Underregistration and Underreporting of Stem Cell Clinical Trials in Neurological Disorders

Time to publication for results of clinical trials

BACKGROUND

Researchers conducting trials have a responsibility to publish the results of their work in a peer-reviewed journal, and failure to do so may introduce bias that affects the accuracy of available evidence. Moreover, failure to publish results constitutes research waste.

OBJECTIVES

To systematically review research reports that followed clinical trials from their inception and their investigated publication rates and time to publication. We also aimed to assess whether certain factors influenced publication and time to publication.

SEARCH METHODS

We identified studies by searching MEDLINE, Embase, Epistemonikos, the Cochrane Methodology Register (CMR) and the database of the US Agency for Healthcare Research and Quality (AHRQ), from inception to 23 August 2023. We also checked reference lists of relevant studies and contacted experts in the field for any additional studies.

SELECTION CRITERIA

Studies were eligible if they tracked the publication of a cohort of clinical trials and contained analyses of any aspect of the publication rate or time to publication of these trials.

DATA COLLECTION AND ANALYSIS

Two review authors performed data extraction independently. We extracted data on the prevalence of publication and the time from the trial start date or completion date to publication. We also extracted data from the clinical trials included in the research reports, including country of the study's first author, area of health care, means by which the publication status of these trials were sought and the risk of bias in the trials.

MAIN RESULTS

A total of 204 research reports tracking 165,135 trials met the inclusion criteria. Just over half (53%) of these trials were published in full. The median time to publication was approximately 4.8 years from the enrolment of the first trial participant and 2.1 years from the trial completion date. Trials with positive results (i.e. statistically significant results favouring the experimental arm) were more likely to be published than those with negative or null results (OR 2.69, 95% CI 2.02 to 3.60; 19 studies), and they were published in a shorter time (adjusted HR 1.92, 95% CI 1.51 to 2.45; 4 studies). On average, trials with positive results took 2 years to publish, whereas trials with negative or null results took 2.6 years. Large trials were more likely to be published than smaller ones (adjusted OR 1.92, 95% CI 1.33 to 2.77; 11 studies), and they were published in a shorter time (adjusted HR 1.41, 95% CI 1.18 to 1.68; 7 studies). Multicentre trials were more likely to be published than single-centre trials (adjusted OR 1.20, 95% CI 1.03 to 1.40; 2 studies). We found no difference between multicentre and single-centre trials in time to publication. Trials funded by non-industry sources (e.g.governments or universities) were more likely to be published than trials funded by industry (e.g. pharmaceutical companies or for-profit organisations) (adjusted OR 2.13, 95% CI 1.82 to 2.49; 14 studies); they were also published in a shorter time (adjusted HR 1.46, 95% CI 1.15 to 1.86; 7 studies).

AUTHORS' CONCLUSIONS

Our updated review shows that trial publication is poor, with only half of all trials that are conducted being published. Factors that may make publication more likely and lead to faster publication are positive results, large sample size and being funded by non-industry sources. Differences in publication rates result in publication bias and time-lag bias that may influence findings and therefore ultimately affect treatment decisions. Systematic review authors should consider the possibility of time-lag bias when conducting a systematic review, especially when updating their review.

FUNDING

This Cochrane review had no dedicated funding.

REGISTRATION

This review combines and updates two earlier Cochrane reviews. The two protocols and previous versions of the two updated reviews are available via 10.1002/14651858.MR000006 and 10.1002/14651858.MR000006.pub3 and 10.1002/14651858.MR000011 and 10.1002/14651858.MR000011.pub2.

Future Perspectives in Spinal Cord Repair: Brain as Saviour? TSCI with Concurrent TBI: Pathophysiological Interaction and Impact on MSC Treatment

Traumatic spinal cord injury (TSCI), commonly caused by high energy trauma in young active patients, is frequently accompanied by traumatic brain injury (TBI). Although combined trauma results in inferior clinical outcomes and a higher mortality rate, the understanding of the pathophysiological interaction of co-occurring TSCI and TBI remains limited. This review provides a detailed overview of the local and systemic alterations due to TSCI and TBI, which severely affect the autonomic and sensory nervous system, immune response, the blood-brain and spinal cord barrier, local perfusion, endocrine homeostasis, posttraumatic metabolism, and circadian rhythm. Because currently developed mesenchymal stem cell (MSC)-based therapeutic strategies for TSCI provide only mild benefit, this review raises awareness of the impact of TSCI-TBI interaction on TSCI pathophysiology and MSC treatment. Therefore, we propose that unravelling the underlying pathophysiology of TSCI with concomitant TBI will reveal promising pharmacological targets and therapeutic strategies for regenerative therapies, further improving MSC therapy.

Cell Therapies for Spinal Cord Injury: Trends and Challenges of Current Clinical Trials

Cell therapies have the potential to revolutionize the treatment of spinal cord injury. Basic research has progressed significantly in recent years, with a plethora of cell types now reaching early-phase human clinical trials, offering new strategies to repair the spinal cord. However, despite initial enthusiasm for preclinical and early-phase clinical trials, there has been a notable hiatus in the translation of cell therapies to routine clinical practice. Here, we review cell therapies that have reached clinical trials for spinal cord injury, providing a snapshot of all registered human trials and a summary of all published studies. Of registered trials, the majority have used autologous cells and approximately a third have been government funded, a third industry sponsored, and a third funded by university or healthcare systems. A total of 37 cell therapy trials have been published, primarily using stem cells, although a smaller number have used Schwann cells or olfactory ensheathing cells. Significant challenges remain for cell therapy trials in this area, including achieving stringent regulatory standards, ensuring appropriately powered efficacy trials, and establishing sustainable long-term funding. However, cell therapies hold great promise for human spinal cord repair and future trials must continue to capitalize on the exciting developments emerging from preclinical studies.

Clinical Trial Registration and Reporting: Drug Therapy and Prevention of Cardiac-Related Infections

Objective: Clinical trials are the source of evidence. ClinicalTrials.gov is valuable for analyzing current conditions. Until now, the state of drug interventions for heart infections is unknown. The purpose of this study was to comprehensively assess the characteristics of trials on cardiac-related infections and the status of drug interventions.

Methods: The website ClinicalTrials.gov was used to obtain all registered clinical trials on drug interventions for cardiac-related infections as of February 16, 2019. All registration studies were collected, regardless of their recruitment status, research results, and research type. Registration information, results, and weblink-publications of those trials were analyzed.

Results: A total of 45 eligible trials were evaluated and 86.7% of them began from or after 2008 while 91.1% of them adopted interventional study design. Of all trials, 35.6% were completed and 15.6% terminated. Besides, 62.2% of interventional clinical trials recruited more than 100 subjects. Meanwhile, 86.7% of the eligible trials included adult subjects only. Of intervention trials, 65.8% were in the third or fourth phase; 78.1% adopted randomized parallel assignment, containing two groups; 53.6% were masking, and 61.0% described treatment. Moreover, 41.5% of the trials were conducted in North America while 29.3% in Europe. Sponsors for 40.0% of the studies were from the industry. Furthermore, 48.9% of the trials mentioned information on monitoring committees, 24.4% have been published online, and 13.3% have uploaded their results. Drugs for treatments mainly contained antibiotics, among which glycopeptides, β-lactams, and lipopeptides were the most commonly studied ones in experimental group, with the former ones more common. Additionally, 16.2% of the trials evaluated new antimicrobials.

Conclusions: Most clinical trials on cardiac-related infections registered at ClinicalTrials.gov were interventional randomized controlled trials (RCTs) for treatment. Most drugs focused in trials were old antibiotics, and few trials reported valid results. It is necessary to strengthen supervision over improvements in results, and to combine antibacterial activity with drug delivery regimens to achieve optimal clinical outcomes.

Wharton's Jelly Mesenchymal Stem Cell Administration Improves Quality of Life and Self-Sufficiency in Children with Cerebral Palsy: Results from a Retrospective Study

The aim of this paper was to describe the outcome of the therapeutic administration of allogenic mesenchymal stem cells obtained from Wharton's jelly (WJ-MSCs) in children with cerebral palsy (CP) during a medical therapeutic experiment. We retrospectively analyzed the records of 109 patients recruited in daily clinical practice. Each patient received 1-10 injections and was examined by the same neurologist (study investigator (SI)) on the day of each infusion. The SI used a 6-point Likert scale to assess the quality of life (QoL) and self-sufficiency of the patients on the basis of the neurological examination. Children with >50% follow-ups after this administration were included into the quantitative analysis. In addition, the assessments of the parents and other health care professionals were obtained for 23 patients and compared with those of the SI. Forty-eight of 54 analyzed patients (88.9%) achieved some improvement in health status. Forty-eight (88.9%) patients experienced an increase in their QoL, and 21 patients (38.9%) achieved an increase in their self-sufficiency level. Improvement was achieved in 17 areas. Adverse events were mild and temporary except one case of epilepsy deterioration leading to treatment discontinuation. Age, body mass, and cell dose were not significant predictors of QoL response, contrary to epilepsy; developmental breakthrough was dose-dependent.