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The evidence base for psychotropic drugs approved by the European Medicines Agency: a meta-assessment of all European Public Assessment Reports

AIMS

To systematically assess the level of evidence for psychotropic drugs approved by the European Medicines Agency (EMA).

METHODS

Cross-sectional analysis of all European Public Assessment Reports (EPARs) and meta-analyses of the many studies reported in these EPARs. Eligible EPARs were identified from the EMA's website and individual study reports were requested from the Agency when necessary. All marketing authorisation applications (defined by the drug, the route of administration and given indications) for psychotropic medications for adults (including drugs used in psychiatry and addictology) were considered. EPARs solely based on bioequivalence studies were excluded. Our primary outcome measure was the presence of robust evidence of comparative effectiveness, defined as at least two 'positive' superiority studies against an active comparator. Various other features of the approvals were assessed, such as evidence of non-inferiority v. active comparator and superiority v. placebo. For studies with available data, effect sizes were computed and pooled using a random effect meta-analysis for each dose of each drug in each indication.

RESULTS

Twenty-seven marketing authorisations were identified. For one, comparative effectiveness was explicitly considered as not needed in the EPAR. Of those remaining, 21/26 (81%) did not provide any evidence of superiority against an active comparator, 2/26 (8%) were based on at least two trials showing superiority against active comparator and three (11%) were based on one positive trial; 1/26 provided evidence for two positive non-inferiority analyses v. active comparator and seven (26%) provided evidence for one. In total, 20/27 (74%) evaluations reported evidence of superiority v. placebo with two or more trials. Among the meta-analyses of initiation studies against active comparator (57 available comparisons), the median effect size was 0.051 (range -0.503; 0.318). Twenty approved evaluations (74%) reported evidence of superiority v. placebo on the basis of two or more initiation trials and seven based on a single trial. Among meta-analyses of initiation studies against placebo (125 available comparisons), the median effect size was -0.283 (range -0.820; 0.091). Importantly, among the 89 study reports requested on the EMA website, only 19 were made available 1 year after our requests.

CONCLUSIONS

The evidence for psychiatric drug approved by the EMA was in general poor. Small to modest effects v. placebo were considered sufficient in indications where an earlier drug exists. Data retrieval was incomplete after 1 year despite EMA's commitment to transparency. Improvements are needed.

Is the efficacy of antidepressants in panic disorder mediated by adverse events? A mediational analysis

It has been hypothesised that the perception of adverse events in placebo-controlled antidepressant clinical trials may induce patients to conclude that they have been randomized to the active arm of the trial, leading to the breaking of blind. This may enhance the expectancies for improvement and the therapeutic response. The main objective of this study is to test the hypothesis that the efficacy of antidepressants in panic disorder is mediated by the perception of adverse events. The present analysis is based on a systematic review of published and unpublished randomised trials comparing antidepressants with placebo for panic disorder. The Baron and Kenny approach was applied to investigate the mediational role of adverse events in the relationship between antidepressants treatment and efficacy. Fourteen placebo-controlled antidepressants trials were included in the analysis. We found that: (a) antidepressants treatment was significantly associated with better treatment response (ß = 0.127, 95% CI 0.04 to 0.21, p = 0.003); (b) antidepressants treatment was not associated with adverse events (ß = 0.094, 95% CI -0.05 to 0.24, p = 0.221); (c) adverse events were negatively associated with treatment response (ß = 0.035, 95% CI -0.06 to -0.05, p = 0.022). Finally, after adjustment for adverse events, the relationship between antidepressants treatment and treatment response remained statistically significant (ß = 0.122, 95% CI 0.01 to 0.23, p = 0.039). These findings do not support the hypothesis that the perception of adverse events in placebo-controlled antidepressant clinical trials may lead to the breaking of blind and to an artificial inflation of the efficacy measures. Based on these results, we argue that the moderate therapeutic effect of antidepressants in individuals with panic disorder is not an artefact, therefore reflecting a genuine effect that doctors can expect to replicate under real-world conditions.

A new approach to psychiatric drug approval in Europe

Corrado Barbui and Irene Bighelli question the current rules governing registration of new medicines in Europe, using the example of psychiatric drugs, and argue that the concept of absolute efficacy should be replaced by the concept of added value whereby evidence from studies comparing a new product with an active comparator should guide the drug approval process. Please see later in the article for the Editors' Summary.