1. Snapshot of the Clinical Trials Enterprise as revealed by ClinicalTrials.gov
Download date: Sept 2011

2. Background
Background on ClinicalTrials.gov and the creation of the AACT database is available at
The ClinicalTrials.gov website:
CTTI’s website:

3. 2011 Update of the Database for the Aggregate Analysis of ClinicalTrials.gov (AACT)
Design
Downloaded XML dataset of all clinical studies from ClinicalTrials.gov on September 27*, 2011
Designed and implemented relational database to facilitate aggregate analysis of data
Uses of Aggregate Data
Examine the “Clinical Research Enterprise”
Provide information to specific user communities
Examine the quality and completeness of reporting
* Includes studies publicly released by ClinicalTrials.gov through 25 September 2011

4. Studies registered at ClinicalTrials.gov
Studies included in Sep 2011 download
N=113,909
Interventional Studies
N=92,946
Registered prior to Oct 2007
N=38,388
Registered on/after 1 Oct 2007
N=54,558
Observational Studies
N=20,448
Expanded Access Studies
N=145
Study Type not applicable
N=370
Snapshot analysis is focused on these studies.

5. Overview
Funding
Study Phase
Intervention Types

6. Funding
Derived as follows:

7. Funding

8. Study Phase

9. Funding by Phase

10. A study may have more than one intervention type
Intervention Types
A study may have more than one intervention type
N=1 study missing intervention type information

11. Intervention Types
Studies of drugs, biologics and devices in phases 2-4 are required to be registered by FDAAA.
+ Includes behavioral, radiation, dietary supplement, in addition to other interventions
N=1 study missing intervention type information

12. Intervention Types by Phase
Studies of drugs, biologics and devices in phases 2-4 are required to be registered by FDAAA.
+ Includes behavioral, radiation, dietary supplement, in addition to other interventions
N=1 study missing intervention type information

13. Sites/Participants Single- and multi-center studies
Number of sites for multi-center studies
Enrollment
Location of sites
Eligibility: sex
Eligibility: age restrictions and exclusions

14. Single-Center and Multi-center Studies
N=4,007 studies missing information about number of centers

15. Single-center and Multi-center Studies by Phase
N=4,007 studies missing information about number of centers

16. Median Number of Sites/Study for Multi-center Studies
Based on N=17,279 multi-center studies with information about number of sites

17. Number of Subjects/Study (Anticipated or Actual enrollment)
N=701 studies have missing enrollment

18. Median Enrollment by Phase
N=701 studies have missing enrollment

19. Median Enrollment by Funding
N=701 studies have missing enrollment

20. Location of Study Sites
N=3,378 studies have missing information about location of study sites
A study can have sites in multiple regions
Location information based on the address of facilities listed in the study record, and countries where sites were previously listed but removed from the current study record.
Regions are defined according to
Central and South America combined into C&S America Pacifica, and East, North, South, and Southeast Asia combined into Pacifica/Asia

21. Studies with Sites in U.S. and Rest of World (R.O.W.)
N=3,378 studies have missing information on U.S. locations

22. Eligibility: Sex

23. Eligibility: Age Restrictions
+ All studies under consideration (N=54,558) provided information on minimum and maximum age restrictions, although some indicated that there were no restrictions (responded “N/A”). The % of studies with restrictions was calculated among all studies.

24. Eligibility: Age Exclusions
+ All studies under consideration (N=54,558) provided information on minimum and maximum age restrictions, although some indicated that there were no restrictions (responded “N/A”). The % of studies with restrictions was calculated among all studies.

25. Study Characteristics
Primary Purpose
Number of arms
Randomization
Masking — knowledge of intervention assignments (open label, single-blind, or double-blind)
Data Monitoring Committee — whether a data monitoring committee was appointed for this study

26. Primary Purpose N=3,668 studies have missing primary purpose
+ Includes the categories supportive care, screening, health services research, and basic science

27. Primary Purpose by Phase
N=3,668 studies have missing primary purpose
+ Includes the categories supportive care, screening, health services research, and basic science

28. Number of Arms
N=1,878 studies have missing information on number of arms and 2 studies reported no arms

29. Number of Arms by Phase
N=1,878 studies have missing information on number of arms and 2 studies reported no arms

30. Randomization
N=1,797 studies have missing randomization information

31. Randomization by Phase
N=1,797 studies have missing randomization information

32. Masking
N=1,131 studies have missing masking information

33. Masking by Phase
N=1,131 studies have missing masking information

34. Data Monitoring Committee (DMC)

35. DMC by Phase

36. Regression Analyses of DMC use, Blinding, and Randomization
Associations Between Study Characteristics and DMC use, blinding, and randomization
Logistic regression analysis of
DMC use (yes versus no)
Blinding (single- or double-blind masking versus unblinded)
Randomization (yes versus no or NA: single-arm)

37. DMC Use: Multivariable Odds Ratios
Odds Ratio (95% CI)
Funding
(vs. Industry)
Phase
(vs. Phase 3)
Intervention
(vs. Drug/Biological)
Purpose
(vs. Treatment)
* Per 1000 participants; # Per increment of 2 yrs; + Includes supportive care, screening, health services research, and basic science

38. Blinding: Multivariable Odds Ratios
Odds Ratio (95% CI)
Funding
(vs. Industry)
Phase
(vs. Phase 3)
Intervention
(vs. Drug/Biological)
Purpose
(vs. Treatment)
* Per 1000 participants; # Per increment of 2 yrs; + Includes supportive care, screening, health services research, and basic science

39. Randomization: Multivariable Odds Ratios
Odds Ratio (95% CI)
Funding
(vs. Industry)
Phase
(vs. Phase 3)
Intervention
(vs. Drug/Biological)
Purpose
(vs. Treatment)
* Per 1000 participants; # Per increment of 2 yrs; + Includes supportive care, screening, health services research, and basic science

40. Trends in Data 2007-2011 Change in Number of Trials Funding
Decrease in trials funded by industry
Increase in trials funded by “other” (Not industry or NIH)
Type and Purpose of Trials
Concomitant decrease in trials including a drug intervention, and trials with treatment as the primary purpose
Trial Phase
Decrease in number of trials appears to be similar across phases I-IV
Location
Decrease in trials with sites in the US
Increase in trials with only non-US sites

41. Trends in Data 2007-2011 Enrollment
remained fairly constant over time within trial phase
NIH supported studies have larger median enrollment compared to studies funded by industry or other sources (although NIH supports a smaller number of studies overall)
Trial Arms
Two arm trials predominate (>6000 registered per year)
Large portion of the clinical trials portfolio consists of single arm trials (~4000 registered per year)
most common in phase 1-2, but are also reported to be used in phases 2/3, 3, and 4 and in trials where phase is not applicable

42. Funding Disclosure
Financial support for this work was provided by grant U19FD from the U.S. Food and Drug Administration awarded to Duke University for the Clinical Trials Transformation Initiative