The use of placebos in clinical trials for acute schizophrenia

Is the ongoing use of placebo in relapse-prevention clinical trials in schizophrenia justified?

BACKGROUND

Placebo-controlled randomised controlled trials (RCTs) continue to be required or recommended by regulatory authorities for the licensing of new drugs for schizophrenia, despite ongoing concerns regarding the risks to trial participants.

METHODS

In this article we consider the scientific and ethical pros and cons associated with use of placebo in RCTs in schizophrenia, systematically review the published relapse-prevention placebo-controlled RCTs with second generation antipsychotics (SGAs) in schizophrenia, and examine the risks associated with these trials.

RESULTS

We identified 12 studies involving 2842 participants of which 968 received placebo. Relapse rates were 56% for placebo and 17.4% for active treatment groups. There is a lack of well-designed longitudinal studies investigating the psychosocial and biological consequences of exposure to placebo, to treatment discontinuation and to relapse in schizophrenia.

CONCLUSION

In the absence of such studies it is risky to assume that patients are not at risk of significant distress and long-term harm, and therefore it is difficult to justify the ongoing use of placebo in relapse-prevention RCTs in schizophrenia.

Treatment response after relapse in a placebo-controlled maintenance trial in schizophrenia

While placebo-controlled studies continue to be required by regulatory authorities for the licensing of new drugs for schizophrenia to demonstrate maintenance of effect, the long-term risks to participants are largely unknown. We compared the response to treatment with paliperidone palmitate before and after relapse in such a study. This was a post-hoc analysis of 97 patients with schizophrenia who relapsed while receiving placebo in a multinational relapse prevention clinical trial. Patients underwent an initial open-label treatment phase of 33 weeks (comprising a 9-week transition phase to switch patients to paliperidone palmitate, a 12-week flexible-dose phase and a 12-week fixed-dose phase); a double-blind phase of variable duration during which stabilized patients were randomized 1:1 to either continue paliperidone palmitate or receive placebo; and an optional 52-week open-label flexible-dose extension phase. There was a small but significant increase in PANSS total scores after eight months of treatment following relapse (56.7[12.68]) compared with prerelapse endpoint (54.5[11.74]) (p=0.026). Fourteen of 97 (14.4%) patients who had initially responded favorably to treatment met predefined nonresponse criteria in the postrelapse treatment phase, suggesting that treatment refractoriness may evolve in a subset of patients after relapse. However, relapses occurred in 18% of patients randomized to ongoing treatment in the double-blind phase, raising the possibility that treatment failure may also evolve in patients receiving continuous treatment. These findings may help inform decisions regarding the future of placebo-controlled trials in schizophrenia.

Ethical and Scientific Perspectives of Placebo-controlled Trials in Schizophrenia

Clinical trials for development of new medications are essential in all fields of medicine. The requirement for a placebo arm in pharmaceutical trials presents ethical and clinical dilemmas that are especially complicated with regard to mentally ill persons whose free choice and ability to provide informed consent may be questionable. On the other hand, we do not believe that this predicament justifies unconditional rejection of placebo use in psychiatry, when the investigational drug may ultimately provide substantial benefit for some patients. At the same time it is the psychiatrist's responsibility to insure that investigators are adequately trained to conduct clinical trials and that stringent regulatory committees supervise the scientific, clinical and ethical aspects of the trials.

KEYWORDS

Placebo-control; Schizophrenia; Medical ethics; Clinical trials.

An algorithm for evaluating the ethics of a placebo-controlled trial

The purpose of this article is to clarify the decision points that are important to consider when evaluating the ethics of a placebo-controlled trial. The ethical requirements for research involving human subjects are reviewed, and the rationale for and potential problems with concomitant placebo control are explained. A series of case discussions are used to illustrate each decision point. The critical decision points in the evaluation of the ethics of a placebo-controlled trial are as follows: (i) Is placebo being used in place of standard therapy? (ii) Is standard therapy likely to be effective? (iii) Is the toxicity of standard therapy such that patients routinely refuse this treatment? (iv) Could the use of placebo result in severe suffering or irreversible harm? (v) Is the variability in the placebo response such that it is reasonable to consider other options for the control group? (vi) Would a reasonable person with an average degree of altruism and risk aversiveness agree to participate in this study? The algorithm presented in this article gives researchers and research monitors (such as Institutional Review Board members) the tools they need to evaluate the ethics of a study that uses concomitant placebo control.

The ethics of social risk reduction in the era of the biological brain

In keeping with our transdisciplinary orientation, in this article we try to do several things at once. We address research on preventing mental illness and its relation to existing conceptions of public health, a topic to which insufficient attention has been paid in the era of the biological brain, while using this case study to illustrate the limits of conventional approaches in bioethics. After identifying the crucial need for methodological self-consciousness in prevention research and policy, we explore the implications as they relate to (i) the values embedded in the choice of research designs and strategies, and (ii) contrasting intellectual starting points regarding the biological plausibility of preventing mental illness. We then draw attention to the need for more thoughtful analysis of the appropriate role and limits of economics in making choices about prevention of mental illness.

Consistency of atypical antipsychotic superiority to placebo in recent clinical trials

BACKGROUND

The use of control placebos in clinical trials of new antipsychotic medications is increasingly under examination. The active controlled equivalence study could offer a potential alternative design. First, however, it must be clear that any proposed standard control agent has been consistently superior to placebo in previous studies.

METHODS

Through a Freedom of Information Act request, we identified nine placebo-controlled trials of risperidone, olanzapine, or quetiapine.

RESULTS

Meta-analysis indicated that the pooled estimate of the true population effect size +/- SE was 0.46 +/- 0.06 for categorical response rates and >0.53 +/- 0.07 for the continuous Brief Psychiatric Rating Scale change score outcome measure. If the desired detectable effect size is set very conservatively at a 95% confidence lower bound for the estimate of true effect size, statistical power for random samples of 80 per group drawn from a population of subjects similar to that of the nine meta-analyzed studies is.67 for categorical response rates and >.82 for the continuous measure, based on one-sided alpha =.05.

CONCLUSIONS

These data suggest substantial confidence that a therapeutic dose of an atypical antipsychotic will be statistically superior to placebo in an adequately sized randomized trial, when reporting a continuous measure as the principal outcome.

Placebo-controlled trials in psychiatric research: an ethical perspective

The placebo-controlled trial is widely regarded as the gold standard for testing the efficacy of new treatments; however, this research design is subject to ethical controversy, especially when standard treatments of proven efficacy exist. After examining regulatory standards and ethical codes relevant to placebo-controlled trials, I offer a critique of arguments against the use of placebo control groups in psychiatric research. An absolute ethical prohibition of placebo-controlled trials in psychiatric disorders for which standard, effective treatments exist is rejected because it is based on a flawed conception of research ethics, ignores important contextual factors characteristic of psychiatric research, and could lead to the approval and use of new medications that appear equivalent in efficacy to standard treatments but may be no more effective than placebos. Four standards governing the ethical use of placebos in psychiatric clinical trials are explicated: 1) placebo-controlled trials should have scientific and clinical merit; 2) risks should be minimized and justified by the anticipated benefits of generating clinically relevant scientific knowledge and the expected benefits, if any, to individual patient volunteers; 3) patient volunteers should give informed consent; and 4) investigators should offer short-term treatment optimization to patient volunteers after completion of research participation.

Subject selection for the placebo- and comparator-controlled trials of neuroleptics in schizophrenia

It has been suggested that inclusion of a placebo treatment arm in controlled clinical trials might bias the selection of study subjects. Presumably, patients in the placebo-controlled studies are more stable, but there are no data available to support such an assumption. The authors tested the hypothesis in a set of randomized trials of neuroleptics in treating schizophrenia by comparing placebo-controlled (PCTs) and comparator-controlled trials (CCTs) in terms of basic patient characteristics. The results, based on a total of 296 studies, showed that the patients in PCTs, compared with those in CCTs, were older (p < 0.002), had a longer duration of illness (p < 0.001), and a lower initial symptom severity (p < 0.02). No difference was found in the number of subjects per treatment arm or in the proportion of female subjects. However, investigation of studies which used same-gender study subjects revealed that female-only populations were more likely to be tested in PCTs (p < 0.03) than in CCTs. To investigate current trends in psychopharmacologic research, the authors tested separately a subset of trials of new atypical antipsychotics. The results indicated a significantly smaller number of females participating in the latest PCTs (p < 0.0003). Moreover, our findings suggest that the characteristics of patients in the current controlled trials are rather uniform; thus, the generalizability of new study findings for certain groups of patients with schizophrenia (e.g., with early or late onset or brief duration of illness) may be compromised.

Retention rates in placebo- and nonplacebo-controlled clinical trials of schizophrenia

OBJECTIVE

To determine if the inclusion of a placebo control in clinical trials of schizophrenia affects retention rates in the first 35 days of inclusion relative to trials that did not have a placebo control.

METHOD

This was a retrospective study of 8 double-blind clinical trials, 5 of which had a placebo control while 3 did not. Using survival analysis, retention rates between the placebo-controlled trials (PCTs) and the nonplacebo-controlled trials (NPCTs) were compared. Screening and percentage improvement on Brief Psychiatric Rating Scale and Positive and Negative Syndrome Scale scores were compared.

RESULTS

Significantly more patients were retained in the 35-day period for NPCTs. Also, the PCT group had significantly more psychopathology at screening than did the NPCT group.

CONCLUSIONS

Differences in retention rates between PCTs and NPCTs cannot be uniquely attributed to placebo itself.

Placebo-controlled study of the D4/5-HT2A antagonist fananserin in the treatment of schizophrenia

OBJECTIVE

The authors' objective was to assess the potential efficacy of fananserin (RP62203), a potent antagonist at the D4 and serotonin2A (5-HT2A) receptors, on symptoms of schizophrenia.

METHOD

A double-blind, placebo-controlled study was conducted in 97 patients. Doses of fananserin reached 250 mg b.i.d. over 28 days, starting with an 8-day escalation. Most of the patients were men with paranoid schizophrenia; they were approximately 38 years old. The primary outcome measure was the total Positive and Negative Syndrome Scale score. The patients' mean score on the Positive and Negative Syndrome Scale at entry was 91.8 (SD=16.5). A low dropout rate was observed in both groups of patients (19 [30%] of those given fananserin and nine [27%] of those given placebo).

RESULTS

The total Positive and Negative Syndrome Scale score of the patients given fananserin decreased at endpoint by a mean of 4.2 points (SD=15.4); the score of the patients given placebo decreased by 6.7 points (SD=19.6). No differences between treatments were found on secondary measures such as the Clinical Global Impression, Positive and Negative Syndrome Scale subscores or individual items, and Brief Psychiatric Rating Scale total score. The patients' extrapyramidal symptoms did not worsen during the trial, but the patients given fananserin had an increase in akathisia. The safety profile was good in both groups of patients.

CONCLUSIONS

The results of this study do not support the prediction that a selective D4 antagonist associated with strong 5-HT2A antagonism will exhibit an antipsychotic effect.

Clinical trials and tribulations: implementation processes in schizophrenia research outcome

This article focuses on an area in clinical drug trials for new antipsychotic medications for the treatment of schizophrenia which has not received sufficient attention in the literature: the day-to-day implementation tasks performed by research staff which have potential effects on study results. Implementation tasks are viewed as dynamic processes involving interactions among research and nonresearch staff, patients, families, and pharmaceutical company staff. Research-related demands and possible sources of stress for all participants in the process, such as recruiting and maintaining patients in studies, are discussed. Suggestions are offered for increasing the ease of participation. Further investigation is called for in several areas including variability in the effectiveness of research teams and in the rarely discussed interactions between site staff and pharmaceutical company personnel, as they may affect research outcomes. It is posited that increased knowledge about implementation processes in schizophrenia drug development is needed to more fully understand study results and to enhance patients' and their families' willingness to participate.

Placebos in clinical trials of psychotropic medication

This paper represents the position of the Canadian Psychiatric Association on the ethical and scientific issues related to the use of placebos in the evaluation of new psychotropic drugs. The position taken by the Association is that new psychotropic medications must be shown to be effective and must be weighed against the best current interventions. Placebo controls may be appropriate under certain circumstances, even when an established intervention is effective. These include situations in which placebo response rates are high, variable, or close to response rates for effective therapies. Placebo controls are also appropriate when established interventions carry a high risk of side effects or are effective against only certain symptoms of the disorder.

Tubefeeding and mortality in children with severe disabilities and mental retardation

OBJECTIVE

To study the contribution of tubefeeding to mortality for children with severe disabilities and mental retardation. Previous research has suggested an association between tubefeeding and mortality. However, risk has never been determined using population-based data or defined in regard to patient variables.

METHODS

Retrospective analysis of a comprehensive statewide data set comprised of 4921 children with severe disabilities and mental retardation living in community and congregate care settings. The outcome measure was mortality; primary study variables included the presence of a feeding tube, measures of functional independence, type of residence, and medical comorbidity.

RESULTS

There were four findings. First, the use of a feeding tube was associated with virtually every disability. Second, when no study variables were controlled, statistically significant differences in mortality rates were noted between children who were tubefed and those who were not. The relative risk of mortality associated with use of a feeding tube was 2.1. Third, the use of a feeding tube was associated with a reduction in relative risk of mortality in children with tracheostomy (relative risk of mortality: .55). However, this association did not achieve statistical significance. Fourth, when study variables were controlled in a multivariate analysis, feeding tube use was associated with no identifiable increase in mortality among children with very severe disabilities, but was associated with an approximated doubled mortality rate among those with less severe disabilities.

CONCLUSIONS

We hypothesize that the increased mortality associated with tubefeeding may be attributable to a differential increase in pulmonary disease secondary to overly vigorous nutritional maintenance and subsequent aspiration after tube placement. For children with tracheostomy this risk may be reduced. If tracheostomy proves to be associated with a relatively more favorable outcome for tubefeeding, we hypothesize that it would reflect the benefits of tracheostomy in allowing access to the airway for suctioning and ventilation. Given the observed higher mortality rates among the less severely disabled children who are tubefed and the substantial costs associated with tubefeeding, a prospective, controlled study may be clinically indicated, ethically justifiable, and economically warranted.