Medicine. Moving toward transparency of clinical trials

Public availability of results of observational studies evaluating an intervention registered at ClinicalTrials.gov

BACKGROUND

Observational studies are essential for assessing safety. The aims of this study were to evaluate whether results of observational studies evaluating an intervention with safety outcome(s) registered at ClinicalTrials.gov were published and, if not, whether they were available through posting on ClinicalTrials.gov or the sponsor website.

METHODS

We identified a cohort of observational studies with safety outcome(s) registered on ClinicalTrials.gov after October 1, 2007, and completed between October 1, 2007, and December 31, 2011. We systematically searched PubMed for a publication, as well as ClinicalTrials.gov and the sponsor website for results. The main outcomes were the time to the first publication in journals and to the first public availability of the study results (i.e. published or posted on ClinicalTrials.gov or the sponsor website). For all studies with results publicly available, we evaluated the completeness of reporting (i.e. reported with the number of events per arm) of safety outcomes.

RESULTS

We identified 489 studies; 334 (68%) were partially or completely funded by industry. Results for only 189 (39%, i.e. 65% of the total target number of participants) were published at least 30 months after the study completion. When searching other data sources, we obtained the results for 53% (n = 158; i.e. 93% of the total target number of participants) of unpublished studies; 31% (n = 94) were posted on ClinicalTrials.gov and 21% (n = 64) on the sponsor website. As compared with non-industry-funded studies, industry-funded study results were less likely to be published but not less likely to be publicly available. Of the 242 studies with a primary outcome recorded as a safety issue, all these outcomes were adequately reported in 86% (114/133) when available in a publication, 91% (62/68) when available on ClinicalTrials.gov, and 80% (33/41) when available on the sponsor website.

CONCLUSIONS

Only 39% of observational studies evaluating an intervention with safety outcome(s) registered at ClinicalTrials.gov had their results published at least 30 months after study completion. The registration of these observational studies allowed searching other sources (results posted at ClinicalTrials.gov and sponsor website) and obtaining results for half of unpublished studies and 93% of the total target number of participants.

Sharing Individual Participant Data (IPD) within the Context of the Trial Reporting System (TRS)

Deborah Zarin and Tony Tse of ClinicalTrials.Gov consider how sharing individual participant data can and cannot help improve the reporting of clinical trials.

Analysis of 473 US Head and Neck Cancer Trials (1996-2014): Trends, Gaps, and Opportunities

OBJECTIVE

To report on types of investigations being conducted in US clinical trials, the types of therapeutic investigations that predominate, and the publication rates.

STUDY DESIGN

Retrospective analysis.

SETTINGS

US head and neck cancer clinical trials.

SUBJECTS AND METHODS

We used the information available on ClinicalTrials.gov to identify trends in head and neck squamous cell carcinoma clinical trials to characterize the types of trials and treatments being investigated. The publication rate for these trials was also examined with PubMed.gov.

RESULTS

Of the 473 trials analyzed, similar drug regimens have been used repeatedly in head and neck cancer clinical trials. Drug studies are highly represented, composing 62% of all trials. The most common drugs studied were cisplatin, cetuximab, and docetaxel. Among all head and neck cancer clinical trials, 33% included radiation therapy in their treatment, while 10% included a surgical component. Forty-nine percent of trials had their results published in a medical journal, and 70% of the publications reported positive results.

CONCLUSION

Head and neck cancer trials are heavily weighted toward drug trials and demonstrate redundancy. Other therapies are underrepresented, especially surgery. There is a gap between the trials conducted and the rate of reporting, with an emphasis on positive results. Better balance in studying treatment modalities, less redundancy in clinical trials, and reporting all results have potential benefits for head and neck cancer and the public good.

From Protocols to Publications: A Study in Selective Reporting of Outcomes in Randomized Trials in Oncology

PURPOSE

The decision by journals to append protocols to published reports of randomized trials was a landmark event in clinical trial reporting. However, limited information is available on how this initiative effected transparency and selective reporting of clinical trial data.

METHODS

We analyzed 74 oncology-based randomized trials published in Journal of Clinical Oncology, the New England Journal of Medicine, and The Lancet in 2012. To ascertain integrity of reporting, we compared published reports with their respective appended protocols with regard to primary end points, nonprimary end points, unplanned end points, and unplanned analyses.

RESULTS

A total of 86 primary end points were reported in 74 randomized trials; nine trials had greater than one primary end point. Nine trials (12.2%) had some discrepancy between their planned and published primary end points. A total of 579 nonprimary end points (median, seven per trial) were planned, of which 373 (64.4%; median, five per trial) were reported. A significant positive correlation was found between the number of planned and nonreported nonprimary end points (Spearman r = 0.66; P < .001). Twenty-eight studies (37.8%) reported a total of 65 unplanned end points; 52 (80.0%) of which were not identified as unplanned. Thirty-one (41.9%) and 19 (25.7%) of 74 trials reported a total of 52 unplanned analyses involving primary end points and 33 unplanned analyses involving nonprimary end points, respectively. Studies reported positive unplanned end points and unplanned analyses more frequently than negative outcomes in abstracts (unplanned end points odds ratio, 6.8; P = .002; unplanned analyses odd ratio, 8.4; P = .007).

CONCLUSION

Despite public and reviewer access to protocols, selective outcome reporting persists and is a major concern in the reporting of randomized clinical trials. To foster credible evidence-based medicine, additional initiatives are needed to minimize selective reporting.

Guidelines for the Reporting of Treatment Trials for Alcohol Use Disorders

BACKGROUND

The primary goals in conducting clinical trials of treatments for alcohol use disorders (AUDs) are to identify efficacious treatments and determine which treatments are most efficacious for which patients. Accurate reporting of study design features and results is imperative to enable readers of research reports to evaluate to what extent a study has achieved these goals. Guidance on quality of clinical trial reporting has evolved substantially over the past 2 decades, primarily through the publication and widespread adoption of the Consolidated Standards of Reporting Trials statement. However, there is room to improve the adoption of those standards in reporting the design and findings of treatment trials for AUD.

METHODS

This paper provides a narrative review of guidance on reporting quality in AUD treatment trials.

RESULTS

Despite improvements in the reporting of results of treatment trials for AUD over the past 2 decades, many published reports provide insufficient information on design or methods.

CONCLUSIONS

The reporting of alcohol treatment trial design, analysis, and results requires improvement in 4 primary areas: (i) trial registration, (ii) procedures for recruitment and retention, (iii) procedures for randomization and intervention design considerations, and (iv) statistical methods used to assess treatment efficacy. Improvements in these areas and the adoption of reporting standards by authors, reviewers, and editors are critical to an accurate assessment of the reliability and validity of treatment effects. Continued developments in this area are needed to move AUD treatment research forward via systematic reviews and meta-analyses that maximize the utility of completed studies.

Likelihood of Null Effects of Large NHLBI Clinical Trials Has Increased over Time

Background

We explore whether the number of null results in large National Heart Lung, and Blood Institute (NHLBI) funded trials has increased over time.

Methods

We identified all large NHLBI supported RCTs between 1970 and 2012 evaluating drugs or dietary supplements for the treatment or prevention of cardiovascular disease. Trials were included if direct costs >$500,000/year, participants were adult humans, and the primary outcome was cardiovascular risk, disease or death. The 55 trials meeting these criteria were coded for whether they were published prior to or after the year 2000, whether they registered in clinicaltrials.gov prior to publication, used active or placebo comparator, and whether or not the trial had industry co-sponsorship. We tabulated whether the study reported a positive, negative, or null result on the primary outcome variable and for total mortality.

Results

17 of 30 studies (57%) published prior to 2000 showed a significant benefit of intervention on the primary outcome in comparison to only 2 among the 25 (8%) trials published after 2000 (χ²=12.2,df= 1, p=0.0005). There has been no change in the proportion of trials that compared treatment to placebo versus active comparator. Industry co-sponsorship was unrelated to the probability of reporting a significant benefit. Pre-registration in clinical trials.gov was strongly associated with the trend toward null findings.

Conclusions

The number NHLBI trials reporting positive results declined after the year 2000. Prospective declaration of outcomes in RCTs, and the adoption of transparent reporting standards, as required by clinicaltrials.gov, may have contributed to the trend toward null findings.

Results availability for analgesic device, complex regional pain syndrome, and post-stroke pain trials: comparing the RReADS, RReACT, and RReMiT databases

Evidence-based medicine rests on the assumption that treatment recommendations are robust, free from bias, and include results of all randomized clinical trials. The Repository of Registered Analgesic Clinical Trials search and analysis methodology was applied to create databases of complex regional pain syndrome (CRPS) and central post-stroke pain (CPSP) trials and adapted to create the Repository of Registered Analgesic Device Studies databases for trials of spinal cord stimulation (SCS), repetitive transcranial magnetic stimulation (rTMS), and transcranial direct current stimulation (tDCS). We identified 34 CRPS trials, 18 CPSP trials, 72 trials of SCS, and 92 trials of rTMS/tDCS. Irrespective of time since study completion, 45% of eligible CRPS and CPSP trials and 46% of eligible SCS and rTMS/tDCS trials had available results (peer-reviewed literature, results entered on registry, or gray literature); peer-reviewed publications could be found for 38% and 39%, respectively. Examining almost 1000 trials across a spectrum of painful disorders (fibromyalgia, diabetic painful neuropathy, post-herpetic neuralgia, migraine, CRPS, CPSP) and types of treatment, no single study characteristic consistently predicts unavailability of results. Results availability is higher 12 months after study completion but remains below 60% for peer-reviewed publications. Recommendations to increase results availability include supporting organizations advocating for transparency, enforcing existing results reporting regulations, enabling all primary registries to post results, stating trial registration numbers in all publication abstracts, and reducing barriers to publishing "negative" trials. For all diseases and treatment modalities, evidence-based medicine must rigorously adjust for the sheer magnitude of missing results in formulating treatment recommendations.

A machine learning approach to identify clinical trials involving nanodrugs and nanodevices from ClinicalTrials.gov

BACKGROUND

Clinical Trials (CTs) are essential for bridging the gap between experimental research on new drugs and their clinical application. Just like CTs for traditional drugs and biologics have helped accelerate the translation of biomedical findings into medical practice, CTs for nanodrugs and nanodevices could advance novel nanomaterials as agents for diagnosis and therapy. Although there is publicly available information about nanomedicine-related CTs, the online archiving of this information is carried out without adhering to criteria that discriminate between studies involving nanomaterials or nanotechnology-based processes (nano), and CTs that do not involve nanotechnology (non-nano). Finding out whether nanodrugs and nanodevices were involved in a study from CT summaries alone is a challenging task. At the time of writing, CTs archived in the well-known online registry ClinicalTrials.gov are not easily told apart as to whether they are nano or non-nano CTs-even when performed by domain experts, due to the lack of both a common definition for nanotechnology and of standards for reporting nanomedical experiments and results.

METHODS

We propose a supervised learning approach for classifying CT summaries from ClinicalTrials.gov according to whether they fall into the nano or the non-nano categories. Our method involves several stages: i) extraction and manual annotation of CTs as nano vs. non-nano, ii) pre-processing and automatic classification, and iii) performance evaluation using several state-of-the-art classifiers under different transformations of the original dataset.

RESULTS AND CONCLUSIONS

The performance of the best automated classifier closely matches that of experts (AUC over 0.95), suggesting that it is feasible to automatically detect the presence of nanotechnology products in CT summaries with a high degree of accuracy. This can significantly speed up the process of finding whether reports on ClinicalTrials.gov might be relevant to a particular nanoparticle or nanodevice, which is essential to discover any precedents for nanotoxicity events or advantages for targeted drug therapy.

How transparent are migraine clinical trials? Repository of Registered Migraine Trials (RReMiT)

Transparency in research requires public access to unbiased information prior to trial initiation and openly available results upon study completion. The Repository of Registered Migraine Trials is a global snapshot of registered migraine clinical trials and scorecard of results availability via the peer-reviewed literature, registry databases, and gray literature. The 295 unique clinical trials identified employed 447 investigational agents, with 30% of 154 acute migraine trials and 11% of 141 migraine prophylaxis trials testing combinations of agents. The most frequently studied categories in acute migraine trials were triptans, nonsteroidal anti-inflammatory drugs, antiemetics, calcitonin gene-related peptide antagonists, and acetaminophen. Migraine prophylaxis trials frequently studied anticonvulsants, β-blockers, complementary/alternative therapies, antidepressants, and botulinum toxin. Overall, 237 trials were eligible for a results search. Of 163 trials completed at least 12 months earlier, 57% had peer-reviewed literature results, and registries/gray literature added another 13%. Using logistic regression analysis, studies with a sample size below the median of 141 subjects were significantly less likely to have results, but the dominant factor associated with availability of results was time since study completion. In unadjusted models, trials registered on ClinicalTrials.gov and trials with industry primary sponsorship were significantly more likely to have results. Recently completed trials rarely have publicly available results; 2 years after completion, the peer-reviewed literature contains results for fewer than 60% of completed migraine trials. To avoid bias, evidence-based therapy algorithms should consider factors affecting results availability. As negative trials are less likely to be published, special caution should be exercised before recommending a therapy with a high proportion of missing trial results.

How frequently do the results from completed US clinical trials enter the public domain?--A statistical analysis of the ClinicalTrials.gov database

BACKGROUND

Achieving transparency in clinical trials, through either publishing results in a journal or posting results to the ClinicalTrials.gov (CTG) web site, is an essential public health good. However, it remains unknown what proportion of completed studies achieve public disclosure of results (PDOR), or what factors explain these differences.

METHODS

We analyzed data from 400 randomly selected studies within the CTG database that had been listed as 'completed' and had at least four years in which to disclose results. Using Kaplan-Meier curves, we calculated times from completion to PDOR (defined as publishing the primary outcomes in a journal and/or posting results to CTG), and identified explanatory variables predicting these outcomes using Cox proportional hazards models.

FINDINGS

Among the 400 clinical trials, 118 (29.5%) failed to achieve PDOR within four years of completion. The median day from study completion to PDOR among 282 studies (70.5%) that achieved PDOR was 602 days (mean 647 days, SD 454 days). Studies were less likely to achieve PDOR if at earlier stages (phase 2 vs. phase 3/4, adjusted HR 0.60, 95% CI 0.47-0.78), if they only included adult subjects (adjusted HR 0.61, 95% CI 0.45-0.83), involved randomization (adjusted HR 0.62, 95% CI 0.46-0.83), or had smaller sample sizes (≤50 subjects vs. >50, adjusted HR 0.60, 95% CI 0.44-0.83). Industry-funded studies were significantly less likely to be published than non-industry or blended studies (adjusted HR 0.49, 95% CI 0.36-0.66).

CONCLUSIONS

A significant proportion of completed studies did not achieve PDOR within the four years of follow-up, particularly smaller studies at earlier stages of development with industry funding. This constitutes reporting bias and threatens the validity of the clinical research literature in the US.

RReACT goes global: perils and pitfalls of constructing a global open-access database of registered analgesic clinical trials and trial results

Eliminating publication bias requires ensuring public awareness of studies and access to results. Clinical trial registries provide basic trial information, but access to unbiased trial results is inadequate. Nearly all studies of trial registration and results reporting have been limited to the ClinicalTrials.gov registry. We analyzed trial registration, registry functionality, cross-registry harmonization, and results reporting on all 15 primary registries in the World Health Organization International Clinical Trials Registry Platform (ICTRP) for postherpetic neuralgia, painful diabetic neuropathy, and fibromyalgia. A total of 447 unique trials were identified, with 86 trials listed on more than one registry. A comprehensive search algorithm was used to find trial results in the peer-reviewed literature and the grey literature. Creating a global database of registered trials and trial results proved surprisingly difficult for several reasons: (1) ICTRP does not reliably identify trials listed on multiple registries, manual searches are necessary; (2) Searching ICTRP yields different results than searching individual registries; (3) Outcome measure descriptions for multiply registered trials vary between registries; (4) Registry-publication pairings are often inaccurate or incomplete; (5) Grey literature results are not permanent. Overall, only 46% of all trials had results available. Trials registered on ClinicalTrials.gov were significantly more likely to have results (52% vs. 18%, P<0.001), partly due to the ability to post results directly to the registry. In addition to the simple remedy of including trial registration numbers on all meeting abstracts and peer-reviewed papers, specific strategies are offered to facilitate identifying multiply registered studies and ensuring accurate pairing of results and publications.

Reporting discrepancies between the ClinicalTrials.gov results database and peer-reviewed publications

BACKGROUND

ClinicalTrials.gov requires reporting of result summaries for many drug and device trials.

PURPOSE

To evaluate the consistency of reporting of trials that are registered in the ClinicalTrials.gov results database and published in the literature.

DATA SOURCES

ClinicalTrials.gov results database and matched publications identified through ClinicalTrials.gov and a manual search of 2 electronic databases.

STUDY SELECTION

10% random sample of phase 3 or 4 trials with results in the ClinicalTrials.gov results database, completed before 1 January 2009, with 2 or more groups.

DATA EXTRACTION

One reviewer extracted data about trial design and results from the results database and matching publications. A subsample was independently verified.

DATA SYNTHESIS

Of 110 trials with results, most were industry-sponsored, parallel-design drug studies. The most common inconsistency was the number of secondary outcome measures reported (80%). Sixteen trials (15%) reported the primary outcome description inconsistently, and 22 (20%) reported the primary outcome value inconsistently. Thirty-eight trials inconsistently reported the number of individuals with a serious adverse event (SAE); of these, 33 (87%) reported more SAEs in ClinicalTrials.gov. Among the 84 trials that reported SAEs in ClinicalTrials.gov, 11 publications did not mention SAEs, 5 reported them as zero or not occurring, and 21 reported a different number of SAEs. Among 29 trials that reported deaths in ClinicalTrials.gov, 28% differed from the matched publication.

LIMITATION

Small sample that included earliest results posted to the database.

CONCLUSION

Reporting discrepancies between the ClinicalTrials.gov results database and matching publications are common. Which source contains the more accurate account of results is unclear, although ClinicalTrials.gov may provide a more comprehensive description of adverse events than the publication.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality.

Manipulating In-House Designed Drug Databases For The Prediction of pH-Dependent Aqueous Drug Solubility

Chemical, pharmacokinetic, and pharmacodynamics properties are available in the package inserts of every Food and Drug Administration (FDA) approved prescription drug, including all available chemotherapy drugs. These inserts follow a specific format imposed by the FDA. Whether chemotherapy drugs are administered via the parenteral route or alimentary tract, a significant factor affecting their bioavailability, elimination and consequently the drug's effectiveness and potency, is its state of aqueous solubility. Water solubility has always lent itself poorly to the different predictive and experimental measures employed in the determination of a useful quantitative assessment. In this project, we first built a chemical structure based searchable database for 85 FDA approved chemotherapy drugs and then used Bio-Rad's KnowItAll^® Informatics suite to focus on the drugs pH-dependent water solubility prediction. We compared the predicted values for water solubility to the available values reported in the drug inserts, testing the practical utility and the predictive ability of our model in reporting such a clinically relevant, underreported pharmacokinetic parameter. A relational cancer drug database (MySQL) was created to further facilitate analysis and/or prediction of a chemotherapy compound's missing pharmacokinetic properties.

Toward a jurisprudence of drug regulation

Efforts to foster transparency in biopharmaceutical regulation are well underway: drug manufacturers are, for example, legally required to register clinical trials and share research results in the United States and Europe. Recently, the policy conversation has shifted toward the disclosure of clinical trial data, not just trial designs and basic results. Here, I argue that clinical trial registration and disclosure of clinical trial data are necessary but insufficient. There is also a need to ensure that regulatory decisions that flow from clinical trials - whether positive (i.e., product approvals) or negative (i.e., abandoned products, product refusals, and withdrawals) - are open to outside scrutiny. Further, a jurisprudence of drug regulation is needed. I develop two arguments motivated by (1) innovation concerns and (2) the value of good governance in support of openly publishing all final decisions for approved, abandoned, refused, and withdrawn products. After articulating why greater transparency in regulatory decision-making is needed, I distil four essential features of a jurisprudence of drug regulation that prescribe policy changes in terms not only of the transparency of regulatory outcomes and the underlying reasoning, but also regulatory organization.

Timing and completeness of trial results posted at ClinicalTrials.gov and published in journals

BACKGROUND

The US Food and Drug Administration Amendments Act requires results from clinical trials of Food and Drug Administration-approved drugs to be posted at ClinicalTrials.gov within 1 y after trial completion. We compared the timing and completeness of results of drug trials posted at ClinicalTrials.gov and published in journals.

METHODS AND FINDINGS

We searched ClinicalTrials.gov on March 27, 2012, for randomized controlled trials of drugs with posted results. For a random sample of these trials, we searched PubMed for corresponding publications. Data were extracted independently from ClinicalTrials.gov and from the published articles for trials with results both posted and published. We assessed the time to first public posting or publishing of results and compared the completeness of results posted at ClinicalTrials.gov versus published in journal articles. Completeness was defined as the reporting of all key elements, according to three experts, for the flow of participants, efficacy results, adverse events, and serious adverse events (e.g., for adverse events, reporting of the number of adverse events per arm, without restriction to statistically significant differences between arms for all randomized patients or for those who received at least one treatment dose). From the 600 trials with results posted at ClinicalTrials.gov, we randomly sampled 50% (n = 297) had no corresponding published article. For trials with both posted and published results (n = 202), the median time between primary completion date and first results publicly posted was 19 mo (first quartile = 14, third quartile = 30 mo), and the median time between primary completion date and journal publication was 21 mo (first quartile = 14, third quartile = 28 mo). Reporting was significantly more complete at ClinicalTrials.gov than in the published article for the flow of participants (64% versus 48% of trials, p<0.001), efficacy results (79% versus 69%, p = 0.02), adverse events (73% versus 45%, p<0.001), and serious adverse events (99% versus 63%, p<0.001). The main study limitation was that we considered only the publication describing the results for the primary outcomes.

CONCLUSIONS

Our results highlight the need to search ClinicalTrials.gov for both unpublished and published trials. Trial results, especially serious adverse events, are more completely reported at ClinicalTrials.gov than in the published article.

Evolution of interventional vancomycin trials in light of new antibiotic development in the USA, 1999-2012

Use of vancomycin has increased following the emergence of resistant Gram-positive bacterial infections. Investigation into recent vancomycin clinical studies provides insight into the optimal use of vancomycin and the development of novel antibiotics for the treatment of resistant infections. Interventional vancomycin trials registered in ClinicalTrials.gov from January 1999 to December 2012 were identified. Trial trends and characteristics were evaluated in the context of vancomycin use and new antibiotic development. Overall, 122 interventional vancomycin trials were identified, with a significant increase in the number of registered trials per year (P<0.001). The top three indications studied were skin and soft-tissue infections (28.7%), Clostridium difficile infections (13.1%) and surgical prophylaxis (12.3%). Trials testing vancomycin as an experimental agent differed from trials using vancomycin as an active comparator. Experimental agent trials commonly investigated new formulations, dosing regimen optimisation and combination therapy, which were less likely to be in phase 2 or 3 (25% vs. 70%; P<0.001), adopt a randomisation procedure (70% vs. 98%; P<0.001), report results (15% vs. 35%; P=0.02) or be funded by industry (8% vs. 76%; P<0.001). Active comparator trials mainly focused on monotherapy, which led to six FDA-approved drug products and ten investigational new drugs in late-phase development. This study demonstrated a significant increase in interventional vancomycin trials and its recent success, which resulted in several novel agents against resistant Gram-positive bacteria. Further studies are warranted to determine how these agents can best be incorporated within clinical practice.

Public availability of results of trials assessing cancer drugs in the United States

PURPOSE

To evaluate to what extent results of completed trials of cancer drugs conducted in the United States are publicly available at ClinicalTrials.gov, as required by the Food and Drug Administration Amendments Act (FDAAA), or are published in journals.

METHODS

We searched ClinicalTrials.gov for cancer trials governed by the FDAAA: phase II to IV trials assessing drugs in the United States with a primary completion date between December 26, 2007, and May 31, 2010. For each trial, we also searched PubMed to identify the publication of results. We assessed the cumulative percentages of posted or published results over time by using the Kaplan-Meier method.

RESULTS

We identified 646 trials, including 209 randomized controlled trials (RCTs). At 12 months after completion of the trials, the cumulative percentages of trials with results posted at ClinicalTrials.gov, published in journals, and available either at ClinicalTrials.gov or in journals were 9% (95% CI, 7% to 11%), 12% (95% CI, 10% to 15%), and 20% (95% CI, 17% to 23%), respectively, and for RCTs, the percentages were 12% (95% CI, 8% to 16%), 5% (95% CI, 2% to 8%), and 17% (95% CI, 12% to 22%), respectively. At 36 months, these percentages were 31% (95% CI, 28% to 35%), 35% (95% CI, 31% to 39%), and 55% (95% CI, 51% to 59%), respectively, and for RCTs, they were 38% (95% CI, 31% to 45%), 32% (95% CI, 25% to 39%), and 56% (95% CI, 48% to 62%), respectively. Public availability of phase III trials was 15% (95% CI, 7% to 23%) at 12 months, 39% (95% CI, 27% to 49%) at 24 months, and 64% (95% CI, 50% to 73%) at 36 months.

CONCLUSION

Despite the FDAAA, results for nearly half the trials of cancer drugs in the United States were not publicly available 3 years after completion of the trials.

Publication bias, with a focus on psychiatry: causes and solutions

Publication bias undermines the integrity of the evidence base by inflating apparent drug efficacy and minimizing drug harms, thus skewing the risk-benefit ratio. This paper reviews the topic of publication bias with a focus on drugs prescribed for psychiatric conditions, especially depression, schizophrenia, bipolar disorder, and autism. Publication bias is pervasive; although psychiatry/psychology may be the most seriously afflicted field, it occurs throughout medicine and science. Responsibility lies with various parties (authors as well as journals, academia as well as industry), so the motives appear to extend beyond the financial interests of drug companies. The desire for success, in combination with cognitive biases, can also influence academic authors and journals. Amid the flood of new medical information coming out each day, the attention of the news media and academic community is more likely to be captured by studies whose results are positive or newsworthy. In the peer review system, a fundamental flaw arises from the fact that authors usually write manuscripts after they know the results. This allows hindsight and other biases to come into play, so data can be "tortured until they confess" (a detailed example is given). If a "publishable" result cannot be achieved, non-publication remains an option. To address publication bias, various measures have been undertaken, including registries of clinical trials. Drug regulatory agencies can provide valuable unpublished data. It is suggested that journals borrow from the FDA review model. Because the significance of study results biases reviewers, results should be excluded from review until after a preliminary judgment of study scientific quality has been rendered, based on the original study protocol. Protocol publication can further enhance the credibility of the published literature.

Biosafety data as confidential business information

Removal of confidentiality claims on biosafety data is necessary to adhere to standard scientific procedures of quality assurance, to increase transparency, to minimize impacts of conflicts of interests, and ultimately to improve public confidence in GMOs.

Systematic identification of pharmacogenomics information from clinical trials

Recent progress in high-throughput genomic technologies has shifted pharmacogenomic research from candidate gene pharmacogenetics to clinical pharmacogenomics (PGx). Many clinical related questions may be asked such as 'what drug should be prescribed for a patient with mutant alleles?' Typically, answers to such questions can be found in publications mentioning the relationships of the gene-drug-disease of interest. In this work, we hypothesize that ClinicalTrials.gov is a comparable source rich in PGx related information. In this regard, we developed a systematic approach to automatically identify PGx relationships between genes, drugs and diseases from trial records in ClinicalTrials.gov. In our evaluation, we found that our extracted relationships overlap significantly with the curated factual knowledge through the literature in a PGx database and that most relationships appear on average 5 years earlier in clinical trials than in their corresponding publications, suggesting that clinical trials may be valuable for both validating known and capturing new PGx related information in a more timely manner. Furthermore, two human reviewers judged a portion of computer-generated relationships and found an overall accuracy of 74% for our text-mining approach. This work has practical implications in enriching our existing knowledge on PGx gene-drug-disease relationships as well as suggesting crosslinks between ClinicalTrials.gov and other PGx knowledge bases.

Deficiencies in the transfer and availability of clinical trials evidence: a review of existing systems and standards

Background

Decisions concerning drug safety and efficacy are generally based on pivotal evidence provided by clinical trials. Unfortunately, finding the relevant clinical trials is difficult and their results are only available in text-based reports. Systematic reviews aim to provide a comprehensive overview of the evidence in a specific area, but may not provide the data required for decision making.

Methods

We review and analyze the existing information systems and standards for aggregate level clinical trials information from the perspective of systematic review and evidence-based decision making.

Results

The technology currently used has major shortcomings, which cause deficiencies in the transfer, traceability and availability of clinical trials information. Specifically, data available to decision makers is insufficiently structured, and consequently the decisions cannot be properly traced back to the underlying evidence. Regulatory submission, trial publication, trial registration, and systematic review produce unstructured datasets that are insufficient for supporting evidence-based decision making.

Conclusions

The current situation is a hindrance to policy decision makers as it prevents fully transparent decision making and the development of more advanced decision support systems. Addressing the identified deficiencies would enable more efficient, informed, and transparent evidence-based medical decision making.

Results and outcome reporting In ClinicalTrials.gov, what makes it happen?

Background

At the end of the past century there were multiple concerns regarding lack of transparency in the conduct of clinical trials as well as some ethical and scientific issues affecting the trials’ design and reporting. In 2000 ClinicalTrials.gov data repository was developed and deployed to serve public and scientific communities with valid data on clinical trials. Later in order to increase deposited data completeness and transparency of medical research a set of restrains had been imposed making the results deposition compulsory for multiple cases.

Methods

We investigated efficiency of the results deposition and outcome reporting as well as what factors make positive impact on providing information of interest and what makes it more difficult, whether efficiency depends on what kind of institution was a trial sponsor. Data from the ClinicalTrials.gov repository has been classified based on what kind of institution a trial sponsor was. The odds ratio was calculated for results and outcome reporting by different sponsors’ class.

Results

As of 01/01/2012 118,602 clinical trials data deposits were made to the depository. They came from 9068 different sources. 35344 (29.8%) of them are assigned as FDA regulated and 25151 (21.2%) as Section 801 controlled substances. Despite multiple regulatory requirements, only about 35% of trials had clinical study results deposited, the maximum 55.56% of trials with the results, was observed for trials completed in 2008.

Conclusions

The most positive impact on depositing results, the imposed restrains made for hospitals and clinics. Health care companies showed much higher efficiency than other investigated classes both in higher fraction of trials with results and in providing at least one outcome for their trials. They also more often than others deposit results when it is not strictly required, particularly, in the case of non-interventional studies.

Despite law, fewer than one in eight completed studies of drugs and biologics are reported on time on ClinicalTrials.gov

Clinical trial registries are public databases created to prospectively document the methods and measures of prescription drug studies and retrospectively collect a summary of results. In 2007 the US government began requiring that researchers register certain studies and report the results on ClinicalTrials.gov, a public database of federally and privately supported trials conducted in the United States and abroad. We found that although the mandate briefly increased trial registrations, 39 percent of trials were still registered late after the mandate's deadline, and only 12 percent of completed studies reported results within a year, as required by the mandate. This result is important because there is evidence of selective reporting even among registered trials. Furthermore, we found that trials funded by industry were more than three times as likely to report results than were trials funded by the National Institutes of Health. Thus, additional enforcement may be required to ensure disclosure of all trial results, leading to a better understanding of drug safety and efficacy. Congress should also reconsider the three-year delay in reporting results for products that have been approved by the Food and Drug Administration and are in use by patients.

Impact of reporting bias in network meta-analysis of antidepressant placebo-controlled trials

BACKGROUND

Indirect comparisons of competing treatments by network meta-analysis (NMA) are increasingly in use. Reporting bias has received little attention in this context. We aimed to assess the impact of such bias in NMAs.

METHODS

We used data from 74 FDA-registered placebo-controlled trials of 12 antidepressants and their 51 matching publications. For each dataset, NMA was used to estimate the effect sizes for 66 possible pair-wise comparisons of these drugs, the probabilities of being the best drug and ranking the drugs. To assess the impact of reporting bias, we compared the NMA results for the 51 published trials and those for the 74 FDA-registered trials. To assess how reporting bias affecting only one drug may affect the ranking of all drugs, we performed 12 different NMAs for hypothetical analysis. For each of these NMAs, we used published data for one drug and FDA data for the 11 other drugs.

FINDINGS

Pair-wise effect sizes for drugs derived from the NMA of published data and those from the NMA of FDA data differed in absolute value by at least 100% in 30 of 66 pair-wise comparisons (45%). Depending on the dataset used, the top 3 agents differed, in composition and order. When reporting bias hypothetically affected only one drug, the affected drug ranked first in 5 of the 12 NMAs but second (n = 2), fourth (n = 1) or eighth (n = 2) in the NMA of the complete FDA network.

CONCLUSIONS

In this particular network, reporting bias biased NMA-based estimates of treatments efficacy and modified ranking. The reporting bias effect in NMAs may differ from that in classical meta-analyses in that reporting bias affecting only one drug may affect the ranking of all drugs.

Research without results: inadequate public reporting of clinical trial results

OBJECTIVE

In order to increase transparency in the medical literature, the Food and Drug Administration (FDA) Modernization Act of 1997 and the FDA Amendment Act of 2007 required registration of all "applicable trials" with required "basic results" reporting. We evaluated the rate of compliance with the FDA mandatory results reporting in www.clinicaltrials.gov.

METHODS

All completed registered interventional studies that may be subject to FDA regulation, one year prior to required results reporting (October 2006 to September 2007, n = 1097) and during the two years after required reporting (October 2007 to September 2008 (07-08), n = 2231 and October 2008 to September 2009 (08-09), n = 2923).

RESULTS

Downloading all 99,315 records from clinicaltrials.gov, we excluded all non-applicable studies. Results reporting increased from 6.8% (n = 75) prior to mandatory reporting to 19.1% (n = 427, p<.01) in 07-08 and 10.8% (n = 316, p<.01) in 08-09. The odds ratio for results reporting using the 06-07 time period as the reference was 3.31 (95% CI 2.54-4.32) for 07-08 and 1.74 (1.33-2.28) for 08-09. Of the 818 trials with results in clinicaltrials.gov, the rate of published articles found decreased from 60% (n = 45) in the year prior to required reporting to 33% (n = 140, p<.001) for 07-08 and 20% (n = 63, p<.001) for 08-09 time period.

CONCLUSION

The majority of studies registered in clinicaltrials.gov are not required to report data. Of studies that may be required to report data, compliance with data reporting has improved. The clinicaltrials.gov website is not yet a comprehensive resource for study results.

Comparative effectiveness research: an empirical study of trials registered in ClinicalTrials.gov

Background

The $1.1 billion investment in comparative effectiveness research will reshape the evidence-base supporting decisions about treatment effectiveness, safety, and cost. Defining the current prevalence and characteristics of comparative effectiveness (CE) research will enable future assessments of the impact of this program.

Methods

We conducted an observational study of clinical trials addressing priority research topics defined by the Institute of Medicine and conducted in the US between 2007 and 2010. Trials were identified in ClinicalTrials.gov. Main outcome measures were the prevalence of comparative effectiveness research, nature of comparators selected, funding sources, and impact of these factors on results.

Results

231 (22.3%; 95% CI 19.8%–24.9%) studies were CE studies and 804 (77.7%; 95% CI, 75.1%–80.2%) were non-CE studies, with 379 (36.6%; 95% CI, 33.7%–39.6%) employing a placebo control and 425 (41.1%; 95% CI, 38.1%–44.1%) no control. The most common treatments examined in CE studies were drug interventions (37.2%), behavioral interventions (28.6%), and procedures (15.6%). Study findings were favorable for the experimental treatment in 34.8% of CE studies and greater than twice as many (78.6%) non-CE studies (P<0.001). CE studies were more likely to receive government funding (P = 0.003) and less likely to receive industry funding (P = 0.01), with 71.8% of CE studies primarily funded by a noncommercial source. The types of interventions studied differed based on funding source, with 95.4% of industry trials studying a drug or device. In addition, industry-funded CE studies were associated with the fewest pediatric subjects (P<0.001), the largest anticipated sample size (P<0.001), and the shortest study duration (P<0.001).

Conclusions

In this sample of studies examining high priority areas for CE research, less than a quarter are CE studies and the majority is supported by government and nonprofits. The low prevalence of CE research exists across CE studies with a broad array of interventions and characteristics.

How to keep your integrity when performing sponsored (imaging) trials

The broadening of imaging capabilities and the increasing capacity of imaging to quantitate biologic processes has increased industry interest in using imaging methods in new drug development. Investigators participating in industry-sponsored trials should be aware of how such trials differ from investigator-initiated, grant-funded research. In particular, investigators should be cognizant of possible ethical conflicts in the care of patients, the development and analysis of data, and issues related to the dissemination of results.

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.

Why it is important to include unpublished data in systematic reviews

It is known that studies with statistically significant results have a higher probability to be published (publication bias). Therefore, studies with no statistically significant differences (or not favoring the investigational drug) may not be found in commonly accessed databases and remain unpublished. Moreover, unpublished data may also refer to information that are not included in study reports published in scientific journals but that may be important to estimate study outcomes. Retrieving unpublished evidence represents a compelling challenge for researchers, and in the present paper we explore how to do it.

The ClinicalTrials.gov results database--update and key issues

BACKGROUND

The ClinicalTrials.gov trial registry was expanded in 2008 to include a database for reporting summary results. We summarize the structure and contents of the results database, provide an update of relevant policies, and show how the data can be used to gain insight into the state of clinical research.

METHODS

We analyzed ClinicalTrials.gov data that were publicly available between September 2009 and September 2010.

RESULTS

As of September 27, 2010, ClinicalTrials.gov received approximately 330 new and 2000 revised registrations each week, along with 30 new and 80 revised results submissions. We characterized the 79,413 registry and 2178 results of trial records available as of September 2010. From a sample cohort of results records, 78 of 150 (52%) had associated publications within 2 years after posting. Of results records available publicly, 20% reported more than two primary outcome measures and 5% reported more than five. Of a sample of 100 registry record outcome measures, 61% lacked specificity in describing the metric used in the planned analysis. In a sample of 700 results records, the mean number of different analysis populations per study group was 2.5 (median, 1; range, 1 to 25). Of these trials, 24% reported results for 90% or less of their participants.

CONCLUSIONS

ClinicalTrials.gov provides access to study results not otherwise available to the public. Although the database allows examination of various aspects of ongoing and completed clinical trials, its ultimate usefulness depends on the research community to submit accurate, informative data.

Result publication of Chinese trials in World Health Organization primary registries

Background

Result publication is the key step to improve the transparency of clinical trials.

Objective

To investigate the result publication rate of Chinese trials registered in World Health Organization (WHO) primary registries.

Method

We searched 11 WHO primary registries for Chinese trials records. The progress of each trial was analyzed. We searched for the full texts of result publications cited in the registration records. For completed trials without citations, we searched PubMed, Embase, Chinese Biomedical Literature Database (Chinese), China Knowledge Resource Integrated Database, and Chinese Science and Technology Periodicals Database for result publications. The search was conducted on July 14, 2009. We also called the investigators of completed trials to ask about results publication.

Results

We identified 1294 Chinese trials records (428 in ChiCTR,743 in clinicaltrials.gov,55 in ISRCTN, 21 in ACTRN). A total of 443 trials had been completed. The publication rate of the Chinese trials in WHO primary registries is 35.2%(156/443).The publication rate of Chinese trials in clinicaltrials.gov, ChiCTR, ISRCTN, and ACRTN was 36.5% (53/145), 36.3% (89/245), 26.0%(9/44), and 55.6%(5/9), respectively. The publication rate of trials sponsored by industry(23.8%) was lower than that of sponsored by central and local government(31.7%), hospital(35.1%), and universities (40.7%). The publication rate for randomized trials was higher than that of cohort study and case-control study (33.2% versus 16.7%, 22.2%). The publication rate for interventional studies and observational studies was similar(33.4% versus 33.3%).

Conclusion

The publication rate of the registered Chinese trials was low, with no significant difference between ChiCTR and clinicaltrials.gov. An effective mechanism is needed to promote publication of results for registered trials in China.

Outcome reporting among drug trials registered in ClinicalTrials.gov

BACKGROUND

Clinical trial registries are in widespread use to promote transparency around trials and their results.

OBJECTIVE

To describe characteristics of drug trials listed in ClinicalTrials.gov and examine whether the funding source of these trials is associated with favorable published outcomes.

DESIGN

An observational study of safety and efficacy trials for anticholesteremics, antidepressants, antipsychotics, proton-pump inhibitors, and vasodilators conducted between 2000 and 2006.

SETTING

ClinicalTrials.gov, a Web-based registry of clinical trials launched in 1999.

MEASUREMENTS

Publications resulting from the trials for the 5 drug categories of interest were identified, and data were abstracted on the trial record and publication, including timing of registration, elements of the study design, funding source, publication date, and study outcomes. Assessments were based on the primary funding categories of industry, government agencies, and nonprofit or nonfederal organizations.

RESULTS

Among 546 drug trials, 346 (63%) were primarily funded by industry, 74 (14%) by government sources, and 126 (23%) by nonprofit or nonfederal organizations. Trials funded by industry were more likely to be phase 3 or 4 trials (88.7%; P < 0.001 across groups), to use an active comparator in controlled trials (36.8%; P = 0.010 across groups), to be multicenter (89.0%; P < 0.001 across groups), and to enroll more participants (median sample size, 306 participants; P < 0.001 across groups). Overall, 362 (66.3%) trials had published results. Industry-funded trials reported positive outcomes in 85.4% of publications, compared with 50.0% for government-funded trials and 71.9% for nonprofit or nonfederal organization-funded trials (P < 0.001). Trials funded by nonprofit or nonfederal sources with industry contributions were also more likely to report positive outcomes than those without industry funding (85.0% vs. 61.2%; P = 0.013). Rates of trial publication within 24 months of study completion ranged from 32.4% among industry-funded trials to 56.2% among nonprofit or nonfederal organization-funded trials without industry contributions (P = 0.005 across groups).

LIMITATIONS

The publication status of a trial could not always be confirmed, which could result in misclassification. Additional information on study protocols and comprehensive trial results were not available to further explore underlying factors for the association between funding source and outcome reporting.

CONCLUSION

In this sample of registered drug trials, those funded by industry were less likely to be published within 2 years of study completion and were more likely to report positive outcomes than were trials funded by other sources.

PRIMARY FUNDING SOURCE

National Library of Medicine and National Institute of Child Health and Human Development, National Institutes of Health.

Outcome reporting among drug trials registered in ClinicalTrials.gov

BACKGROUND

Clinical trial registries are in widespread use to promote transparency around trials and their results.

OBJECTIVE

To describe characteristics of drug trials listed in ClinicalTrials.gov and examine whether the funding source of these trials is associated with favorable published outcomes.

DESIGN

An observational study of safety and efficacy trials for anticholesteremics, antidepressants, antipsychotics, proton-pump inhibitors, and vasodilators conducted between 2000 and 2006.

SETTING

ClinicalTrials.gov, a Web-based registry of clinical trials launched in 1999.

MEASUREMENTS

Publications resulting from the trials for the 5 drug categories of interest were identified, and data were abstracted on the trial record and publication, including timing of registration, elements of the study design, funding source, publication date, and study outcomes. Assessments were based on the primary funding categories of industry, government agencies, and nonprofit or nonfederal organizations.

RESULTS

Among 546 drug trials, 346 (63%) were primarily funded by industry, 74 (14%) by government sources, and 126 (23%) by nonprofit or nonfederal organizations. Trials funded by industry were more likely to be phase 3 or 4 trials (88.7%; P < 0.001 across groups), to use an active comparator in controlled trials (36.8%; P = 0.010 across groups), to be multicenter (89.0%; P < 0.001 across groups), and to enroll more participants (median sample size, 306 participants; P < 0.001 across groups). Overall, 362 (66.3%) trials had published results. Industry-funded trials reported positive outcomes in 85.4% of publications, compared with 50.0% for government-funded trials and 71.9% for nonprofit or nonfederal organization-funded trials (P < 0.001). Trials funded by nonprofit or nonfederal sources with industry contributions were also more likely to report positive outcomes than those without industry funding (85.0% vs. 61.2%; P = 0.013). Rates of trial publication within 24 months of study completion ranged from 32.4% among industry-funded trials to 56.2% among nonprofit or nonfederal organization-funded trials without industry contributions (P = 0.005 across groups).

LIMITATIONS

The publication status of a trial could not always be confirmed, which could result in misclassification. Additional information on study protocols and comprehensive trial results were not available to further explore underlying factors for the association between funding source and outcome reporting.

CONCLUSION

In this sample of registered drug trials, those funded by industry were less likely to be published within 2 years of study completion and were more likely to report positive outcomes than were trials funded by other sources.

PRIMARY FUNDING SOURCE

National Library of Medicine and National Institute of Child Health and Human Development, National Institutes of Health.

Industry sponsorship and selection of comparators in randomized clinical trials

BACKGROUND

Most clinical trials on medical interventions are sponsored by the industry. The choice of comparators shapes the accumulated evidence. We aimed to assess how often major companies sponsor trials that involve only their own products.

METHODS

Studies were identified by searching ClinicalTrials.gov for trials registered in 2006. We focused on randomized trials involving the 15 companies that had sponsored the largest number of registered trials in ClinicalTrials.gov in that period.

RESULTS

Overall, 577 randomized trials were eligible for analysis and 82% had a single industry sponsor [89% (166/187) of the placebo-control trials, 87% (91/105) of trials comparing different doses or ways of administration of the same intervention, and 78% (221/285) of other active control trials]. The compared intervention(s) belonged to a single company in 67% of the trials (89%, 81% and 47% in the three categories respectively). All 15 companies strongly preferred to run trials where they were the only industry sponsor or even the only owner of the assessed interventions. Co-sponsorship typically reflected co-ownership of the same intervention by both companies. Head-to-head comparison of different active interventions developed by different companies occurred in only 18 trials with two or more industry sponsors.

CONCLUSIONS

Each company generates a clinical research agenda that is strongly focused on its own products, while comparisons involving different interventions from different companies are uncommon. This diminishes the ability to understand the relative merits of different interventions for the same condition.