Discontinuation and nonpublication of interventional clinical trials conducted in patients with mild cognitive impairment and Alzheimer's disease

Publication Rates of Registered Corneal Trials on ClinicalTrials.gov

PURPOSE

This study aimed to characterize cornea-centered clinical trials, completed before 2020, registered on ClinicalTrials.gov and identify discrepancies in publication.

METHODS

ClinicalTrials.gov, a database from the National Institutes of Health, was queried to identify registered cornea-related clinical trials. Trials were included if they were interventional and completed before January 1, 2020. ClinicalTrials.gov, PubMed.gov, and Google Scholar were then searched to evaluate publications from the trial. Data collected for each trial included sponsor, intervention type, phase, dry eye focus, and location of the principal investigator.

RESULTS

A total of 520 trials were included in the final analysis. Of all studies, 270 (51.9%) were found to have published results. Industry-sponsored studies were associated with drug intervention trials, dry eye focus, and the principal investigator's location within the United States ( P < 0.05 for all). Nonindustry sponsors were associated with device and procedure intervention trials ( P < 0.05 for both). Overall, trials that were categorized as procedure interventions were published at a significantly higher rate than other interventional categories (64.2% vs. 50.1%; P = 0.03). Subgroup analysis revealed that among nonindustry studies, late-phase trials and procedural-based trials were published at a significantly higher rate compared with other studies (67.2% vs. 51.6%; P = 0.04 and 67.8% vs. 51.6%; P = 0.03).

CONCLUSIONS

Only 51.9% of registered interventional cornea-based clinical trials result in publications in the peer-reviewed literature, highlighting potential publishing discrepancies.

What Factors Are Associated with Clinical Trial Discontinuation in Orthopaedic Surgery: An Analysis of Clinical Trials Between 2007 and 2022

BACKGROUND

Clinical trials play a crucial role in advancing medical knowledge and have the potential to change standards of care. The present study evaluated the prevalence of discontinued clinical trials in orthopaedic surgery. Additionally, we sought to identify the study characteristics associated with and the rationale behind trial discontinuation.

METHODS

A cross-sectional survey of orthopaedic clinical trials using the ClinicalTrials.gov registry and results database was performed for trials between October 1, 2007, and October 7, 2022. Interventional trials listed as "completed," "terminated," "withdrawn," or "suspended" were included. Study characteristics were collected and clinical trial abstracts were reviewed in order to assign the appropriate subspecialty category. A univariate linear regression analysis was performed to determine whether the percentage of discontinued trials changed between 2008 and 2021. Univariate and multivariable hazard ratios (HRs) were calculated to identify factors associated with trial discontinuation.

RESULTS

A total of 8,603 clinical trials were included in the final analysis, of which 1,369 (16%) were discontinued, with the highest rates of discontinuation found in oncology (25%) and trauma (23%). The most common rationales for discontinuation were insufficient patient accrual (29%), technical or logistical issues (9%), business decision (9%), and lack of funding or resources (9%). Industry-funded studies were more likely than government-funded studies to be discontinued (HR: 1.81; p < 0.001). There was no change in the percentage of discontinued trials for each orthopaedic subspecialty between 2008 and 2021 (p = 0.21). As shown on multivariable regression analysis, trials for devices (HR: 1.63 [95% confidence interval, 1.20 to 2.21]; p = 0.002) and drugs (HR: 1.48 [1.10 to 2.02]; p = 0.013) as well as Phase-2 trials (HR: 1.35 [1.09 to 1.69]; p = 0.010), Phase-3 trials (HR: 1.39 [1.09 to 1.78]; p = 0.010), and Phase-4 trials (HR: 1.44 [1.14 to 1.81]; p = 0.010) had a higher likelihood of early discontinuation. However, pediatric trials were less likely to be discontinued (HR: 0.58 [0.40 to 0.86]; p = 0.007).

CONCLUSIONS

The results of the present study suggest the need for continued efforts to ensure the completion of orthopaedic clinical trials in order to limit publication bias and to employ resources and patient contributions more efficiently for research.

CLINICAL RELEVANCE

Discontinued trials contribute to publication bias, which limits the comprehensiveness of the literature available to support evidence-based patient care interventions. Therefore, identifying the factors associated with and the prevalence of orthopaedic trial discontinuation encourages orthopaedic surgeons to design future trials to be more resistant to early discontinuation.

Why a clinical trial is as good as its outcome measure: A framework for the selection and use of cognitive outcome measures for clinical trials of Alzheimer's disease

A crucial aspect of any clinical trial is using the right outcome measure to assess treatment efficacy. Compared to the rapidly evolved understanding and measurement of pathophysiology in preclinical and early symptomatic stages of Alzheimer's disease (AD), relatively less progress has been made in the evolution of clinical outcome assessments (COAs) for those stages. The current paper aims to provide a benchmark for the design and evaluation of COAs for use in early AD trials. We discuss lessons learned on capturing cognitive changes in predementia stages of AD, including challenges when validating novel COAs for those early stages and necessary evidence for their implementation in clinical trials. Moving forward, we propose a multi-step framework to advance the use of more effective COAs to assess clinically meaningful changes in early AD, which will hopefully contribute to the much-needed consensus around more appropriate outcome measures to assess clinical efficacy of putative treatments. HIGHLIGHTS: We discuss lessons learned on capturing cognitive changes in predementia stages of AD. We propose a framework for the design and evaluation of performance based cognitive tests for use in early AD trials. We provide recommendations to facilitate the implementation of more effective cognitive outcome measures in AD trials.

A novel bio-inspired strategy to prevent amyloidogenesis and synaptic damage in Alzheimer's disease

Alzheimer's disease (AD) is an irreversible neurodegenerative disorder that affects millions of people worldwide. AD pathogenesis is intricate. It primarily involves two main molecular players-amyloid-β (Aβ) and tau-which actually have an intrinsic trend to generate molecular assemblies that are toxic to neurons. Incomplete knowledge of the molecular mechanisms inducing the onset and sustaining the progression of the disease, as well as the lack of valid models to fully recapitulate the pathogenesis of human disease, have until now hampered the development of a successful therapy for AD. The overall experience with clinical trials with a number of potential drugs-including the recent outcomes of studies with monoclonal antibodies against Aβ-seems to indicate that Aβ-targeting is not effective if it is not accompanied by an efficient challenge of Aβ neurotoxic properties. We took advantage from the discovery of a naturally-occurring variant of Aβ (AβA2V) that has anti-amyloidogenic properties, and designed a novel bio-inspired strategy for AD based on the intranasal delivery of a six-mer peptide (Aβ1-6A2V) retaining the anti-amyloidogenic abilities of the full-length AβA2V variant. This approach turned out to be effective in preventing the aggregation of wild type Aβ and averting the synaptic damage associated with amyloidogenesis in a mouse model of AD. The results of our preclinical studies inspired by a protective model already existing in nature, that is the human heterozygous AβA2V carriers which seem to be protected from AD, open the way to an unprecedented and promising approach for the prevention of the disease in humans.

The European Prevention of Alzheimer's Dementia Programme: An Innovative Medicines Initiative-funded partnership to facilitate secondary prevention of Alzheimer's disease dementia

INTRODUCTION

Tens of millions of people worldwide will develop Alzheimer's disease (AD), and only by intervening early in the preclinical disease can we make a fundamental difference to the rates of late-stage disease where clinical symptoms and societal burden manifest. However, collectively utilizing data, samples, and knowledge amassed by large-scale projects such as the Innovative Medicines Initiative (IMI)-funded European Prevention of Alzheimer's Dementia (EPAD) program will enable the research community to learn, adapt, and implement change.

METHOD

In the current article, we define and discuss the substantial assets of the EPAD project for the scientific community, patient population, and industry, describe the EPAD structure with a focus on how the public and private sector interacted and collaborated within the project, reflect how IMI specifically supported the achievements of the above, and conclude with a view for future.

RESULTS

The EPAD project was a €64-million investment to facilitate secondary prevention of AD dementia research. The project recruited over 2,000 research participants into the EPAD longitudinal cohort study (LCS) and included over 400 researchers from 39 partners. The EPAD LCS data and biobank are freely available and easily accessible via the Alzheimer's Disease Data Initiative's (ADDI) AD Workbench platform and the University of Edinburgh's Sample Access Committee. The trial delivery network established within the EPAD program is being incorporated into the truly global offering from the Global Alzheimer's Platform (GAP) for trial delivery, and the almost 100 early-career researchers who were part of the EPAD Academy will take forward their experience and learning from EPAD to the next stage of their careers.

DISCUSSION

Through GAP, IMI-Neuronet, and follow-on funding from the Alzheimer's Association for the data and sample access systems, the EPAD assets will be maintained and, as and when sponsors seek a new platform trial to be established, the learnings from EPAD will ensure that this can be developed to be even more successful than this first pan-European attempt.

Early Discontinuation, Results Reporting, and Publication of Pediatric Clinical Trials

BACKGROUND AND OBJECTIVES

Unique ethical, epidemiological, and economic factors are barriers to performing research in children. The landscape of pediatric clinical trials, including drivers of completion and timely dissemination of results, is not well understood. We aimed to characterize the prevalence of and factors associated with early discontinuation, results reporting, and publication of pediatric clinical trials registered at ClinicalTrials.gov.

METHODS

Cross-sectional analysis of clinical trials enrolling participants <18 years old registered at ClinicalTrials.gov from October 2007 to March 2020. Multivariable logistic regressions were performed to assess the association between trial characteristics and primary outcomes. Publication data were obtained through PubMed, ClinicalTrials.gov, Embase, and Scopus.

RESULTS

Overall, 11.1% trials were stopped early, with recruitment failure being the predominant reason for discontinuation. Only 23.5% of completed trials reported results, and 38.8% were published within 3 years of completion. Rates of discontinuation and publication significantly improved over the study period. Among funding sources, government-sponsored trials (adjusted odds ratio [aOR], 0.72; 95% CI, 0.47-0.97) and academic trials (aOR, 0.64; 95% CI, 0.50-0.82) had lower odds of discontinuation compared with industry trials and were more likely to be published (government: aOR, 1.94 [95% CI, 1.52-2.48] academic: aOR, 1.61 [95% CI, 1.35-1.92). Academic trial investigators were the least likely to report results (aOR, 0.34; 95% CI, 0.31-0.52).

CONCLUSIONS

Early discontinuation and nonreporting/nonpublication of findings remain common in registered pediatric clinical trials and were associated with funding source and other trial features. Targeted efforts are needed to support trial completion and timely results dissemination toward strengthening evidence-based pediatric medicine.

Alzheimer Disease Clinical Trials Targeting Amyloid: Lessons Learned From Success in Mice and Failure in Humans

BACKGROUND

The goal of slowing or halting the development of Alzheimer disease (AD) has resulted in the huge allocation of resources by academic institutions and pharmaceutical companies to the development of new treatments. The etiology of AD is elusive, but the aggregation of amyloid-β and tau peptide and oxidative processes are considered critical pathologic mechanisms. The failure of drugs with multiple mechanisms to meet efficacy outcomes has caused several companies to decide not to pursue further AD studies and has left the field essentially where it has been for the past 15 years. Efforts are underway to develop biomarkers for detection and monitoring of AD using genetic, imaging, and biochemical technology, but this is of minimal use if no intervention can be offered.

REVIEW SUMMARY

In this review, we consider the natural progression of AD and how it continues despite present attempts to modify the amyloid-related machinery to alter the disease trajectory. We describe the mechanisms and approaches to AD treatment targeting amyloid, including both passive and active immunotherapy as well as inhibitors of enzymes in the amyloidogenic pathway.

CONCLUSION

Lessons learned from clinical trials of amyloid reduction strategies may prove crucial for the leap forward toward novel therapeutic targets to treat AD.

Discontinuation and non-publication of heart failure randomized controlled trials: a call to publish all trial results

Aims

Discontinuation or non‐publication of trials may hinder scientific progress and violates the commitment made to research participants. We sought to identify the prevalence of discontinuation and non‐publication of heart failure (HF) clinical trials.

Methods and results

We conducted a cross‐sectional search of ClinicalTrials.gov to identify all completed and discontinued HF clinical trials. We limited our search to only include trials that were completed by 31 December 2017. Trials were investigated to identify reasons for discontinuation. Informative termination was defined as trial termination due to safety or efficacy concerns. Data pertaining to the trial phase, funding, intervention, enrolment, and trial completion date were extracted for each trial. A total of 572 trials were included. Of these, 21% (n = 118) were discontinued before completion. Patient accrual was the most frequently cited reason (n = 42; 36%) for trial discontinuation, followed by informative termination (n = 16; 14%) and funding (n = 14; 12%). Overall, 24 780 patients were enrolled in trials that were terminated. Of trials that were completed and not terminated, nearly one‐third (n = 131/454; 29%) were not published. Seventy‐nine (24%) trials were published within 12 months, 192 (59%) within 24 months, and 252 (78%) trials within 36 months.

Conclusions

Discontinuation and non‐publication of HF trials is common. This raises ethical concerns towards participants who volunteer for research and are exposed to potential risks, inconvenience, and discomfort without furthering scientific progress.

Redundant trials can be prevented, if the EU clinical trial regulation is applied duly

The problem of wasteful clinical trials has been debated relentlessly in the medical community. To a significant extent, it is attributed to redundant trials - studies that are carried out to address questions, which can be answered satisfactorily on the basis of existing knowledge and accessible evidence from prior research. This article presents the first evaluation of the potential of the EU Clinical Trials Regulation 536/2014, which entered into force in 2014 but is expected to become applicable at the end of 2021, to prevent such trials. Having reviewed provisions related to the trial authorisation, we propose how certain regulatory requirements for the assessment of trial applications can and should be interpreted and applied by national research ethics committees and other relevant authorities in order to avoid redundant trials and, most importantly, preclude the unnecessary recruitment of trial participants and their unjustified exposure to health risks.

Smart treatment strategies for alleviating tauopathy and neuroinflammation to improve clinical outcome in Alzheimer's disease

Alzheimer's disease (AD) is a complex neurodegenerative disease leading to progressive loss of memory that mainly affects people above 60 years of age. It is one of the leading causes of deaths in the USA. Given its inherent heterogeneity and a still-incomplete understanding of its pathology, biomarkers, and targets available for therapy, it is a challenge to design an effective therapeutic strategy. Several hypotheses have been proposed to understand the disease and to identify reliable markers and targets for treatments. However, none have resulted in strong support from clinical trials. In this review, we objectively discuss the various therapeutic strategies and mechanistic approaches to improve the current clinical outcome of AD therapy.

The purinergic P2X7 receptor as a potential drug target to combat neuroinflammation in neurodegenerative diseases

Neurodegenerative diseases (NDDs) represent a huge social burden, particularly in Alzheimer's disease (AD) in which all proposed treatments investigated in murine models have failed during clinical trials (CTs). Thus, novel therapeutic strategies remain crucial. Neuroinflammation is a common pathogenic feature of NDDs. As purinergic P2X7 receptors (P2X7Rs) are gatekeepers of inflammation, they could be developed as drug targets for NDDs. Herein, we review this challenging hypothesis and comment on the numerous studies that have investigated P2X7Rs, emphasizing their molecular structure and functions, as well as their role in inflammation. Then, we elaborate on research undertaken in the field of medicinal chemistry to determine potential P2X7R antagonists. Subsequently, we review the state of neuroinflammation and P2X7R expression in the brain, in animal models and patients suffering from AD, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, multiple sclerosis, and retinal degeneration. Next, we summarize the in vivo studies testing the hypothesis that by mitigating neuroinflammation, P2X7R blockers afford neuroprotection, increasing neuroplasticity and neuronal repair in animal models of NDDs. Finally, we reviewed previous and ongoing CTs investigating compounds directed toward targets associated with NDDs; we propose that CTs with P2X7R antagonists should be initiated. Despite the high expectations for putative P2X7Rs antagonists in various central nervous system diseases, the field is moving forward at a relatively slow pace, presumably due to the complexity of P2X7Rs. A better pharmacological approach to combat NDDs would be a dual strategy, combining P2X7R antagonism with drugs targeting a selective pathway in a given NDD.

New approaches for the treatment of Alzheimer's disease

Alzheimer's disease (AD) is the most prevalent chronic neurodegenerative disease. Current approved therapies are symptomatic treatments having some effect on cognitive function. Therapies that target β-amyloid (Aβ) have been the focus of efforts to develop a disease modification treatment for AD but these approaches have failed to show any clinical benefit so far. Beyond the 'Aβ hypothesis', there are a number of newer approaches to treat AD with neuroinflammation emerging as a very active area of research based on risk gene analysis. This short review will summarize approved drug therapies, recent clinical trials and new approaches for the treatment of AD.