Placebo-controlled Clinical Trials (placebo-controlled + clinical_trials)

Distribution by Scientific Domains
Distribution within Medical Sciences

Selected Abstracts

Does elimination of placebo responders in a placebo run-in increase the treatment effect in randomized clinical trials?

A meta-analytic evaluation
Abstract The use of a placebo run-in phase, in which placebo responders are withdrawn from a study before random assignment to treatment condition, has been criticized as favoring the active treatment in clinical trials. We compared the effect size of randomized, placebo-controlled clinical trials (in the treatment of depression with selective serotonin reuptake inhibitors [SSRIs]) that include a placebo run-in phase with those that do not, using a meta-analytic approach. This study differed from earlier meta-analytic studies in that it considered only SSRIs and included only studies using continuous measures of depression, allowing for a more refined assessment of effect size. An extensive literature search identified 43 datasets published between 1980 and 2000 comparing placebo with SSRI and using a continuous measure of depression (usually the Hamilton Depression Rating Scale). We included only studies of at least 6 weeks' duration focusing on treatment for primary acute major depression in adults 18,65 years of age. Studies focusing on depression in specific medical illnesses were not included. Analysis of efficacy was based on 3,047 subjects treated with an SSRI antidepressant and 3,740 subjects treated with a placebo. There was no statistically significant difference in effect size between the clinical trials that had a placebo run-in phase followed by withdrawal of placebo responders and those trials that did not. Despite the lack of a statistically significant difference between studies of withdrawing early placebo responders and those not using this procedure, this approach is likely to continue to be used widely because it produces large absolute effect sizes. It is recommended that future studies clearly describe these procedures and report the number of subjects dropped from the study for early placebo response and other reasons. Depression and Anxiety 19:10,19, 2004. 2004 Wiley-Liss, Inc. [source]

Treatment of nicotine dependence with bupropion SR: review of its efficacy, safety and pharmacological profile

Bupropion hydrochloride, an atypical antidepressant, is the first non-nicotine product that, in its sustained release form (bupropion SR), has been licensed as an aid for smoking cessation. The specialized literature on bupropion SR and smoking cessation is critically reviewed. The pharmacological profile, dosage and administration, contraindications, as well as the clinical efficacy, safety and tolerability data of bupropion are discussed. Recent reports suggest that its mode of actions might be different to what had originally been proposed. When prescribed appropriately, it appears to be a safe, well-tolerated and effective medication in combination with smoking cessation counselling,for a wide range of smokers, as shown in several multicentre double-blind, placebo-controlled clinical trials. Further research is needed on aspects such as the optimal duration of treatment, the potential role of combination therapy with NRT and psychological interventions, and to establish its effectiveness in smokers with other psychiatric disorders or when used with only minimal support by general practitioners. [source]

Recombinant human interferon beta in relapsing,remitting multiple sclerosis: a review of the major clinical trials

M. Chofflon
The beneficial effects of interferon beta (IFN-,) on disease activity in relapsing,remitting multiple sclerosis (RRMS) have been confirmed in several clinical trials. Three IFN-, products are currently available and licensed for use in RRMS at different dosages and with different routes of administration. For the prescribing physician, therefore, questions remain about the effect these differences may have on the success of therapy. This paper reviews the four large placebo-controlled clinical trials that have been conducted with IFN-, in patients with RRMS. The evidence available indicates that optimal results are likely to be achieved with the highest tolerable dosage of IFN-,. Furthermore, as inflammatory brain lesions in MS have been shown to exhibit more extensive and early axonal damage than previously suspected, early treatment may be advisable in order to delay disease progression in RRMS. [source]

Antiepileptic Drugs in Migraine Prevention

HEADACHE, Issue 2001
Ninan T. Mathew MD
Migraineurs may continue to experience attacks, despite daily use of one or more agents from a wide range of drugs, including , -blockers, calcium channel blockers, serotonin antagonists, tricyclic antidepressants, monoamine oxidase inhibitors, and antiepileptic agents. Divalproex sodium is the only antiepileptic drug approved for migraine prevention. Gabapentin, topiramate, and other antiepileptic agents are being evaluated for migraine prevention and treatment. Prospective, double-blind, placebo-controlled clinical trials of divalproex, gabapentin, and topiramate for migraine prevention generally were composed of a prospective baseline period, a dose titration period, and a fixed-dose treatment period. The primary efficacy variable was a reduction in the 28-day frequency of migraine headache. Patients receiving divalproex for 12 weeks at doses up to 1500 mg/day achieved significant decreases in the migraine frequency (P<.05), corresponding to reductions of 30% to 40% compared with baseline. Nearly half of the divalproex-treated patients had a 50% or more reduction from baseline in headache frequencies (P.05). Asthenia, vomiting, somnolence, tremor, and alopecia were common adverse events associated with divalproex. Significant reductions in migraine frequency were also observed with gabapentin (1800 to 2400 mg/day) when compared with placebo (P<.01), and nearly half of all patients treated at the highest dose experienced a reduction in headache rate of 50% or more. Somnolence was the most commonly reported adverse event among the gabapentin-treated patients. Two single-center, double-blind, placebo-controlled clinical trials evaluated topiramate for migraine prevention. A lower 28-day migraine frequency was seen during 18 weeks of administration at a maximum daily dose of 200 mg (P = .09). In a second study, a significantly lower mean 28-day migraine frequency was observed during 16 weeks of treatment with topiramate (P = .0015). Mean reduction in migraine frequency was also significantly greater in topiramate-treated patients (P = .0037). Paresthesias, diarrhea, somnolence, and altered taste were commonly reported adverse events in the topiramate-treated patients. Unlike some patients given divalproex or gabapentin, some given topiramate reported weight loss. Large, double-blind, placebo-controlled trials may prove the effectiveness of novel antiepileptic drugs in migraine prevention. [source]

Safety and tolerability of duloxetine in the treatment of major depressive disorder: analysis of pooled data from eight placebo-controlled clinical trials

James I. Hudson
Abstract Objective To examine the safety and tolerability of the antidepressant duloxetine across multiple studies for major depressive disorder (MDD). Method Safety data were integrated from the acute phases of eight double-blind, placebo-controlled trials in which patients were randomized to duloxetine (40,120,mg/d; n,=,1139) or placebo (n,=,777) for up to 9 weeks. This data set included all acute-phase clinical trials that formed the basis of the New Drug Application (United States) or European Union submission package for duloxetine in the treatment of MDD. Two studies included continuation phases in which acute treatment responders received duloxetine or placebo for an additional 26 weeks. Safety assessments included serious adverse event reports, rates of discontinuation, spontaneously reported treatment-emergent adverse events, changes in vital signs and laboratory values, and electrocardiograms. Results The rates of serious adverse events for duloxetine- and placebo-treated patients were 0.3% and 0.6%, respectively (p,=,0.282). Adverse events led to discontinuation in 9.7% of duloxetine-treated patients, compared with 4.2% of patients receiving placebo (p,<,0.001). Treatment-emergent adverse events with an incidence for duloxetine ,,5.0% and significantly greater than placebo were nausea, dry mouth, constipation, insomnia, dizziness, fatigue, somnolence, increased sweating and decreased appetite. Mean changes in blood pressure and heart rate were small, and the incidence of increases above normal ranges was low. Duloxetine-treated patients had a mean decrease in weight of 0.5,kg compared with an increase of 0.2,kg for patients receiving placebo (p,<,0.001). No significant differences were found between duloxetine and placebo in the incidence of potentially clinically significant laboratory values at anytime while on treatment. Conclusion These results are consistent with those obtained previously from smaller pooled data sets, and suggest that duloxetine is safe and well tolerated in patients with MDD. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Testosterone Supplementation Therapy for Older Men: Potential Benefits and Risks

David A. Gruenewald MD
Serum testosterone levels decline gradually and progressively with aging in men. Many manifestations associated with aging in men, including muscle atrophy and weakness, osteoporosis, reduced sexual functioning, and increased fat mass, are similar to changes associated with testosterone deficiency in young men. These similarities suggest that testosterone supplementation may prevent or reverse the effects of aging. A MEDLINE search was performed to identify studies of testosterone supplementation therapy in older men. A structured, qualitative review was performed of placebo-controlled trials that included men aged 60 and older and evaluated one or more physical, cognitive, affective, functional, or quality-of-life outcomes. Studies focusing on patients with severe systemic diseases and hormone deficiencies related to specific diseases were excluded. In healthy older men with low-normal to mildly decreased testosterone levels, testosterone supplementation increased lean body mass and decreased fat mass. Upper and lower body strength, functional performance, sexual functioning, and mood were improved or unchanged with testosterone replacement. Variable effects on cognitive function were reported, with improvements in some cognitive domains (e.g., spatial, working, and verbal memory). Testosterone supplementation improved exercise-induced coronary ischemia in men with coronary heart disease, whereas angina pectoris was improved or unchanged. In a few studies, men with low testosterone levels were more likely to experience improvements in lumbar bone mineral density, self-perceived functional status, libido, erectile function, and exercise-induced coronary ischemia with testosterone replacement than men with less marked testosterone deficiency. No major unfavorable effects on lipids were reported, but hematocrit and prostate specific antigen levels often increased. Based on these results, testosterone supplementation cannot be recommended at this time for older men with normal or low-normal testosterone levels and no clinical manifestations of hypogonadism. However, testosterone replacement may be warranted in older men with markedly decreased testosterone levels, regardless of symptoms, and in men with mildly decreased testosterone levels and symptoms or signs suggesting hypogonadism. The long-term safety and efficacy of testosterone supplementation remain uncertain. Establishment of evidence-based indications will depend on further demonstrations of favorable clinical outcomes and symptomatic, functional, and quality-of-life benefits in carefully performed, long-term, randomized, placebo-controlled clinical trials. J Am Geriatr Soc 51:101,115, 2003. [source]

Magnetic resonance imaging as a potential surrogate for relapses in multiple sclerosis: A meta-analytic approach,

Maria Pia Sormani MscStat
Objective The aim of this work was to evaluate whether the treatment effects on magnetic resonance imaging (MRI) markers at the trial level were able to predict the treatment effects on relapse rate in relapsing-remitting multiple sclerosis. Methods We used a pooled analysis of all the published randomized, placebo-controlled clinical trials in relapsing-remitting multiple sclerosis reporting data both on MRI variables and relapses. We extracted data on relapses and on MRI "active" lesions. A regression analysis weighted on trial size and duration was performed to study the relation between the treatment effect on relapses and the treatment effect on MRI lesions. We validated the estimated relation on an independent set of clinical trials satisfying the same inclusion criteria but with a control arm other than placebo. Results A set of 23 randomized, double-blind, placebo-controlled trials in relapsing-remitting multiple sclerosis was identified, for a total of 63 arms, 40 contrasts, and 6,591 patients. A strong correlation was found between the effect on the relapses and the effect on MRI activity. The adjusted R2 value of the weighted regression line was 0.81. The regression equation estimated using the placebo-controlled trials gave a satisfactory prediction of the treatment effect on relapses when applied to the validation set. Interpretation More than 80% of the variance in the effect on relapses between trials is explained by the variance in MRI effects. Smaller and shorter phase II studies based on MRI lesion end points may give indications also on the effect of the treatment on relapse end points. Ann Neurol 2009;65:268,275 [source]

Lamotrigine in the acute treatment of bipolar depression: results of five double-blind, placebo-controlled clinical trials

Joseph R Calabrese
Objectives:, The efficacy of lamotrigine as maintenance treatment for bipolar disorder (BD), particularly for delaying depressive episodes, is well established, but its efficacy in the acute treatment of bipolar depression is less clear. This paper reports the results of five randomized, double-blind, placebo-controlled trials of lamotrigine monotherapy for the acute treatment of bipolar depression. Methods:, Adult subjects with bipolar I or II disorder experiencing a depressive episode were randomized to placebo or lamotrigine monotherapy (after titration, at a fixed dose of 50 mg or 200 mg daily in Study 1; a flexible dose of 100,400 mg daily in Study 2; or a fixed dose of 200 mg daily in Studies 3, 4 and 5) for 7,10 weeks. Results:, Lamotrigine did not differ significantly from placebo on primary efficacy endpoints [17-item Hamilton Depression Rating Scale in Studies 1 and 2; Montgomery,Asberg Depression Rating Scale (MADRS) in Studies 3, 4 and 5]. In Study 1, lamotrigine significantly separated from placebo on some secondary measures of efficacy, including the MADRS, the Clinical Global Impressions-Severity (CGI-S) and the CGI-Improvement (CGI-I), but seldom differed on secondary efficacy endpoints for the other studies. Conclusions:, Lamotrigine monotherapy did not demonstrate efficacy in the acute treatment of bipolar depression in four out of five placebo-controlled clinical studies. Lamotrigine was well tolerated in the acute treatment of bipolar depression. [source]

Omega-3 Dietary Supplements and the Risk of Cardiovascular Events: A Systematic Review

FCCM, Paul E. Marik MD
Background Epidemiologic data suggest that omega-3 fatty acids derived from fish oil reduce cardiovascular disease. The clinical benefit of dietary fish oil supplementation in preventing cardiovascular events in both high and low risk patients is unclear. Objective To assess whether dietary supplements of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) decrease cardiovascular events across a spectrum of patients. Data Sources MEDLINE, Embase, the Cochrane Database of Systematic Reviews, and citation review of relevant primary and review articles. Study Selection Prospective, randomized, placebo-controlled clinical trials that evaluated clinical cardiovascular end points (cardiovascular death, sudden death, and nonfatal cardiovascular events) and all-cause mortality in patients randomized to EPA/DHA or placebo. We only included studies that used dietary supplements of EPA/DHA which were administered for at least 1 year. Data Extraction Data were abstracted on study design, study size, type and dose of omega-3 supplement, cardiovascular events, all-cause mortality, and duration of follow-up. Studies were grouped according to the risk of cardiovascular events (high risk and moderate risk). Meta-analytic techniques were used to analyze the data. Data Synthesis We identified 11 studies that included a total of 39 044 patients. The studies included patients after recent myocardial infarction, those with an implanted cardioverter defibrillator, and patients with heart failure, peripheral vascular disease, and hypercholesterolemia. The average dose of EPA/DHA was 1.8 ± 1.2 g/day and the mean duration of follow-up was 2.2 ± 1.2 years. Dietary supplementation with omega-3 fatty acids significantly reduced the risk of cardiovascular deaths (odds ratio [OR]: 0.87, 95% confidence interval [CI]: 0.79,0.95, p = 0.002), sudden cardiac death (OR: 0.87, 95% CI: 0.76,0.99, p = 0.04), all-cause mortality (OR: 0.92, 95% CI: 0.85,0.99, p = 0.02), and nonfatal cardiovascular events (OR: 0.92, 95% CI: 0.85,0.99, p = 0.02). The mortality benefit was largely due to the studies which enrolled high risk patients, while the reduction in nonfatal cardiovascular events was noted in the moderate risk patients (secondary prevention only). Meta-regression failed to demonstrate a relationship between the daily dose of omega-3 fatty acid and clinical outcome. Conclusions Dietary supplementation with omega-3 fatty acids should be considered in the secondary prevention of cardiovascular events. Copyright © 2009 Wiley Periodicals, Inc. [source]