Schizophrenia: do we really need placebo-controlled studies?

The Evolution of Drug Regulatory Sciences in the Netherlands: More than a Country Report

In the Netherlands, drug regulatory science is a vibrant national and internationally oriented community. In this review, we present the factors that have contributed to this successful collaboration between relevant stakeholders and that led to a surge of activities around how regulatory science became embedded in the ecosystem of medicines research, clinical pharmacology, policymaking and regulation. We distinguished three pivotal episodes: (i) TI Pharma Escher-project, (ii) Dutch Medicines Evaluation Board as catalyst of the big jump, and (iii) Regulatory Science Network Netherlands and multistakeholder engagement. The research agenda has been influenced by the dynamic evolution of legal frameworks in Europe, such as the EU orphan medicines legislation of 2001 and the EU pharmacovigilance legislation of 2012. All these developments have inspired and have raised pertinent regulatory sciences questions. Furthermore, clinical pharmacology as a discipline has been very influential in shaping regulatory science, contributing to discussions on the level of clinical evidence that is necessary to justify marketing approval of a new medicine. With a growing interest of multiple parties such as academics, European Medicines Agency, national agencies, patient organizations and EFPIA, connecting regulatory science activities is key.

Changing the Drug Delivery System: Does It Add to Non-Compliance Ramifications Control? A Simulation Study on the Pharmacokinetics and Pharmacodynamics of Atypical Antipsychotic Drug

This study investigates the pharmacokinetic (PK) and pharmacodynamic (PD) consequences of shifting from Quetiapine fumarate immediate-release (IR) to extended-release (XR) formulation in non-adherent schizophrenia patients. Monte-Carlo simulations using population PK and PD models were implemented to predict the time course of plasma concentration and Brief Psychiatric Rating Scale (BPRS) scores following the oral administration of 200 mg Seroquel^® every 12 h and 400 mg Seroquel XR^® every 24 h in patients experiencing dose delay, omission or doubling. Parameters were computed and their distributions were compared using the Kolmogorov–Smirnov test. Dose irregularities with both formulations had different effects on plasma concentration and %reduction in BPRS scores from baseline. However, the odds ratio of getting a %reduction in BPRS below 14%, or plasma concentration exceeding 500 µg/L, were comparable for adherent and non-adherent patients. Plasma therapeutic concentration after treatment cessation was maintained for <24 h in 48% and 29.6% of patients, and a steady state recovery time of <48 h was achieved in 51% and 13.4% of patients on the IR and XR formulations, respectively. Monte-Carlo simulations predict that the risks associated with the IR dose irregularities are not worsened when the XR formulation is used instead. Non-adherence events involving a single dose of either formulation do not require rescue doses.

Asenapine versus placebo for schizophrenia

BACKGROUND

Schizophrenia is a highly prevalent and chronic disorder that comprises a wide range of symptomatology. Asenapine is a recently developed atypical antipsychotic that is approved by the US Food and Drug Administration (FDA) for the treatment of schizophrenia.

OBJECTIVES

To determine the clinical effects of asenapine for adults with schizophrenia or other schizophrenia-like disorders by comparing it with placebo.

SEARCH METHODS

We searched the Cochrane Schizophrenia Group's Trials Register (July 04, 2014) which is based on regular searches of MEDLINE, EMBASE, CINAHL, BIOSIS, AMED, PubMed, PsycINFO, and registries of clinical trials. There are no language, date, document type, or publication status limitation for inclusion of records into the register. We inspected references of all included studies for further relevant studies.

SELECTION CRITERIA

Our review includes randomised controlled trials (RCTs) comparing asenapine with placebo in adults (however defined) with schizophrenia or related disorders, including schizophreniform disorder, schizoaffective disorder and delusional disorder, again, by any means of diagnosis.

DATA COLLECTION AND ANALYSIS

We inspected citations from the searches and identified relevant abstracts, and extracted data from all included studies. For binary data we calculated risk ratio (RR) with 95% confidence intervals (CI), and for continuous data we calculated mean differences (MD). We used the GRADE approach to produce a 'Summary of findings' table which included our outcomes of interest, where possible. We used a fixed-effect model for our analyses.

MAIN RESULTS

We obtained and scrutinised 41 potentially relevant records, and from these we could include only six trials (n = 1835). Five of the six trials had high risk of attrition bias and all trials were sponsored by pharmaceutical companies. Results showed a clinically important change in global state (1 RCT, n = 336, RR 0.81, 95% CI 0.68 to 0.97, low-quality evidence) and mental state (1 RCT, n = 336, RR 0.72, 95% CI 0.59 to 0.86, very low-quality evidence) at short-term amongst people receiving asenapine. People receiving asenapine demonstrated significant reductions in negative symptoms (1 RCT, n = 336, MD -1.10, 95% CI -2.29 to 0.09, very low-quality evidence) at short-term. Individuals receiving asenapine demonstrated significantly fewer incidents of serious adverse effects (1 RCT, n = 386, RR 0.29, 95% CI 0.14 to 0.63, very low-quality evidence) at medium-term. There was no clear difference in people discontinuing the study for any reason between asenapine and placebo at short-term (5 RCTs, n = 1046, RR 0.91, 95% CI 0.80 to 1.04, very low-quality evidence). No trial reported data for extrapyramidal symptoms or costs.

AUTHORS' CONCLUSIONS

There is some, albeit preliminary, evidence that asenapine provides an improvement in positive, negative, and depressive symptoms, whilst minimising the risk of adverse effects. However due to the low-quality and limited quantity of evidence, it remains difficult to recommend the use of asenapine for people with schizophrenia. We identify a need for large-scale, longer-term, better-designed and conducted randomised controlled trials investigating the clinical effects and safety of asenapine.

Bayesian model of Hamilton Depression Rating Score (HDRS) with memantine augmentation in bipolar depression

AIM

Presynaptic and post-synaptic glutamatergic modulation is associated with antidepressant activity that takes several weeks to reach a maximal full effect. Limiting mood elevating effects after single drug administration may be the result of compensatory synaptic processes. Therefore, using augmentation treatment with agents having presynaptic and post-synaptic effects on the glutamatergic system, this study aims to evaluate the effect of augmentation therapy on the rate of change in mood elevation in patients with bipolar depression.

METHODS

In a pilot study, 29 outpatients with bipolar depression on a stable lamotrigine dose regimen received placebo or memantine pills daily (titrated up by 5 mg week⁻¹ to 20 mg) in a randomized, double-blind, parallel group, 8 week study. Patients were evaluated weekly using the 17-item Hamilton Depression Rating Score (HDRS) and all data were analyzed simultaneously. Linear, exponential, maximal effect, Gompertz and inverse Bateman functions were evaluated using a Bayesian approach population pharmacodynamic model framework. In these models, differences in parameters were examined across the memantine and placebo augmentation groups.

RESULTS

A Gompertz function with a treatment switch on the parameter describing the speed of HDRS decline (γ, 95% confidence interval [CI]) best described the data (γ(memantine) = 1.8, 95% CI 0.9, 3.6), γ(placebo) = 1.2, 95% CI 0.5, 3.5)). Between subject variability was identified on baseline HDRS (2.9, 95% CI 1.5, 4.4) and amplitude of score improvement (4.3, 95% CI 2.7, 6.5).

CONCLUSIONS

This pharmacodynamic approach identified an increased speed of response after memantine augmentation, compared with placebo augmentation in bipolar depression patients.

The placebo arm in clinical studies for treatment of psychiatric disorders: a regulatory dilemma

BACKGROUND

The use of placebo in clinical trials, and, related to this, ethical and feasibility aspects, are often debated. However, regulatory authorities must ensure that only new drugs with a positive benefit/risk would be granted a marketing authorization. It is therefore not surprising that they often put forward the need for placebo control in clinical trials in an area where many trials fail, and assay sensitivity is not self-evident. To illustrate the complexity that regulatory authorities encounter when faced with the registration dossier of products in the main psychiatric therapeutic areas, Major Depressive Disorder (MDD) and schizophrenia, the trial outcome for products receiving an opinion in the EU during the past 15 years were reviewed.

DATA SOURCE

European Public Assessment Reports and registration files.

RESULTS

A total of 45 studies qualified for analysis. For the indication MDD 38% of the studies (10/26) were recorded as failed, and another 15% (4/26) as negative. For schizophrenia, these figures were 16% (3/19) and 11% (2/19). Further exploration of the trials in MDD revealed an inconsistent pattern in terms of magnitude of placebo- and drug-mediated response (i.e. similar studies with consistent placebo response provided different treatment outcomes).

CONCLUSION

From a regulatory perspective the dilemma of a priori exclusion of the placebo arm in clinical trials in the domains of depression or schizophrenia cannot be solved at this time as long as factors influencing trial variability are not better identified or understood. This counts in particular for MDD where the added drug effect is not consistent across trials with almost identical inclusion criteria. Unfortunately, this trend has not changed over the past 15 years. However, all efforts should be taken to optimize the clinical development of drugs in the psychiatric domain, and improve the intrinsic quality of the clinical trials in order to allow for a different viewpoint.

Structural models describing placebo treatment effects in schizophrenia and other neuropsychiatric disorders

Large variation in placebo response within and among clinical trials can substantially affect conclusions about the efficacy of new medications in psychiatry. Developing a robust placebo model to describe the placebo response is important to facilitate quantification of drug effects, and eventually to guide the design of clinical trials for psychiatric treatment via a model-based simulation approach. In addition, high dropout rates are very common in the placebo arm of psychiatric clinical trials. While developing models to evaluate the effect of placebo response, the data from patients who drop out of the trial should be considered for accurate interpretation of the results. The objective of this paper is to review the various empirical and semi-mechanistic models that have been used to quantify the placebo response in schizophrenia trials. Pros and cons of each placebo model are discussed. Additionally, placebo models used in other neuropsychiatric disorders like depression, Alzheimer's disease and Parkinson's disease are also reviewed with the objective of finding those placebo models that could be useful for clinical studies of both acute and chronic schizophrenic disease conditions. Better understanding of the patterns of dropout and the factors leading to dropouts are crucial in identifying the true placebo response. We therefore also review dropout models that are used in the development of models for treatment effects and in the optimization of clinical trials by simulation approaches. The use of an appropriate modelling strategy that is capable of identifying the potential sources of variable placebo responses and dropout rates is recommended for improving the sensitivity in discriminating between the effects of active treatment and placebo.

Modeling the effectiveness of paliperidone ER and olanzapine in schizophrenia: meta-analysis of 3 randomized, controlled clinical trials

The time course of Positive and Negative Syndrome Scale (PANSS) scores in adult schizophrenia patients was modeled, and the effectiveness of paliperidone extended-release tablets (paliperidone ER) and olanzapine was quantified. Data from 3 randomized, double-blind phase III studies were used. Patients received paliperidone ER (3, 6, 9, 12, or 15 mg), olanzapine 10 mg, or matched placebo once daily for 6 consecutive weeks. An indirect response model implemented using a nonlinear mixed effects approach described the time course of the PANSS. Deterioration rate was modeled as a function of baseline PANSS score, placebo, and drug effects, and the dropout effect. An exponential decrease of the placebo response was also implemented. Paliperidone ER and olanzapine treatment were characterized by a long-lasting drug effect (13%), with a larger but short-lasting placebo effect (40%) and a notable dropout rate. The covariate exploration failed to identify any clinically relevant factors. The nonparametric bootstrap analysis confirmed the acceptable precision of parameter estimates. The visual predictive check supported the model's adequacy to reproduce observed PANSS time courses. The population model describes the time course of PANSS scores in schizophrenia patients and is appropriate for use in clinical trial simulation activities.

Efficacy and safety of paliperidone extended-release tablets: results of a 6-week, randomized, placebo-controlled study

BACKGROUND

Paliperidone extended-release tablet (paliperidone ER; Invega, Janssen L.P., Titusville, New Jersey) is an oral psychotropic for schizophrenia treatment.

METHODS

Efficacy and safety of once-daily paliperidone ER (6 and 12 mg) were assessed versus placebo in 444 patients with acute schizophrenia in a 6-week, multicenter, double-blind, randomized, parallel-group study. An olanzapine (10 mg) treatment arm was included to confirm trial validity.

RESULTS

Both doses of paliperidone ER demonstrated significant improvement in Positive and Negative Syndrome Scale (PANSS) total score (p < or = .006) and certain PANSS Marder factor scores compared with placebo (p < or = .025); PANSS total score also improved in the olanzapine treatment arm. Paliperidone ER 6 mg (p < or = .008), but not 12 mg, was associated with significant improvements in personal and social performance. The incidence of treatment-emergent adverse events (AEs) for paliperidone ER 6 mg was comparable with placebo and slightly greater with paliperidone ER 12 mg. Changes in blood glucose and lipid levels with paliperidone ER were comparable with placebo. Two patients treated with paliperidone ER experienced glucose-related AEs. Body-weight increases of 1-2 kg were observed with paliperidone ER. Although there were increases in plasma prolactin levels with paliperidone ER treatment, the incidence of prolactin-related AEs was < or =1%.

CONCLUSIONS

In this study, paliperidone ER, particularly the 6-mg dose, was effective and well tolerated, and provides a valuable new treatment option for schizophrenia.

Psychiatric drug trials and placebo

The placebo-controlled trial has been the standard method to demonstrate efficacy and safety of drugs. The trials are regulated by standards and principles that aim to safeguard patient safety and to ensure the faultless availability of reliable information about the object of the survey. The use of a placebo group in clinical drug trials is still as well founded as ever, and is especially important in conditions where the severity of the disorder is associated with variation in time, the possibility of a spontaneous recovery, or in conditions involving a significant proportion of subjective experience. In this systematic review, the present guidelines for developing new compounds for psychiatric disorders are discussed.

Placebos and paradoxes in psychiatric research: an ethics perspective

The use of placebos in clinical trials, particularly in research with mentally ill people, has emerged as a subject of considerable controversy. We first outline ethical aspects of the primary scientific arguments for and against placebo use in research. Three examples of paradoxical aspects of the ethical use of placebos are discussed: involvement of relatively more vulnerable populations, use of apparently "less than standard" therapy, and the omission of information in placebo comparisons. In the current scientific and regulatory context, placebo use in psychiatric research may be necessary for scientific reasons, and when certain conditions are present, it may be justified on ethical grounds. Four key recommendations to facilitate the ethical use of placebos in research trials are presented. We conclude that placebo trials should be undertaken only after careful evaluation of alternative scientific strategies and, as with all human research, with great respect and genuine consideration for the individuals who choose to participate in these protocols.

Alternatives to placebo-controlled trials in psychiatry. ECNP Consensus Meeting, September 26, 1996, Amsterdam. European College of Neuropsychopharmacology

Patients receiving placebo do not merely receive an inert substance but also receive support, concern, and reassurance that assists the therapeutic alliance and encourages the positive attitude that forms the basis of cognitive treatment. Response to non-specific factors is seen in all fields of medicine but is particularly potent in psychiatry. The placebo response is variable across settings and across time and is unpredictable. Historical data cannot therefore provide an adequate control for treatment effects in studies of new drugs. The scientific position is clear that a comparison against placebo is required for the unequivocal demonstration of the efficacy of a treatment. Evidence from at least two positive well designed and conducted placebo-controlled studies is generally accepted as appropriate to establish the efficacy of a drug. Attention to diagnosis, severity of illness, and to possible comorbid conditions is needed in the design and conduct of placebo-controlled studies in order to optimise the chance of obtaining valid data. The use of all data obtained, including dropouts due to lack of efficacy, should be maximised. The use of placebo may not be possible in some conditions that represent medical emergencies or may be difficult to justify in serious disorders where an effective treatment has already been established. Alternative designs to placebo-controlled studies can be considered. Consistent superior efficacy compared with a well accepted, effective treatment, given in an easily defended dose, is considered to be good evidence of efficacy provided that the studies are well designed and well conducted. Evidence of superior efficacy to an established effective comparator treatment may be regarded as evidence of efficacy. The demonstration of a dose-response relationship where one dose is found to be significantly better than another, can be taken as evidence for efficacy, particularly where there is already placebo-controlled evidence of the efficacy of the identified dose. Where a new treatment is found, under controlled conditions, to be equivalent to an existing well accepted comparator treatment, given at a clearly effective dose, this may be taken as evidence of efficacy, but only if the comparator is consistently superior to placebo and if equivalence has been defined beforehand. The claims for efficacy based on results from equivalence studies are less easily sustained than the evidence from placebo-controlled studies or studies demonstrating superior efficacy, due to the fact that those studies have no internal validation.