How representative of everyday clinical populations are schizophrenia patients enrolled in clinical trials?

INTRODUCTION: There has been considerable discussion whether clinical trials accurately depict everyday practice. Restrictive inclusion/exclusion criteria, ethical considerations, differences in the severity of psychopathology between clinical and trial patients, or safety issues may bias results, which in turn may rather represent outcome for the "ideal" than for the "average"patient. Therefore, translation into psychiatric practice may be difficult. METHODS: A retrospective case-control study was performed. Schizophrenia inpatients at the LMU Department of Psychiatry, Munich, Germany, who had participated in clinical trials were compared to regular patients serving as controls. Probands and controls were matched by DSM-IV diagnosis, gender and age. The AMDP module, CGI and GAF were used to compare psychopathology. In addition, charts were reviewed for medication dosages, concurrent medical and neurological illness, and clinical history such as age of onset or family history. RESULTS: A total of 200 probands (100/100) were enrolled in the study. With respect to psychopathology, formally thought disordered or suicidal patients were significantly less likely to be study participants (n = 3) than controls (n = 22; p < or = 0.05). Similarly, negative schizophrenia symptoms were significantly less often present in study participants (n = 17) than in controls (n = 38; p < or = 0.05). Study participants were also medically and neurologically healthier than controls. (p = 0.05 respectively). No differences in overall illness severity as depicted by CGI and GAF were observed. CONCLUSION: We found the patients included in our clinical trials representative of the patient encountered in routine clinical practice. Adherence to inclusion and exclusion criteria prevents inclusion of severely ill (e. g. suicidal) patients requiring a more intensive treatment setting. Illness severity was found to be similar in trial participants and controls, and indicates an overall comparably severe psychopathology. The more chronic, rather treatment refractory patients were also not reflected in the trial participant pool; this population may arguably not represent the average clinical patient either. A more careful administration of antipsychotic medication was found in trial participants and may effectively be considered "good clinical practice".     

How can we improve clinical trials in amyotrophic lateral sclerosis?

Since the approval of riluzole for the treatment of amyotrophic lateral sclerosis (ALS) 17 years ago, more than 30 large clinical trials have been conducted, but none has proved successful. The failure to translate positive preclinical results into the clinical setting raises questions about the validity of the rodent model that is used to study ALS, and about the quality of both preclinical and clinical studies. However, the greatest challenge is the disease itself as, with rare exceptions, the causes are unknown. In this Perspectives article, we highlight key issues related to the pathophysiology, preclinical studies and clinical trials that should be addressed in the future. These areas include the relationships between different disease mechanisms, the challenges presented by the heterogeneity of the disease, and the need for early intervention, optimal dose selection and effective biomarkers.     

Are subjects in pharmacological treatment trials of depression representative of patients in routine clinical practice?

OBJECTIVE: The methods used to evaluate the efficacy of antidepressants differ from treatment for depression in routine clinical practice. The rigorous inclusion/exclusion criteria used to select subjects for participation in efficacy studies potentially limit the generalizability of these trials' results. It is unknown how much impact these criteria have on the representativeness of subjects in efficacy trials. This study estimated the proportion of depressed patients treated in routine clinical practice who would meet standard inclusion/exclusion criteria for an efficacy trial. METHOD: A total of 803 individuals, aged 16--65 years, who were seen at intake at an outpatient practice underwent a thorough diagnostic evaluation, including the administration of semistructured diagnostic interviews; 346 patients had current major depression. Common inclusion/exclusion criteria used in efficacy studies of antidepressants were applied to the depressed patients to determine how many would have qualified for an efficacy trial. RESULTS: Approximately one-sixth of the 346 depressed patients would have been excluded from an efficacy trial because they had a bipolar or psychotic subtype of depression. The presence of a comorbid anxiety or substance use disorder, insufficient severity of depressive symptoms, or current suicidal ideation would have excluded 86.0% (N=252) of the remaining 293 outpatients with nonpsychotic unipolar major depressive disorder from an antidepressant efficacy trial. CONCLUSIONS: Subjects treated in antidepressant trials represent a minority of patients treated for major depression in routine clinical practice. These results show that antidepressant efficacy trials tend to evaluate a subset of depressed individuals with a specific clinical profile.     

How effective are second-generation antipsychotic drugs? A meta-analysis of placebo-controlled trials

We conducted a systematic review and meta-analysis of randomized controlled trials that compared second-generation antipsychotic (SGA) drugs with placebo in schizophrenic patients and which considered 13 different outcome measures. Thirty-eight randomized controlled trials with 7323 participants were included. All SGA drugs were more effective than placebo, but the pooled effect size (ES) for overall symptoms (primary outcome) was moderate (-0.51). The absolute difference (RD) in responder rates was at 18% (41% responded to drug compared with 24% to placebo, number needed to treat=6). Similar ESs were found for the other efficacy parameters: negative symptoms (ES=-0.39), positive symptoms (ES=-0.48), depression (ES=-0.26), relapse (RD 20%) and discontinuation due to inefficacy (RD 17%). Curiously, the efficacy of haloperidol for negative and depressive symptoms was similar to that of the SGA drugs. In contrast to haloperidol, there was no difference in terms of EPS between any SGA drugs and placebo, and there was also no difference in terms of dropouts due to adverse events. Meta-regression showed a decline in treatment response over time, and a funnel plot suggested the possibility of publication bias. We conclude that the drug versus placebo difference of SGA drugs and haloperidol in recent trials was moderate, and that there is much room for more efficacious compounds. Whether methodological issues account in part for the relatively low efficacy ESs and the scarcity of adverse event differences compared with placebo needs to be established.     

How statins could be evaluated successfully in clinical trials for Alzheimer's disease?

Over the last decade, a large number of experimental observations have suggested a relationship between alterations in cholesterol homeostasis and Alzheimer's disease (AD). Moreover, epidemiological studies have pointed an association between statin treatment and a decrease in the risk of having AD. For these reasons, a large number of clinical trials have been carried out to determine whether the statins can prevent the progression of AD. However, these studies did not provide clear evidence for the therapeutic efficacy in AD. We consider that there are a number of explanations for this failure that may provide guidance for selecting and clinically developing statins with therapeutic efficacy in AD.     

How should efficacy be evaluated in randomized clinical trials of treatments for depression?

The present system of conducting studies of promising antidepressant therapies has evolved through the collaborative efforts of government, industry, and academicians and is costly and inefficient. At least one third of the published clinical trials of approved antidepressants are negative for efficacy, which can be partly explained by the clinical and neurobiological heterogeneity of the depressive disorder and partly because of methodological inadequacies. Unfortunately, too little attention is given to ensuring the reliability of diagnoses and dependent measures, sample sizes are seldom large enough to detect modest yet honestly significant differences, and too many trials are pursued before dose-response characteristics are fully understood. At present, the only data beyond 1 year of treatment--and the only evidence about protection against recurrent depression--come during postmarketing or phase 4 of the drug development process. Moreover, efficacy data for depressed children and adolescents, bipolar depression, psychotic depression, dysthymia, and frail or medically ill elderly patients are rarely available at the time a drug is introduced. Thus, it is remarkable how little clinicians know about a new antidepressant at the time it is first approved for general use. Within a research strategy, tactics that ensure reliability, encourage attention to adherence, and lessen attrition at the outset of a study will increase the power and design sensitivity of a particular trial. Additionally, the issues of research funding-including division of the research pie-and the relationship of the Food and Drug Administration and investigators to the pharmaceutical industry and the National Institute of Mental Health need to be revisited. Finally, extension of a compound's patent life might be considered to expand the necessary postmarketing research. This article describes the process of conducting the clinical trials that support a New Drug Application, discusses issues in evaluating efficacy, and offers suggestions for modifying and improving the drug development process so that clinicians can better judge new drugs.     

Are patients enrolled in first episode psychosis drug trials representative of patients treated in routine clinical practice?

BACKGROUND: Evidence on efficacy of antipsychotic medications comes primarily from controlled trials which select eligible consenting patients for experimental and regimented treatments, who do not abuse drugs, and are in good general health. Thus, it is not clear to what extent results are generalizable to most individuals treated for a psychotic illness who may not be eligible for such trials. OBJECTIVE: This study compared characteristics of patients treated in a large randomized trial of persons with early psychosis to a cohort from a large epidemiological study of first episode psychosis. METHODS: Included were the 535 patients enrolled in a controlled trial of antipsychotic medication and 179 similarly diagnosed persons from the Suffolk County Mental Health epidemiological study. Drug trial exclusion criteria were used to estimate the number of patients from the epidemiological study who would have been ineligible for the drug trial. The two samples were compared on key characteristics. RESULTS: Thirty-three percent (n=59) of the epidemiological sample did not meet inclusion criteria for the drug trial (due to antidepressant treatment, n=26; current substance abuse, n=18; recent suicide attempt, n=9; and for more than one reason, n=6). There were no significant differences between the two study samples on age of onset, age, gender and premorbid functioning. Drug trial patients had higher Brief Psychiatric Rating Scale (BPRS), slightly lower Clinical Global Impression (CGI), and less formal education than those in the epidemiological study. CONCLUSIONS: While some patients in the epidemiological sample would have been excluded from the drug trial, patients in the two studies were similar on several key variables.     

How predictive are photosensitive epilepsy models as proof of principle trials for epilepsy?

PurposeHuman photosensitive epilepsy models have been used as proof of principle (POP) trials for epilepsy. Photosensitive patients are exposed to intermittent photic stimulation and the reduction in sensitivity to the number of standard visual stimulation frequencies is used as an endpoint. The aim of this research was to quantify the predictive capabilities of photosensitive POP trials, through a survey of current literature.MethodsA literature search was undertaken to identify articles describing photosensitive POP trials. Minimally efficacious doses (MEDs) in epilepsy were compared to doses in the POP trials that produced 50–100% response (ED_50–100). Ratios of these doses were calculated and summarised statistically.ResultsThe search identified ten articles describing a total of 17 anti-epileptic drugs. Of these, data for both MED and ED_50–100 were available for 13 anti-epileptic drugs. The average ratio of MED to ED_50–100 was 0.95 (95% CI 0.60–1.30). The difference in MED to ED_50–100 ratios between partial epilepsy (0.82) was not significantly different from that of generalised epilepsy (1.08) (p = 0.51).ConclusionPhotosensitive POP trials are a useful tool to quantitatively predict efficacy in epilepsy, and can be useful as early and informative indicators in anti-epileptic drug discovery and development.     

How fast are antidepressants?

BACKGROUND: For years, investigators have tried to determine the speed of onset of antidepressant drugs. Claims that particular drugs may produce a faster response in patients than other agents have been made, but such claims have never been confirmed. METHOD: The authors reviewed reports from studies of the speed of onset of antidepressant therapies and other studies that revealed information on this topic. We compiled a list of factors that can affect the results of such studies and interpretations of study results. In addition, we reviewed literature concerned with methods of speeding up antidepressant responses. RESULTS: No antidepressant medication currently available has been shown conclusively to have a more rapid onset of action than any other. However, some methods of augmentation may have the potential to speed responses. Somatic therapies such as electroconvulsive therapy, phototherapy, and therapeutic sleep deprivation may be the fastest options available at this time. CONCLUSION: All available antidepressant medications are usually taken for several weeks before future responders will display a significant therapeutic benefit. If a patient does not show at least a 20% improvement within the first 2 to 4 weeks of treatment, the treatment regimen should be altered. For patients who do show early benefits from a medication trial, one can expect additional benefits to accrue over an 8- to 12-week period and to improve overall outcome compared with those slower to respond. Future trials need to address methodological confounds, but a truly "faster antidepressant" will probably require new neuroscience technology.     

How should we deal with missing data in clinical trials involving Alzheimer's disease patients?

Missing data are frequent in Alzheimer's disease (AD) trials due to the age of participants and the nature of the disease. This can lead to bias and decreased statistical power. We assessed the level and causes of missing data in a 2-year randomised trial of an AD patient management program (PLASA study), and conducted sensitivity analyses on the primary endpoint (functional decline), using various methods for handling missing data: complete case, LOCF, Z-score LOCF, longitudinal mixed effects model, multiple imputation. By 2 years, 32% of the 1131 subjects had dropped out, with the commonest reasons being death (28% of dropouts) and refusal (22%). Baseline cognitive and functional status were predictive of dropout. All sensitivity analyses led to the same conclusion: no effect of the intervention on the rate of functional decline. All analyses demonstrated significant functional decline over time in both groups, but the magnitude of decline and between-group (intervention versus usual care) differences varied across methods. In particular, the LOCF analysis substantially underestimated 2-year decline in both groups compared to other methods. Our results suggest that data were not "missing completely at random", meaning that the complete case method was unsuitable. The LOCF method was also unsuitable since it assumes no decline after dropout. Methods based on the more plausible "missing at random" hypothesis (multiple imputation, longitudinal mixed effects models, z-score LOCF) appeared more appropriate. This work highlights the importance of considering the validity of the underlying hypotheses of methods used for handling missing data in AD trials.     

Melatonin agonists in primary insomnia and depression-associated insomnia: are they superior to sedative-hypnotics?

Current pharmacological treatment of insomnia involves the use of sedative-hypnotic benzodiazepine and non-benzodiazepine drugs. Although benzodiazepines improve sleep, their multiple adverse effects hamper their application. Adverse effects include impairment of memory and cognitive functions, next-day hangover and dependence. Non-benzodiazepines are effective for initiating sleep but are not as effective as benzodiazepines for improving sleep quality or efficiency. Furthermore, their prolonged use produces adverse effects similar to those observed with benzodiazepines. Inasmuch as insomnia may be associated with decreased nocturnal melatonin, administration of melatonin is a strategy that has been increasingly used for treating insomnia. Melatonin can be effective for improving sleep quality without the adverse effects associated with hypnotic-sedatives. Ramelteon, a synthetic analog of melatonin which has a longer half life and a stronger affinity for MT1 and MT2 melatonergic receptors, has been reportedly effective for initiating and improving sleep in both adult and elderly insomniacs without showing hangover, dependence, or cognitive impairment. Insomnia is also a major complaint among patients suffering from depressive disorders and is often aggravated by conventional antidepressants especially the specific serotonin reuptake inhibitors. The novel antidepressant agomelatine, a dual action agent with affinity for melatonin MT1 and MT2 receptors and 5-HT2c antagonistic properties, constitutes a new approach to the treatment of major depressive disorders. Agomelatine ameliorates the symptoms of depression and improves the quality and efficiency of sleep. Taken together, the evidence indicates that MT1/MT2 receptor agonists like ramelteon or agomelatine may be valuable pharmacological tools for insomnia and for depression-associated insomnia.     

Does evidence from clinical trials in psychopharmacology apply in clinical practice?

The art of psychopharmacology derives from the science of psychopharmacology, but still requires wisdom, judgment, and experience to translate findings from clinical trials of a new drug into clinical practice.     

Is subcortical vascular dementia a clinical entity for clinical drug trials?

Several therapeutic trials have been performed for vascular dementia, with drugs differing in type and mechanism of action. The results have been almost invariably inconclusive. Given the current notion that there are different subtypes of vascular dementia according to pathophysiological mechanisms, it is reasonable to suspect that one of the main causes of the disappointing results was that the study samples included patients not fitting with the rationale of selective treatments. Testing this hypothesis is difficult because characterization of patients in relation to different subtypes of vascular dementia is not available for most studies. However, attempts are ongoing to reclassify patients entered in some trials for post hoc subgroup analyses with some preliminary interesting results. We propose that (1) specific subtypes of vascular dementia should be the target in any single trial using a treatment with a proper rationale; and (2) subcortical vascular dementia, caused by small vessel disease leading to lacunar infarcts and subcortical white matter changes, represents a clinically and radiologically well-defined entity to be considered for future trials designed specifically for testing adequate drugs.