How should zoster trials be conducted?

In 1994, an international group of interested clinicians and biostatisticians met to discuss the design of clinical trials in herpes tester. They agreed that trials in herpes tester should have prospectively agreed definitions of all outcome measures and plans for data analysis. In immunocompetent individuals, in whom pain is the major outcome measure, trials should only include patients over the age of 50 years, and for those recruited within 72 fi of rash onset, should be designed to demonstrate superiority of any new therapy over existing antivirals. The primary endpoint should be time to cessation of pain for at least 4 weeks and, for the purposes of statistical analysis of its duration, the pain associated with herpes tester ought to be considered as a continuum. All other variables, including the incidence of post-herpetic neuralgia and effects upon quality of life should be considered as secondary end-points. Evaluation of treatment effects on primary endpoints should be based upon an intent-to-treat (ITT) analysis and subgroup analysis should be used only to support the findings of the ITT analysis. These elements of good study design should be borne in mind in the evaluation of current and future trails of antiviral drugs in herpes zoster

Zidovudine in persons with asymptomatic HIV infection and CD4+ cell counts greater than 400 per cubic millimeter

Background. Zidovudine therapy is of benefit in the treatment of symptomatic and asymptomatic human immunodeficiency virus (HIV) infection in persons with CD4+ cell counts of less than 500 per cubic millimeter. The efficacy, safety, and duration of benefit of zidovudine in those with 500 or more CD4+ cells per cubic millimeter are uncertain. Methods. In a double-blind, placebo-controlled trial, 993 patients with asymptomatic HIV infection and CD4+ cell counts above 400 per cubic millimeter were randomly assigned to receive zidovudine (500 mg twice daily) or placebo for three years. The primary end point was progression of disease, as defined by the development of Centers for Disease Control and Prevention (CDC) group IV disease (including recurrent oral candidiasis, hairy leukoplakia, or progressive diarrhea) or two CD4+ cell counts below 350 per cubic millimeter. This outcome measure was changed from the original end point of the acquired immunodeficiency syndrome (AIDS) or advanced AIDS-related complex to reflect changes in recommendations for management. The study was terminated after the first interim analysis. Results. Disease progression was significantly less frequent in the zidovudine group (relative risk, 0.56; 95 percent confidence interval, 0.43 to 0.75; P<0.001 by the log-rank test). The probability of disease progression at two years was 0.19 with zidovudine, as compared with 0.34 with placebo (95 percent confidence interval for the difference, -0.21 to -0.08). Progression to CDC group IV disease was reduced by half in the zidovudine recipients (relative risk, 0.49; P = 0.049) and decline in CD4+ cell counts to below 350 per cubic millimeter was reduced by 40 percent (relative risk, 0.60; P<0.001). The inclusion of early HIV disease events (oral candidiasis, oral hairy leukoplakia, and herpes zoster) as end points confirmed the effects of zidovudine on the progression of clinical disease (relative risk, 0.55; 95 percent confidence interval, 0.37 to 0.84; P = 0.004). The median duration of treatment was 94 weeks. Severe hematologic or clinical side effects were rare. Conclusions. Treatment with zidovudine benefits HIV-infected persons with CD4+ cell counts above 400 per cubic millimeter. Despite the use of doses larger than those now generally prescribed, zidovudine was well tolerated for up to three years by most of our patients.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Building a biodiversity problem-solving environment

In the Biodiversity World project, our goal is to create a flexible and extensible Grid environment in which heterogeneous distributed biodiversity-related data sets and analytical tools are made available to be located and assembled by users unfamiliar with the Grid into workflows to perform complex scientific analyses. We have previously defined and described an architecture containing a number of kinds of components which conform to a common model of Grid interoperability. In this paper, we concentrate on the components and strategies which are important for the assembly of a complete working environment. We describe recent work on three main components of the environment: the workflow system, which provides both workflow design and enactment facilities based on Triana; the metadata repository, implemented using simple flexible entity-attribute-value triples; and the user interface, which consists of parts to control the workflow engine, the metadata repository and tasks as they are executed. We discuss various issues which arose during this work, some of which have not yet been fully resolved, including data set management and access, resource location and invocation, metadatabase representation, wrapping techniques for legacy resources, and user interaction with them

Zidovudine in persons with asymptomatic HIV infection and CD4+ cell counts greater than 400 per cubic millimeter

Background: Zidovudine therapy is of benefit in the treatment of symptomatic and asymptomatic human immunodeficiency virus (HIV) infection in persons with CD4+ cell counts of less than 500 per cubic millimeter. The efficacy, safety, and duration of benefit of zidovudine in those with 500 or more CD4+ cells per cubic millimeter are uncertain. Methods: In a double-blind, placebo-controlled trial, 993 patients with asymptomatic HIV infection and CD4+ cell counts above 400 per cubic millimeter were randomly assigned to receive zidovudine (500 mg twice daily) or placebo for three years. The primary end point was progression of disease, as defined by the development of Centers for Disease Control and Prevention (CDC) group IV disease (including recurrent oral candidiasis, hairy leukoplakia, or progressive diarrhea) or two CD4+ cell counts below 350 per cubic millimeter. This outcome measure was changed from the original end point of the acquired immunodeficiency syndrome (AIDS) or advanced AIDS-related complex to reflect changes in recommendations for management. The study was terminated after the first interim analysis. Results: Disease progression was significantly less frequent in the zidovudine group (relative risk, 0.56; 95 percent confidence interval, 0.43 to 0.75; P<0.001 by the log-rank test). The probability of disease progression at two years was 0.19 with zidovudine, as compared with 0.34 with placebo (95 percent confidence interval for the difference, -0.21 to -0.08). Progression to CDC group IV disease was reduced by half in the zidovudine recipients (relative risk, 0.49; P = 0.049) and decline in CD4+ cell counts to below 350 per cubic millimeter was reduced by 40 percent (relative risk, 0.60; P<0.001). The inclusion of early HIV disease events (oral candidiasis, oral hairy leukoplakia, and herpes zoster) as end points confirmed the effects of zidovudine on the progression of clinical disease (relative risk, 0.55; 95 percent confidence interval, 0.37 to 0.84; P = 0.004). The median duration of treatment was 94 weeks. Severe hematologic or clinical side effects were rare. Conclusions: Treatment with zidovudine benefits HIV-infected persons with CD4+ cell counts above 400 per cubic millimeter. Despite the use of doses larger than those now generally prescribed, zidovudine was well tolerated for up to three years by most of our patients