Association of End Point Definition and Randomized Clinical Trial Duration in Clinical Trials of Schizophrenia Medications

Current status and challenges of model-informed drug discovery and development in China

In the past decade, biopharmaceutical research and development in China has been notably boosted by government policies, regulatory initiatives and increasing investments in life sciences. With regulatory agency acting as a strong driver, model-informed drug development (MIDD) is transitioning rapidly from an academic pursuit to a critical component of innovative drug discovery and development within the country. In this article, we provided a cross-sectional summary on the current status of MIDD implementations across early and late-stage drug development in China, illustrated by case examples. We also shared insights into regulatory policy development and decision-making. Various modeling and simulation approaches were presented across a range of applications. Furthermore, the challenges and opportunities of MIDD in China were discussed and compared with other regions where these practices have a more established history. Through this analysis, we highlighted the potential of MIDD to enhance drug development efficiency and effectiveness in China's evolving pharmaceutical landscape.

Effects of PDE10A inhibitor MK-8189 in people with an acute episode of schizophrenia: A randomized proof-of-concept clinical trial

BACKGROUND

PDE10A inhibition represents a potential mechanism for treating schizophrenia. PDE10A inhibitors increase cyclic nucleotides in striatal neurons, thereby mimicking the effects of dopamine receptor D2 antagonists and D1 agonists. We evaluated the PDE10A inhibitor MK-8189 for treating schizophrenia.

METHODS

Randomized, double-blind, placebo and active-controlled, phase 2a, multicenter, inpatient trial in adults experiencing an acute episode of schizophrenia. Participants were randomized 2:2:1 to once-daily MK-8189 12 mg, placebo, or risperidone 6 mg (active control) for 4-weeks. The primary outcome was change-from-baseline in total score on the Positive and Negative Syndrome Scale (PANSS) at 4 weeks.

RESULTS

The number of treated participants was 90 for MK-8189, 89 for placebo, and 45 for risperidone. MK-8189 demonstrated a trend towards improvement versus placebo for change-from-baseline in PANSS total score after 4 weeks (difference = -4.7 [95 % CI: -9.8,0.5], P = 0.074). The active control risperidone was superior to placebo on PANNS total score (difference = -7.3 [95 % CI: -14.0,-0.6], P = 0.033), demonstrating assay sensitivity, while MK-8189 and risperidone did not significantly differ (difference = 2.6 [95 % CI: -4.0,9.2], P = 0.440). MK-8189 had a nominally significant effect on PANSS positive subscale score compared to placebo (difference = -2.2 [95 % CI: -3.8,-0.5], P = 0.011). Discontinuation of MK-8189 treatment due to an adverse event was low (<10 %). Extrapyramidal symptoms occurred with MK-8189 but were mostly mild and transient. Compared with placebo, MK-8189 reduced body weight while risperidone increased weight.

CONCLUSIONS

These findings suggest that PDE10A inhibition may produce antipsychotic effects and associated weight loss and that further trials with PDE10A inhibitors are warranted.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT03055338.

Non-invasive brain stimulation for treatment-resistant schizophrenia: protocol of a systematic review and network meta-analysis

BACKGROUND

Non-invasive brain stimulation (NIBS) is a promising intervention for treatment-resistant schizophrenia. However, there are multiple available techniques and a comprehensive synthesis of evidence is lacking. Thus, we will conduct a systematic review and network meta-analysis to investigate the comparative efficacy and safety of NIBS techniques as an add-on to antipsychotics for treatment-resistant schizophrenia.

METHODS

We will include single- and double-blind randomized-controlled trials (RCT) comparing any NIBS technique with each other or with a control intervention as an add-on to antipsychotics in adult patients with treatment-resistant schizophrenia. We will exclude studies focusing on predominant negative symptoms, maintenance treatment, and single sessions. The primary outcome will be a change in overall symptoms, and secondary outcomes will be a change in symptom domains, cognitive performance, quality of life, functioning, response, dropouts, and side effects. We will search for eligible studies in previous reviews, multiple electronic databases and clinical trial registries from inception onwards. At least two independent reviewers will perform the study selection, data extraction, and risk of bias assessment. We will measure the treatment differences using standardized mean difference (SMD) and odds ratio (OR) for continuous and dichotomous outcomes, respectively. We will conduct pairwise and network meta-analysis within a frequentist framework using a random-effects model, except for rare event outcomes where we will use a fixed-effects Mantel-Haenszel method. We will investigate potential sources of heterogeneity in subgroup analyses. Reporting bias will be assessed with funnel plots and the Risk of Bias due to Missing Evidence in Network meta-analysis (ROB-MEN) tool. The certainty in the evidence will be evaluated using the Confidence in Network Meta-analysis (CINeMA) approach.

DISCUSSION

Our network meta-analysis would provide an up-to-date synthesis of the evidence from all available RCTs on the comparative efficacy and safety of NIBS for treatment-resistant schizophrenia. This information could guide evidence-based clinical practice and improve the outcomes of patients.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO-ID CRD42023410645.

The effect of differences in trial design on estimates of efficacy of olanzapine in randomized studies

BACKGROUND

Differences in trial design may affect estimates of efficacy of psychotropic drugs. The purpose of this meta-analysis is to evaluate whether the use of Olanzapine (OLZ) as either investigational or control drug affects the observed efficacy of OLZ.

METHODS

We performed a search for Randomized-Controlled Trials (RCTs) in which the efficacy of OLZ is assessed in patients with schizophrenia or schizoaffective disorder. We assessed overall efficacy of OLZ and performed subgroup analyses of studies with OLZ as intervention or comparator. Mixed-effect meta-regression analyses were performed.

RESULTS

Of the 25 RCTs included, OLZ was considered as investigational drug or active control in 13 and 12 studies, respectively. The reduction of PANSS score was greater in trials in which OLZ was used as investigational drug. Multivariate meta-regression models showed that a higher PANSS score at baseline and trial duration were the main predictors of greater PANSS score reduction.

CONCLUSIONS

Trials with OLZ used as investigational drug differ from those of trials with OLZ as comparator for baseline PANSS scores and study duration; these differences may produce differences in estimates of efficacy. As a consequence, the severity of illness at enrollment and trial duration should be carefully considered to ensure the reliability of indirect comparisons among antipsychotics.

Pipeline progress and portfolio management of the top 30 pharma companies over the past two decades

For pharmaceutical companies, it is essential to define their long-term corporate strategy. This especially involves the pipeline progress of pharmaceuticals and portfolio management. The objective of this study was to give a broad overview of study durations of the clinical trials from the top 30 pharmaceutical companies worldwide and to investigate what could possibly impact these study durations (e.g., indication areas, companies themselves, etc.) We worked with the clinicaltrials.gov database to examine the pipeline (phase 1-3) and portfolio (after regulatory approval) of the top 30 pharma companies worldwide over 20 years (from 2000-2020). We further calculated the study duration of each clinical study as the difference between the start date and end date. To analyze changes in our measure we estimated multiple linear regression to evaluate the impact of indication areas and companies on the study duration. Most of the clinical studies were conducted in the areas of ONCIM (N = 2720), and META (N = 1993). The indication with the highest study duration was ONCIM (on average 3.9 years per clinical study, SD: 0.8). Values for the study duration vary widely across companies. Mostly they range between 1 and 4 years (e.g., Merck Sharp & Dohme (MSD) on average 2.2 years per clinical study, SD: 1.0). Correlation analysis showed that study phases were positively correlated with the study duration (+ 0.36, p < 0.000), i.e., the higher the study phase, the higher the study duration. Furthermore, we found that indication areas influenced the study duration significantly (+ 0.17, p < 0.000). However, there were wide variations in effect sizes across indications. The results suggest that different indication areas influence the study duration to different extents. Pipeline progress and portfolio management differ widely between indications, companies and over the years. Research findings could help corporate strategy managers to make more informed decisions regarding their business development strategy.

Trace amine-associated receptor 1 (TAAR1) agonists for psychosis: protocol for a living systematic review and meta-analysis of human and non-human studies

BACKGROUND

There is an urgent need to develop more effective and safer antipsychotics beyond dopamine 2 receptor antagonists. An emerging and promising approach is TAAR1 agonism. Therefore, we will conduct a living systematic review and meta-analysis to synthesize and triangulate the evidence from preclinical animal experiments and clinical studies on the efficacy, safety, and underlying mechanism of action of TAAR1 agonism for psychosis.

METHODS

Independent searches will be conducted in multiple electronic databases to identify clinical and animal experimental studies comparing TAAR1 agonists with licensed antipsychotics or other control conditions in individuals with psychosis or animal models for psychosis, respectively. The primary outcomes will be overall psychotic symptoms and their behavioural proxies in animals. Secondary outcomes will include side effects and neurobiological measures. Two independent reviewers will conduct study selection, data extraction using predefined forms, and risk of bias assessment using suitable tools based on the study design. Ontologies will be developed to facilitate study identification and data extraction. Data from clinical and animal studies will be synthesized separately using random-effects meta-analysis if appropriate, or synthesis without meta-analysis. Study characteristics will be investigated as potential sources of heterogeneity. Confidence in the evidence for each outcome and source of evidence will be evaluated, considering the summary of the association, potential concerns regarding internal and external validity, and reporting biases. When multiple sources of evidence are available for an outcome, an overall conclusion will be drawn in a triangulation meeting involving a multidisciplinary team of experts. We plan trimonthly updates of the review, and any modifications in the protocol will be documented. The review will be co-produced by multiple stakeholders aiming to produce impactful and relevant results and bridge the gap between preclinical and clinical research on psychosis.

PROTOCOL REGISTRATION

PROSPERO-ID: CRD42023451628.

Antipsychotic dose, dopamine D2 receptor occupancy and extrapyramidal side-effects: a systematic review and dose-response meta-analysis

Antipsychotic drugs differ in their propensity to cause extrapyramidal side-effects (EPS), but their dose-effects are unclear. Therefore, we conducted a systematic review and dose-response meta-analysis. We searched multiple electronic databases up to 20.02.2023 for fixed-dose studies investigating 16 second-generation antipsychotics and haloperidol (all formulations and administration routes) in adults with acute exacerbations of schizophrenia. The primary outcome was the number of participants receiving antiparkinsonian medication, and if not available, the number of participants with extrapyramidal side-effects (EPS) and the mean scores of EPS rating scales were used as proxies. The effect-size was odds ratio (ORs) compared with placebo. One-stage random-effects dose-response meta-analyses with restricted cubic splines were conducted to estimate the dose-response curves. We also examined the relationship between dopamine D2 receptor (D2R) occupancy and ORs by estimating occupancies from administrated doses. We included data from 110 studies with 382 dose arms (37193 participants). Most studies were short-term with median duration of 6 weeks (range 3-26 weeks). Almost all antipsychotics were associated with dose-dependent EPS with varied degrees and the maximum ORs ranged from OR = 1.57 95%CI [0.97, 2.56] for aripiprazole to OR = 7.56 95%CI [3.16, 18.08] for haloperidol at 30 mg/d. Exceptions were quetiapine and sertindole with negligible risks across all doses. There was very low quality of findings for cariprazine, iloperidone, and zotepine, and no data for clozapine. The D2R occupancy curves showed that the risk increased substantially when D2R occupancy exceeded 75-85%, except for D2R partial agonists that had smaller ORs albeit high D2R occupancies. In conclusion, we found that the risk of EPS increases with rising doses and differs substantially in magnitude among antipsychotics, yet exceptions were quetiapine and sertindole with negligible risks. Our data provided additional insights into the current D2R therapeutic window for EPS.

Negative symptoms in schizophrenia: Newly emerging measurements, pathways, and treatments

The negative symptoms of schizophrenia, which often appear earlier than any other symptom, are prominent and clinically relevant in the majority of patients. As a result, interest in their treatment has increased. Patients who exhibit significant negative symptoms have worse functional outcomes than those without, resulting in impairments in occupational, household, and recreational functioning, as well as difficulties in relationships. Yet treatment with currently available medications does not lead to any significant improvements in this core component of schizophrenia. An increased understanding of the pathophysiology underlying negative symptoms and the discovery of novel treatments that do not directly target dopamine offer the potential to develop therapies that may reduce negative symptoms and increase quality of life for patients. The current article will discuss the impact of negative symptoms, outline current measurement tools for the assessment of negative symptoms, and examine how these measures may be improved. Insights into the neural circuitry underlying negative symptoms will be discussed, and promising targets for the development of effective treatments for these symptoms will be identified. As more prospective, large-scale, randomized studies focus on the effects of treatments on negative symptoms, progress in this area is foreseeable. However, improvements in clinical assessment instruments, a better understanding of the underlying neural mechanisms, development of novel treatments with varied targets, and a greater focus on personalized treatment are all important to produce significant benefits for patients with negative symptoms of schizophrenia.

The future of psychopharmacology: a critical appraisal of ongoing phase 2/3 trials, and of some current trends aiming to de-risk trial programmes of novel agents

Despite considerable progress in pharmacotherapy over the past seven decades, many mental disorders remain insufficiently treated. This situation is in part due to the limited knowledge of the pathophysiology of these disorders and the lack of biological markers to stratify and individualize patient selection, but also to a still restricted number of mechanisms of action being targeted in monotherapy or combination/augmentation treatment, as well as to a variety of challenges threatening the successful development and testing of new drugs. In this paper, we first provide an overview of the most promising drugs with innovative mechanisms of action that are undergoing phase 2 or 3 testing for schizophrenia, bipolar disorder, major depressive disorder, anxiety and trauma-related disorders, substance use disorders, and dementia. Promising repurposing of established medications for new psychiatric indications, as well as variations in the modulation of dopamine, noradrenaline and serotonin receptor functioning, are also considered. We then critically discuss the clinical trial parameters that need to be considered in depth when developing and testing new pharmacological agents for the treatment of mental disorders. Hurdles and perils threatening success of new drug development and testing include inadequacy and imprecision of inclusion/exclusion criteria and ratings, sub-optimally suited clinical trial participants, multiple factors contributing to a large/increasing placebo effect, and problems with statistical analyses. This information should be considered in order to de-risk trial programmes of novel agents or known agents for novel psychiatric indications, increasing their chances of success.

Review: Role of Model-Informed Drug Development Approaches in the Lifecycle of Drug Development and Regulatory Decision-Making

Model-informed drug development (MIDD) is a powerful approach to support drug development and regulatory review. There is a rich history of MIDD applications at the U.S. Food and Drug Administration (FDA). MIDD applications span across the life cycle of the development of new drugs, generics, and biologic products. In new drug development, MIDD approaches are often applied to inform clinical trial design including dose selection/optimization, aid in the evaluation of critical regulatory review questions such as evidence of effectiveness, and development of policy. In the biopharmaceutics space, we see a trend for increasing role of computational modeling to inform formulation development and help strategize future in vivo studies or lifecycle plans in the post approval setting. As more information and knowledge becomes available pre-approval, quantitative mathematical models are becoming indispensable in supporting generic drug development and approval including complex generic drug products and are expected to help reduce overall time and cost. While the application of MIDD to inform the development of cell and gene therapy products is at an early stage, the potential for future application of MIDD include understanding and quantitative evaluation of information related to biological activity/pharmacodynamics, cell expansion/persistence, transgene expression, immune response, safety, and efficacy. With exciting innovations on the horizon, broader adoption of MIDD is poised to revolutionize drug development for greater patient and societal benefit.

Validation of Chinese Version of Positive and Negative Syndrome Scale-6 in Clinical Setting: A Preliminary Study

Background

The Positive and Negative Syndrome Scale-6 (PANSS-6) is a brief measure to assess the core symptoms of schizophrenia. Psychometric characteristics of PANSS-6 in clinical settings are to be determined. We conducted this study among Chinese inpatients of schizophrenia in clinical settings, to determine psychometric characteristics of PANSS-6, and its' accuracy for identifying antipsychotic efficacy.

Methods

Two hundred sixteen inpatients of schizophrenia were interviewed at baseline, week 4 and week 8 by experienced psychiatrists to collect information for rating PANSS-30 and PANSS-6. Internal consistency was estimated by the Cronbach's α; criterion validity was determined by Spearman's correlations between sum scores of PANSS-6 and PANSS-30; factorial validity was determined by confirmatory factor analysis (CFA); the sensitivity, specificity, positive predictive value (PPV); and negative predictive value (NPV) of PANSS-6 for identifying responders and remitters were calculated.

Results

The Cronbach's α coefficients of PANSS-6 were 0.72 (95% CI: 0.66-0.78) at baseline. Sum scores of PANSS-6 were significantly correlated with that of PANSS-30. Confirmatory factor analysis confirmed this 2-factor model fit well: χ2/df = 1.331, P = .223; CFI = 0.994; TLI = 0.988, RMSEA = 0.037 (90% CI: 0.000-0.090); SRMR = 0.033. Standard factor loadings of each item ranged from 0.60 to 0.89. At week 8, 92 (48.42%) and 63 (33.16%) inpatients were classified as responders and remitters. The sensitivity of PANSS-6 for identifying responders and remitters was 0.77 and 1.0, specificities were 0.84 and 0.86.

Conclusion

Positive and Negative Syndrome Scale-6 is a sound scale for measuring psychotic severity and monitoring treatment outcomes of schizophrenia in clinical settings.

A meta-analysis of effectiveness of real-world studies of antipsychotics in schizophrenia: Are the results consistent with the findings of randomized controlled trials?

Randomized controlled trials (RCTs) have been considered as gold standard for establishing the efficacy and safety of investigational new drugs; nonetheless, the generalizability of their findings has been questioned. To address this issue, an increasing number of naturalistic studies and real-world database analyses have been conducted. The question of how much information from these two approaches is congruent or discrepant with each other is of great importance for the clinical practice. To answer this question, we focused on data from the antipsychotic (AP) treatment of schizophrenia. Our aim was two-fold: to conduct a meta-analysis of real-world studies (RWS), and to compare the results of RWS meta-analysis with previously published meta-analyses of RCTs. The principal measure of effectiveness was all-cause treatment discontinuation for both RWS and RCTs (when not available, then drop out for RCTs). We included publications for 8 selected APs (oral formulations of amisulpride, aripiprazole, clozapine, haloperidol, olanzapine, quetiapine, risperidone, and long-acting injectable (LAI) risperidone). We identified 11 RWS and 7 RCT meta-analyses for inclusion. Our results indicated that the RWS yielded statistically conclusive and consistent findings across individual investigations. For the overwhelming majority of the comparisons where both RWS and RCT meta-analyses were available, there was good congruency between the RWS and the RCT results. Our results support that RCTs, despite their limitations, provide evidence which is generalizable to real-world settings. This is an important finding for both regulators and clinicians. RWS can provide guidance for situations where no evidence is available from double-blind clinical trials.