Registration of clinical trials still moving ahead--September 2008 update to Uniform Requirements for Manuscripts Submitted to Biomedical Journals

Fifteen Years of Clinical Trials in Huntington's Disease: A Very Low Clinical Drug Development Success Rate

BACKGROUND

Drug development in Huntington's disease (HD) is particularly challenging, and only two compounds are approved by the FDA. It is therefore essential to appraise drug development programs in order to understand the reasons for their failure during the early stages of development.

OBJECTIVES

To describe the landscape of HD therapeutic development and critically explore the causes of compound attrition in the different stages of drug development, from phase 1 to phase 4.

METHODS

All HD clinical trials registered in the WHO International Clinical Trials Search Portal, from inception to May 2017, were analyzed. Two independent authors selected and extracted data. Success rate in a trial phase was calculated as the number of compounds that progressed to the next trial phase divided by the number of compounds in that phase. The overall success rate was calculated as the ratio between the number of compounds that receive regulatory approval and the total number of compounds.

RESULTS

Ninety-nine trials assessing 41 compounds and eleven non-pharmacological interventions (devices and cell therapies) were identified. Twenty-four (24.2%) were phase 1 trials, 46 (46.5%) phase 2, 20 (20.2%) phase 3, and two (2.0%) phase 4. Sixty trials (60.6%) received industry sponsorship. The most frequently studied compounds were creatine, latrepirdine and pridopidine. The mean number of participants enrolled was 92.0 and the length of treatment was 262.9 days, and both increased from phase 1 to phase 3 trials. The success rate was 25.0% from phase 1 to phase 2, 19.4% from phase 2 to phase 3, and 14.3% from phase 3 to approval. The overall success rate was 3.5%.

CONCLUSIONS

Although HD is a rare condition, 99 HD trials were identified in a comprehensive clinical trial registry. We found a low success rate at earlier phases of drug-development and a very low trial success rate at later phases. There is a significant gap between drug discovery and development success rates that warrants careful appraisal and improvement.

Linking ClinicalTrials.gov and PubMed to track results of interventional human clinical trials

Objective

In an effort to understand how results of human clinical trials are made public, we analyze a large set of clinical trials registered at ClinicalTrials.gov, the world’s largest clinical trial registry.

Materials and Methods

We considered two trial result artifacts: (1) existence of a trial result journal article that is formally linked to a registered trial or (2) the deposition of a trial’s basic summary results within the registry.

Results

The study sample consisted of 8907 completed, interventional, phase 2-or-higher clinical trials that were completed in 2006-2009. The majority of trials (72.2%) had no structured trial-article link present. Atotal of 2367 trials (26.6%) deposited basic summary results within the registry. Ofthose, 969 trials (10.9%) were classified as trials with extended results and 1398 trials (15.7%) were classified as trials with only required basic results. The majority of the trials (54.8%) had no evidence of results, based on either linked result articles or basic summary results (silent trials), while a minimal number (9.2%) report results through both registry deposition and publication.

Discussion

Our study analyzes the body of linked knowledge around clinical trials (which we refer to as the “trialome”). Our results show that most trials do not report results and, for those that do, there is minimal overlap in the types of reporting. We identify several mechanisms by which the linkages between trials and their published results can be increased.

Conclusion

Our study shows that even when combining publications and registry results, and despite availability of several information channels, trial sponsors do not sufficiently meet the mandate to inform the public either via a linked result publication or basic results submission.

Evaluating adherence to the International Committee of Medical Journal Editors' policy of mandatory, timely clinical trial registration

OBJECTIVE

To determine whether two specific criteria in Uniform Requirements for Manuscripts (URM) created by the International Committee of Medical Journal Editors (ICMJE)--namely, including the trial ID registration within manuscripts and timely registration of trials, are being followed.

MATERIALS AND METHODS

Observational study using computerized analysis of publicly available Medline article data and clinical trial registry data. We analyzed a purposive set of five ICMJE founding journals looking at all trial articles published in those journals during 2010-2011, and data from the ClinicalTrials.gov (CTG) trial registry. We measured adherence to trial ID inclusion policy as the percentage of trial journal articles that contained a valid trial ID within the article (journal-based sample). Adherence to timely registration was measured as the percentage of trials that registered the trial before enrolling the first participant within a 60-day grace period. We also examined timely registration rates by year of all phase II and higher interventional trials in CTG (registry-based sample).

RESULTS

To determine trial ID inclusion, we analyzed 698 clinical trial articles in five journals. A total of 95.8% (661/690) of trial journal articles included the trial ID. In 88.3% the trial-article link is stored within a structured Medline field. To evaluate timely registration, we analyzed trials referenced by 451 articles from the selected five journals. A total of 60% (272/451) of articles were registered in a timely manner with an improving trend for trials initiated in later years (eg, 89% of trials that began in 2008 were registered in a timely manner). In the registry-based sample, the timely registration rates ranged from 56% for trials registered in 2006 to 72% for trials registered in 2011.

DISCUSSION

Adherence to URM requirements for registration and trial ID inclusion increases the utility of PubMed and links it in an important way to clinical trial repositories. This new integrated knowledge source can facilitate research prioritization, clinical guidelines creation, and precision medicine.

CONCLUSIONS

The five selected journals adhere well to the policy of mandatory trial registration and also outperform the registry in adherence to timely registration. ICMJE's URM policy represents a unique international mandate that may be providing a powerful incentive for sponsors and investigators to document clinical trials and trial result publications and thus fulfill important obligations to trial participants and society.

Precision and negative predictive value of links between ClinicalTrials.gov and PubMed

One of the goals of translational science is to shorten the time from discovery to clinical use. Clinical trial registries were established to increase transparency in completed and ongoing clinical trials, and they support linking trials with resulting publications. We set out to investigate precision and negative predictive value (NPV) of links between ClinicalTrials.gov (CT.gov) and PubMed. CT.gov has been established to increase transparency in clinical trials and the link to PubMed is crucial for supporting a number of important functions, including ascertaining publication bias. We drew a random sample of trials downloaded from CT.gov and performed manual review of retrieved publications. We characterize two types of links between trials and publications (NCT-link originating from MEDLINE and PMID-link originating from CT.gov).The link precision is different based on type (NCT-link: 100%; PMID-link: 63% to 96%). In trials with no linked publication, we were able to find publications 44% of the time (NPV=56%) by searching PubMed. This low NPV shows that there are potentially numerous publications that should have been formally linked with the trials. Our results indicate that existing trial registry and publisher policies may not be fully enforced. We suggest some automated methods for improving link quality.

Completeness and changes in registered data and reporting bias of randomized controlled trials in ICMJE journals after trial registration policy

Objective

We assessed the adequacy of randomized controlled trial (RCT) registration, changes to registration data and reporting completeness for articles in ICMJE journals during 2.5 years after registration requirement policy.

Methods

For a set of 149 reports of 152 RCTs with ClinicalTrials.gov registration number, published from September 2005 to April 2008, we evaluated the completeness of 9 items from WHO 20-item Minimum Data Set relevant for assessing trial quality. We also assessed changes to the registration elements at the Archive site of ClinicalTrials.gov and compared published and registry data.

Results

RCTs were mostly registered before 13 September 2005 deadline (n = 101, 66.4%); 118 (77.6%) started recruitment before and 31 (20.4%) after registration. At the time of registration, 152 RCTs had a total of 224 missing registry fields, most commonly ‘Key secondary outcomes’ (44.1% RCTs) and ‘Primary outcome’ (38.8%). More RCTs with post-registration recruitment had missing Minimum Data Set items than RCTs with pre-registration recruitment: 57/118 (48.3%) vs. 24/31 (77.4%) (χ²₁ = 7.255, P = 0.007). Major changes in the data entries were found for 31 (25.2%) RCTs. The number of RCTs with differences between registered and published data ranged from 21 (13.8%) for Study type to 118 (77.6%) for Target sample size.

Conclusions

ICMJE journals published RCTs with proper registration but the registration data were often not adequate, underwent substantial changes in the registry over time and differed in registered and published data. Editors need to establish quality control procedures in the journals so that they continue to contribute to the increased transparency of clinical trials.

Reporting of methodologic information on trial registries for quality assessment: a study of trial records retrieved from the WHO search portal

Background

Although randomized clinical trials (RCTs) are considered the gold standard of evidence, their reporting is often suboptimal. Trial registries have the potential to contribute important methodologic information for critical appraisal of study results.

Methods and Findings

The objective of the study was to evaluate the reporting of key methodologic study characteristics in trial registries. We identified a random sample (n = 265) of actively recruiting RCTs using the World Health Organization International Clinical Trials Registry Platform (ICTRP) search portal in 2008. We assessed the reporting of relevant domains from the Cochrane Collaboration's ‘Risk of bias’ tool and other key methodological aspects. Our primary outcomes were the proportion of registry records with adequate reporting of random sequence generation, allocation concealment, blinding, and trial outcomes. Two reviewers independently assessed each record. Weighted overall proportions in the ICTRP search portal for adequate reporting of sequence generation, allocation concealment, blinding (including and excluding open label RCT) and primary outcomes were 5.7% (95% CI 3.0–8.4%), 1.4% (0–2.8%), 41% (35–47%), 8.4% (4.1–13%), and 66% (60–72%), respectively. The proportion of adequately reported RCTs was higher for registries that used specific methodological fields for describing methods of randomization and allocation concealment compared to registries that did not. Concerning other key methodological aspects, weighted overall proportions of RCTs with adequately reported items were as follows: eligibility criteria (81%), secondary outcomes (46%), harm (5%) follow-up duration (62%), description of the interventions (53%) and sample size calculation (1%).

Conclusions

Trial registries currently contain limited methodologic information about registered RCTs. In order to permit adequate critical appraisal of trial results reported in journals and registries, trial registries should consider requesting details on key RCT methods to complement journal publications. Full protocols remain the most comprehensive source of methodologic information and should be made publicly available.