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There is currently no licensed vaccine for respiratory syncytial virus (RSV). Here, we assess the effect of RSV fusion protein (F) conformation on B cell responses in a post hoc comparison of samples from the DS-Cav1 [prefusion (pre-F)] and MEDI7510 [postfusion (post-F)] vaccine clinical trials. We compared the magnitude and quality of the serological and B cell responses across time points and vaccines. We measured RSV A and B neutralization, F-binding immunoglobulin G titers, and competition assays at week 0 (before vaccination) and week 4 (after vaccination) to evaluate antibody specificity and potency. To compare B cell specificity and activation, we used pre-F and post-F probes in tandem with a 17-color immunophenotyping flow cytometry panel at week 0 (before vaccination) and week 1 (after vaccination). Our data demonstrate that both DS-Cav1 and MEDI7510 vaccination robustly elicit F-specific antibodies and B cells, but DS-Cav1 elicited antibodies that more potently neutralized both RSV A and B. The superior potency was mediated by antibodies that bind antigenic sites on the apex of pre-F that are not present on post-F. In the memory (CD27 + ) B cell compartment, vaccination with DS-Cav1 or MEDI7510 elicited B cells with different epitope specificities. B cells preferentially binding the pre-F probe were activated in DS-Cav1–vaccinated participants but not in MEDI7510-vaccinated participants. Our findings emphasize the importance of using pre-F as an immunogen in humans because of its deterministic role in eliciting highly potent neutralizing antibodies and memory B cells.

Objective: Functional HDL (high-density lipoprotein) particles that facilitate cholesterol efflux may be cardioprotective. EL (endothelial lipase) hydrolyzes phospholipids promoting catabolism of HDL and subsequent renal excretion. MEDI5884 is a selective, humanized, monoclonal, EL-neutralizing antibody. We sought to determine the safety, pharmacokinetics, and pharmacodynamic effects of multiple doses of MEDI5884 in patients with stable coronary artery disease. Approach and Results: LEGACY was a phase 2a, double-blind, placebo-controlled, parallel-design trial that randomized 132 patients with stable coronary artery disease receiving high-intensity statin therapy to 3 monthly doses of 1 of 5 dose levels of MEDI5884 (50, 100, 200, 350, or 500 mg SC) or matching placebo. The primary end point was the safety and tolerability of MEDI5884 through the end of the study (day 151). Additional end points included change in HDL cholesterol and cholesterol efflux from baseline to day 91, hepatic uptake of cholesterol at day 91, changes in various other lipid parameters. The incidence of adverse events was similar between the placebo and MEDI5884 groups. In a dose-dependent manner, MEDI5884 increased HDL cholesterol up to 51.4% ( P P P P =0.04) was observed with MEDI5884. However, at the potential target doses for future studies, there was no meaningful increase in LDL cholesterol or apoB. Conclusions: Inhibition of EL by MEDI5884 increases the quantity and quality of functional HDL in patients with stable coronary artery disease on high-intensity statin therapy without an adverse safety signal at the likely dose to be used. These data support further clinical investigation. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03351738.

Cardiovascular disease (CVD) is the leading global cause of death, and treatments that further reduce CV risk remain an unmet medical need. Epidemiological studies have consistently identified low high-density lipoprotein cholesterol (HDL-C) as an independent risk factor for CVD, making HDL elevation a potential clinical target for improved CVD resolution. Endothelial lipase (EL) is a circulating enzyme that regulates HDL turnover by hydrolyzing HDL phospholipids and driving HDL particle clearance. Using MEDI5884, a first-in-class, EL-neutralizing, monoclonal antibody, we tested the hypothesis that pharmacological inhibition of EL would increase HDL-C by enhancing HDL stability. In nonhuman primates, MEDI5884 treatment resulted in lasting, dose-dependent elevations in HDL-C and circulating phospholipids, confirming the mechanism of EL action. We then showed that a favorable lipoprotein profile of elevated HDL-C and reduced low-density lipoprotein cholesterol (LDL-C) could be achieved by combining MEDI5884 with a PCSK9 inhibitor. Last, when tested in healthy human volunteers, MEDI5884 not only raised HDL-C but also increased HDL particle numbers and average HDL size while enhancing HDL functionality, reinforcing EL neutralization as a viable clinical approach aimed at reducing CV risk.

Background: Infections with respiratory syncytial virus (RSV) cause significant morbidity and hospitalization in older adults. We studied the humoral, mucosal and B cell responses of an investigational adjuvanted RSV sF vaccine, MEDI7510, in older adults. Methods: In a substudy of a randomized (1:1), double-blind, placebo-controlled study of MEDI7510 in adults ≥60 years of age, we collected blood and nasal secretions at days 0, 8, 29, 91 and 180 post-vaccination to measure F-specific IgG and IgA antibodies by ELISA, and plasmablasts and memory B cells by IgA/IgG dual-color fluorospot. Results: The 27 vaccine- and 18 placebo-recipients had a mean age of 73 years and included 24 women. Among vaccinees, 93% had significant increases in F-specific plasma IgG 85% had increased plasma IgA; 74% had increased nasal IgG and 26% nasal IgA; 93% had IgG and 89% IgA plasmablasts on Day 8 post-immunization; and 82% had IgG and 7.4% IgA memory B cell responses to the vaccine. Vaccinees

Immunogenicity data from phase 1 vaccine studies can be difficult to interpret, especially in seropositive populations and when multiple assays are used. We developed 3 statistical methods (Youden index [YI] threshold, receiver-operating characteristic relative to baseline [ROC-B], and ROC of postdose levels [ROC-P]) to characterize complex immunogenicity data by assessing the proportion of a study population that achieved values above thresholds. The YI method calculates a single threshold per assay. Both ROC methods construct ROC curves for individual assays and surfaces for assay combinations to assess degree of separation of postdose values from a reference distribution; the ROC-B method uses overall predose values as the reference distribution and the ROC-P method uses pooled postdose values. All methods are applicable to a seropositive population with overlapping distributions of baseline and postdose measurements and can evaluate results of multiple assays jointly. The ROC-P method is also applicable when postdose levels are fully separated from baseline levels, as is common in a seronegative population. These methods were demonstrated using data from a phase 1a study of respiratory syncytial virus vaccines formulated with and without an adjuvant in a seropositive population of adults aged ≥60 years. All 3 methods provided a comprehensive assessment of vaccine immunogenicity effects with results presented in easily interpretable formats. In the example data, the methods demonstrated antigen dose response trend and contribution of adjuvant to response in multiple assays individually and jointly where optimal responses in assay combinations (humoral and cellular) are important.

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections in infants worldwide and also causes significant disease in the elderly. Despite 60 years of RSV research and vaccine development, there is only one approved medicine to prevent RSV infections. Palivizumab, a monoclonal antibody (mAb) against the RSV fusion (F) protein, is indicated for preterm infants and children at high-risk for RSV infections. It is an active time in RSV vaccine and mAb development with 14 vaccines and 2 mAbs currently being tested in clinical trials as of 13 February 2017. Active vaccination of women in the third trimester or passive immunization of infants with a mAb are particularly attractive approaches as the most severe disease occurs within the first 6 months of life. Areas covered: Here, we review current approaches for preventing RSV in the young and old, describe proposed clinical endpoints for studies in pediatric and adult clinical trials and highlight results from recent and ongoing clinical studies. Expert commentary: With 16 candidates in clinical development, approval of the first RSV vaccine or mAb for the prevention of RSV in all infants or the elderly is likely to occur in the next five years.

Objectives There are no approved vaccines for respiratory syncytial virus (RSV), and consensus on methods to assess RSV vaccine efficacy has not been established. In this study of an adjuvanted RSV vaccine, we evaluated an RSV disease endpoint using a patient-reported outcome instrument (the inFLUenza Patient-Reported Outcome instrument [FLU-PRO]) and molecular testing for virologic confirmation. Methods In a randomized, blinded efficacy study (NCT02508194), 1900 adult participants aged ≥60 years who had any respiratory symptom lasting ≥24 hours recorded symptoms in a FLU-PRO–based workbook for 21 days, self-collected nasal swabs on illness days 2 to 4, and had a site-collected swab obtained on (approximately) day 4. The endpoint, acute RSV-associated respiratory illness (ARA-RI), required specific symptoms with virologic confirmation. Results The FLU-PRO demonstrated reliability, ability to detect change, and validity and had high participant adherence and acceptable patient burden in the setting of an RSV prevention trial. The ARA-RI endpoint definition captured all 33 virologically confirmed RSV illnesses for which symptom data were provided, and in 32 of these, at least 1 lower respiratory symptom was reported. Sensitivity analysis with an endpoint requiring ≥2 lower respiratory symptoms captured greater symptom severity but fewer cases. Results of self- and site-collected swabs were highly correlated. Self-swabbing detected 9 additional cases that would have been missed by site swabbing only. Conclusions These results demonstrated the reliability and validity of the ARA-RI definition and of the FLU-PRO for use in RSV studies. Self-swabbing improved RSV detection.

This is the second phase 1 study of a respiratory syncytial virus (RSV) vaccine containing RSV fusion protein (sF) adjuvanted with glucopyranosyl lipid A (GLA) in a squalene-based 2% stable emulsion (GLA-SE). In this randomized, double-blind study, 261 subjects aged ≥60 years received inactivated influenza vaccine (IIV), a vaccine containing 120 μg sF with escalating doses of GLA (1, 2.5, or 5 μg) in SE, or a vaccine containing 80 μg sF with 2.5 μg GLA in SE. Subjects receiving 120 μg sF with 2.5 or 5 μg GLA were also randomized to receive IIV or placebo. Immunity to RSV was assessed by detection of microneutralizing, anti-F immunoglobulin G, and palivizumab-competitive antibodies and F-specific gamma interferon enzyme-linked immunosorbent spot assay T-cell responses. Higher adjuvant doses increased injection site discomfort, but at the highest dose, the reactogenicity was similar to that of IIV. Significant humoral and cellular immune responses were observed. The 120 μg sF plus 5.0 μg GLA formulation resulted in the highest responses in all subjects and in older subjects. These results confirm previous observations of vaccine tolerability, safety, and immunogenicity and were used to select the 120 μg sF plus 5.0 μg GLA formulation for phase 2 evaluation. (This study has been registered at ClinicalTrials.gov under registration no. NCT02289820.)

Background: Nosocomial pneumonia is a leading cause of hospital-acquired infection. However, evidence is limited regarding resource utilization and healthcare costs associated with nosocomial pneumonia in France. Methods: This retrospective case-control study used a nationwide hospital claims database for cases of nosocomial pneumonia caused by P. aeruginosa or Pseudomonas aeruginosa. Hospital stay costs were retrieved during index hospitalization and at 30-days and 90-days post-discharge. Cost was calculated using Diagnosis Related Group (DRG) codes and daily cost estimates. Results: Of 7,793 patients discharged with S. aureus or P. aeruginosa pneumonia between January 2010 and December 2011, 1,453 and 1,449 cases were included, respectively. Cases were matched with controls in terms of DRG root, age, gender, Charlson comorbidity score, and hospital region. Cases demonstrated significantly higher Charlson comorbidity scores (p

Objectives MEDI3902 is a bivalent, bispecific human immunoglobulin G1κ monoclonal antibody that binds to both the Pseudomonas aeruginosa PcrV protein involved in host cell cytotoxicity and the Psl exopolysaccharide involved in P. aeruginosa colonization and tissue adherence. MEDI3902 is being developed for the prevention of nosocomial P. aeruginosa pneumonia in high-risk patients. Methods This phase 1 dose-escalation study (NCT02255760) evaluated the safety, pharmacokinetics, antidrug antibody (ADA) responses and ex vivo anticytotoxicity and opsonophagocytic killing activities of MEDI3902 after a single intravenous infusion in healthy adults aged 18 to 60 years. Fifty-six subjects were randomized in a 3:1 ratio to receive 250, 750, 1500 or 3000 mg of MEDI3902 or placebo and followed for 60 days afterwards. Results Treatment-emergent adverse events (TEAEs) were mild or moderate in severity; no serious TEAEs were observed. The most common TEAEs were infusion-related reactions. MEDI3902 exhibited approximately linear pharmacokinetics across the 250, 750 and 1500 mg doses and nonlinear pharmacokinetics between the 1500 and 3000 mg doses. One subject in the 3000 mg group tested positive for ADA on day 61 and had a lower MEDI3902 serum concentration from days 43 to 61 than ADA-negative subjects. Serum anticytotoxicity antibody concentrations and opsonophagocytic killing activity were correlated with MEDI3902 serum concentrations across all doses. Conclusions Phase 1 study results of MEDI3902 in healthy subjects support further evaluation of its safety and efficacy in subjects at risk for P. aeruginosa pneumonia.

Please cite this paper as: Ambrose et al. (2011) An integrated, multistudy analysis of the safety of Ann Arbor strain live attenuated influenza vaccine in children aged 2–17 years. Influenza and Other Respiratory Viruses 5(6), 389–397. Background Trivalent, Ann Arbor strain, live attenuated influenza vaccine (LAIV) is approved in several countries for use in eligible children aged ≥2 years. Objective To describe the safety of Ann Arbor strain LAIV in children aged 2–17 years. Methods An integrated analysis of randomized, controlled trials of LAIV. Results A total of 4245 and 10 693 children received ≥1 dose of LAIV in year 1 of 6 trivalent inactivated influenza vaccine (TIV)-controlled and 14 placebo-controlled studies, respectively; 3212 children were revaccinated in year 2 of 4 placebo-controlled studies. Compared with placebo for days 0–10 post-vaccination, LAIV recipients exhibited increased runny/stuffy nose (+7%), headache (+7%), and tiredness/decreased activity (+2%) after dose 1; and a higher rate of decreased appetite (+4%) after year 2 revaccination. Compared with TIV, only runny/stuffy nose was increased (dose 1, +12%; dose 2, +4%). Compared with initial vaccination, LAIV reactogenicity was lower after dose 2 in year 1 and revaccination in year 2. Unsolicited adverse events (AEs) increased with LAIV in some comparisons were headache, nasal congestion/rhinorrhea, rhinitis, and pyrexia; ear pain and lower respiratory illness were decreased. There was no evidence of an increase in any potential vaccine-related serious AE in LAIV recipients. Among children aged 2–17 years and specifically aged 24–35 months, there was no evidence that lower respiratory illness or wheezing illness occurred at a higher rate in LAIV recipients. Conclusion This analysis supports the safety of Ann Arbor strain LAIV in children aged 2–17 years and provides a consensus assessment of events expected after vaccination.

Idiopathic CD4+ lymphocytopenia (ICL) is a rare non–HIV-related syndrome with unclear natural history and prognosis. This prospective natural history cohort study describes the clinical course, CD4 T lymphocyte kinetics, outcome, and prognostic factors of ICL. Thirty-nine patients (17 men, 22 women) 25 to 85 years old with ICL were evaluated between 1992 and 2006, and 36 were followed for a median of 49.5 months. Cryptococcal and nontuberculous mycobacterial infections were the major presenting opportunistic infections. Seven patients presented with no infection. In 32, CD4 T-cell counts remained less than 300/mm3 throughout the study period and in 7 normalized after an average of 31 months. Overall, 15 (41.6%) developed an opportunistic infection in follow-up, 5 (13.8%) of which were “AIDS-defining clinical conditions,” and 4 (11.1%) developed autoimmune diseases. Seven patients died, 4 from ICL-related opportunistic infections, within 42 months after diagnosis. Immunologic analyses revealed increased activation and turnover in CD4 but not CD8 T lymphocytes. CD8 T lymphocytopenia (< 180/mm3) and the degree of CD4 T cell activation (measured by HLA-DR expression) at presentation were associated with adverse outcome (opportunistic infection-related death; P = .003 and .02, respectively). This trial is registered at http://clinicaltrials.gov as #NCT00001319.

Background Staphylococcus aureus and Pseudomonas aeruginosa are major causes of pneumonia in intensive care unit (ICU) patients. Limited data exist regarding the health economic impact of S. aureus and P. aeruginosa pneumonias in the ICU setting. Methods We conducted a retrospective observational cohort study using a 29.6 million enrollee US medical and pharmacy administrative claims database. ICU patients with S. aureus or P. aeruginosa infection per International Classification of Diseases, 9th ed. coding between 01/01/2007-8/31/2012 were compared with ICU patients without any pneumonia or infections of interest. Primary outcomes were costs in 2012 US dollars, healthcare utilization and all-cause mortality associated with hospital-acquired S. aureus or P. aeruginosa pneumonia, and the relative odds of incurring higher costs due to a comorbid condition. Results Patients with S. aureus or P. aeruginosa pneumonia had longer mean hospital (37.9 or 55.4 vs 7.2 days, P

Study objective To investigate a potential correlation between exposure to oral midazolam, a commonly used cytochrome P450 (CYP) 3A probe, and saquinavir and indinavir exposure. Design Open-label, prospective, pharmacokinetic study. Setting Outpatient research center. Subjects Thirty-six healthy volunteers aged 22-50 years. Intervention Subjects received a single oral dose of midazolam 8 mg; 4 hours later, blood was drawn to determine their serum midazolam concentrations. Midazolam phenotyping was followed by successive administration of the protease inhibitors indinavir and saquinavir, with blood sampling and pharmacokinetic analyses performed at steady state. Measurements and main results Pharmacokinetic parameters of each protease inhibitor were evaluated to assess for a potential relationship with 4-hour concentrations of midazolam. No correlations between phenotype results for midazolam and any pharmacokinetic parameter for indinavir or saquinavir were identified (r(2)=0.00002-0.073). When the results were analyzed based on race, significant correlations were identified in five African-American subjects, including correlations between 4-hour midazolam levels and apparent oral clearance of saquinavir (r(2)=0.734, p=0.064), area under the plasma concentration-time curve from 0-8 hours (r(2)=0.914, p=0.011), minimum concentration (r(2)=0.857, p=0.024), and maximum concentration (r(2)=0.969, p=0.002). These findings for African-American subjects were not seen with indinavir. No correlation was found between indinavir and saquinavir pharmacokinetic parameters (r(2)=0.017-0.261). Conclusion Oral midazolam was not a useful probe for predicting saquinavir or indinavir exposure at steady state. Reasons for the lack of correlation likely included differences between midazolam and protease inhibitor P-glycoprotein specificity, differences in the relative contribution of CYP3A5-mediated metabolism, and/or variation in intestinal and hepatic CYP3A specificity. The strong correlation between midazolam phenotype and pharmacokinetic parameters for saquinavir in African-American subjects indicated a racial difference in one or more of these confounding variables.

Background: Understanding the selection and decay of drug-resistant HIV-1 variants is important for designing optimal antiretroviral therapy. Objective: To develop a high-throughput, real-time reverse transcriptase (RT) polymerase chain reaction (PCR) assay to quantify non-nucleoside reverse transcriptase inhibitor (NNRTI)-resistant variants K103 N (AAT or AAC alleles) at frequencies as low as 0.1%, and to apply this to monitor these variants before, during, and after NNRTI therapy. Methods: HIV-1 RNA in longitudinal plasma samples obtained from patients starting and stopping NNRTI therapy was converted to cDNA and the target sequence region amplified and quantified by real-time PCR. Approximately 10 7 copies/reaction provided a template for a second round of PCR using primers that discriminated between the mutant and wild-type alleles. Amplification specificity was confirmed by thermal denaturation analysis. Results: Frequencies of 103N similar to assay background (0.029%) were observed in longitudinal samples from 9 of 12 treatment-naive patients; three patients had transient increases in 103N frequency to a range of 0.21-0.48%, which was 7-16.5 times assay background. Analysis of longitudinal plasma samples from six NNRTI-experienced patients showed three patterns: persistence of 103N variants after stopping NNRTI therapy, codon switching of 103N between AAC and AAT during NNRTI therapy, and decay of 103N variants to below assay background after cessation of NNRTI therapy. Conclusions: Allele-specific RT-PCR quantified the emergence and decay of drug-resistant variants in patients over a broad range of frequencies (0.1 - 100%). The rate of decay of K103N variants after stopping NNRTI therapy was highly variable.

Aims To examine the influence of sex on steady-state saquinavir pharmacokinetics in HIV-seronegative volunteers administered saquinavir without a concomitant protease inhibitor. Methods Thirty-eight healthy volunteers (14 female) received saquinavir soft-gel capsules 1200 mg three times daily for 3 days to achieve steady-state conditions. Following administration of the 10th dose, blood was collected serially over 8 h for measurement of saquinavir plasma concentrations. Saquinavir pharmacokinetic parameter values were determined using noncompartmental methods and compared between males and females. CYP3A phenotype (using oral midazolam) and MDR-1 genotypes at positions 3435 and 2677 were determined for all subjects in order to characterize possible mechanisms for any observed sex-related differences. Results There was no significant difference in saquinavir AUC0−8 or any other pharmacokinetic parameter value between the sexes. These findings persisted after mathematically correcting for total body weight. The mean weight-normalized AUC0−8 was 29.9 (95% confidence interval 15.5, 44.3) and 29.8 (18.6, 40.9) ng h−1 ml−1 kg−1 for males and females, respectively. No significant difference in CYP3A phenotype was observed between the groups; likewise, the distribution of MDR-1 genotypes was similar for males and females. Conclusion In contrast to previous study findings, results from this investigation showed no difference in saquinavir pharmacokinetics between males and females. The discrepancy between our findings and those previously reported may be explained by the fact that we evaluated HIV-seronegative volunteers and administered saquinavir in the absence of concomitant protease inhibitors such as ritonavir. Caution must be exercised when extrapolating pharmacokinetic data from healthy volunteer studies (including sex-based pharmacokinetic differences) to HIV-infected populations or to patients receiving additional concurrent medications.

HIV infection leads to decreases in the number of CD4+ T lymphocytes and an increased risk for opportunistic infections and neoplasms. The administration of intermittent cycles of IL-2 to HIV-infected patients can lead to profound increases (often greater than 100%) in CD4 cell number and percentage. Using in vivo labeling with 2H-glucose and BrdU, we have been able to demonstrate that, although therapy with IL-2 leads to high levels of proliferation of CD4 as well as CD8 lymphocytes, it is a remarkable preferential increase in survival of CD4 cells (with half-lives that can exceed 3 years) that is critical to the sustained expansion of these cells. This increased survival was time-dependent: the median half-life, as determined by semiempirical modeling, of labeled CD4 cells in 6 patients increased from 1.7 weeks following an early IL-2 cycle to 28.7 weeks following a later cycle, while CD8 cells showed no change in the median half-life. Examination of lymphocyte subsets demonstrated that phenotypically naive (CD27+CD45RO–) as well as central memory (CD27+CD45RO+) CD4 cells were preferentially expanded, suggesting that IL-2 can help maintain cells important for host defense against new antigens as well as for long-term memory to opportunistic pathogens.

Interleukin-2 (IL-2) is a cytokine that regulates the proliferation and differentiation of lymphocytes, and is currently used clinically in the treatment of assorted malignancies. Additionally, IL-2 is being actively investigated in clinical trials for treatment of human immunodeficiency virus (HIV) infection. Patients treated with IL-2 are susceptible to autoimmune thyroid disease (AITD), presenting as thyroiditis, which leads to either thyrotoxicosis or hypothyroidism, if not correctly and promptly identified and treated. IL-2-induced hypothyroidism can also sometimes follow a thyrotoxic phase. However, the development of Graves' disease (GD) in this clinical setting has not been reported to date. Here, we report the case of a 39-year-old HIV-infected man in whom GD developed after IL-2 therapy. We correlated the immunologic parameters pertinent to the patient's HIV infection status with clinical, hormonal, and serologic evidence of GD during its emergence. This revealed an association between peripheral blood cell numbers of specific lymphocyte subpopulations (CD4(+), CD3(+)CD25(+), and naïve T-cells) and serum levels of markers for AITD (free thyroxine [T(4)] and thyroid-stimulating immunoglobulin). Interestingly, no association was found between natural killer (NK) cell numbers and AITD markers. The immunopathogenesis of GD in this patient may be similar to that hypothesized for the GD that occurs in immune-reconstituted patients after combination antiretroviral therapy. From a practical standpoint, we propose that patients who have received or are receiving treatment with IL-2 who show signs of hyperthyroidism need to be carefully evaluated for GD.

In recent years, the quantification of T cell responses to pathogens or immunogens has become a common tool in the evaluation of disease pathogenesis or vaccine immunogenicity. Such measurements are usually limited to enumerating IFN-γ-producing cells after ex vivo stimulation with Ag, but little is known about the phenotype or complete functional repertoire of the Ag-specific cells. We used 12-color flow cytometry to characterize Ag-specific T cells elicited by vaccines or natural infection to determine lineage and differentiation status as well as the capacity to produce four cytokines (IFN-γ, TNF-α, IL-2, and IL-4) and a chemokine (MIP1β). As expected, responding cells had a typical memory phenotype; however, the cytokine profiles associated with the responses were highly complex. The pattern of cytokine coexpression in response to specific Ags was a skewed subset of the complete repertoire (revealed by polyclonal stimulation). We found significant differences in the patterns of cytokines elicited by vaccination (where IFN-γ was by far a subdominant response) vs natural infection; in addition, there was fairly significant intersubject variation. Our findings illustrate the limitation of the evaluation of immune responses using single functional measurements (such as IFN-γ); in fact, it is likely that sensitive evaluation of Ag-specific T cells will require the coordinate measurement of several cytokines. The presence and variability of these complex response profiles introduce the possibility that selective functional expression patterns may provide correlates for vaccine efficacy or disease progression.

Our objective was to examine the influence of ritonavir on P-glycoprotein (P-gp) activity in humans by characterizing the effect of ritonavir on the pharmacokinetics of the P-gp substrate digoxin in individuals with known MDR1 genotypes. Healthy volunteers received a single dose of digoxin 0.4 mg orally before and after 14 days of ritonavir 200 mg twice daily. After each digoxin dose blood and urine were collected over 72 hours and analyzed for digoxin. Digoxin pharmacokinetic parameter values were determined using noncompartmental methods. MDR1 genotypes at positions 3435 and 2677 in exons 26 and 21, respectively, were determined using PCR-RFLP analysis. Ritonavir increased the digoxin AUC(0-72) from 26.20 +/- 8.67 to 31.96 +/- 11.24 ng x h/mL (P = 0.03) and the AUC(0-8) from 6.25 +/- 1.8 to 8.04 +/- 2.22 ng x h/mL (P = 0.02) in 12 subjects. Digoxin oral clearance decreased from 149 +/- 101 mL/h x kg to 105 +/- 57 mL/h x kg (P = 0.04). Other digoxin pharmacokinetic parameter values, including renal clearance, were unaffected by ritonavir. Overall, 75% (9/12) of subjects had higher concentrations of digoxin after ritonavir administration. The majority of subjects were heterozygous at position 3435 (C/T) (6 subjects) and position 2677 (G/T,A) (7 subjects); although data are limited, the effect of ritonavir on digoxin pharmacokinetics appears to occur across all tested MDR1 genotypes. Concomitant low-dose ritonavir reduced the nonrenal clearance of digoxin, thereby increasing its systemic availability. The most likely mechanism for this interaction is ritonavir-associated inhibition of P-gp. Thus, ritonavir can alter the pharmacokinetics of coadministered medications that are P-gp substrates.

Intermittent administration of interleukin (IL)-2 produces significant and sustained increases in CD4(+) T lymphocyte count in human immunodeficiency virus (HIV)-infected subjects but can be associated with dose-limiting toxicities. The primary objective of this study was to determine whether concomitant administration of prednisone could decrease these toxicities. HIV-seropositive adults receiving highly active antiretroviral therapy (HAART) were randomized to receive either (1) intermittent subcutaneous IL-2 and placebo, (2) intermittent subcutaneous IL-2 and prednisone, (3) intermittent prednisone, or (4) intermittent placebo. Prednisone decreased levels of proinflammatory cytokines during IL-2 cycles but, despite induction of expression of CD25, blunted increases in IL-2-associated CD4(+) T lymphocyte count. Whereas intermittent administration of IL-2 reduced basal proliferation of CD4(+) T cells, this effect was inhibited by prednisone, suggesting that prednisone potentially interferes with IL-2's long-term effects on survival of T lymphocytes.

Objective To determine HIV-1 reverse transcriptase (RT) and protease (PRO) mutations selected in isolates from antiretroviral therapy (ART)-experienced patients receiving an efavirenz/abacavir/amprenavir salvage regimen. Methods Open-label, single arm of abacavir, 300 mg twice daily, amprenavir, 1200 mg twice daily and efavirenz, 600 mg once daily, in ART-experienced patients of which 42% were non-nucleoside reverse transcriptase inhibitor-naive. The virology population examined consisted of all patients who took at least 16 weeks of study drugs (n=74). Plasma population sequencing was carried out at baseline and last time point at which patients were still taking the three study drugs ± other ART. The median follow-up was 48 weeks (range week 16–72). Results Baseline (n=73) and on-therapy (n=49) genotypes were obtained. By 48 weeks, 51% of isolates had ≥3 non-nucleoside reverse transcriptase inhibitor (NNRTI) mutations. NNRTI mutations selected on therapy were K103N (51%), substitutions at position 190 (17/49, 35%): G to A (n=11) / S (n=4) / E (n=1) and T (n=1); L100I (37%) and V108I (20%) mutations. P225H was not observed in this study. L100I and G190A/S/E/T mutations were rarely detected in the same viral population and baseline Y181C favoured the G190 mutations (OR=8.9, PConclusion Prior NNRTI and NRTI therapy influences the pathway of resistance to efavirenz. In this study, the prevalence of mutations selected by efavirenz were different from those described in less ART-experienced patients. Baseline Y181C was associated with the development of mutations at position 190, but not L100I or K103N. In this patient population, abacavir with efavirenz preferentially selected for L74V but not for thymidine analogue mutations. M184V was rarely selected and was maintained in only 77% of patients who did not add lamivudine or didanosine. Finally, amprenavir-specific mutations were selected in the background of other primary protease inhibitor mutations, confirming the distinct resistance profile of amprenavir.

To assess the safety and efficacy of three new drugs in patients with antiretroviral failure and to correlate retrospectively baseline factors with virological response.Open-label, 48-week, single-arm, multi-center phase II trial conducted at nine US university or government clinics and private practices.Patients with HIV-1 RNAor =500 copies/ml despiteor =20 weeks of treatment with at least one protease inhibitor received abacavir 300 mg twice a day, amprenavir 1200 mg twice a day and efavirenz 600 mg once a day. Other antiretrovirals were prohibited until week 16 except for substitutions for possible abacavir hypersensitivity.HIV RNA at weeks 16 and 48.A total of 101 highly treatment-experienced patients enrolled; 60 were naive to non-nucleoside analog reverse transcriptase inhibitors (NNRTI). HIV RNA400 copies/ml was attained in 25 out of 101 (25%) patients at 16 weeks (35% of NNRTI-naive and 10% of -experienced patients) and 23 (23%) patients at 48 weeks (33% of naive and 7% of experienced patients). CD4 cells increased by a median of 15 x 10(6) and 43 x 10(6) cells/l at weeks 16 and 48, respectively. Drug-related rash occurred in 50 out of 99 (51%) of patients, and 17 out of 99 (17%) permanently discontinued one or more drugs as a result. Lower baseline viral load, fewer NNRTI-related mutations, absence of decreased abacavir (or =4-fold) and efavirenz (or =10-fold) susceptibility, and greater number of drugs to which virus was susceptible were associated with virological response at week 16.Abacavir, amprenavir and efavirenz durably reduced HIV RNA and increased CD4 cell counts in a subset of treatment-experienced adults. Baseline viral load and some genotypic and phenotypic markers of resistance correlated with HIV RNA response.

We examined the effects of human immunodeficiency virus infection on the turnover of CD4 and CD8 T lymphocytes in 17 HIV-infected patients by 30 min in vivo pulse labeling with bromodeoxyuridine (BrdU). The percentage of labeled CD4 and CD8 T lymphocytes was initially higher in lymph nodes than in blood. Labeled cells equilibrated between the two compartments within 24 h. Based on mathematical modeling of the dynamics of BrdU-labeled cells in the blood, we identified rapidly and slowly proliferating subpopulations of CD4 and CD8 T lymphocytes. The percentage, but not the decay rate, of labeled CD4 or CD8 cells in the rapidly proliferating pool correlated significantly with plasma HIV RNA levels for both CD4 (r = 0.77, P < 0.001) and CD8 (r = 0.81, P < 0.001) T cells. In six patients there was a geometric mean decrease of greater than 2 logs in HIV levels within 2 to 6 mo after the initiation of highly active antiretroviral therapy; this was associated with a significant decrease in the percentage (but not the decay rate) of labeled cells in the rapidly proliferating pool for both CD4 (P = 0.03) and CD8 (P < 0.001) T lymphocytes. Neither plasma viral levels nor therapy had an effect on the decay rate constants or the percentage of labeled cells in the slowly proliferating pool. Monocyte production was inversely related to viral load (r = −0.56, P = 0.003) and increased with therapy (P = 0.01). These findings demonstrate that HIV does not impair CD4 T cell production but does increase CD4 and CD8 lymphocyte proliferation and death by inducing entry into a rapidly proliferating subpopulation of cells.

Interleukin (IL)-7 is known to up-regulate thymopoietic pathways of T-cell regeneration. Recent work also has shown it to potently enhance thymic-independent peripheral expansion and to restore immunocompetence in athymic T-cell-depleted hosts. We hypothesized that endogenous IL-7 could contribute to the restoration of T-cell homeostasis following T-cell depletion. To analyze this, we evaluated circulating IL-7 levels and lymphocyte subsets in multiple clinical cohorts with T-cell depletion of varying etiologies. In pediatric (n = 41) and adult (n = 51) human immunodeficiency virus-infected CD4-depleted patients, there were strong inverse correlations between IL-7 levels and CD4 counts (r = -0.77, P

To characterize the immunological effects of intermittent IL-2 therapy, which leads to selective increases in CD4+ T lymphocytes in HIV-infected patients, 11 patients underwent extensive immunological evaluation. While IL-2 induced changes in both CD4+ and CD8+ cell number acutely, only CD4+ cells showed sustained increases following discontinuation of IL-2. Transient increases in expression of the activation markers CD38 and HLA-DR were seen on both CD4+ and CD8+ cells, but CD25 (a chain of the IL-2 receptor) increased exclusively on CD4+ cells. This increase in CD25 expression was sustained for months following discontinuation of IL-2, and was seen in naive as well as memory cells. IL-2 induced cell proliferation, but tachyphylaxis to these proliferative effects developed after 1 week despite continued IL-2 administration. It thus appears that sustained CD25 expression selectively on CD4+ cells is a critical component of the immunological response to IL-2, and that intermittent administration of IL-2 is necessary to overcome the tachyphylaxis to IL-2-induced proliferation.

The combination of an amino acid deletion at codon 67 (Δ67) and Thr-to-Gly change at codon 69 (T69G) in the reverse transcriptase (RT) of human immunodeficiency virus type 1 (HIV-1) is associated with high-level resistance to multiple RT inhibitors. To determine the relative contributions of the Δ67 and T69G mutations on viral fitness, we performed a series of studies of HIV replication using recombinant variants. A high-level 3′-azido-3′-deoxythymidine (AZT)-resistant variant containing Δ67 plus T69G/K70R/L74I/K103N/T215F/K219Q in RT replicated as efficiently as wild-type virus (Wt). In contrast, the construct without Δ67 exhibited impaired replication (23% of growth of Wt). A competitive fitness study failed to reveal any differences in replication rates between the Δ67+T69G/K70R/L74I/K103N/T215F/K219Q mutant and Wt. Evaluation of proviral DNA sequences over a 3-year period in a patient harboring the multiresistant HIV revealed that the T69G mutation emerged in the context of a D67N/K70R/T215F/K219Q mutant backbone prior to appearance of the Δ67 deletion. To assess the impact of this stepwise accumulation of mutations on viral replication, a series of recombinant variants was constructed and analyzed for replication competence. The T69G mutation was found to confer 2′,3′-dideoxyinosine resistance at the expense of fitness. Subsequently, the development of the Δ67 deletion led to a virus with improved replication and high-level AZT resistance.

OBJECTIVE To compare the architecture and HIV-1 RNA and Gag p24 protein expression in lymph nodes (LN) excised from individuals during chronic highly active antiretroviral therapy (HAART) with LN removed from the same patient after plasma virus rebound following the interruption of HAART. MATERIALS AND METHODS Six HIV-1-infected patients on HAART, with CD4 cell counts greater than 350 cells/microl, and plasma HIV-1 RNA less than 50 copies/ml, underwent inguinal LN excision upon discontinuation of HAART, and again after rebound of plasma virus. Lymph nodes were evaluated by immunohistochemical staining for Gag p24 antigen and Ki67, in-situ hybridization for HIV-1 RNA and H3-histone, and transmission electron microscopy (TEM). RESULTS LN at baseline were quiescent to mildly hyperplastic and generally contained more primary than secondary follicles. Only one LN had detectable follicular dendritic cell (FDC)-associated p24 antigen, none had HIV RNA. Few mononuclear cells (MNC) expressed RNA or p24 antigen. Plasma virus at the second biopsy ranged from 329 to 3.2 x 10(6) copies/ml. CD4 cell count decline ranged from 5 to 51% during drug hiatus, and was greatest in patients with highest viral rebound. Four of six of the second LN were more hyperplastic than the initial LN, two showed paracortical hyperplasia. MNC expression of HIV RNA in the second LN paralleled the level of plasma viremia. Increased Ki67 and H3-histone signal occurred in the second LN. CONCLUSION Quiescent LN from individuals on HAART rapidly become hyperplastic and activated within 1-2 months after treatment interruption. As in acute HIV infection, virus expression by LN MNC parallels the rebound in plasma viremia and fall in CD4 cell count.

A variant of human immunodeficiency virus type 1 (HIV-1) possessing a deletion in the reverse transcriptase (RT) gene at codon 67 was identified in a patient who had failed combination antiretroviral therapy. This deletion initially emerged under the selective pressure of combination therapy with 3′-azido-3′-deoxythymidine (AZT) plus 2′,3′-dideoxyinosine. It has persisted for more than 3 years in association with the accumulation of a variety of other well-described drug resistance mutations and an uncharacterized mutation at RT codon 69 (T69G). Phenotypic studies demonstrated that the codon 67 deletion by itself had little effect on AZT sensitivity. However, in the context of the T69G mutation and three other mutations known to be associated with AZT resistance (K70R, T215F, and K219Q), this deletion led to a increase in AZT resistance from 8.5-fold to 445-fold. A further increase in resistance (up to 1,813-fold) was observed when two mutations associated with nonnucleoside RT inhibitor resistance (K103N and L74I) were added to the deletion T69G K70R T215F K219Q construct. Hence, these results establish that a deletion at RT codon 67 may be selected for in the presence of antiretroviral therapy and may lead to high-level resistance to AZT.

Identifying the immunologic and virologic consequences of discontinuing antiretroviral therapy in HIV-infected patients is of major importance in developing long-term treatment strategies for patients with HIV-1 infection. We designed a trial to characterize these parameters after interruption of highly active antiretroviral therapy (HAART) in patients who had maintained prolonged viral suppression on antiretroviral drugs. Eighteen patients with CD4 + T cell counts ≥ 350 cells/μl and viral load below the limits of detection for ≥1 year while on HAART were enrolled prospectively in a trial in which HAART was discontinued. Twelve of these patients had received prior IL-2 therapy and had low frequencies of resting, latently infected CD4 cells. Viral load relapse to >50 copies/ml occurred in all 18 patients independent of prior IL-2 treatment, beginning most commonly during weeks 2–3 after cessation of HAART. The mean relapse rate constant was 0.45 (0.20 log 10 copies) day −1 , which was very similar to the mean viral clearance rate constant after drug resumption of 0.35 (0.15 log 10 copies) day −1 ( P = 0.28). One patient experienced a relapse delay to week 7. All patients except one experienced a relapse burden to >5,000 RNA copies/ml. Ex vivo labeling with BrdUrd showed that CD4 and CD8 cell turnover increased after withdrawal of HAART and correlated with viral load whereas lymphocyte turnover decreased after reinitiation of drug treatment. Virologic relapse occurs rapidly in patients who discontinue suppressive drug therapy, even in patients with a markedly diminished pool of resting, latently infected CD4 + T cells.

To evaluate changes in architecture, viral RNA, and viral protein over 6 months in lymph nodes from retroviral-naïve HIV-infected persons before and after commencing highly active antiretroviral therapy (HAART).Nine antiretroviral-naïve HIV-infected persons had lymph nodes excised at baseline and at 2 and 6-8 months after beginning a four-drug combination regimen containing zidovudine, lamivudine, nevirapine, and indinavir. Two patients had AIDS. Lymph nodes were examined by immunohistochemical staining for Gag p24 HIV, CD3, CD21, CD20, HAM 56, and Ki67 antigens and by in-situ hybridization (ISH) for HIV RNA and H3-histone RNA.Eight of nine baseline lymph nodes showed follicular hyperplasia and germinal center and paracortical mononuclear cell activation. At 2 months, the lymph nodes from seven patients, including the AIDS patients, showed more follicular hyperplasia and activation than their baseline specimens but with decreased mononuclear cell activation. By 6 months, seven lymph nodes were less hyperplastic and activated than their corresponding 2 month specimens. Combined ISH/immunohistochemical staining of baseline lymph nodes revealed productively infected T (CD3) and B (CD20) cells and macrophages (HAM56+). HIV RNA-positive mononuclear cells were infrequent at 2 months, and rare at 6 months. HIV RNA was still associated with follicular dendritic cells (FDC) at 2 months, but not at 6 months. HIV p24-positive antigen in germinal centers persisted through all 6, and the one 8 month specimens. The baseline lymph nodes from one of the AIDS patients was involuted and T cell depleted, whereas the follow-up lymph nodes were hyperplastic with normal T cell levels.Follicular hyperplasia and cell activation, possibly caused by persistent viral protein in germinal centers, may help explain why HIV viremia rebounds so rapidly after the interruption of HAART. Restoration of architecture may follow the treatment of patients with AIDS who initially had involuted and CD4 cell-depleted lymph nodes.

Study objective To evaluate the pharmacokinetics and safety of atovaquone suspension in volunteers infected with the human immunodeficiency virus ((HIV). Design Open-label, nonrandomized study. Setting Two clinical research centers. Patients Twenty-two HIV-infected volunteers with a median CD4 cell count of 37 cells/mm3. Interventions Patients received atovaquone suspension fasting or fed for 2-week periods with crossover at dosages of 500 mg/day, and randomization to fasting or fed at dosages of 750 and 1000 mg/day. A subset of patients also received 750 mg twice/day with food, and a subset of those who received 1000 mg/day fasting also received 1000 mg with food. During a long-term dosing phase, a subset of subjects were evaluated for an interaction between atovaquone and trimethoprim-sulfamethoxazole (TMP-SMX). Measurements and main results Average steady-state atovaquone concentrations at 500 mg were 6.7 +/- 3.2 microg/ml fasted and 11.3 +/- 5.0 microg/ml with food; at 750 mg, 9.9 +/- 7.1 microg/ml fasted and 12.5 +/- 5.9 microg/ml with food; at 1000 mg, 9.7 +/- 4.3 microg/ml fasted and 13.6 +/- 5.0 microg/ml with food; and at 1500 mg, 21.1 +/- 5.0 microg/ml with food. Thus, plasma concentrations were not proportional to dose. Concomitant food ingestion resulted in a 1.3- to 1.7-fold increase in values. Average steady-state concentrations were less than 10 microg/ml in 21% and more than 15 microg/ml in 36% of patients at 1000 mg/day with food; at 750 mg twice/day, all five patients had levels above 15 microg/ml. Atovaquone suspension was well tolerated; diarrhea, nausea, fatigue, and rash were the most common adverse events. Concomitant administration of TMP-SMX did not change atovaquone concentrations and resulted in small decreases in concentrations of TMP (16%) and SMX (10%). Conclusion Plasma concentrations are significantly higher when atovaquone suspension is administered with food compared with fasting. Total doses of 1500 mg/day are likely to achieve concentrations effective for prophylaxis of Pneumocystis carinii pneumonia.

We designed, synthesized, and identified JE-2147, an allophenylnorstatine-containing dipeptide HIV protease inhibitor (PI), which is potent against a wide spectrum of HIV-1, HIV-2, simian immunodeficiency virus, and various clinical HIV-1 strains in vitro . Drug-resistant clinical HIV-1 strains, isolated from seven patients who had failed 9–11 different anti-HIV therapeutics after 32–83 months, had a variety of drug-resistance-related amino acid substitutions and were highly and invariably resistant to all of the currently available anti-HIV agents. JE-2147 was, however, extremely potent against all such drug-resistant strains, with IC 50 values ranging from 13–41 nM (50 compared with that of wild-type HIV-1). The emergence of JE-2147-resistant HIV-1 variants in vitro was substantially delayed compared with that of HIV-1 resistant to another allophenylnorstatine-containing compound, KNI-272, and other related PIs. Structural analysis revealed that the presence of a flexible P2′ moiety is important for the potency of JE-2147 toward wild-type and mutant viruses. These data suggest that the use of flexible components may open a new avenue for designing PIs that resist the emergence of PI-resistant HIV-1. Further development of JE-2147 for treating patients harboring multi-PI-resistant HIV-1 is warranted.

Forty-nine outpatients infected with human immunodeficiency virus with baseline CD4 cell counts >/=500/mm3, who were on stable antiretroviral therapy, were randomized to receive 5-day cycles of either low-dose (1.5 million IU [MIU] twice a day) or high-dose (7.5 MIU twice a day) subcutaneous (sc) interleukin (IL)-2 every 4 or every 8 weeks. High-dose recipients experienced mean slopes of +116.1 cells/month and +2.7 %/month in CD4 cells and percents, respectively, whereas low-dose recipients displayed mean slopes of +26.7 and +1.3% in the same parameters. At month 6, high-dose recipients achieved a 94.8% increase in mean CD4 cells over baseline compared with a 19.0% increase in low-dose recipients. While high-dose recipients encountered more constitutional side effects, these were generally not dose-limiting. High-dose scIL-2 therapy in outpatients with early HIV-1 infection was well tolerated and induced dramatic, sustained rises in CD4 cells.

Summary Background After the addition of the protease inhibitor indinavir to combination drug regimens for HIV-1 infection, some patients have experienced an increase in abdominal girth with symptoms of abdominal fullness, distension, or bloating. We aimed to find out whether this collection of symptoms was associated with changes in abdominal fat and whether such changes were associated with indinavir use. Methods Abdominal computed tomography was used in ten HIV-1-positive patients who had such abdominal symptoms to measure total adipose tissue (TAT) and visceral adipose tissue (VAT) at the umbilicus (L4 vertebral level). The VAT:TAT ratio in the ten cases was compared with that in ten HIV-1-infected patients who had been using indinavir without abdominal symptoms for at least 6 months and ten HIV-1-infected patients who were not using indinavir. Findings The mean VAT:TAT ratios for the three groups— non-users, symptom-free indinavir users, and symptomatic indinavir users—were 0·40 (SD 0·15), 0·59 (0·18), and 0·70 (0·20), respectively (p=0·004). The VAT:TAT ratio correlated with duration of indinavir use (r=0·47, p=0·01). The mean areas of VAT for the three groups were 106 cm 2

The immunodeficiency caused by human immunodeficiency virus (HIV) infection may be related to loss of diversity in the T cell receptor (TCR) repertoire. A cross-sectional study of the CD4 TCR repertoire was done for patients at various stages of HIV infection. Semiquantitative polymerase chain reaction was used to study the relative usage of the variable chain beta (BV) subfamilies and the size distributions of transcripts (CDR3 size analysis) within these subfamilies. The relative usage of the TCRBV subfamilies of patients and controls was not significantly different. The proportion of subfamilies with abnormal CDR3 size patterns was higher in the HIV-infected patients (25%, 95% confidence interval [CI], 17%-33%) than in the controls (7.2%, 95% CI, 2.3%-12.1%; P < .001), with a significant negative correlation between the number of CD4 cells and the percentage of abnormal TCRBV subfamilies. These results indicate that progressive loss of CD4 T cells is accompanied by increasing disruptions within the T cell receptor repertoire.

The use of antiretroviral agents and drugs for the treatment and prophylaxis of opportunistic infections has lengthened the survival of persons with AIDS. In the era of multidrug therapy, drug interactions are important considerations in designing effective and tolerable regimens. Clarithromycin has had a significant impact on the treatment of disseminated Mycobacterium avium complex infection, and zidovudine is the best-studied and one of the most widely used antiretroviral agents in this population. We conducted a study to determine the maximally tolerated dose of clarithromycin and the pharmacokinetics of clarithromycin and zidovudine individually and in combination. Mixing studies were conducted to simulate potential interaction in the gastric environment. The simultaneous administration of zidovudine and clarithromycin had little impact on the pharmacokinetics of clarithromycin or of its major metabolite. However, coadministration of zidovudine and clarithromycin at three doses (500 mg orally [p.o.] twice daily [b.i.d.], 1,000 mg p.o. b.i.d., and 2,000 mg p.o. b.i.d.) reduced the maximum concentration of zidovudine by 41% (P < 0.005) and the area under the concentration-time curve from 0 to 4 h for zidovudine by 25% (P < 0.05) and increased the time to maximum concentration of zidovudine by 84% (P < 0.05), compared with zidovudine administered alone. Mixing studies did not detect the formation of insoluble complexes due to chelation, suggesting that the decrease in zidovudine concentrations results from some other mechanism. Simultaneous administration of zidovudine and clarithromycin appears to decrease the levels of zidovudine in serum, and it may be advisable that these drugs not be given at the same time. Drug interactions should be carefully evaluated in persons with advanced human immunodeficiency virus infection who are receiving multiple pharmacologic agents.

The safety and efficacy were assessed of 5-day cycles of subcutaneous (sc) interleukin-2 (IL-2) every 8 weeks in human immunodeficiency virus type 1-infected outpatients with >200 CD4 cells/ mm 3 . Immunologic, virologic, and toxicity parameters were measured in 18 patients receiving standard antiretrovirals plus 5-day courses of sc IL-2 (3-18 MIU/day) every 2 months. Systemic toxicities established the maximally tolerated dose (MTD) of IL-2 as 15 MIU/day. CD4 cell responses appeared to correlate directly with baseline CD4 cell counts, with several patients experiencing a dramatic rise after 3 cycles. Virus load increased only transiently in the peri-injection period. It was concluded that serial cycles of outpatient sc IL-2 can be administered safely, with an MTD of 15 MIU/day. Patients with higher baseline counts appear to have a greater CD4 cell response to sc IL-2 therapy.

Influenza B is responsible for significant morbidity in children and adults worldwide. For more than 25 years, two antigenically distinct lineages of influenza B viruses, B/Yamagata and B/Victoria, have cocirculated globally. Current influenza vaccine formulations are trivalent and contain two influenza subtype A strains (A/H1N1 and A/H3N2) but only one B strain. In a half of recent influenza seasons, the predominant circulating influenza B lineage was different from that contained in trivalent influenza vaccines. A quadrivalent live-attenuated influenza vaccine (Q/LAIV) that contains two B strains, one from each lineage, has been developed to help provide broad protection against influenza B. Q/LAIV was recently approved for use in the USA in eligible individuals 2–49 years of age. This review summarizes clinical trial data in support of Q/LAIV.

Cidofovir (HPMPC; (S)-1-[3-hydroxy-2-(phosphonylmethoxy)propyl]cytosine) is a nucleotide analog with activity against human cytomegalovirus (CMV). A phase I/II dose escalation trial was conducted with asymptomatic human immunodeficiency virus (HIV)-infected patients with CMV viruria to determine its pharmacokinetics, maximally tolerated dose, and preliminary antiviral activity against CMV. Qualitative CMV blood and urine cultures were monitored weekly to assess anti-CMV activity. Twenty-one HIV-infected persons with CD4 counts from 0 to 389 cells per microliters (median, 39) were enrolled in six dose-ranging groups. The first five groups enrolled four patients each to receive cidofovir infusions either weekly or biweekly for 4 weeks or every 3 weeks for 12 weeks. The sixth group enrolled one patient who received infusions of 5 mg/kg of body weight every other week. Patients receiving 0.5 or 1.5 mg/kg twice weekly experienced no serious toxicity. The first two patients who received 5 mg/kg twice weekly developed glycosuria and 2+ proteinuria. Subsequent patients received concomitant probenecid to attempt to ameliorate renal toxicity. Seventeen patients experienced proteinuria on one or more occasions; 6 of them experienced at least 2+ proteinuria. Four patients did not complete the study as planned because of renal toxicity. Positive CMV urine cultures reverted to negative in 2 of 8 patients receiving doses of < or = 1.5 mg/kg twice weekly and 11 of 13 patients receiving higher doses. Cidofovir has in vivo anti-CMV activity demonstrated by prolonged clearing of CMV viruria, although this observation is tempered by the fact that clearance of viremia could not be demonstrated. The dose-limiting toxicity is renal; however, concurrent administration of probenecid may be protective. The maximally tolerated weekly intravenous dose with probenecid is approximately 5 mg/kg. Efficacy trials with CMV disease will define the therapeutic utility and optimal dosing interval for cidofovir.

Influenza B viruses from 2 lineages cocirculate annually. Because the single B strain contained in trivalent vaccines may not match the major circulating strain, adding a second B virus could enhance protection. This study compared the safety and immunogenicity of an investigational quadrivalent Ann Arbor strain live attenuated influenza vaccine (Q/LAIV) with that of 2 trivalent vaccines (T/LAIV), each containing a B strain from a different lineage.This randomized, double-blind study was designed to demonstrate the immunologic noninferiority of Q/LAIV compared with T/LAIV in children 2-17 years of age by comparing postdose geometric mean titers of hemagglutination inhibition antibodies. Children were randomized 3:1:1 to receive Q/LAIV or 1 of 2 T/LAIV vaccines. Those subjects who were 9-17 years of age received 1 dose, and those 2-8 years of age received 2 doses 1 month apart. Serum immune responses were evaluated 1 month after dose 1 (dose 2 for influenza vaccine-naive subjects aged 2-8 years).Q/LAIV was noninferior to T/LAIV: upper bounds for all four 95% confidence intervals for the postdose geometric mean titer ratios (T/LAIV divided by Q/LAIV) were ≤1.5, the predefined noninferiority margin. The overall seroresponse rates (4-fold rise) were comparable between treatment groups. Safety events were comparable, except that fever was more common after dose 1 in Q/LAIV subjects (5.1%) than in T/LAIV subjects (3.1%) 2-8 years of age.The immunogenicity of Q/LAIV was noninferior to that of T/LAIV in children aged 2-17 years; safety was also comparable. Q/LAIV may broaden the protection against influenza B strains provided by current trivalent influenza vaccines.

The safety and pharmacokinetics of weekly dapsone and weekly dapsone plus pyrimethamine were examined in adult patients with human immunodeficiency virus infection who were at risk for pneumocystis pneumonia because of a prior episode or a CD4+ T-cell count less than 250 cells per mm3. Groups of patients received 100, 200, and 300 mg of dapsone as a single weekly dose. The maximum tolerated dose of weekly dapsone was established as 200 mg per week in patients receiving at least 500 mg of zidovudine concomitantly. This dose of dapsone was then found to be well tolerated when combined with pyrimethamine at 25 mg. Further patients were randomized to dapsone at 200 mg or dapsone at 200 mg plus pyrimethamine at 25 mg once weekly. Twenty-six patients each were followed for a median of 33 weeks on dapsone alone and 45 weeks on the combination. Seven patients in each group withdrew because of toxicity. Five patients receiving dapsone developed documented pneumocystis pneumonia, while four and two patients receiving dapsone plus pyrimethamine developed documented and presumptive pneumocystis pneumonia, respectively. To evaluate the tolerability of a higher dose of pyrimethamine, 11 patients had their regimen changed to dapsone at 200 mg plus pyrimethamine at 75 mg, which was well tolerated by 10 of the patients for a median period of 11 weeks. The pharmacokinetics of dapsone and pyrimethamine were examined by using a population pharmacokinetic model. Decreases in the apparent volume of the peripheral compartment were observed when multiple-dose regimens of dapsone were compared with single-dose dapsone and when multiple-dose regimens of dapsone with pyrimethamine were compared with multiple-dose dapsone alone. When administered weekly, dapsone at 200 mg and dapsone at 200 mg with pyrimethamine at 25 mg are both well-tolerated regimens. This preliminary study suggests that the efficacy of these regimens in preventing pneumocystis pneumonia, however, may be less than that of trimethoprim-sulfamethoxazole.

Respiratory syncytial virus (RSV) and parainfluenza virus type 3 (PIV3) are important causes of lower respiratory tract illness and hospitalization in young children. Currently, there is no licensed vaccine against RSV or PIV3.In this randomized, phase 1, double-blind, placebo-controlled, dose-escalating study, 49 healthy RSV/PIV3-seronegative children 6 to24 months of age were randomized 2:1 to receive 3 doses (at 10, 10, or 10 median tissue culture infective dose [TCID50]) of MEDI-534 (a live, attenuated RSV/PIV3 chimeric virus vaccine candidate) or placebo at 2-month intervals. Solicited adverse events (SEs) and unsolicited adverse events (AEs) were recorded during days 0 to 28 after each dose. Nasal wash samples were collected 3 times (days 7-10, 12-18, and 28-34) after each dose and at unscheduled illness visits. Blood for antibody response was collected at baseline and 28 days after each dose. Subjects were followed for 180 days after the last dose or to the end of the RSV season.Overall, there was no difference in the incidence of SEs and AEs between the RSV/PIV3 vaccine and placebo arms. Runny/stuffy nose was the most commonly reported SE. Medically attended lower respiratory illness rates were balanced between treatment arms, and there was no evidence of enhanced RSV disease or vaccine-related serious AEs. Vaccine virus was detected in most vaccinees on days 7 to 10 after dose 1 in a dose-dependent manner. Seroresponse to RSV and PIV3 was highest in subjects receiving the 10 dosage.The safety profile and vaccine take as measured by shedding and/or seroresponse in this RSV/PIV3-seronegative pediatric population support the continued development of this RSV/PIV3 pediatric vaccine candidate.

Objective To evaluate the safety, tolerability, immunogenicity, and viral shedding profiles of a recombinant, live, attenuated human parainfluenza virus type 3 (HPIV3) vaccine, rHPIV3cp45, in healthy HPIV3-seronegative infants 6 to Methods In this double-blind, multicenter study, subjects were randomized 2:1 to receive a 105 TCID50 dose of rHPIV3cp45 (n = 20) or placebo (n = 10) at enrollment and at 2 and 4 months after the first dose. Blood for evaluation of antibody to HPIV3 was collected at baseline and approximately 1 month after each dose. Solicited adverse events (SEs) and unsolicited adverse events (AEs) were collected on days 0–28 after each dose. Nasal wash samples for vaccine virus shedding were collected 3 times after each dose (7–10, 12–18, and 28–34 days post dose) and at unscheduled illness visits. Subjects were followed for 180 days after the last dose. Results Vaccine virus was shed by 85% of vaccine recipients after dose 1, by 1 subject after dose 2, and was not shed by any subject after dose 3. The highest titer of shed virus was detected on day 7 after dose 1. The attenuation phenotype and the genotype of the vaccine virus were stable in shed virus. Seroresponse (≥4-fold rise in HPIV3 antibody from baseline) occurred in 61% of subjects after dose 1 and in 77% after dose 3. Either seroresponse or shedding occurred in 95% of vaccine subjects. Adverse events were similar in vaccine and placebo recipients. Conclusion The safety, shedding, and immunogenicity profiles of rHPIV3cp45 in HPIV3-seronegative infants 6 to ClinicalTrials.gov Identifier: NCT00508651 .