OBJECTIVE: large-scale multicentre clinical trials conducted by cooperative groups have generated a lot of evidence to establish better standard treatments. The Clinical Trials Act was enforced on 1 April 2018, in Japan, and it has remarkably increased the operational burden on investigators, but its long-term impact on cancer cooperative groups is unknown.
METHODS: a survey was conducted across the nine major cooperative groups that constitute the Japan Cancer Trials Network to assess the impact of Clinical Trials Act on the number of newly initiated trials from fiscal year (from 1 April to 31 March) 2017 to 2022 and that of ongoing trials on 1 April in each year from 2018 to 2023.
RESULTS: the number of newly initiated trials dropped from 38 trials in fiscal year 2017 to 26 trials in fiscal year 2018, surged to 50 trials in fiscal year 2019, but then gradually decreased to 25 trials by fiscal year 2022. Specified clinical trials decreased from 32 trials in fiscal year 2019 to 12 trials in fiscal year 2022. The number of ongoing trials was 220 trials in 2018, peaked at 245 trials in 2020, but then gradually decreased to 219 trials by 2023. The number of specified clinical trials has been in consistent decline. By April 2023, of the 20 ongoing non-specified clinical trials, nine adhered to Clinical Trials Act and 11 followed the Ethical Guidelines for Medical and Health Research Involving Human Subjects.
CONCLUSIONS: the number of multicentre clinical trials in oncology gradually decreased after the Clinical Trials Act\'s enforcement, which underscores the need for comprehensive amendment of the Clinical Trials Act to streamline the operational process.

BACKGROUND: The provision of data sharing statements (DSS) for clinical trials has been made mandatory by different stakeholders. DSS are a device to clarify whether there is intention to share individual participant data (IPD). What is missing is a detailed assessment of whether DSS are providing clear and understandable information about the conditions for data sharing of IPD for secondary use.
METHODS: A random sample of 200 COVID-19 clinical trials with explicit DSS was drawn from the ECRIN clinical research metadata repository. The DSS were assessed and classified, by two experienced experts and one assessor with less experience in data sharing (DS), into different categories (unclear, no sharing, no plans, yes but vague, yes on request, yes with specified storage location, yes but with complex conditions).
RESULTS: Between the two experts the agreement was moderate to substantial (kappa=0.62, 95% CI [0.55, 0.70]). Agreement considerably decreased when these experts were compared with a third person who was less experienced and trained in data sharing (\"assessor\") (kappa=0.33, 95% CI [0.25, 0.41]; 0.35, 95% CI [0.27, 0.43]). Between the two experts and under supervision of an independent moderator, a consensus was achieved for those cases, where both experts had disagreed, and the result was used as \"gold standard\" for further analysis. At least some degree of willingness of DS (data sharing) was expressed in 63.5% (127/200) cases. Of these cases, around one quarter (31/127) were vague statements of support for data sharing but without useful detail. In around half of the cases (60/127) it was stated that IPD could be obtained by request. Only in in slightly more than 10% of the cases (15/127) it was stated that the IPD would be transferred to a specific data repository. In the remaining cases (21/127), a more complex regime was described or referenced, which could not be allocated to one of the three previous groups. As a result of the consensus meetings, the classification system was updated.
CONCLUSIONS: The study showed that the current DSS that imply possible data sharing are often not easy to interpret, even by relatively experienced staff. Machine based interpretation, which would be necessary for any practical application, is currently not possible. Machine learning and / or natural language processing techniques might improve machine actionability, but would represent a very substantial investment of research effort. The cheaper and easier option would be for data providers, data requestors, funders and platforms to adopt a clearer, more structured and more standardised approach to specifying, providing and collecting DSS.
BACKGROUND: The protocol for the study was pre-registered on ZENODO ( https://zenodo.org/record/7064624#.Y4DIAHbMJD8 ).

OBJECTIVE: To determine whether clinical trial register (CTR) searches can accurately identify a greater number of completed randomized clinical trials (RCTs) than electronic bibliographic database (EBD) searches for systematic reviews of interventions, and to quantify the number of eligible ongoing trials.
METHODS: We performed an evaluation study and based our search for RCTs on the eligibility criteria of a systematic review that focused on the underrepresentation of people with chronic kidney disease in cardiovascular RCTs. We conducted a combined search of ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform through the Cochrane Central Register of Controlled Trials to identify eligible RCTs registered up to June 1, 2023. We searched Cochrane Central Register of Controlled Trials, EMBASE, and MEDLINE for publications of eligible RCTs published up to June 5, 2023. Finally, we compared the search results to determine the extent to which the two sources identified the same RCTs.
RESULTS: We included 92 completed RCTs. Of these, 81 had results available. Sixty-six completed RCTs with available results were identified by both sources (81% agreement [95% CI: 71-88]). We identified seven completed RCTs with results exclusively by CTR search (9% [95% CI: 4-17]) and eight exclusively by EBD search (10% [95% CI: 5-18]). Eleven RCTs were completed but lacked results (four identified by both sources (36% [95% CI: 15-65]), one exclusively by EBD search (9% [95% CI: 1-38]), and six exclusively by CTR search (55% [95% CI: 28-79])). Also, we identified 42 eligible ongoing RCTs: 16 by both sources (38% [95% CI: 25-53]) and 26 exclusively by CTR search (62% [95% CI: 47-75]). Lastly, we identified four RCTs of unknown status by both sources.
CONCLUSIONS: CTR searches identify a greater number of completed RCTs than EBD searches. Both searches missed some included RCTs. Based on our case study, researchers (eg, information specialists, systematic reviewers) aiming to identify all available RCTs should continue to search both sources. Once the barriers to performing CTR searches alone are targeted, CTR searches may be a suitable alternative.

UNASSIGNED: Selective publication of studies has important scientific, ethical, and public health implications.
UNASSIGNED: We studied selective publication among mood disorder research protocols registered in the Clinical Trials Registry of India (CTRI) database. We also examined the frequency and nature of protocol deviations among the published articles.
UNASSIGNED: Using a systematic search strategy, we examined the publication status of all mood disorder-related research protocols registered in the CTRI database from inception till December 31, 2019. Logistic regression analysis was used to identify variables associated with selective publication.
UNASSIGNED: Of 129 eligible protocols identified, only a third (n = 43, 33.3%) were published in literature; among those published, only 28 (21.7%) were placed in MEDLINE indexed journals. Protocol deviations were observed in more than half of the published papers (n = 25, 58.1%); many of these (41.9%) were related to sample size deviations, though, importantly, deviations in primary and secondary outcomes were also noted (16.2%). Retrospective registration of trials (odds ratio, 2.98, 95% confidence interval, 1.32-6.71) was significantly associated with publication; other variables, such as funding status or multicentric sampling, were not associated with eventual publication.
UNASSIGNED: Two out of three mood disorder research protocols registered in India do not translate into published research. These findings from a low- and middle-income country with limited spending on health care research and development represent wastage of resources and raise scientific and ethical concerns about unpublished data and futile patient participation in research.

Publication bias is a major concern in conducting systematic reviews and meta-analyses. Various sensitivity analysis or bias-correction methods have been developed based on selection models, and they have some advantages over the widely used trim-and-fill bias-correction method. However, likelihood methods based on selection models may have difficulty in obtaining precise estimates and reasonable confidence intervals, or require a rather complicated sensitivity analysis process. Herein, we develop a simple publication bias adjustment method by utilizing the information on conducted but still unpublished trials from clinical trial registries. We introduce an estimating equation for parameter estimation in the selection function by regarding the publication bias issue as a missing data problem under the missing not at random assumption. With the estimated selection function, we introduce the inverse probability weighting (IPW) method to estimate the overall mean across studies. Furthermore, the IPW versions of heterogeneity measures such as the between-study variance and the I2 measure are proposed. We propose methods to construct confidence intervals based on asymptotic normal approximation as well as on parametric bootstrap. Through numerical experiments, we observed that the estimators successfully eliminated bias, and the confidence intervals had empirical coverage probabilities close to the nominal level. On the other hand, the confidence interval based on asymptotic normal approximation is much wider in some scenarios than the bootstrap confidence interval. Therefore, the latter is recommended for practical use.

BACKGROUND: Rotavirus is a primary infectious virus causing childhood diarrhoea and is associated with significant mortality in children. Three African countries (Nigeria, the Democratic Republic of Congo, and Angola) are among the five countries that account for 50% of all diarrheal-related deaths worldwide. This indicates that much needs to be done to reduce this burden. The World Health Organization International Clinical Trial Registry Platform (WHO ICTRP) is a global repository for primary registries reporting on clinical trials. This study aimed to identify and describe planned, ongoing, and completed rotavirus vaccine trials conducted globally.
METHODS: We searched WHO-ICTRP on 17 June 2021 and conducted a cross-sectional analysis of rotavirus studies listed in the database. Data extraction included trial location, participant age, source of the trial record, trial phase, sponsor, and availability of results. We used the Microsoft Excel 365 package to generate descriptive summary statistics.
RESULTS: We identified 242 rotavirus vaccine trials registered from 2004 to 2020. Most of these trials were registered retrospectively, with only 26% of the rotavirus vaccine trials reporting the availability of results in their registries. Most of the trials are studying children aged less than 5 years. The recruitment status for these trials is currently shown in the WHO-ICTRP as \"not recruiting\" for 80.17% of trials, \"recruiting\" for 11.57% of trials recruiting, and unknown for 6.61% of trials. The continents in which these rotavirus vaccine trials have recruitment sites in Asia (41%) and North America (20%), with the maximum number of trials in the clinical trial registries coming from India (21%) and the USA (11%) with most being sponsored by the pharmaceutical industry. Our analysis shows that only 26% of the rotavirus vaccine trials report the availability of results in their registries.
CONCLUSIONS: Mapping rotavirus vaccine clinical trial activity using data from the WHO ICTRP beneficial provides valuable information on planned, ongoing, or completed trials for researchers, funders, and healthcare decision-makers. Despite the high rotavirus disease burden in low- and middle-income countries, including Africa, there is minimal clinical trial activity related to the condition on the continent. The clinical trial registries as a valuable tool to share interim results of the trials.

Driven by the use cases of PubChemRDF and SCAIView, we have developed a first community-based clinical trial ontology (CTO) by following the OBO Foundry principles. CTO uses the Basic Formal Ontology (BFO) as the top level ontology and reuses many terms from existing ontologies. CTO has also defined many clinical trial-specific terms. The general CTO design pattern is based on the PICO framework together with two applications. First, the PubChemRDF use case demonstrates how a drug Gleevec is linked to multiple clinical trials investigating Gleevec\'s related chemical compounds. Second, the SCAIView text mining engine shows how the use of CTO terms in its search algorithm can identify publications referring to COVID-19-related clinical trials. Future opportunities and challenges are discussed.

UNASSIGNED: Clinical trials (CTs) are research investigations in which participants receive medical treatments, interventions, or tests to assess their safety and efficacy. Each planned clinical is registered through local or national medical agencies, which may differ in the amount of administrative and legal procedures. The objective of this study was to systematically analyze the registration process for clinical trials in Bosnia and Herzegovina in comparison to other Balkan countries.
UNASSIGNED: The search strategy was based using two online databases: Clinicaltrials.gov (CTGR) and Cortellis Clinical Trials Intelligence (cTi). Search engines included studies until 26th April 2021 and countries were compared in terms of the number of studies, status, type, funding, clinical phases and demographic data.
UNASSIGNED: The total number of clinical trials from Bosnia and Herzegovina recorded in the CTGR database was 219, while the cTi database comprised 254 registered studies. The total number of reported clinical trials in CTGR and cTi databases were highest in Serbia (n = 1229, n = 1438), followed by Croatia (n = 1142, n = 1300), and Slovenia (n = 801, n = 948), respectively. However, the highest number of clinical trials per capita is in Slovenia (3.85e-4 in CTGR; 4.56e-4 in cTi), followed by Croatia (2.78e-4 in CTGR; 3.17e-4 in cTi), Serbia (1.41e-4 in CTGR; 1.65e-4 in cTi), and Bosnia and Herzegovina (0.67e-4 CTGR; 0.78e-4 cTi).
UNASSIGNED: Our analysis showed that Bosnia has the lowest number of clinical trials in the Balkans. Furthermore, the registration process is complex and longer than in developed countries. Since the healthcare system has been in a transition in the past decade, clinical trials are underutilized as a tool for the improvement of patient care. The clinical trial registration process could be improved by establishing an ethical committee at the state level and by enabling a parallel submission process to ethical committees and databases.

BACKGROUND: Previous analysis of registered clinical trials has found a number of protocols result in changes in the registered primary outcome measures. This investigation determined if reported primary outcomes in chiropractic-related clinical trials registered in clinicaltrials.gov match their published results. Additionally, we assessed secondary outcomes, publication status and whether raw data were posted to the registry.
METHODS: Clinicaltrials.gov was searched for chiropractic-related trials and having a completed status. If the study was published, outcome measures were compared between the clinicaltrials.gov entry and the published paper to assess for consistency.
RESULTS: Within clinicaltrials.gov 171 chiropracticrelated protocols were identified with 102 of those published (59.6% publication rate). Ninety-two of the published papers (90.2%) had agreement between their primary outcome and the entry on clinicaltrials.gov and 82 (80.4%) agreed with the secondary outcomes.
CONCLUSIONS: A modest rate of agreement between clinicaltrials.gov entries and the published papers was found. While chiropractic-related clinical trials are fewer compared to medical trials, chiropractic-related research has a substantially better rate of primary and secondary outcome concordance with registered protocols.
BACKGROUND: En examinant des essais cliniques enregistrés, on s’est rendu compte qu’un certain nombre de protocoles faisaient varier les résultats principaux. On a mené une étude pour savoir si les résultats primaires d’essais cliniques sur la chiropratique enregistrés sur clinicaltrials.gov correspondaient à ceux publiés. On a aussi examiné les résultats secondaires, l’état de publication et cherché à savoir si les données brutes étaient publiées dans le registre.
UNASSIGNED: Dans la base de données Clinicaltrials.gov, on a repéré des essais cliniques sur la chiropratique qui étaient terminés. Lorsque l’essai clinique avait été publié, on a comparé les résultats au moment de son enregistrement sur clinicaltrials.gov à ceux parus dans des publications pour savoir s’ils concordaient.
UNASSIGNED: Sur le site clinicaltrials.gov, on a trouvé 171 études sur la chiropratique, dont 102 avaient été publiés (taux de publication:59,6 %). Pour quatrevingt-douze publications (90,2 %), on a observé une concordance entre les résultats primaires au moment de l’enregistrement sur clinicaltrials.gov et 82 (80,4 %) et les résultats secondaires.
CONCLUSIONS: On a observé un taux modeste de concordance entre les données à l’enregistrement sur clinicaltrails.gov et les données publiées. Les essais cliniques sur la chiropratique sont moins nombreux que des essais cliniques de médicaments. Mais le taux de concordance entre les résultats primaires et les résultats secondaires était considérablement plus élevé lorsque les protocoles de recherches sur la chiropratique sont enregistrés.

BACKGROUND: The characteristics and comparison of countries regarding clinical trials for cancer were unknown. The World Health Organization-International Clinical Trials Registry Platform (WHO-ICTRP) are providing data from various countries and releases them generally in a downloadable format. We aimed to examine and descriptively identify the number of cancer clinical trials registered in the world and the fundamental characteristics in Asian 4 countries of China, India, Japan and South Korea, focusing on study characteristics, e.g., phase or targeted size, using the WHO-ICTRP.
METHODS: We extracted information on cancer clinical studies in the ICTRP database on September 20, 2019. Then, we performed a cross-sectional study on the annual number of registered studies and country, registered registry, phase, target sizes and sponsors.
RESULTS: We identified 80,677 cancer clinical studies. The annual number of registered cancer clinical studies significantly increased between 2005 and 2018 (3,172 to 8,156, β =382.2, 95% CI: 329.6, 434.8). Among the Asian 4 countries, the numbers of trials were significantly increasing in 2005-2018 (P<0.001). The characteristics on interventional studies for cancer differed in those 4 countries, e.g., the registered registries, phase and sponsors, compared with the US.
CONCLUSIONS: This study descriptively clarified an increase and the characteristics of cancer clinical trials in Asian 4 countries. It suggests to take that characteristics into account and select a database or data source discreetly for analysis of clinical trials, according to the purpose of the research and the required data.