Controlled clinical trials
-
Control Clin Trials · Aug 2001
Randomized Controlled Trial Clinical TrialThe inhaled Steroid Treatment as Regular Therapy in early asthma (START) study: rationale and design.
Although the beneficial effects of treatment with inhaled steroids in asthma are widely accepted, the role of early intervention in patients with mild asthma remains unsettled. Conventional efficacy trials are often of short duration and involve highly selected patient populations that exclude many patients typical of those encountered in routine clinical practice. Hence, a large "real-world" effectiveness study is needed to evaluate the benefits of early intervention with inhaled steroids in patients with mild, persistent asthma. ⋯ Lung function will be measured by spirometry using standardized techniques at 3-month intervals throughout the study, and bronchodilator reversibility will be measured annually. The primary outcome measures are the time to the first severe asthma-related event during the first 3 years of the study and the change in postbronchodilator forced expiratory volume in 1 second (FEV(1)) from baseline during the entire 5-year study period. These measures have been chosen to reflect the progression of mild asthma toward more severe asthma and the extent of irreversible airflow limitation, which should reflect the degree of airway remodeling.
-
Control Clin Trials · Jun 2001
Randomized Controlled Trial Clinical TrialThe prehospital treatment of status epilepticus (PHTSE) study: design and methodology.
Status epilepticus is a neurological emergency that is typically first encountered and managed in the prehospital environment. Although aggressive pharmacological treatment of status epilepticus is well established in the emergency department and hospital settings, the relative risks and benefits of active therapy for status epilepticus in the prehospital setting are not known. ⋯ The initial phase of the PHTSE study began in January 1994 and was completed in February 1999 after the successful enrollment of 205 patients into the three treatment arms. In this paper, we describe the rationale for the conceptualization of the study and details of the study design and methodology, and emphasize some aspects of study implementation that are unique to research involving the emergency medical system.
-
The ethical tension in research design is often characterized as that between individual and collective ethics. While adaptive clinical trials (ACTs) are generally considered to be more sensitive to individual ethics, the concomitant loss of statistical power associated with them is often used to justify randomized clinical trials (RCTs). This paper challenges this characterization of the central ethical problem in research design. ⋯ However, in desperate medical situations the process of informed consent is often undermined. It is argued that in such situations ACTs are ethically required. We introduce "the principle of interchangeability" and argue that it must be satisfied if research in desperate medical situations is to be justified.
-
Control Clin Trials · Feb 2001
Randomized Controlled Trial Multicenter Study Comparative Study Clinical TrialCloseout 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. ⋯ 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
-
Control Clin Trials · Aug 2000
The phase II/III transition. Toward the proof of efficacy in cancer clinical trials.
Few phase III investigations show a benefit for an experimental treatment when compared to a standard therapy or placebo. This illustrates the need for more reliable estimates of treatment effects from the phase II investigations used to design the more definitive phase III trials. ⋯ In each area, problems with the conventional approaches are discussed and alternatives for the successful transition of phase II results to a phase III setting are suggested. An application of the design for patients with androgen-independent prostate cancer is illustrated.