viral replication may be important determinants of the level of HIV-1-specific precursor CTL.

Objective: To evaluate the antiretroviral activity and safety of multiple escalating doses of amprenavir administered alone, and in combination with abacavir in HIV-1-infected adults., Design: Sixty-two HIV-1-infected subjects were enrolled in a multicentre, open-label, non-randomized, dose-escalating trial., Methods: Subjects were assigned to one of six dose groups and received amprenavir 300 mg twice daily, 300 mg three times daily, 900, 1050, or 1,200 mg twice daily for 4 weeks. One dose group received amprenavir 900 mg twice daily in combination with abacavir 300 mg twice daily for 4 weeks. Antiretroviral activity was assessed by measuring changes from baseline in plasma HIV-1 RNA levels and CD4 cell counts. Safety was evaluated by monitoring clinical adverse events and changes in laboratory values. Genotypic and phenotypic analyses were performed using ABI sequencing and the recombinant virus assay, respectively., Results: At week 4, amprenavir monotherapy (900, 1,050, or 1,200 mg twice daily) resulted in marked decreases in plasma HIV-1 RNA levels (1.3-1.6 log10 copies/ml), and substantial increases in CD4 cell counts in the two dose groups who received 1,050 mg twice daily (118 x 10(6) cells/mm3) or 1,200 mg twice daily (114 x 10(6) cells/mm3). Amprenavir/abacavir resulted in median plasma HIV-1 RNA reductions of 1.8 log10 copies/ml, and median CD4 cell count increases of 138 x 10(6) cells/mm3. Amprenavir was reasonably well tolerated with few treatment-limiting adverse events. No known active site mutations associated with amprenavir resistance were selected in any of the dose groups, and no significant phenotypic resistance to amprenavir developed during 4 weeks of therapy., Conclusions: The antiviral effect of amprenavir monotherapy increased with escalating doses, and all amprenavir doses were reasonably well tolerated over 4 weeks of therapy. Amprenavir/abacavir combination therapy elicited a potent antiviral effect. The three highest doses of amprenavir (900, 1,050 and 1,200 mg twice daily) were selected to design subsequent Phase II and III studies that confirmed the safety profile and efficacy of amprenavir in combination regimens and led to the approval of amprenavir in the USA in 1999.

Current models suggest that during human immunodeficiency virus type 1 (HIV-1) transmission virions are selected that use the CCR5 chemokine receptor on macrophages and/or dendritic cells. A gradual evolution to CXCR4 chemokine receptor use causes a shift in the proportion of productively infected cells to the CD4 cell population. Productively infected cells during acute and early infection in lymphoid tissue were assessed, as well as the impact of productive infection on the T cell population in 21 persons who had biopsies performed on days 2-280 after symptoms of acute HIV-1 seroconversion. Even in the earliest stages of infection, most productively infected cells were T lymphocytes. There were sufficient infected cells in lymphoid tissue (LT) to account for virus production and virus load in plasma. Despite the relatively high frequency of productively infected cells in LT, the impact on the size of the T cell population in LT at this stage was minor.

Clinical research has undergone remarkable and beneficial expansion in the past 25 years, but with this growth has come an unprecedented increase in workload for the human subjects protection system. Recently, a major change in federal oversight of local institutional review boards (IRBs) became evident. Although it was not announced publicly, in 1998 and 1999 federal regulatory actions against local IRBs increased threefold. Particularly notable was the marked increase in regulatory actions taken against the IRBs of academic medical centers (1 in 1997 compared with 14 in 1999). Ironically, this apparent federal crackdown began at the same time that two federal review panels called for major changes in the regulations governing local IRBs. A key factor in the current crisis in the function of local IRBs is the ascendance of multicenter clinical trials as the dominant form of clinical research. Local IRBs were not designed to handle the initial evaluation and ongoing review required by the rapidly increasing number of multicenter clinical trials. Furthermore, local IRB review of the thousands of safety reports from multicenter clinical trials monopolizes resources without promoting patient safety. Instead of rigid enforcement of outmoded regulations that do not contribute to patient safety, the responsibilities of the local IRB in the oversight of multicenter clinical trials must be systematically evaluated.

The potential role of human immunodeficiency virus type 1 (HIV-1)-specific immune responses in controlling viral replication in vivo has stimulated interest in enhancing virus-specific immunity by vaccinating infected individuals with HIV-1 or its components. These studies were undertaken to define patient populations most likely to respond to vaccination, with the induction of novel HIV-1-specific cellular immune responses, and to compare the safety and immunogenicity of several candidate recombinant HIV-1 envelope vaccines and adjuvants. New lymphoproliferative responses (LPRs) developed in <30% of vaccine recipients. LPRs were elicited primarily in study participants with a CD4 cell count >350 cells/mm(3) and were usually strain restricted. Responders tended to be more likely than nonresponders to have an undetectable level of HIV-1 RNA at baseline (P=.067). Induction of new cellular immune responses by HIV-1 envelope vaccines is a function of the immunologic stage of disease and baseline plasma HIV-1 RNA level and exhibits considerable vaccine strain specificity.

Objective: To determine the relationship between human herpesvirus 8 (HHV-8 or Kaposi's sarcoma-associated herpesvirus) peripheral blood virus load and Kaposi's sarcoma (KS) clinical stage., Design: Blinded, cross-sectional analysis of peripheral blood HHV-8 DNA levels in persons with AIDS-related KS in Harare, Zimbabwe., Methods: Subjects were stratified by KS clinical stage. The amount of HHV-8 DNA in plasma and peripheral blood mononuclear cells (PBMC) was determined by quantitative real-time PCR amplification of the HHV-8 open reading frame 26., Results: Thirty-one HIV-1/HHV-8-coinfected persons were studied: 26 subjects had histologically confirmed KS (one stage II, 11 stage III and 14 stage IV) and five subjects had antibodies to HHV-8 but did not have KS. The age, CD4 lymphocyte count and plasma HIV-1 RNA levels were similar in all groups. HHV-8 DNA was detected in the plasma of all HHV-8-infected subjects (range < 2.4 to 5.2 log10 copies/ml), but plasma HHV-8 DNA levels were not associated with KS disease stage. In contrast, the amount of HHV-8 DNA in PBMC (range < 0.7 to 4.5 log10 copies/microg) was strongly associated with KS clinical stage (P = 0.005). Among stage IV KS cases, there was a linear relationship between plasma and PBMC HHV-8 DNA levels (r2 = 0.42; P = 0.01)., Conclusion: The strong association observed between the extent of KS disease and the levels of HHV-8 DNA in PBMC provides further evidence for a relationship between HHV-8 virus load and KS pathogenesis.

Objective: To update recommendations for antiretroviral therapy for adult human immunodeficiency virus type 1 (HIV-1) infection, based on new information and drugs that are available., Participants: A 17-member international physician panel with antiretroviral research and HIV patient care experience initially convened by the International AIDS Society-USA in December 1995., Evidence: Available clinical and basic science data including phase 3 controlled trials; data on clinical, virologic, and immunologic end points; research conference reports; HIV pathogenesis data; and panel expert opinion. Recommendations were limited to therapies available (US Food and Drug Administration approved) in 1999., Consensus Process: The panel assesses new research reports and interim results and regularly meets to consider how the new data affect therapy recommendations. Recommendations are updated via full-panel consensus. Guidelines are presented as recommendations if the supporting evidence warrants routine use in the particular situation and as considerations if data are preliminary or incomplete but suggestive., Conclusions: The availability of new antiretroviral drugs has expanded treatment choices. The importance of adherence, emerging long-term complications of therapy, recognition and management of antiretroviral failure, and new monitoring tools are addressed. Optimal care requires individualized management and ongoing attention to relevant scientific and clinical information in the field.

Granulocyte colony-stimulating factor (r-met Hu G-CSF; filgrastim; 10 microgram/kg/day for 7 days) was used to mobilize CD34+stem cells into the peripheral blood of human immunodeficiency virus type 1 (HIV-1)-infected individuals and a group of HIV-1-uninfected donors as a measure of immunologic reserve in HIV-1-infected people. G-CSF mobilized CD34+ cells of HIV-1-infected individuals with cell counts >500 CD4+ cells/mm3, as well as in HIV-1-uninfected donors. In contrast, CD34 cell mobilization was significantly blunted in HIV-1-infected individuals with cell counts <500 CD4+ cells/mm3 (<200 cell days vs. >650 cell days, P<.0005, compared with the >500 CD4+ cell cohort). At least 1.75x10(7) CD34 cells were harvested by leukapheresis from patients in each study cohort. CD34+ cell viability and the ability to differentiate precursor cells into myeloid and erythroid progenitor cells were not affected by HIV-1 infection.

Genetic modification of hemopoietic progenitor cells ex vivo, followed by the infusion of the genetically modified cells into the human immunodeficiency virus-1 (HIV-1) infected donor, has been proposed as a treatment for HIV-1 infection. The current study was undertaken to evaluate the effect of hemopoietic stem cell mobilization and harvesting on HIV-1 replication in persons with HIV-1 infection. Eighteen HIV-1-infected persons received recombinant granulocyte colony-stimulating factor (G-CSF; Filgrastim) 10 microg/kg per day, for 7 days. On days 4 and 5, peripheral blood mononuclear cells were harvested by leukapheresis. The CD4+ lymphocyte count at entry was >500/microL for 6 subjects, 200 to 500/microL for 6 subjects, and <200/microL for 6 subjects. For 9 of 18 subjects, plasma HIV-1 RNA levels increased 4- to 100-fold (>0.6 log(10)) above baseline between days 4 and 7 and returned to baseline by day 27. Significant increases of plasma HIV-1 RNA levels occurred in 5 subjects despite 3-drug antiretroviral therapy. Changes in CD4+ and CD34+ cells during mobilization and harvesting were similar in all subjects whether they had or did not have increased plasma HIV-1 RNA levels. Thus, mobilization and harvesting of bone marrow progenitor cells from persons infected with HIV-1 induced a transient increase in viral replication in some patients but was not associated with adverse effects. (Blood. 2000;95: 48-55)

Objective: To determine the prevalence of human herpesvirus 8 (HHV-8) infection in men treated for HIV-1 infection in Denver, Colorado., Design: Cross-sectional analysis, Methods: Blood samples were obtained from 216 HIV-1-infected men. Antibody to latency-associated nuclear antigen (LANA) was detected by an immunofluorescent assay and the presence of HHV-8 in peripheral blood mononuclear cells (PBMC) was detected by polymerase chain reaction amplification., Results: Among HIV-1-infected men who did not have Kaposi's sarcoma (KS), prevalence of HHV-8 infection was 46% (95% confidence interval [CI], 0.39-0.52). LANA seropositivity was common both among subjects with KS and subjects without KS (69% versus 42%; p = .06), but detection of HHV-8 DNA in peripheral blood was strongly associated with a diagnosis of KS (44% versus 10%; p = .001). In a univariate analysis of study subjects without KS, neither the odds of LANA seropositivity nor detection of HHV-8 DNA in PBMC was significant for CD4+ lymphocyte count, HIV-1 virus load, the use of three drug antiretroviral regimens or the prior occurrence of non-KS AIDS-related conditions., Conclusion: Although antibodies to HHV-8 are common among HIV-1-infected men, detection of HHV-8 DNA in PBMC is uncommon and is associated with a diagnosis of Kaposi's sarcoma.

The effect of a 4-fold increase in alpha1-acid glycoprotein (AGP) on the antiviral efficacy of 5 human immunodeficiency virus (HIV) protease inhibitors (PIs) was examined by the effect of HIV PIs on p24 production in peripheral blood mononuclear cells infected with protease wild-type and PI-resistant HIV isolates. For wild-type virus, the efficacy of the PIs at trough concentrations was unaffected by a 4-fold increase in AGP. With the partially HIV PI-resistant isolate, a 4-fold increase in AGP resulted in 2%, 30%, 37%, 37%, and 42% loss of activity for indinavir, saquinavir, nelfinavir, ritonavir, and amprenavir, respectively. The high-level HIV PI-resistant isolate had a greater loss in activity. The change in IC50 secondary to the addition of AGP was the greatest for ritonavir, nelfinavir, and amprenavir and lowest for indinavir. These data suggest that the target plasma concentration for the highly bound HIV PIs may need to be raised in subjects with elevated AGP who harbor partially PI-resistant isolates.

With the development of more potent and better tolerated antiretroviral regimens, durable antiviral responses are being observed in an increasing fraction of patients. Substantial benefits are associated with these responses: Initially memory, then naive, CD4 cell counts may rise by 150-200 cells/mm3; CD8 cell numbers also rise sharply but then fall below pretreatment levels, presumably as antigenic stimuli driving the CD8 response decline; cellular activation markers decline; distortions in the T cell repertoire gradually lessen; and increases in proliferative responses to mitogens and recall antigens are more easily elicited. Clinical benefits directly accompany these immunologic benefits. Other than peripheral neuropathy, few long-term toxicities are associated with nucleoside analogue reverse transcriptase inhibitors. Recent reports, however, link protease inhibitors with hyperlipidemia, redistribution of body fat, and diabetes mellitus. As more human immunodeficiency virus type 1-infected persons receive long-term antiviral maintenance therapy, successful management of these toxicities will require more attention.

Objectives: To evaluate, over 12 weeks, the antiretroviral activity and safety of abacavir, used alone and in combination with zidovudine (ZDV), as treatment for HIV-1-infected subjects who had limited or no antiretroviral treatment., Design: Seventy-nine HIV-1-infected subjects, with CD4 cell counts 200-500 x 10(6)/l and <12 weeks of previous treatment with ZDV were enrolled in a multicenter study. Subjects were randomly assigned to one of four cohorts receiving abacavir monotherapy for the first 4 weeks (200, 400, or 600 mg every 8 h daily, or 300 mg every 12 h daily) and, thereafter, combination therapy of abacavir with 600 mg ZDV or ZDV placebo, administered in a double-blind manner for an additional 8 weeks., Methods: Antiretroviral activity was assessed by measuring changes in plasma HIV-1 RNA levels and CD4+ cell counts. Safety was assessed by monitoring clinical adverse events and laboratory abnormalities during the 12-week period and for 4 weeks post-treatment., Results: Treatment with abacavir, alone or in combination with ZDV, produced marked decreases in plasma HIV-1 RNA loads and increases in CD4+ cell counts in all groups. At week 4, median plasma HIV-1 RNA loads decreased by 1.11-1.77 log10 copies/ml and median CD4+ cell counts increased by 63-111 x 10(6)/l in all groups. At week 12, median HIV-1 RNA loads decreased by 1.02-2.24 log10 copies/ml (abacavir monotherapy) and by 1.81-2.01 log10 copies/ml (abacavir-ZDV); median CD4+ cell counts increased by 79-195 x 10(6)/l (abacavir monotherapy) and by 93-142 x 10(6)/l (abacavir-ZDV). At week 12, the percentage of subjects who had plasma HIV-1 RNA levels below 400 and 40 copies/ml were 28 and 11%, respectively (abacavir monotherapy) and 69 and 22%, respectively (abacavir-ZDV). Eight subjects (10%) discontinued the study prematurely because of adverse events; nausea (n = 4) and hypersensitivity (n = 3) were the most common reasons for withdrawal. There were no deaths among the study subjects., Conclusions: In HIV-infected subjects who have received little or no prior antiretroviral therapy, treatment with abacavir alone or in combination with ZDV is well tolerated and resulted in sustained improvements in key immunologic and virologic efficacy parameters through 12 weeks.

The prevalence of human herpesvirus 8 (HHV-8; Kaposi's sarcoma [KS] herpesvirus) infection was determined by IFA in 297 persons living in Brazil and Colorado. The prevalence of antibody to HHV-8 in human immunodeficiency virus (HIV) type 1-seropositive gay men with and without KS was similar in Brazil and Colorado. In Brazil, the prevalence of HHV-8 antibody was significantly greater in HIV-1-seronegative gay men than in HIV-1-seronegative male intravenous drug users. HHV-8-seropositive Brazilian gay men who had a clinical diagnosis of KS or who were infected with HIV-1 had significantly higher titers of HHV-8 antibody than did HHV-8-seropositive, HIV-1-seronegative Brazilian gay men. These findings provide further support for the association between HHV-8 infection and KS and suggest that, as in the United States, HHV-8 infection is transmitted sexually in Brazil.

Objective: To evaluate initial changes in CD4 cell count as a surrogate endpoint for clinical outcome in HIV-infected patients., Design: Meta-analysis of all relevant Phase II and III randomized clinical trials undertaken by the Adult AIDS Clinical Trials Group., Methods: Individual patient data were obtained from each clinical trial, and the difference between a pair of treatments in their effect on clinical outcome (AIDS or death, or death alone) during 2 years of follow-up was evaluated. The proportion of treatment effect explained (PTE) was the proportion of this difference explained by the change in CD4 cell count 6 months after starting treatment, evaluated using proportional hazards models. A weighted average PTE across treatment comparisons was obtained. The association between the difference between treatments in clinical outcome, expressed as hazard ratio, and the difference in mean change in CD4 cell count was evaluated using regression analysis., Results: There were 15 clinical trials involving 24 treatment comparisons. The weighted average PTE for both progression to AIDS or death was 0.16 [95% confidence interval (Cl), 0.07-0.26] and for death was 0.10 (95% Cl, 0.00-0.20). There were significant associations between treatment differences in effect on AIDS or death, and on death alone, and the difference in mean change in CD4 cell count. A difference in mean change in CD4 cell count of 30 or 40 x 10(6)/l or more in favor of the test treatment indicated with high probability that there was a corresponding difference in progression to AIDS or death., Conclusions: The small PTE suggest that other mechanisms of drug action not captured by initial change in CD4 cells are important. CD4 cell count is a weak surrogate endpoint, but has some value as an aid for screening treatments for drug development or preliminary regulatory approval.

Objective: A Phase II, open-label, randomized, parallel-arm, multicentre trial to compare the antiviral activity and safety of two formulations of saquinavir (SQV), soft gelatin (SQV-SGC) and hard gelatin (SQV-HGC) capsules, in combination with two nucleoside reverse transcriptase inhibitors (NRTI), in antiretroviral-naive, HIV-1-infected individuals., Participants: A total of 171 people of > or = 13 years, with plasma HIV-1 RNA levels > or = 5000 copies/ml, who had received no protease inhibitor therapy, < or = 4 weeks NRTI therapy and no antiretroviral treatment within 28 days of screening. Eighty-one people were randomized to the SQV-HGC group and 90 to the SQV-SGC group. A total of 148 patients completed 16 weeks of therapy., Intervention: Therapy for 16 weeks with either SQV-SGC 1200 mg or SQV-HGC 600 mg, both three times a day, in combination with two NRTI., Results: Using an on-treatment analysis, patients taking SQV-SGC had a larger reduction in plasma HIV-1 RNA than those taking SQV-HGC (-2.0 versus -1.6 log10 copies/ml). Eighty per cent of those on SQV-SGC had < 400 copies HIV RNA/ml, compared with 43% in the SQV-HGC group (P = 0.001). A statistically significant difference in the area under the curve (AUC) values between the SQV-SGC and SQV-HGC arms (-1.7 versus -1.5 log10 copies/ml, respectively; P = 0.0054) was observed when withdrawals prior to week 12, major protocol violators and patients with < 75% compliance were excluded from the analysis; however, the difference between the values for the intent-to-treat population was not significant (P = 0.1929). Adverse events (mostly mild) included diarrhoea and nausea., Conclusions: SQV-SGC was generally well tolerated and gave significantly more potent suppression of plasma HIV-1 RNA in antiretroviral-naive patients than SQVHGC.

We studied the in vitro effects of IL-12 on HIV-1-specific CTL lines derived from PBMC of HIV-1-infected children. HIV-1-specific CTL lines were derived by limiting dilution following Ag-specific stimulation of PBMC from HIV-1-infected children and were maintained with repeated anti-CD3 stimulation. Following incubation with IL-12 for 5 to 7 days, HIV-1-specific cytotoxicity was augmented in a dose-dependent fashion (mean increase, 94 +/- 83 lytic units; p = 0.0006). Experiments performed with CD3-blocking Abs and MHC-mismatched targets demonstrated that the IL-12-enhanced activity was MHC restricted and dependent on cells bearing CD3. The effect of IL-12 on proliferation of the CTL lines as tested by [3H]TdR uptake was minimal, with stimulation indexes ranging from 1.25 to 4.9. The effects of IL-12 on cytotoxicity were not significantly altered by addition of Ab to the IL-2R (anti-Tac) in quantities sufficient to block exogenous IL-2 (p = 0.15), demonstrating that endogenous IL-2 activity is not required for IL-12-enhanced cytolytic activity. Likewise, addition of neutralizing Ab specific for IFN-gamma did not change IL-12-enhanced cytotoxicity (p = 0.61). The in vivo role of IL-12 in the generation and the stimulation of CTL remains to be determined; however, its ability to augment HIV-1-specific CTL in vitro adds additional support for IL-12 as a candidate for immune-based therapy of HIV-1.