Contemporary clinical trials
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The traditional development paradigm for phase II trials in oncology has been challenged in recent years by the introduction of cytostatic therapies. These agents slow the growth of tumors rather than cause high rates of shrinkage, this argues for the use of endpoints that measure growth inhibition such as progression free survival. We have previously argued the need for randomized trials in this setting. ⋯ We also discuss other design features to maximize the information yielded in a phase II setting. We advocate the creation of progression endpoints that utilize all available progression data rather than early fixed time-point analyses and show that little is to be gained by assessing progression status any more frequently than would be required in routine clinical practice. Such design and analysis measures will optimize the development decision made at the end of phase II clinical evaluation.
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Contemp Clin Trials · Feb 2007
ReviewImproving the design of phase II trials of cytostatic anticancer agents.
This paper examines the design of phase II trials in oncology and recommends departing from the traditional uncontrolled trial design. Entrance into phase II clinical evaluation represents a key milestone in the development of any new cancer therapy. As novel molecular-targeted therapies are introduced, whose primary action is to slow the growth of tumors, it will be important to ensure that the clinical trial design will effectively capture any clinical benefit of these agents. ⋯ This paper will review the various approaches to phase II trial design in oncology and provide a framework for fully powered randomized trials of a moderate size. For example, a randomized trial of just 100 patients could lead to the termination of development of 90% of inactive agents whereas at least 80% of agents with a meaningful and realistic increase in progression-free survival would be identified for confirmatory study. We believe randomized studies with progression-free survival endpoints are the most powerful and economical method of determining the clinical activity of new cytostatic agents.
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The relatively low participation of African Americans in phase III clinical trials has raised concerns about the appropriateness of generalizing study results to African American populations. If African American enrollment in clinical trials continues to be low, the society may continue to see disparities in the treatment of diseases as well as unanswered questions as to why the population fares less than others when diagnosed with certain diseases such as cancer and diabetes. Additionally, more clinical trials are needed to explicitly monitor the difference in outcomes across different populations. This article discusses the various reasons why African American patient recruitment and participation is sub-optimal; the critical role of clinical trials in therapies; recommendations by important authorities; and a new practice model (Collaborative Care Model) as an innovative strategy to augment participation rates of African Americans [and other minorities] in clinical trials.
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Contemp Clin Trials · Jan 2007
Randomized Controlled TrialDesign paper: the DEMO trial: a randomized, parallel-group, observer-blinded clinical trial of aerobic versus non-aerobic versus relaxation training for patients with light to moderate depression.
In western countries, the yearly incidence of depression is estimated to be 3-5% and the lifetime prevalence is 17%. In patient populations with chronic diseases the point prevalence may be 20%. Depression is associated with increased risk for various conditions such as osteoporoses, cardiovascular diseases, and dementia. WHO stated in 2000 that depression was the fourth leading cause of disease burden in terms of disability. In 2000 the cost of depression in the US was estimated to 83 billion dollars. A predominance of trials suggests that physical exercise has a positive effect on depressive symptoms. However, a meta-analysis from 2001 stated: "The effectiveness of exercise in reducing symptoms of depression cannot be determined because of a lack of good quality research on clinical populations with adequate follow-up." ⋯ The trial is designed as a randomized, parallel-group, observer-blinded clinical trial. Patients are recruited through general practitioners and psychiatrist and randomized to three different interventions: 1) non-aerobic, -- progressive resistance training, 2) aerobic training, -- cardio respiratory fitness, and 3) relaxation training with minimal impact on strength or cardio respiratory fitness. Training for all three groups takes place twice a week for 4 months. Evaluation of patients' symptoms takes place four and 12 months after inclusion. The trial is designed to include 45 patients in each group. Statistical analysis will be done as intention to treat (all randomized patients). Results from the DEMO trial will be reported according to the CONSORT guidelines in 2008-2009.
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Contemp Clin Trials · Aug 2006
Randomized Controlled TrialRationale and design of the TRANSFACT project phase I: a study to assess the effect of the two different dietary sources of trans fatty acids on cardiovascular risk factors in humans.
Detrimental effects of consumption of industrial trans fatty acids (TFA) from partially hydrogenated vegetable oils (PHVO) on cardiovascular disease (CVD) risk factors are well documented. However, very little information is available on the effect of natural sources of TFA coming from milk fat, dairy products and ruminant meat. In fact, due to the naturally low level of TFA in milk fat, it is almost impossible to conduct a clinical trial with a limited number of subjects (<200). ⋯ We have shown that it is technically feasible to perform a clinical trial on the comparative effects of natural and industrial sources of TFA isomers on CVD risk factors. Results are expected by mid-2006.