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Biomedical subjects

Brian Conway

Publications and source records attributed to Brian Conway.

At least 19 recordsLinked to original sources

A multicenter observational study of the potential benefits of initiating combination antiretroviral therapy during acute HIV infection.

OBJECTIVE: Uncontrolled studies have suggested a benefit, after treatment discontinuation, of initiating highly active antiretroviral therapy (HAART) during primary human immunodeficiency virus (HIV) infection. We assessed whether initiation of HAART within 2 weeks of (acute treatment) or between 2 weeks and 6 months after (early treatment) HIV seroconversion was associated with improvements in the viral load and the CD4+ T cell count after discontinuation of treatment in an observational cohort. METHODS: Subjects from the multicenter Acute Infection and Early Disease Research Program cohort were enrolled in the present study within 6 months of HIV seroconversion and self-selected whether to initiate HAART. Subjects who received acute (n=13) or early (n=45) treatment received HAART for at least 12 weeks and then subsequently stopped treatment, whereas untreated subjects (n=337) declined treatment. HIV RNA levels and CD4+ T cell counts at 24, 48, and 72 weeks after treatment cessation in the 2 treatment groups were compared with those noted in the untreated group during the same periods of observation after enrollment. RESULTS: The acute treatment group had lower mean HIV RNA levels at 24 weeks without therapy (-0.48 log(10) copies/mL [95% confidence interval {CI}, -0.82 to -0.13 log(10) copies/mL]) and higher mean CD4+ T cell counts (112 cells/ mu L [95% CI, 20-205 cells/ microL]), compared with the untreated group at 24 weeks. The differences in the laboratory values for the acute treatment group versus the untreated group at 72 weeks without therapy were as follows: for the HIV RNA level, -0.35 log(10) copies/mL (95% CI, -0.91 to 0.21 log(10) copies/mL) and, for the CD4 T+ cell count, 112 cells/ microL (95% CI, -15 to 213 cells/ microL). The early treatment group had lower HIV RNA levels at 24 weeks than did the untreated group, but differences were no longer apparent by week 48; CD4+ T cell counts were higher in the early treatment group at week 24 (116 cells/ microL [95% CI, 75-157 cells/ microL]) and week 72 (70 cells/ microL [95% CI, 2-138 cells/ microL]). CONCLUSIONS: Initiation of HAART within 2 weeks of antibody seroconversion was associated with viral load and CD4+ T cell count benefits for 24 weeks after termination of HAART, with there being trends toward a longer-term benefit. Later initiation of HAART was associated with a persistent but decreasing CD4+ T cell count benefit and a loss of the viral load benefit by week 72 after discontinuation of treatment.

Acute Disease↗

Hepatitis C virus reinfection in injection drug users.

Spontaneous clearance of hepatitis C (HCV) may provide protection against reinfection. In a large community-based cohort study of 3,553 inner-city residents (mainly injection drug users), we identified HCV-infected individuals in whom virological clearance had occurred and compared the rate of reinfection in this group with that observed in previously uninfected members of the same cohort. We identified 926 HCV-uninfected and 658 HCV-infected viremic subjects at baseline, with 152 of 658 (23.1%) spontaneously clearing viremia over a median follow-up of 5.2 years (IQR, 2.8-7.4). At baseline, individuals with HCV clearance were more likely to be HIV coinfected (P < .001) and to be engaged in frequent illicit drug use (P = .004) and injection drug use (P < .001). The occurrence of HCV infection was lower in individuals with previous infection (14/152, 9.2%) compared with that in those without previous infection (172/926, 18.6%), with incidence rates of 1.8 (95% CI, 0.9-3.0 cases/100 person-years) and 8.1 (95% CI, 6.9-9.4 cases/100 person-years) cases/100 person-years, respectively, after accounting for follow-up. In a logistic regression analysis, with previous HCV infection assessed as a covariate with other potential confounding variables (age, sex, ethnicity, HIV infection, housing status, and illicit and injection drug use), individuals with previous HCV infection and viral clearance were 4 times less likely to develop infection than those infected for the first time (adjusted odds ratio, 0.23; 95% CI, 0.10-0.51, P < .001). In conclusion, individuals with clearance of HCV infection may have a lower risk of acquiring HCV than individuals who have never been infected, despite ongoing exposure to HCV.

Adult↗

A systematic approach to the treatment of HIV and hepatitis C virus infection in the inner city: a Canadian perspective.

The treatment of injection drug users (IDUs) coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) presents multiple challenges, many of which could be addressed by the development of directly observed therapy programs. This is made all the more feasible by the validation of once-daily treatment regimens for HIV. We have demonstrated that virological suppression can be achieved and maintained in as many as 80% of active IDUs who have received highly active antiretroviral therapy for 48 months. This approach has now been validated in first- and second-line therapy, as well as for the treatment of bacterial infections in this population, achieving therapeutic results similar to those reported in the general population. The model is now being applied to the treatment of HCV infection, focusing on patients with infection due to HCV genotype 2 or 3, in whom the likelihood of response may exceed 80%. Our ultimate goal is to ensure that, even in treating IDUs in the inner city, no patient is left behind.

Antiretroviral Therapy, Highly Active↗

Accuracy, precision, and consistency of expert HIV type 1 genotype interpretation: an international comparison (The GUESS Study).

BACKGROUND: Resistance testing is considered standard of care in HIV medicine, but there is no standard interpretation system for genotype tests. We sought to determine how much agreement exists within a group of experts in the interpretation of complex genotypes. METHODS: Genotypes from clinical specimens were sent to an international panel of 12 resistance experts. Phenotypic susceptibility testing of these clinical isolates was performed with antivirogram. Experts predicted phenotype fold change category (<2.5-fold change, 2.5-4.0-fold change, >4.0- to 7.0-fold change, >7.0- to 10-fold change, >10- to 20-fold change, or >20-fold change) and predicted expected drug activity for each of 16 antiretroviral drugs. Experts were also asked to make treatment recommendations on the basis of the genotype. RESULTS: The experts predicted the exact phenotype fold change category correctly 44% of the time, but they varied widely by antiretroviral drug (range, 25%-74%). The highest accuracy was observed for lamivudine (74%) and the nonnucleoside reverse transcriptase inhibitors (66%-69%). Experts generally predicted higher levels of resistance to the remaining nucleoside reverse transcriptase inhibitors than what was found by phenotypic testing. Agreement among experts in predicting phenotype fold change category ranged widely depending on the drug (median agreement, 42% [range, 28%-74%]); the same pattern was observed in predicting expected drug activity (median agreement, 45% [range, 32%-87%]). Experts agreed on treatment recommendations in a median of 79% of instances, and recommendations were consistent over time, with blinded retesting. CONCLUSIONS: Although their ability to predict phenotype from a genotype varied for individual antiretroviral drugs, this expert panel had a high degree of agreement in deriving treatment recommendations from the genotype.

Anti-HIV Agents↗

Directly observed therapy for the management of HIV-infected patients in a methadone program.

The objective of this prospective, observational clinical study was to evaluate the safety and efficacy of once-daily and twice-daily directly observed therapy (DOT) in human immunodeficiency virus (HIV)-infected patients undergoing methadone treatment. Methadone and highly active antiretroviral therapy (HAART) were dispensed daily as DOT, with patients in the twice-daily HAART group self-administering the second dose. Clinical and laboratory end points were monitored, along with the impact of ongoing cocaine use. We studied 54 patients coinfected with HIV and hepatitis C virus. At baseline, the median virus load was 111,000 copies/mL, and the median CD4+ cell count was 165 cells/mm3. After a median of 24 months, 17 of 29 patients in the once-daily HAART group and 18 of 25 in the twice-daily HAART group had virus loads of <400 copies/mL, regardless of ongoing cocaine use. Thirty-two patients required methadone dose adjustment, which was managed without modification of HAART. Treatment-limiting hepatic toxicity was rare. A DOT program of coadministered methadone and HAART can be implemented with good results, even for patients who continue to use cocaine.

Anti-HIV Agents↗

A phase II dose-escalating trial of clevudine in patients with chronic hepatitis B.

Current therapies available for the treatment of chronic hepatitis B are limited in their ability to result in a cure. Clevudine is a new pyrimidine analog with potent anti-hepatitis B virus (HBV) activity in vitro. A multicenter dose-escalation study evaluated clevudine at 10, 50, 100, and 200 mg once daily for 28 days. Eligible patients had HBV DNA levels of 3 x 10(6) copies/mL or more, had not undergone nucleoside treatment, and were without human immunodeficiency or hepatitis C virus coinfection. Thirty-two patients were enrolled (5, 10, 10, and 7 patients in the 10-, 50-, 100-, and 200-mg dose groups, respectively), 81% were male, 81% Asian, and 88% were hepatitis Be antigen (HBeAg) positive at baseline. Median pretreatment serum HBV DNA levels ranged from 7.3 to 8.8 log(10) copies/mL. After 28 days, the median HBV DNA log(10) change from baseline was -2.5, -2.7, -3.0, and -2.6 log(10). Six months after dosing, median changes from baseline were -1.2, -1.4, -2.7 and -1.7 log(10) in the 10-, 50-, 100-, and 200-mg cohorts, respectively. Six of 27 patients lost HBeAg, and 3 of 27 patients seroconverted to HBe antibody. Clevudine was well tolerated, with no dose-limiting toxicities. A transient increase in alanine aminotransferase of up to 7.8 times the upper limit of normal (increase ranged from 20 to 186 IU/L) was observed in six patients in the 100-mg cohort, without signs of liver failure. These increases were associated with improved viral suppression. The pharmacokinetic profile of clevudine was proportional to the dose. In conclusion, these results demonstrate the tolerability and potent activity of clevudine in HBV-infected patients and support further clinical study.

Adult↗

Monoclonal antibody hNM01 in HIV-infected patients: a phase I study.

BACKGROUND: hNM01 is a humanized monoclonal antibody that binds to the V(3) region of the HIV-1 envelope protein gp120. This binding leads to the activation of complement and the disruption of the viral envelope. OBJECTIVES AND STUDY DESIGN: The aim of this study was to investigate the clinical responses of the individuals when treated with the humanized antibody NMO1. In this phase I study, four HIV-1 infected patients with CD4 counts between 50 and 500 cells/mul received a total of four doses of hNM01 in an intrapatient dose escalation fashion: day 1-0.2 mg/kg, day 15-1 mg/kg, day 29-5 mg/kg, and day 43-5mg/kg. Patients were required to have virus that reacted to hNM01 by a virion capture assay and to have a viral load > or =15,000 copies/mL. RESULTS AND CONCLUSION: The antibody was well-tolerated; no significant adverse events were observed even at the highest dose tolerated. None of the patient developed either human anti-hNM01 (anti-idiotype) or human anti-rat antibodies. The mean elimination half-life was 153 h (6.4 days). During hNMO1 therapy effects were observed on CD4 cell counts and plasma viral loads and further dose finding trials are necessary to better determine the therapeutic activity of hNM01 in HIV-infected individuals.

Antibodies, Monoclonal↗

Genetic basis of hypersusceptibility to protease inhibitors and low replicative capacity of human immunodeficiency virus type 1 strains in primary infection.

The initial virus strains from as many as 12% of individuals with primary human immunodeficiency virus (HIV) infection have a 50% inhibitory concentration </=0.4-fold that of HIV type 1(NL4-3) (HIV-1(NL4-3)) to ritonavir (hypersusceptibility [HS]). There is also substantial variation in replicative capacity (RC) or an in vitro assay of the contributions of protease (PR) and reverse transcriptase to viral fitness. In chronically infected antiretrovirally treated patients, amprenavir HS has been associated with the mutation N88S in PR, but this mutation is not seen in untreated patients. In this study, virus strains from 182 cases of primary HIV infection were analyzed, and a highly significant association between HS and low RC (</=10% that of HIV-1(NL4-3)) was observed (P < 10(-6)). Multivariate analysis was used to determine the genotypic basis of ritonavir HS, analyzing all polymorphic amino acid sites and insertions from p7gag through PR. Decision tree models developed on the entire Gag-plus-PR data set and on PR alone gave overall correct classifications of 73 and 72%, respectively, on cross-validation. They were also able to predict low RC, with sensitivities of 69 and 62% and specificities of 84 and 70%, respectively. The analysis shows that ritonavir HS in untreated primary HIV infection is not associated with single mutations but with combinations of amino acids at polymorphic sites and that the same genotypes which confer HS to PR inhibitors confer low RC. This supports the view that variation in PR function is directly responsible for variation in fitness among strains in primary infection.

Decision Trees↗

Quality of life in patients treated with first-line antiretroviral therapy containing nevirapine and/or efavirenz.

OBJECTIVE: To assess whether differences in safety profiles between nevirapine (NVP) and efavirenz (EFV), as observed in the 2NN study, translated into differences in 'health related quality of life' (HRQoL). DESIGN: A sub-study of the 2NN study, with antiretroviral-naive patients randomly allocated to NVP (once or twice daily), EFV or NVP+EFV, in addition to stavudine and lamivudine. METHODS: Comparing differences in changes of HRQoL over 48 weeks as measured with the Medical Outcomes Study HIV Health Survey (MOS-HIV) questionnaire, using analysis of variance. RESULTS: The 2NN study enrolled 1216 patients. No validated questionnaires were available for 244 patients, and 55 patients had no HRQoL data at all, leaving 917 patients eligible for this sub-study. A total of 471 (51%) had HRQoL measurements both at baseline and week 48. The majority (69%) of patients without HRQoL measurements did, however, complete the study. The change in the physical health score (PHS) was 3.9 for NVP, 3.4 for EFV and 2.4 for NVP+EFV (P=0.712). For the mental health score (MHS) these values were 6.1, 7.0 and 3.9, respectively (P=0.098). A baseline plasma HIV-1 RNA concentration (pVL) > or = 100,000 copies/ml and a decline in pVL (per log10) were independently associated with an increase of PHS. An increase of MHS was only associated with pVL decline. Patients experiencing an adverse event during follow-up had a comparable change in PHS but a significantly smaller change in MHS, compared with those without an adverse event. CONCLUSIONS: First-line ART containing NVP and/or EFV leads to an improvement in HRQoL. The gain in HRQoL was similar for NVP and EFV, but slightly lower for the combination of these drugs.

Adult↗

Antiretroviral drug resistance testing in adults infected with human immunodeficiency virus type 1: 2003 recommendations of an International AIDS Society-USA Panel.

New information about the benefits and limitations of testing for resistance to human immunodeficiency virus (HIV) type 1 (HIV-1) drugs has emerged. The International AIDS Society-USA convened a panel of physicians and scientists with expertise in antiretroviral drug management, HIV-1 drug resistance, and patient care to provide updated recommendations for HIV-1 resistance testing. Published data and presentations at scientific conferences, as well as strength of the evidence, were considered. Properly used resistance testing can improve virological outcome among HIV-infected individuals. Resistance testing is recommended in cases of acute or recent HIV infection, for certain patients who have been infected as long as 2 years or more prior to initiating therapy, in cases of antiretroviral failure, and during pregnancy. Limitations of resistance testing remain, and more study is needed to refine optimal use and interpretation.

Adult↗

Successful discontinuation of therapy for disseminated Mycobacterium avium complex infection after effective antiretroviral therapy.

BACKGROUND: Highly active antiretroviral therapy (HAART) is associated with improvement or resolution of several HIV-associated opportunistic infections. Although prophylaxis against disseminated Mycobacterium avium complex infection may be successfully discontinued after a favorable response to HAART, the 1999 guidelines from the U.S. Public Health Service/Infectious Diseases Society of America recommend continuing therapy for disseminated M. avium complex infection, regardless of the response to HAART. OBJECTIVE: To examine the outcome among patients with disseminated M. avium complex infection whose antimycobacterial therapy was discontinued after a favorable response to HAART. DESIGN: Retrospective chart review between May 2000 and May 2001. SETTING: 13 Canadian HIV clinics. PATIENTS: 52 HIV-infected adults (43 men; mean age, 37.3 years) in whom successful antimycobacterial therapy for disseminated M. avium complex infection was discontinued after a favorable virologic response to HAART. MEASUREMENTS: Survival, survival free of disseminated M. avium complex infection, and CD4(+) cell count responses. RESULTS: At the time of diagnosis of disseminated M. avium complex infection, the median CD4(+) cell count was 0.016 x 10(9) cells/L, and the median plasma HIV RNA level was 90 000 copies/mL (plasma HIV RNA levels were available for only 21 patients). The patients received a median of 32 months of antimycobacterial therapy that included ethambutol plus either clarithromycin or azithromycin. When antimycobacterial therapy was discontinued, the median CD4(+) cell count was 0.23 x 10(9) cells/L and the median plasma HIV RNA level was less than 50 copies/mL. A median of 20 months after discontinuation of antimycobacterial therapy, only 1 patient had developed recurrent M. avium complex disease (37 months after stopping antimycobacterial therapy). This patient had stopped HAART 2 months earlier because of uncontrolled HIV viremia. Twenty months after stopping antimycobacterial therapy, the other 51 patients had a median CD4(+) cell count of 0.288 x 10(9) cells/L; 34 (67%) had undetectable plasma HIV RNA levels, and 8 (15%) had plasma HIV RNA levels of 50 to 1000 copies/mL. CONCLUSIONS: Discontinuation of successful disseminated M. avium complex therapy after a successful response to HAART is safe and reduces patients' pill burdens, potential drug adverse effects, drug interactions, and costs of therapy.

AIDS-Related Opportunistic Infections↗

Antiretroviral-drug resistance among patients recently infected with HIV.

BACKGROUND: Among persons in North America who are newly infected with the human immunodeficiency virus (HIV), the prevalence of transmitted resistance to antiretroviral drugs has been estimated at 1 to 11 percent. METHODS: We performed a retrospective analysis of susceptibility to antiretroviral drugs before treatment and drug-resistance mutations in HIV in plasma samples from 377 subjects with primary HIV infection who had not yet received treatment and who were identified between May 1995 and June 2000 in 10 North American cities. Responses to treatment could be evaluated in 202 subjects. RESULTS: Over the five-year period, the frequency of transmitted drug resistance increased significantly. The frequency of high-level resistance to one or more drugs (indicated by a value of more than 10 for the ratio of the 50 percent inhibitory concentration [IC50] for the subject's virus to the IC50 for a drug-sensitive reference virus) increased from 3.4 percent during the period from 1995 to 1998 to 12.4 percent during the period from 1999 to 2000 (P=0.002), and the frequency of multidrug resistance increased from 1.1 percent to 6.2 percent (P=0.01). The frequency of resistance mutations detected by sequence analysis increased from 8.0 percent to 22.7 percent (P<0.001), and the frequency of multidrug resistance detected by sequence analysis increased from 3.8 percent to 10.2 percent (P=0.05). Among subjects infected with drug-resistant virus, the time to viral suppression after the initiation of antiretroviral therapy was longer (P=0.05), and the time to virologic failure was shorter (P=0.05). CONCLUSIONS: The proportion of new HIV infections that involve drug-resistant virus is increasing in North America. Initial antiretroviral therapy is more likely to fail in patients who are infected with drug-resistant virus. Testing for resistance to drugs before therapy begins is now indicated even for recently infected patients.

Adolescent↗

Field evaluation of the Merlin immediate HIV-1 and -2 test for point-of-care detection of human immunodeficiency virus antibodies.

The Merlin Immediate HIV-1 and -2 Test (Merlin point-of-care [POC] test; Merlin Biomedical & Pharmaceutical) is a nitrocellulose membrane flow immunoassay performed at the POC with the use of blood obtained from a fingerprick. The results of this test were compared with those of enzyme immunoassay (EIA) performed on venous blood samples in the laboratory. Positive results of both tests were confirmed by a Western blot (WB). The study included 553 adults with known HIV (human immunodeficiency virus) seropositivity (all of whom had positive Merlin POC test results) and 2659 adults with unknown HIV serostatus (20 of whom had positive EIA/WB results; 19 of the 20 also had positive Merlin-POC test results). The sensitivity of the Merlin POC test was 95.0% for patients with an unknown HIV serostatus and 99.83% for those with a positive serostatus. For previously untested subjects, the test's specificity and positive predictive value were 100%, its negative predictive value was 99.96%, and its overall accuracy was 99.96%. The Merlin POC test is highly accurate for the detection of HIV antibodies.

AIDS Serodiagnosis↗

Evaluation of protocols for reproducible electrospray in-source collisionally induced dissociation on various liquid chromatography/mass spectrometry instruments and the development of spectral libraries.

Mass spectral libraries provide a tool for identifying unknown compounds using both molecular weight and fragmentation information. Mass spectrometers with electrospray ionisation (ESI) and atmospheric chemical ionisation (ApCI) sources have the capability to produce data of this type using in-source collisionally induced dissociation (CID), and in-source CID libraries can be created. Due to the variation in electrospray source design from different instrument manufacturers, the production of reproducible in-source CID spectra that can be used in libraries for all instrument types is not a trivial task. To date, the evaluation of the production of in-source CID libraries has tended to focus on similar instruments from one manufacturer. The studies have also tended to focus on specific compound classes, with a limited molecular weight range.This report describes the findings from the investigation of protocols for the creation of mass spectral libraries using ESI in-source CID on six instruments from four different manufacturers. The overall goal was to create a spectral library for the identification of unknowns. The library could then be applied across all manufacturers' electrospray instruments. Two different experimental protocols were attempted. The first used a tuning compound to establish standard ESI source conditions, with fixed fragmentation potentials. The second involved the attenuation of the [M + H](+) ion to a known degree. A diverse range of compounds (pharmaceutical, photographic, pesticides) was tested to establish the reproducibility of the spectra on the six instruments. Both protocols produced spectra on the various instruments that in many cases were very similar. In other examples, the spectra differed not only in their relative ion abundances, but also in terms of the spectral content. Important observations regarding the effect of ion source design are also reported. The degree of spectral reproducibility was calculated off-line by comparing the five most abundant ions (20% for each ion that matches) from each spectrum on each instrument. This approach was adopted, as we do not possess a software package that met our requirements for spectral comparison. Match factors (% fit) were calculated by comparing each spectrum against the spectra recorded for the same compound and then for all other compounds, on each instrument. The % fit values derived by the off-line approach gave a clear view of the spectral reproducibility from instrument to instrument and also discriminated the spectra of the various compounds from each other. The applicability of this approach was tested using a blind trial in which several compounds were presented as unknowns, their in-source CID spectra recorded and the five-ion approach used for identification.

Chromatography, Liquid↗

Persistence and fitness of multidrug-resistant human immunodeficiency virus type 1 acquired in primary infection.

This study examines the persistence and fitness of multidrug-resistant (MDR) viruses acquired during primary human immunodeficiency virus infection (PHI). In four individuals, MDR infections persisted over the entire study period, ranging from 36 weeks to 5 years, in the absence of antiretroviral therapy. In stark contrast, identified source partners in two cases showed expected outgrowth of wild-type (WT) virus within 12 weeks of treatment interruption. In the first PHI case, triple-class MDR resulted in low plasma viremia (1.6 to 3 log copies/ml) over time compared with mean values obtained for an untreated PHI group harboring WT infections (4.1 to 4.3 log copies/ml). Increasing viremia in PHI patient 1 at week 52 was associated with the de novo emergence of a protease inhibitor-resistant variant through a recombination event involving the original MDR virus. MDR infections in two other untreated PHI patients yielded viremia levels typical of the untreated WT group. A fourth patient's MDR infection yielded low viremia (<50 to 500 copies/ml) for 5 years despite his having phenotypic resistance to all antiretroviral drugs in his treatment regimen. In two of these PHI cases, a rebound to higher levels of plasma viremia only occurred when the M184V mutation in reverse transcriptase could no longer be detected and, in a third case, nondetection of M184V was associated with an inability to isolate virus. To further evaluate the fitness of MDR variants acquired in PHI, MDR and corresponding WT viruses were isolated from index and source partners, respectively. Although MDR viral infectivity (50% tissue culture infective dose) was comparable to that observed for WT viruses, MDR infections in each case demonstrated 2-fold and 13- to 23-fold reductions in p24 antigen and reverse transcriptase enzymatic activity, respectively. In dual-infection competition assays, MDR viruses consistently demonstrated a marked replicative disadvantage compared with WT virus. These results indicate that MDR viruses that are generated following PHI can establish persistent infections as dominant quasispecies despite their impaired replicative competence.

Adult↗