Reported consent processes and demographics: a substudy of the INSIGHT Strategic Timing of AntiRetroviral Treatment (START) trial.

OBJECTIVES: Efforts are needed to improve informed consent of participants in research. The Strategic Timing of AntiRetroviral Therapy (START) study provides a unique opportunity to study the effect of length and complexity of informed consent documents on understanding and satisfaction among geographically diverse participants. METHODS: Interested START sites were randomized to use either the standard consent form or the concise consent form for all of the site's participants. RESULTS: A total of 4473 HIV-positive participants at 154 sites world-wide took part in the Informed Consent Substudy, with consent given in 11 primary languages. Most sites sent written information to potential participants in advance of clinic visits, usually including the consent form. At about half the sites, staff reported spending less than an hour per participant in the consent process. The vast majority of sites assessed participant understanding using informal nonspecific questions or clinical judgment. CONCLUSIONS: These data reflect the interest of START research staff in evaluating the consent process and improving informed consent. The START Informed Consent Substudy is by far the largest study of informed consent intervention ever conducted. Its results have the potential to impact how consent forms are written around the world.

Identification of dynamically distinct subpopulations of T lymphocytes that are differentially affected by HIV.

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.

A randomized, controlled 24-week study of intermittent subcutaneous interleukin-2 in HIV-1 infected patients in Thailand.

OBJECTIVES: To assess the immunological and virological effects, safety profile and feasibility of subcutaneous interleukin-2 (scIL-2) therapy in an HIV-infected Thai population. DESIGN: Seventy-two patients with baseline CD4 cell count of > or = 350 x 10(6)/l and no history of opportunistic infection were randomized to receive antiretroviral therapy plus scIL-2 (scIL-2 group) or antiretroviral therapy alone (control group). scIL-2 was administered at one of three doses for at least 24 weeks. The main measure of treatment efficacy was change in CD4 cell count. RESULTS: The time-weighted mean change in CD4 cell count from baseline to week 24 was + 252 x 10(6)/l for the scIL-2 group compared with + 42 x 10(6)/l for the control group (P< 0.0001). Changes in plasma HIV RNA were not significantly different between the groups over the same time period: there was a 0.83 log10 copies/ml decrease for the scIL-2 group and a 0.70 log copies/ml decrease for the control group (P= 0.362). CONCLUSIONS: This study provides the most extensive experience of scIL-2 therapy in HIV-1 infected women and Asians, and demonstrates the immunological efficacy, tolerability and feasability of scIL-2 therapy in this population. Data from this study were instrumental in guiding the selection of the scIL-2 dosing regimen for ongoing phase III trials.

Ongoing trials in HIV protease inhibitors.

The development of antiretrovirals has led to a revolution in the care of patients infected with HIV. What was once a uniformly fatal syndrome has become a more treatable, chronic, infectious disease. Central to this revolution have been the protease inhibitors, a class of drugs with potent antiretroviral activity. The first member of this class was approved for use in 1995 and there are now five protease inhibitors approved by the US Food and Drug Administration (FDA): amprenavir, indinavir, nelfinavir, ritonavir and saquinavir. As a result of the magnitude of the HIV pandemic coupled with the clinically proven efficacy of protease inhibitors, there are currently hundreds of ongoing clinical trials with these agents. Trial designs include comparisons between the various licensed protease inhibitors, comparisons of protease inhibitors to other classes of potent antiretroviral drugs, investigations with new protease inhibitors, investigations of protease inhibitor-related toxicities and attempts at simplifying current dosing regimens.

Ongoing trials of immune-based therapies for HIV infection in adults.

Highly active antiretroviral therapy (HAART) can significantly alter the clinical course of patients infected with HIV. Unfortunately, effective lifelong HAART may not be a practical or achievable goal because of toxicities, cost, development of viral resistance and patient compliance issues. Immune-based therapies (IBTs) that target the host immune system may serve as rational additions to our current antiretroviral strategies. Investigations into IL-2 have culminated in two large Phase III clinical trials. Multiple therapeutic vaccine candidates are in various phases of investigation. In addition, gene therapy has been proposed as a potential treatment for HIV and Phase I trials are ongoing. Although IBTs are being investigated on many fronts, they remain difficult to study due to a lack of validated surrogate end points.

Closeout of four phase II Vanguard trials and patient rollover into a large international phase III HIV clinical endpoint trial.

Large phase III clinical trials typically require many years of planning and preparation. During this time, proposed study methods and overall trial feasibility can be assessed in smaller pilot studies. However, the patients enrolled in these pilot studies are not routinely included in the larger study. In preparation for a multinational randomized clinical end point trial of interleukin-2 in HIV-infected patients, four phase II "Vanguard" studies were initiated. These Vanguard trials served to increase safety and surrogate marker data in diverse patient cohorts, increase clinical experience with the study medication, and identify the optimal dose of medication for the phase III trial. These trials also served to assess patient recruitment potential and to develop international clinical trial coordination experience. The Vanguard trials were designed to allow continued follow-up of their patients as participants of the phase III trial once the feasibility of the phase III trial was confirmed. The purpose of this paper is to describe the steps taken in the closeout of these four phase II trials while reconsenting these patients to the phase III trial. Specifically, the reconsent process, the data collection transition plan, and the steps taken to minimize bias due to differential reconsent according to the assigned treatment arm in the phase II trial are described. The procedures employed are relevant to the reconsent of patients for long-term follow-up at the completion of clinical trials. Control Clin Trials 2001;22:42-48