Do efficacy results obtained from randomized controlled trials translate to effectiveness data from observational studies for relapsing-remitting multiple sclerosis?

BACKGROUND: Randomized controlled trials are considered the gold standard in regulatory decision making, as observational studies are known to have important methodological limitations. However, real-world evidence may be helpful in specific situations. This review investigates how the effect estimates obtained from randomized controlled trials compare to those obtained from observational studies, using drug therapy for relapsing-remitting multiple sclerosis as an example. STUDY DESIGN AND SETTING: A systematic review of randomized controlled trials and observational studies was conducted. The primary outcome was the annualized relapse rate. Using (network) meta-analysis together with posterior predictive distributions, the drug-specific rate ratios from the network of randomized controlled trials were compared with those from the network of observational studies. RESULTS: Effect estimates from 26 observational studies showed greater magnitudes and were less precise compared to estimates obtained from 21 randomized controlled trials. Twenty of the 28 treatment comparisons between designs had similar rate ratios. Seven inconsistencies in observed rate ratios could be attributed to two specific disease-modifying therapies. CONCLUSION: In this case study, estimates from observational studies predominantly agreed with estimates from randomized controlled trials given their posterior predictive distributions. Multiple observational studies together may therefore supplement additional pivotal randomized controlled trials in relapsing-remitting multiple sclerosis, for instance facilitating the extrapolation of trial results to the broader patient population.

The new European Medicines Agency guideline on antidepressants: a guide for researchers and drug developers.

According to the World Health Organization (WHO), depressive disorders are currently considered as one of the most disabling medical conditions in the world with one of the highest disability-adjusted life years [1] and this situation has apparently been further worsened during the COVID-19 pandemic [2]. Up to two thirds of patients with major depressive disorders (MDD) do not achieve full remission following an adequate first line standard of care and/or experience residual symptoms such as anxiety, impaired cognition, fatigue, sleep disturbance, or anhedonia [3]. Several attempts are often needed to find the most suitable treatment [4]. Thus, there is a need for medicinal products with better efficacy (e.g., faster onset of action, higher rates of response and remission), improved safety and/or more personalised profiles [5].

European regulators' views on a wearable-derived performance measurement of ambulation for Duchenne muscular dystrophy regulatory trials.

Development of novel therapies for Duchenne muscular dystrophy (DMD) are driving the need for more efficient ways of detecting changes in disease- progression in DMD [1]. However, medicines' approval must be based on outcome measures that are acceptable from a regulatory perspective. In this article, European regulators provide an update on the recent regulatory consideration of a new endpoint (Stride Velocity 95th Centile (SV95C)) that could be used in therapeutic DMD trials. This new endpoint aims to quantify a patient's ambulation directly, reliably and continuously in a home environment with a wearable device.

European regulatory use and impact of subgroup evaluation in marketing authorisation applications.

Marketing authorisation application dossiers relating to medicinal products containing new active substances and evaluated by the European Medicines Agency (EMA) over the period 2012-2015 were examined. Major objections and other concerns relating to efficacy and safety of the day 80 assessment reports were reviewed. Overall, approved products have more subgroup concerns than nonapproved products, which seems to be a consistent pattern. Subgroup analyses are mainly assessed to have the insurance that subgroups of patients that might lack a positive benefit: risk ratio will not be wrongly included in the approved treatment indication.

Addressing the regulatory and scientific challenges in multiple sclerosis--a statement from the EU regulators.

Improving and facilitating the process of making new drugs available to patients with multiple sclerosis (MS) requires cooperation among the regulators and other stakeholders. This cooperation will also positively contribute towards developing guidelines of the highest quality in medical, regulatory and scientific aspects. This would be beneficial both in areas that require further guideline development, but also in fields where existing guidance should be adapted to take into account evolution in science. Considering the input from all stakeholders, the European Medicines Agency confirmed its intention to update the relevant guideline and apply a flexible approach towards new drug development strategies in MS. This article is the first official position from the EU regulators, presenting the main changes to be expected in the guidance document.

Interchangeability of generic anti-epileptic drugs: a quantitative analysis of topiramate and gabapentin.

PURPOSE: The objective of this study was to determine whether the so-called "shift" or "drift" problem might occur when generic anti-epileptic drugs are interchanged, and thus to assess if generic anti-epileptic drugs are interchangeable and can be used in an efficacious and safe way on the basis of their bioequivalence to one and the same reference product. METHODS: The bioequivalence of topiramate and gabapentin generics was evaluated. For proper interstudy comparison, individual exposure data (AUC and C(max)) for each bioequivalence study present in the registration dossier was normalized based on the absolute exposure data of one of two innovators. The exposure-normalized plasma concentration curves of the generic product arms between studies were compared, providing indirect evidence of bioequivalence of the different generics. Additionally, comparisons were made for generic-generic as well as innovator-innovator exchange based on absolute exposure data from individual bioequivalence studies. RESULTS: In almost all cases, estimated 90% confidence intervals of the AUC and C(max) ratios for generic-generic interchange were within the routine 80-125% criterion. When absolute, non-corrected exposure data were used for this interstudy comparison, in a number of cases 90% confidence intervals outside the 80-125% criterion were found upon interchanging generics from two studies. However, a similar pattern of 90% confidence intervals outside the 80-125% criterion was observed for the comparison of innovator arms, despite the fact that the innovator was identical in all studies. CONCLUSION: Our results strongly indicate that the so-called drifting problem upon generic-generic substitution does not result in important differences in exposure upon exchanging topiramate generics or gabapentin generics.

Insomnia medication: do published studies reflect the complete picture of efficacy and safety?

Selective publication can have a deleterious effect on evidence based medicine, health policy decision making and treatment guidelines. Using the European Public Assessment Reports (EPARs) as reference, this study examined selective publication and selective reporting of efficacy and safety of insomnia medication. EPARs of with three insomnia medications were used to identify all clinical trials that were performed between 1998 and 2007 for the purpose of registration in the EU. The matching publication for each trial was searched through a systematic literature search. Accuracy of information in the publications was examined by comparison to the information in the EPARs. Only 55% of the trials with insomnia medications identified in EPARs were published. Positive trials were approximately two times more likely to be published. The lag time from study completion to publication was shorter for the positive compared to the negative trials. Sample size did not correlate with publication of negative trials. The meta-analysis of the effect size of insomnia medication was 1.6 times larger in the published data compared to the complete data. While the primary end points of the trials were reported reliably in the publications, remarkable inconsistencies were detected in the reporting of the secondary end points, methods, results and, especially safety. In conclusion, selective publication and reporting lead to an overestimation of efficacy and underestimation of safety of insomnia products. Authors of treatment guidelines should be aware of this bias. EPARs/FDA reviews provide a more unbiased view of the benefit-risk balance of insomnia and other medications and hence these documents should be consulted by e.g. authors of meta-analyses and of treatment guidelines.

Magnitude of effect of lithium in short-term efficacy studies of moderate to severe manic episode.

OBJECTIVES: To provide an accurate estimation of the magnitude of effect of lithium in short-term efficacy studies conducted in patients with moderate to severe manic episode. METHODS: All placebo-controlled randomized studies submitted to the Medicines Evaluation Board (MEB) in which lithium was used as the third study arm were selected for the meta-analysis. The studies were part of registration files submitted to the MEB between the years 1997 and 2005. In addition, Medline and EMbase searches were conducted with the key words 'manic' ('mania' for the EMbase search) and 'placebo' in order to identify additional placebo-controlled studies of lithium. This search was updated until March 1, 2006. Two effect size indicators were used based on the primary outcome measure of each study: Cohen's standardized effect size based on the difference in mean change from baseline, and numbers needed to treat (NNT) based on the difference in treatment response defined as >or=50% improvement from baseline on day 21. RESULTS: Six studies were identified. They involved a combined total of 470 patients in the lithium groups and 562 in the placebo groups. The overall standardized effect size was 0.40 [95% confidence interval (CI): 0.28, 0.53] and the overall NNT for response was 6 (95% CI: 4, 13). In the placebo groups response rates varied from 21% to 47%. CONCLUSIONS: The results indicate that lithium is an effective drug in the treatment of moderate to severe manic episode. The variability in placebo response indicates that a placebo control arm in efficacy studies among patients with moderate to severe manic episode is necessary.

Antidepressants use in children and adolescents and the risk of suicide.

OBJECTIVE: Antidepressants use in paediatric patients has been linked with risk of suicidal behaviours. The aim of this paper, therefore, is to examine whether all antidepressants are associated with such risk. METHOD: All 22 paediatric short-term placebo-controlled trials of SSRIs and NSRIs that were submitted to European registration authorities by pharmaceutical companies were identified and examined for events related to suicidality, which were defined as suicide, suicide attempts or suicidal thoughts. Random effect meta-analysis was used to combine the information from all trials. RESULTS: No completed suicides were reported. However, for each compound there was at least one study with an increased risk for events related to suicidality in the active compound group. The overall OR for these events in the depression studies was 1.67 (95% CI: 1.05-2.65) and for anxiety 1.33 (95% CI: 0.33-5.35). CONCLUSIONS: Caution is called for in the use of all SSRIs and NSRIs in the paediatric population. Furthermore, in the absence of contradictory information, caution in the use of other antidepressants in this population should be exercised as well (e.g. tricyclic antidepressants).

Response to tricyclic antidepressants: independent of gender?

OBJECTIVE: The authors examined gender differences in response to tricyclic antidepressants. METHOD: A total of 30 randomized, placebo-controlled trials that included 3,886 patients (1,555 men and 2,331 women), submitted between 1979 and 1991 in order to obtain marketing authorization, were reviewed. Gender differences in response to treatment were tested in various multiple regression models using a variety of response definitions. RESULTS: Different response definitions all pointed to no gender difference in the efficacy of tricyclic antidepressants. The estimated effect size was similar for women younger and older than age 50 and for men. CONCLUSIONS: Tricyclic antidepressant response is independent of gender.

Amisulpride: is there a treatment for negative symptoms in schizophrenia patients?

In this article we report on a meta-analysis of the published studies of amisulpride conducted in order to demonstrate efficacy on primary negative symptoms in schizophrenia. Four placebo-controlled studies were conducted in patients with predominantly negative symptoms. In all studies a significant improvement was observed on the Scale for the Assessment of Negative Symptoms (SANS) in the amisulpride groups (50-300 mg daily) as compared to placebo. The improvement on the SANS was not accompanied by a simultaneous improvement on the Scale for the Assessment of Positive Symptoms (SAPS) or a decrease in extrapyramidal symptoms (EPS) in three of the four studies, indicating a genuine effect on primary negative symptoms. The overall analysis shows that the improvement on the SANS was accompanied by a small simultaneous improvement on the SAPS. Moreover, in the studies where depressive symptoms were measured, a significant improvement was also shown in favor of amisulpride. However, as the SAPS and the Montgomery Asberg Depression Rating Scale (MADRS) baseline scores were rather low, the improvement on both scales in favor of amisulpride is probably not responsible for the improvement on the SANS. A positive correlation was found between the severity on the mean SANS score at baseline and mean improvement at endpoint, and a surprisingly high success rate was observed in the placebo groups, indicating either that primary negative symptoms are not as persistent as had previously been thought, or that the concept of primary negative symptoms should be reconsidered. Probably amisulpride is efficacious on these nonenduring primary negative symptoms.