Frequency of positive studies among fixed and flexible dose antidepressant clinical trials: an analysis of the food and drug administration summary basis of approval reports

Multi-target strategies for the improved treatment of depressive states: Conceptual foundations and neuronal substrates, drug discovery and therapeutic application

Major depression is a debilitating and recurrent disorder with a substantial lifetime risk and a high social cost. Depressed patients generally display co-morbid symptoms, and depression frequently accompanies other serious disorders. Currently available drugs display limited efficacy and a pronounced delay to onset of action, and all provoke distressing side effects. Cloning of the human genome has fuelled expectations that symptomatic treatment may soon become more rapid and effective, and that depressive states may ultimately be "prevented" or "cured". In pursuing these objectives, in particular for genome-derived, non-monoaminergic targets, "specificity" of drug actions is often emphasized. That is, priority is afforded to agents that interact exclusively with a single site hypothesized as critically involved in the pathogenesis and/or control of depression. Certain highly selective drugs may prove effective, and they remain indispensable in the experimental (and clinical) evaluation of the significance of novel mechanisms. However, by analogy to other multifactorial disorders, "multi-target" agents may be better adapted to the improved treatment of depressive states. Support for this contention is garnered from a broad palette of observations, ranging from mechanisms of action of adjunctive drug combinations and electroconvulsive therapy to "network theory" analysis of the etiology and management of depressive states. The review also outlines opportunities to be exploited, and challenges to be addressed, in the discovery and characterization of drugs recognizing multiple targets. Finally, a diversity of multi-target strategies is proposed for the more efficacious and rapid control of core and co-morbid symptoms of depression, together with improved tolerance relative to currently available agents.

Placebo-controlled trial of agomelatine in the treatment of major depressive disorder

The efficacy and safety of flexible dosing with the antidepressant agomelatine (25-50 mg/day) was evaluated in a 6-week, double-blind, randomized, placebo-controlled study involving 212 patients who met Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition (DSM-IV) criteria for major depressive disorder-current major depressive episode. Patients receiving agomelatine (25 mg and 50 mg/day) had a significantly lower mean Hamilton Rating Scale for Depression (HAM-D) score at endpoint compared with those who received placebo (14.1 +/- 7.7 vs. 16.5 +/- 7.4, p = 0.026). Agomelatine significantly improved the response rate (49.1%; p = 0.03), time to first response (p = 0.032), and Clinical Global Impression-Severity of Illness score (p = 0.017), compared with placebo. These results were confirmed in a subgroup of patients with greater symptom severity. Agomelatine 50 mg also appeared to be effective and well tolerated in patients who failed to show improvement after 2 weeks on a dose of 25 mg/day. These results support the prescription of agomelatine 25 mg as the usual therapeutic dose, and suggest that increasing the dose to 50 mg may be beneficial for some patients without reducing tolerability.

Do recent efficacy data on the drug treatment of acute bipolar depression support the position that drugs other than antidepressants are the treatment of choice? A conceptual review

This conceptual review summarises the results of relevant studies on antidepressants, mood stabilisers such as lithium and anticonvulsants, and second generation antipsychotics in the indication of bipolar depression. Based on methodological and clinical considerations, the position of antidepressants and the possible alternatives in this indication are reviewed very carefully. In addition the regulatory requirements for licensing a drug for the indication "short-term treatment of bipolar depression" are described.

The use of antidepressants to treat depression in children and adolescents

The dramatic increase over the past 10 years in the amount of available clinical research on the use of antidepressants to treat major depression in children and adolescents has substantially improved our knowledge of the safety and efficacy of these medications in the pediatric population. Many questions remain, however, that highlight the need to continue research in this patient population rather than relying on the extrapolation of data from trials involving adults. In this article, we review the current state of research into antidepressant therapy for major depression in children and adolescents. In addition, we discuss methodologic issues and clinical implications specific to the pediatric population.

A controlled study of repetitive transcranial magnetic stimulation in medication-resistant major depression

BACKGROUND

Repetitive transcranial magnetic stimulation (TMS) as a treatment for depression has shown statistically significant effects, but the clinical significance of these effects has been questioned.

METHODS

Patients with medication-resistant depression were randomized to receive 15 sessions of active or sham repetitive TMS delivered to the left dorsolateral prefrontal cortex at 110% the estimated prefrontal cortex threshold. Each session consisted of 32 trains of 10 Hz repetitive TMS delivered in 5-second trains. The primary end point was treatment response defined as a >or=50% decrease in Hamilton Depression Rating Scale (HDRS) score at both 1 and 2 weeks following the final repetitive TMS treatment. Remission was defined as a HDRS score < 8.

RESULTS

The response rate for the TMS group was 30.6% (11/35), significantly (p = .008) greater than the 6.1% (2/33) rate in the sham group. The remission rate for the TMS group was 20% (7/35), significantly (p = .033) greater than the 3% (1/33) rate in the sham group. The HDRS scores showed a significantly (p < .002) greater decrease over time in the TMS group compared with the sham group.

CONCLUSIONS

Transcranial magnetic stimulation can produce statistically and clinically significant antidepressant effects in patients with medication-resistant major depression.

Serotonin a la carte: supplementation with the serotonin precursor 5-hydroxytryptophan

This paper reviews the preclinical and clinical evidence regarding the use of the dietary supplement 5-hydroxytryptophan (5-HTP) for the treatment of depression. In the absence of supplementation with exogenous 5-HTP, the amount of endogenous 5-HTP available for serotonin synthesis depends on the availability of tryptophan and on the activity of various enzymes, especially tryptophan hydroxylase, indoleamine 2,3-dioxygenase, and tryptophan 2,3-dioxygenase (TDO). Factors affecting each of these are reviewed. The amount of 5-HTP reaching the central nervous system (CNS) is affected by the extent to which 5-HTP is converted to serotonin in the periphery. This conversion is controlled by the enzyme amino acid decarboxylase, which, in the periphery, can be blocked by peripheral decarboxylase inhibitors (PDIs) such as carbidopa. Preclinical and clinical evidence for the efficacy of 5-HTP for depression is reviewed, with emphasis on double-blind, placebo-controlled (DB-PC) trials. Safety issues with 5-HTP are also reviewed, with emphasis on eosinophilia myalgia syndrome (EMS) and serotonin syndrome.

Is it always unethical to use a placebo in a clinical trial?

Placebos are used in trials to conceal whether a treatment is being given or not and hence to control for the psychosomatic effects of offering treatment. Placebo-controlled trials are controversial. Critics of such trials argue that if a proven effective therapy exists, a placebo should not be used. But proponents argue that placebo trials are still crucial to prove the efficacy and safety of many treatments.

Comparing the effects of antidepressants: consensus guidelines for evaluating quantitative reviews of antidepressant efficacy

With increasing numbers of treatment options available for patients with major depression over the last decade and the growing body of evidence describing their efficacy and safety, clinicians often find it difficult to determine the best and most appropriate evidence-based treatment for each patient. Systematic reviews utilizing statistical methods that synthesize and evaluate data from a number of studies have become increasingly more available over the past decade. We review major findings and lessons learned from salient examples of quantitative analyses of antidepressant research and provide recommendations for meta-analysts, journal and grant reviewers, and research 'consumers' (ie, clinicians) for conducting, reporting, and evaluating such analyses.

Duloxetine 60 mg once-daily in the treatment of painful physical symptoms in patients with major depressive disorder

BACKGROUND

While emotional symptoms such as depressed mood and loss of interest have traditionally been considered to constitute the core symptoms of major depressive disorder (MDD), the prevalence and importance of painful physical symptoms such as back pain, abdominal pain, and musculoskeletal pain is becoming increasingly appreciated. Antidepressants possessing dual serotonin/norepinephrine (5-HT/NE) reuptake inhibition may demonstrate greater efficacy in the alleviation of pain. The efficacy of duloxetine, a balanced and potent dual reuptake inhibitor of 5-HT and NE, was evaluated within a cohort of depressed patients with associated painful physical symptoms.

METHODS

In this multicenter, double-blind, placebo-controlled study, patients meeting DSM-IV criteria for MDD were randomized to receive placebo (N=141) or duloxetine 60 mg QD (N=141). Patients were required to have a 17-item Hamilton Rating Scale for Depression (HAMD17) total score 15, a Clinical Global Impression of Severity (CGI-S) score 4, and a Brief Pain Inventory (BPI) Average Pain score 2 at baseline. The primary efficacy measure was the BPI Average Pain score, while secondary measures included other BPI items, the HAMD17 total score, CGI-S, the Patient Global Impression of Improvement (PGI-I) scale, Visual Analog Scales (VAS) for pain, and the Symptom Questionnaire, Somatic Subscale (SQSS). Safety was evaluated by recording treatment-emergent adverse events (spontaneously reported), vital signs, and laboratory analytes.

RESULTS

Mean changes in BPI Average Pain for duloxetine- and placebo-treated patients differed significantly at most visits, but only approached significance at endpoint p=0.066. For the main effect of treatment (pooling all visits), significant advantages for duloxetine-treated patients were found in 10 of 11 assessed BPI pain severity and pain interference items, in addition to VAS overall pain and back pain. Mean changes in pain measures for duloxetine-treated patients corresponded to improvements of 25-50%, compared with 19-39% for placebo. Mean changes at endpoint in depression rating scales (HAMD17, CGI-S, PGI-I) did not differ significantly between duloxetine and placebo treatment groups due to unusually high placebo response. The magnitude of placebo treatment effects (as measured by HAMD17 total score and Maier subscale) was significantly smaller in patients with 1 previous depressive episode, compared to those patients with no previous episodes. In patients with 1 previous depressive episode the advantage of duloxetine over placebo was similar to previous studies. Rates of discontinuation due to adverse events were 14.2% vs. 2.1% for duloxetine and placebo, respectively p<0.001. Treatment-emergent adverse events reported at a significantly higher rate by duloxetine-treated patients included nausea, dry mouth, fatigue, and decreased appetite.

CONCLUSIONS

In this study, duloxetine (60 mg QD) was shown to be an effective treatment for the painful physical symptoms which are frequently associated with depression. Improvements in pain severity occurred independently of changes in depressive symptom severity.

5-Hydroxytryptophan plus SSRIs for interferon-induced depression: Synergistic mechanisms for normalizing synaptic serotonin

Interferon-alpha (IFN) is widely used in the treatment of certain cancers and viral infections, including hepatitis C (HCV). Unfortunately, depression is a common side effect of IFN therapy, affecting approximately a third of HCV patients receiving IFN therapy. Studies have shown that selective serotonin reuptake inhibitors (SSRIs) can effectively treat IFN-induced depression in only 63-75% of cases. For the remaining percentage, depression often necessitates dose reduction of or discontinuation from IFN therapy. Emerging evidence indicates that IFN may cause depression by affecting brain serotonin. IFN has been shown to increase serotonin reuptake and to decrease serotonin synthesis. We hypothesize that SSRIs are not fully effective because they affect only serotonin reuptake, not serotonin synthesis, and that effective treatment must address both uptake and synthesis. 5-Hydroxytryptophan (5-HTP) effectively increases central nervous system synthesis of serotonin. It is the immediate precursor of serotonin and is widely available as a dietary supplement, which is well absorbed after an oral dose. Several double-blind studies have shown 5-HTP to be effective in the treatment of nondrug-induced depression. We hypothesize that patients who become depressed on IFN will respond to the synergistic combination of SSRIs plus 5-HTP.

Clinical trials in late life: new science in old paradigms

This article, based on a Lawton Award Lecture, addresses the subject of the need to enhance the evidence base in our field in order to influence processes of policy development. Four issues are identified as critical to this: theory-driven targets of public health significance, use of appropriate and sophisticated approaches to research design and statistical modeling, development of instruments and measures, and conclusions that make a difference. Incentives are discussed with particular attention to regulatory approaches. A broad view of research is taken, with examples from studies of Alzheimer's disease and depression in late life. I conclude that new approaches to methodology will enhance our capacity to translate exciting new findings from the basic sciences into the development of therapeutics and that this will, in turn, enhance our capacity to inform the development of public policy.

Current perspectives in the management of treatment-resistant depression

Depressive disorders are a leading cause of disability worldwide and greatly impact morbidity, health care utilization, and medical costs. Major depression that does not resolve with adequate antidepressant treatment is termed treatment-resistant depression (TRD), There is no universally accepted definition of TRD and several criteria have been suggested to define it. Multiple factors can contribute to treatment resistance, including unrecognized comorbid medical or psychiatric illness, the use of concomitant medications, noncompliance, and psychosocial stressors. TRD is associated with extensive use of depression-related and general medical services, and poses a substantial economic burden. Current approaches to its management include the use of antidepressant strategies, such as increasing the dose of the antidepressant, augmentation strategies, combination strategies, and switching strategies, electroconvulsive therapy, and cognitive behavioral therapy. Although no definite algorithm exists for treating TRD, research in this area has advanced considerably in recent years. One approach to this is a clinical trial called STAR*D (Sequenced Treatment Alternatives to Relieve Depression). This has the potential to increase our understanding about the diagnostic and therapeutic aspects of TRD, to substantially reduce disability, and to enhance the quality of life in individuals with this condition.