Clinical trial data sharing: a cross-sectional study of outcomes associated with two U.S. National Institutes of Health models

The impact and effectiveness of clinical trial data sharing initiatives may differ depending on the data sharing model used. We characterized outcomes associated with models previously used by the U.S. National Institutes of Health (NIH): National Heart, Lung, and Blood Institute's (NHLBI) centralized model and National Cancer Institute's (NCI) decentralized model. We identified trials completed in 2010-2013 that met NIH data sharing criteria and matched studies based on cost and/or size, determining whether trial data were shared, and for those that were, the frequency of secondary internal publications (authored by at least one author from the original research team) and shared data publications (authored by a team external to the original research team). We matched 77 NHLBI-funded trials to 77 NCI-funded trials; among these, 20 NHLBI-sponsored trials (26%) and 4 NCI-sponsored trials (5%) shared data (OR 6.4, 95% CI: 2.1, 19.8). From the 4 NCI-sponsored trials sharing data, we identified 65 secondary internal and 2 shared data publications. From the 20 NHLBI-sponsored trials sharing data, we identified 188 secondary internal and 53 shared data publications. The NHLBI's centralized data sharing model was associated with more trials sharing data and more shared data publications when compared with the NCI's decentralized model.

Consistency between trials presented at conferences, their subsequent publications and press releases

OBJECTIVE

This study examined the extent to which trials presented at major international medical conferences in 2016 consistently reported their study design, end points and results across conference abstracts, published article abstracts and press releases.

DESIGN

Cross-sectional analysis of clinical trials presented at 12 major medical conferences in the USA in 2016. Conferences were identified from a list of the largest clinical research meetings aggregated by the Healthcare Convention and Exhibitors Association and were included if their abstracts were publicly available. From these conferences, all late-breaker clinical trials were included, as well as a random selection of all other clinical trials, such that the total sample included up to 25 trial abstracts per conference.

MAIN OUTCOME MEASURES

First, it was determined if trials were registered and reported results in an International Committee of Medical Journal Editors-approved clinical trial registry. Second, it was determined if trial results were published in a peer-reviewed journal. Finally, information on trial media coverage and press releases was collected using LexisNexis. For all published trials, the consistency of reporting of the following characteristics was examined, through comparison of the trials' conference and publication abstracts: primary efficacy endpoint definition, safety endpoint identification, sample size, follow-up period, primary end point effect size and characterisation of trial results. For all published abstracts with press releases, the characterisation of trial results across conference abstracts, press releases and publications was compared. Authors determined consistency of reporting when identical information was presented across abstracts and press releases. Primary analyses were descriptive; secondary analyses included χ2 tests and multiple logistic regression.

RESULTS

Among 240 clinical trials presented at 12 major medical conferences, 208 (86.7%) were registered, 95 (39.6%) reported summary results in a registry and 177 (73.8%) were published; 82 (34.2%) were covered by the media and 68 (28.3%) had press releases. Among the 177 published trials, 171 (96.6%) reported the definition of primary efficacy endpoints consistently across conference and publication abstracts, whereas 96/128 (75.0%) consistently identified safety endpoints. There were 107/172 (62.2%) trials with consistent sample sizes across conference and publication abstracts, 101/137 (73.7%) that reported their follow-up periods consistently, 92/175 (52.6%) that described their effect sizes consistently and 157/175 (89.7%) that characterised their results consistently. Among the trials that were published and had press releases, 32/32 (100%) characterised their results consistently across conference abstracts, press releases and publication abstracts. No trial characteristics were associated with reporting primary efficacy end points consistently.

CONCLUSIONS

For clinical trials presented at major medical conferences, primary efficacy endpoint definitions were consistently reported and results were consistently characterised across conference abstracts, registry entries and publication abstracts; consistency rates were lower for sample sizes, follow-up periods, and effect size estimates.

REGISTRATION

This study was registered at the Open Science Framework (https://doi.org/10.17605/OSF.IO/VGXZY).

Comparison of Industry Payments to Physicians and Advanced Practice Clinicians

This study uses Open Payments data to characterize and compare payments to physicians and advanced practice clinicians.

Feasibility of Using Real-world Data to Emulate Postapproval Confirmatory Clinical Trials of Therapeutic Agents Granted US Food and Drug Administration Accelerated Approval

This cross-sectional study examines the feasibility of using real-world data, such as billing, claims, and electronic health records, to emulate US Food and Drug Administration–required confirmatory clinical trials for the 50 new therapeutic agents that received accelerated approval between 2009 and 2018.

Characteristics of Clinical Studies Used for US Food and Drug Administration Supplemental Indication Approvals of Drugs and Biologics, 2017 to 2019

IMPORTANCE

After US Food and Drug Administration (FDA) approval of a new drug, sponsors can submit additional clinical data to obtain supplemental approval for use for new indications.

OBJECTIVE

To characterize pivotal trials supporting recent supplemental new indication approvals of drugs and biologics by the FDA and to compare them with pivotal trials that supported these therapeutics' original indication approvals.

DESIGN, SETTING, AND PARTICIPANTS

This is a cross-sectional study characterizing pivotal trials supporting supplemental indication approvals by the FDA between 2017 and 2019 and pivotal trials that supported these therapeutics' original indication approvals. Data analysis was performed from August to October 2020.

MAIN OUTCOMES AND MEASURES

Number and design of pivotal trials supporting both supplemental and original indication approvals.

RESULTS

From 2017 to 2019, the FDA approved 146 supplemental indications for 107 therapeutics on the basis of 181 pivotal efficacy trials. The median (interquartile range) number of trials per supplemental indication was 1 (1-1). Most trials used either placebo (77 trials [42.5%; 95% CI, 35.6%-49.8%]) or active comparators (65 trials [35.9%; 95% CI, 29.3%-43.1%]), and most of these multigroup trials were randomized (141 trials [99.3%; 95% CI, 96.0%-100.0%]) and double-blinded (106 trials [74.5%; 95% CI, 66.6%-81.0%]); 80 trials (44.2%; 95 CI, 37.2%-51.5%) used clinical outcomes as the primary efficacy end point. There was no difference between oncology therapies and those approved for other therapeutic areas to have supplemental indication approvals be based on at least 2 pivotal trials (11.5% vs 20.6%; difference, 9.1%; 95% CI, 2.9%-21.0%; P = .10). Similarly, there was no difference in use of randomization (98.3% vs 100.0%; difference, 1.7%; 95% CI, 1.6%-5.0%; P = .43) among multigroup trials, although these trials were less likely to be double-blinded (50.8% vs 92.3%; difference, 41.5%; 95% CI, 27.4%-55.5%; P < .001); overall, these trials were less likely to use either placebo or active comparators (64.9% vs 86.7%; difference, 21.8% 95% CI, 9.8%-33.9%; P < .001) or to use clinical outcomes as their primary efficacy end point (27.5% vs 61.1%; difference, 33.6%; 95% CI, 14.1%-40.9%; P < .001) and were longer (median [interquartile range], 17 [6-48] weeks vs 95 [39-146] weeks). Original approvals were more likely than supplemental indication approvals to be based on at least 2 pivotal trials (44.0% [95% CI, 33.7%-42.6%] vs 15.8% [95% CI, 10.7%-22.5%]; difference, 28.2%; 95% CI, 17.6%-39.6%; P < .001) and less likely to be supported by at least 1 trial of 12 months' duration (27.6% [95% CI, 17.9%-35.0%] vs 54.8% [95% CI, 46.7%-62.6%]; difference, 27.2%; 95% CI, 14.5%-37.8%; P < .001). Pivotal trial designs were otherwise not significantly different.

CONCLUSIONS AND RELEVANCE

These findings suggest that the number and design of the pivotal trials supporting supplemental indication approvals by the FDA varied across therapeutic areas, with the strength of evidence for cancer indications weaker than that for other indications. There was little difference in the design characteristics of the pivotal trials supporting supplemental indication and original approvals.

Evaluation of Trials Comparing Single-Enantiomer Drugs to Their Racemic Precursors: A Systematic Review

IMPORTANCE

Chiral switching, a strategy in which drug manufacturers develop a single-enantiomer formulation of a drug to be substituted for a racemic formulation, allows manufacturers to maintain market exclusivity for drugs losing patent protection, even without demonstrating superior efficacy or safety.

OBJECTIVE

To identify and characterize all randomized clinical trials (RCTs) directly comparing a Food and Drug Administration (FDA)-approved single-enantiomer drug against a previously approved racemic drug for 1 or more efficacy or safety end points.

EVIDENCE REVIEW

Drugs were identified using the Drugs@FDA database. Randomized clinical trials were identified using Ovid MEDLINE (1949 to October 22, 2019), Ovid Embase (1974 to October 22, 2019), Web of Science Core Collection (all years), ClinicalTrials.gov, and Cochrane Central Registry of Controlled Trials (CENTRAL, Wiley, Issue 8 of 12, October 22, 2019). Trials were characterized as favoring the single-enantiomer or racemic drugs based on whether the primary efficacy, secondary efficacy, and safety end points achieved each study's defined significance level (eg, P < .05). Trials were characterized as favoring neither drug if no statistically significant differences were reported for any end point or if both drugs were found to be superior for 1 or more separate end points.

FINDINGS

Fifteen FDA-approved single-enantiomer drugs were identified with racemic precursors approved in the US or Europe. For 3 single-enantiomer racemic drug pairs, no RCTs directly comparing the drugs were identified. For the remaining 12 pairs, 185 RCTs comparing efficacy or safety of the drug pairs were identified, 124 (67.0%) of which studied 1 pair (levobupivacaine/bupivacaine). There were 179 RCTs directly comparing drug pairs using efficacy end points, of which 23 (12.8%) favored the single enantiomer based on primary efficacy end point results. There were 124 RCTs directly comparing drug pairs using safety end points, of which 17 (13.7%) favored the single-enantiomer drug. For 9 of the 15 single-enantiomer drugs (60.0%), no RCTs were identified providing evidence of improved efficacy, based on primary end point results, or safety as compared with their racemic precursors.

CONCLUSIONS AND RELEVANCE

The results of this systematic review suggest that most newly marketed FDA-approved single-enantiomer drugs are infrequently directly compared with their racemic precursors, and when compared, they are uncommonly found to provide improved efficacy or safety, despite their greater costs.

US Food and Drug Administration utilization of postmarketing requirements and postmarketing commitments, 2009-2018

BACKGROUND/AIMS

The US Food and Drug Administration outlines clinical studies as postmarketing requirements and commitments to be fulfilled following approval of new drugs and biologics ("therapeutics"). Regulators have increasingly emphasized lifecycle evaluation of approved therapeutics, and postmarketing studies are intended to advance our understanding of therapeutic safety and efficacy. However, little is known about the indications that clinical studies outlined in postmarketing requirements and commitments investigate, including whether they are intended to generate evidence for approved or other clinical indications. Therefore, we characterized US Food and Drug Administration postmarketing requirements and commitments for new therapeutics approved from 2009 to 2018.

METHODS

We conducted a cross-sectional study of all novel therapeutics, including small-molecule drugs and biologics, receiving original US Food and Drug Administration approval from 2009 to 2018, using approval letters accessed through the Drug@FDA database. Outcomes included the number and characteristics of US Food and Drug Administration postmarketing requirements and commitments for new therapeutics at original approval, including the types of studies outlined, the indications to be investigated, and the clinical evidence to be generated.

RESULTS

From 2009 to 2018, the US Food and Drug Administration approved 343 new therapeutics with 1978 postmarketing requirements and commitments. Overall, 750 (37.9%) postmarketing requirements and commitments outlined clinical studies. For 71 of 343 (20.7%) therapeutics, no postmarketing requirements or commitments for clinical studies were outlined, while at least 1 was outlined for 272 (79.3%; median 2 (interquartile range: 1-4)). Among these 272 therapeutics, the number of postmarketing requirements and commitments for clinical studies per therapeutic did not change from 2009 (median: 2 (interquartile range: 1-4)) to 2018 (median: 2 (interquartile range: 1-3)). Among the 750 postmarketing requirements and commitments for clinical studies, 448 (59.7%) outlined new prospective cohort studies, registries, or clinical trials, while the remainder outlined retrospective studies, secondary analyses, or completion of ongoing studies. Although 455 (60.7%) clinical studies investigated only original approved therapeutic indications, 123 (16.4%) enrolled from an expansion of the approved disease population and 61 (8.1%) investigated diseases unrelated to approved indications.

CONCLUSIONS

The US Food and Drug Administration approves most new therapeutics with at least 1 postmarketing requirement or commitment for a clinical study, and outlines investigations of safety or efficacy for both approved and unapproved indications. The median number of 2 clinical studies outlined has remained relatively constant over the last decade. Given increasing emphasis by the US Food and Drug Administration on faster approval and lifecycle evaluation of therapeutics, these findings suggest that more postmarketing requirements and commitments may be necessary to address gaps in the clinical evidence available for therapeutics at approval.

Speed, Evidence, and Safety Characteristics of Vaccine Approvals by the US Food and Drug Administration

This cross-sectional study evaluates all of the novel vaccines approved by the US Food and Drug Administration over the last decade.

Reporting of Study Participant Demographic Characteristics and Demographic Representation in Premarketing and Postmarketing Studies of Novel Cancer Therapeutics

IMPORTANCE

Adequate representation of demographic subgroups in premarketing and postmarketing clinical studies is necessary for understanding the safety and efficacy associated with novel cancer therapeutics.

OBJECTIVE

To characterize and compare the reporting of demographic data and the representation of individuals by sex, age, and race in premarketing and postmarketing studies used by the Food and Drug Administration (FDA) to evaluate novel cancer therapeutics.

DESIGN, SETTING, AND PARTICIPANTS

In this cross-sectional study, premarketing and postmarketing studies for novel cancer therapeutics approved by the FDA from 2012 through 2016 were identified. Study demographic information was abstracted from publicly available sources, and US cancer population demographic data was abstracted from US Cancer Statistics. Analyses were conducted from February 25 through September 21, 2020.

MAIN OUTCOMES AND MEASURES

The percentages of trials reporting sex, age, and race/ethnicity were calculated, and participation to prevalence ratios (PPRs) were calculated by dividing the percentage of study participants in each demographic group by the percentage of the US cancer population in each group. PPRs were constructed for premarketing and postmarketing studies and by cancer type. Underrepresentation was defined as PPR less than 0.8.

RESULTS

From 2012 through 2016, the FDA approved 45 cancer therapeutics. The study sample included 77 premarketing studies and 56 postmarketing studies. Postmarketing studies, compared with premarketing studies, were less likely to report patient sex (42 studies reporting [75.0%] vs 77 studies reporting [100%]; P < .001) and race (27 studies reporting [48.2%] vs 62 studies reporting [80.5%]; P < .001). Women were adequately represented in premarketing studies (mean [SD] PPR, 0.91; 95% CI, 0.90-0.91) and postmarketing studies (mean PPR, 1.00; 95% CI, 1.00-1.01). Although older adults and Black patients were underrepresented in premarketing studies (older adults: mean PPR, 0.73; 95% CI, 0.72-0.74; Black patients: mean PPR, 0.32; 95% CI, 0.31-0.32), these groups continued to be underrepresented in postmarketing studies (older adults: mean PPR, 0.75; 95% CI, 0.75-0.76; Black patients: mean PPR, 0.21; 95% CI, 0.21-0.21).

CONCLUSIONS AND RELEVANCE

This study found that older adults and Black patients were underrepresented in postmarketing studies of novel cancer therapeutics to a similar degree that they were underrepresented in premarketing studies. These findings suggest that postmarketing studies are not associated with improvements to gaps in demographic representation present at the time of FDA approval.

Disagreements Within the US Food and Drug Administration Regarding Approval of Novel Therapeutic Agents, 2011-2015

This cross-sectional study examines the frequency of disagreements within the US Food and Drug Administration (FDA) regarding approval of novel therapeutic agents.

Assessment of Clinical Trials Supporting US Food and Drug Administration Approval of Novel Therapeutic Agents, 1995-2017

IMPORTANCE

Since the introduction of the Fast Track designation in 1988, the number of special regulatory programs available for the approval of new drugs and biologics by the US Food and Drug Administration (FDA) has increased, offering the agency flexibility with respect to evidentiary requirements.

OBJECTIVE

To characterize pivotal efficacy trials supporting the approval of new drugs and biologics during the past 3 decades.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study included 273 new drugs and biologics approved by the FDA for 339 indications from 1995 to 1997, from 2005 to 2007, and from 2015 to 2017.

MAIN OUTCOMES AND MEASURES

Therapeutics were classified by product type and therapeutic area as well as orphan designation and use of special regulatory programs, such as Priority Review and Accelerated Approval. Pivotal trials were characterized by use of randomization, blinding, types of comparators, primary end points, number of treated patients, and trial duration, both individually and aggregated by each indication approval.

RESULTS

A total of 273 new drugs and biologics were approved by the FDA in these 3 periods (107 [39.2%] in 1995-1997; 57 [20.9%] in 2005-2007; and 109 [39.9%] in 2015-2017), representing 339 indications (157 [46.3%], 64 [18.9%], and 118 [34.8%], respectively). The proportion of therapeutic approvals using at least 1 special regulatory program increased (37 [34.6%] in 1995-1997; 33 [57.9%] in 2005-2007; and 70 [64.2%] in 2015-2017), as did indication approvals receiving an orphan designation (20 [12.7%] in 1995-1997; 17 [26.6%] in 2005-2007, and 45 [38.1%] in 2015-2017). The most common therapeutic areas differed over time (infectious disease, 53 [33.8%] in 1995-1997 vs cancer, 32 [27.1%] in 2015-2017). When considering the aggregate pivotal trials supporting each indication approval, the proportion of indications supported by at least 2 pivotal trials decreased (80.6% [95% CI, 72.6%-87.2%] in 1995-1997; 60.3% [95% CI, 47.2%-72.4%] in 2005-2007; and 52.8% [95% CI, 42.9%-62.6%] in 2015-2017; P < .001). The proportion of indications supported by only single-group pivotal trials increased (4.0% [95% CI, 1.3%-9.2%] in 1995-1997; 12.7% [95% CI, 5.6%-23.5%] in 2005-2007; and 17.0% [95% CI, 10.4%-25.5%] in 2015-2017; P = .001), whereas the proportion supported by at least 1 pivotal trial of 6 months' duration increased (25.8% [95% CI, 18.4%-34.4%] in 1995-1997; 34.9% [95% CI, 23.3%-48.0%] in 2005-2007; and 46.2% [95% CI, 36.5%-56.2%] in 2015-2017; P = .001).

CONCLUSIONS AND RELEVANCE

In this study, more recent FDA approvals of new drugs and biologics were based on fewer pivotal trials, which, when aggregated by indication, had less rigorous designs but longer trial durations, suggesting an ongoing need for continued evaluation of therapeutic safety and efficacy after approval.

Updating insights into rosiglitazone and cardiovascular risk through shared data: individual patient and summary level meta-analyses

OBJECTIVES

To conduct a systematic review and meta-analysis of the effects of rosiglitazone treatment on cardiovascular risk and mortality using multiple data sources and varying analytical approaches with three aims in mind: to clarify uncertainties about the cardiovascular risk of rosiglitazone; to determine whether different analytical approaches are likely to alter the conclusions of adverse event meta-analyses; and to inform efforts to promote clinical trial transparency and data sharing.

DESIGN

Systematic review and meta-analysis of randomized controlled trials.

DATA SOURCES

GlaxoSmithKline's (GSK's) ClinicalStudyDataRequest.com for individual patient level data (IPD) and GSK's Study Register platforms, MEDLINE, PubMed, Embase, Web of Science, Cochrane Central Registry of Controlled Trials, Scopus, and ClinicalTrials.gov from inception to January 2019 for summary level data.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomized, controlled, phase II-IV clinical trials that compared rosiglitazone with any control for at least 24 weeks in adults.

DATA EXTRACTION AND SYNTHESIS

For analyses of trials for which IPD were available, a composite outcome of acute myocardial infarction, heart failure, cardiovascular related death, and non-cardiovascular related death was examined. These four events were examined independently as secondary analyses. For analyses including trials for which IPD were not available, myocardial infarction and cardiovascular related death were examined, which were determined from summary level data. Multiple meta-analyses were conducted that accounted for trials with zero events in one or both arms with two different continuity corrections (0.5 constant and treatment arm) to calculate odds ratios and risk ratios with 95% confidence intervals.

RESULTS

33 eligible trials were identified from ClinicalStudyDataRequest.com for which IPD were available (21 156 patients). Additionally, 103 trials for which IPD were not available were included in the meta-analyses for myocardial infarction (23 683 patients), and 103 trials for which IPD were not available contributed to the meta-analyses for cardiovascular related death (22 772 patients). Among 29 trials for which IPD were available and that were included in previous meta-analyses using GSK's summary level data, more myocardial infarction events were identified by using IPD instead of summary level data for 26 trials, and fewer cardiovascular related deaths for five trials. When analyses were limited to trials for which IPD were available, and a constant continuity correction of 0.5 and a random effects model were used to account for trials with zero events in only one arm, patients treated with rosiglitazone had a 33% increased risk of a composite event compared with controls (odds ratio 1.33, 95% confidence interval 1.09 to 1.61; rosiglitazone population: 274 events among 11 837 patients; control population: 219 events among 9319 patients). The odds ratios for myocardial infarction, heart failure, cardiovascular related death, and non-cardiovascular related death were 1.17 (0.92 to 1.51), 1.54 (1.14 to 2.09), 1.15 (0.55 to 2.41), and 1.18 (0.60 to 2.30), respectively. For analyses including trials for which IPD were not available, odds ratios for myocardial infarction and cardiovascular related death were attenuated (1.09, 0.88 to 1.35, and 1.12, 0.72 to 1.74, respectively). Results were broadly consistent when analyses were repeated using trials with zero events across both arms and either of the two continuity corrections was used.

CONCLUSIONS

The results suggest that rosiglitazone is associated with an increased cardiovascular risk, especially for heart failure events. Although increased risk of myocardial infarction was observed across analyses, the strength of the evidence varied and effect estimates were attenuated when summary level data were used in addition to IPD. Because more myocardial infarctions and fewer cardiovascular related deaths were reported in the IPD than in the summary level data, sharing IPD might be necessary when performing meta-analyses focused on safety.

SYSTEMATIC REVIEW REGISTRATION

OSF Home https://osf.io/4yvp2/.

[Clinical application value of prognosis of nutrition index and apparent diffusion coefficient in patient with hepatocellular carcinoma underwent transarterial chemoembolization]

Objective: To explore clinical application value of prognostic nutrition index(PNI) and apparent diffusion coefficient(ADC) in treating hepatic arterial chemoembolization (TACE) of patients with hepatic cell carcinoma (HCC). Methods: A total of 77 patients with HHC of BCLC B were retrospectively analyzed in Dalian Medical University Affiliated Second Hospital who were diagnosed for the first time and received TACE treatment from October 2017 to December 2018, of whom 64 Males, 13 females, mean age was 54±13 years.At 1 month after surgery, TACE efficacy was evaluated according to revised solid tumor evaluation criteria (mRECIST), the enrolled patients were divided into TACE effective group (41 cases, 53.2%) and TACE ineffective group (36 cases, 46.8%) to compare ability of PNI and ability of ADC alone or in combination in evaluating efficacy of TACE and the relationship between these two groups. Results: Overall postoperative PNI of enrolled patients was decreased compared with preoperative PNI, 47.7±6.6 vs 48.3±5.9 (P<0.05), preoperative and postoperative PNI of TACE effective group were all higher than that of TACE ineffective group (49.9±6.0 vs 46.6±5.3, 50.6±5.4 vs 44.4±5.1,all P<0.05), there was no significant difference in PNI between the treatment groups (P>0.05). The value of ADC in postoperative tumor region increased compared with that in preoperative tumor region ((1.43±0.15) ×10(-3) vs (1.28±0.08) ×10(-3) mm(2)/s, P<0.05), the difference between postoperative tumor region ADC value and postoperative normal liver parenchyma had no statistical significance(P>0.05). Overall postoperative PNI and tumor region ADC value of enrolled patients had linear correlation (P<0.05).Threshold value of PNI and ADC value in preoperative prediction were 51.05 and 1.32×10(-3) mm(2)/s; postoperative evaluation threshold value were 50.11 and 1.41×10(-3) mm(2)/s.Postoperative combination of PNI and ADC had the highest value in evaluating TACE efficacy. Conclusions: TACE postoperative PNI and tumor region ADC are related. PNI and tumor region ADC could be used in predicting and evaluating TACE efficacy in HCC patients, combination of these two could further increase the efficiency.

Biomarkers as Surrogate Endpoints: Ongoing Opportunities for Validation

Surrogate endpoints are a common application of biomarkers to estimate clinical benefit in clinical trials, despite questions about reliability. This article discusses ongoing opportunities for their validation, in the context of a regulatory environment in which they are increasingly championed.

[Predictive value of diffusion-weighted magnetic resonance imaging in patients with esophageal carcinoma treated with radiotherapy: an animal trial]

Objective: To explore the value of diffusion-weighted magnetic resonance imaging (MR-DWI) technique in predicting the efficacy of radiotherapy in patients with esophageal cancer, using experimental animal models. Methods: BALB/c nude mice were subcutaneously injected with Eca-109 cell lines and then tumor formed. The experimental group (16 cases) received a single dose of 15 Gy (6 MV X-rays) delivered by a medical linear accelerator, while the control group (24 cases) did not receive any treatment. The two groups were scanned every other day, started one day before the radiotherapy. The scanning sequences included T1-weight imaging, T2-weight imaging, and DWI. The observation time was 1 month. According to the changes of the tumor volume and apparent diffusion coefficient (ADC) value of the two groups, 7 key time points were selected to observe the difference of cell density and tissue necrosis ratio between the two groups (6 cases in each group). Results: From day 7 after radiotherapy, the experimental group had statistically smaller volume of transplanted tumors than the control group, namely (1.729±0.906) cm(3) vs (2.671±0.915) cm(3)(P<0.05). From day 3 after radiotherapy, the experimental group had statistically higher ADC values [(1.017±0.255)×10(-6) vs (0.833±0.142)×10(-6) mm(2)/s, P<0.05], lower cell density of transplanted tumor (25.56±1.40 vs 33.48±4.18%, P<0.05), and less proportion of tissue necrosis [(32.19±1.21) % vs (29.16±2.16)%, P<0.05], respectively. The ADC value was negatively correlated with cell density (r=-0.703, P<0.001) and positively correlated with tissue necrosis ratio (r=0.658, P=0.003). Conclusions: Single dose of large fraction radiotherapy could inhibit the growth of xenograft. ADC values may change at the early stage prior to morphological changes of tumor. The change of cell density and necrosis ratio of transplanted tumor are in line with the change of ADC value. MR-DWI has the value of early prediction of esophageal cancer radiotherapy efficacy.

Drug use and its associated factors among money boys in Hunan Province, China

OBJECTIVES

To describe drug use, types of drugs and related factors among money boys in Hunan Province, China.

STUDY DESIGN

A cross-sectional study was conducted between July 2012 and January 2013.

METHODS

Based on respondent-driven sampling, researchers located seven 'seeds' via a gay-dating website: http://www.ixxqy.org. After three waves of recruitment, 234 money boys were enrolled. They were asked to complete a 23-item questionnaire regarding demographic characteristics, drug use, a history of human immunodeficiency virus infection and family environment. Descriptive statistics and logistic regression analysis were conducted using Statistical Package for the Social Sciences Version 20.0.

RESULTS

In total, 205 valid questionnaires were collected. Based on the data collected, 80 (39.0%) money boys had used drugs within the last 3 months. Rush popper (36.6%) and methamphetamine (12.7%) were used most commonly, and other drugs used were ecstasy (7.8%), ketamine (5.9%), marijuana (2.4%), morphine (1.5%), heroin (1.0%) and cocaine (0.5%). Factors included in the logistic regression were length of service (odds ratio [OR] 0.395, 95% confidence interval [CI] 0.175-0.896), being an only child (OR 2.272, 95% CI 1.108-4.659), relationship between parents (OR 0.428, 95% CI 0.213-0.858) and social network (OR 2.387, 95% CI 1.144-4.970). A shorter length of service and a good relationship between parents were protective factors against drug use, while being an only child and having a wide social network were risk factors.

CONCLUSION

Drug use is common among money boys. This study found that length of service, being an only child, relationship between parents and social network are associated with drug use.