United States of America

United States of America


Verified on January 25, 2023

The United States of America (USA) clinical trials registry, ClinicalTrials.gov, is considered as a global platform for registering the clinical trials. It is not a World Health Organization (WHO) recognized primary registry. However, the clinical trials registered on this registry fulfill the criteria for publication of manuscript in an International Committee of Medical Journal Editors (ICMJE) accredited journal. In the USA, registration of protocols and submission of results is governed by the NIH Final Rule (42 CFR Part 11), which has been in effect since January 18, 2017. This regulation requires registration and results reporting for phase 2-4 interventional clinical trials.

Registries at a Glance
Registry PHUSE Categorization Information to be Entered By Route of Data in Registry Study Type Language
ClinicalTrials.gov Country requiring/recommending ClinicalTrials.gov use Sponsor Through a dedicated registration platform (process independent from clinical trial application)


(Phase 2-4)
Registration and Results Requirements
Registry Activity Legal Requirement Timing
ClinicalTrials.gov Registration


Within 21 days of first patient enrollment


Primary Results - within one year of primary completion date (PCD); Subsequent Results - within one year of the last subject last visit for each secondary outcome measure (SOM); Final Results - within one year of the study completion date

Regulation effective since January 18, 2017

Registry Name




Study Type
Interventional required
Observational optional
Study Phase 2 to 4
When to Register Within 21 days of the first subject enrollment
Timing of Registration Prospective and Retrospective
Scope Applicable clinical Trials (ACT) – Interventional Phase 2-4 clinical trials that are either investigational new drug (IND) or investigational device exemption (IDE) trials or conducted in the USA or study drug manufactured/exported from the USA
Registry Site https://clinicaltrials.gov
Registration Site https://register.clinicaltrials.gov/
Language English
Data Fields

Protocol Data Elements

QA Review


Registration Publicly Available


Alternate Registry


Additional Details
  • After submitting (releasing) a study record to ClinicalTrials.gov, it is reviewed by a ClinicalTrials.gov staff member before publishing, for apparent validity (when possible), meaningful entries, logic and internal consistency, and formatting. The review may take up to a few days.
  • Reviewers can provide feedback, clarify items or make corrections to the record before publication. Registration records should be updated within 15 calendar days after feedback was provided.
  • Once the study record is submitted and accepted by review staff for publication, a National Clinical Trial (NCT) Number is assigned. Then the record, including its NCT Number, will be available on ClinicalTrials.gov within 2–5 business days.
  • Registration should be updated within 30 days of a change to any of the following:
    1. Individual Site Status and Overall Recruitment Status data elements on ClinicalTrials.gov.
    2. Primary Completion Date data elements on ClinicalTrials.gov.
  • Other changes or updates to the record must be made at least every 12 months. It is recommended that the Record Verification Date be updated at least every 6 months for studies that are not yet completed, even if there were no changes to the record.
  • There are no requirements for registration of observational studies.
  • In general, clinical trial registration information submitted to ClinicalTrials.gov must be updated not less than once every 12 months.
  • There are no legal requirements for registration of interventional Phase 1 or observational clinical trials. However, sponsors can voluntarily register such trials.
  • The expanded access (EA) record for investigational drug or biological product must be submitted based on when the EA becomes available:
    1.  After the ACT information is submitted: no later than 30 calendar days after it becomes available.
    2.  At the time of ACT information submission: no later than the ACT registration deadline (within 21 calendar days of first enrollment).

Timeline for Disclosure

Figure 1: Timeline of Clinical Trial Disclosures in the USA

Upcoming Changes

There are no changes expected with respect to the registry or the requirement in the near future which may directly affect the protocol registration and result posting procedure.

Registry Updates


  1. ClinicalTrials.gov Protocol Registration Data Element Definitions for Interventional and Observational Studies. ClinicalTrials.gov. https://prsinfo.clinicaltrials.gov/definitions.html. Published June 27, 2018. Accessed March 13, 2019.
  2. ClinicalTrials.gov Results Data Element Definitions for Interventional and Observational Studies. ClinicalTrials.gov. https://prsinfo.clinicaltrials.gov/results_definitions.html. Published June 27, 2018. Accessed March 13, 2019.
  3. Frequently Asked Questions – ClinicalTrials.gov. ClinicalTrials.gov. https://clinicaltrials.gov/ct2/manage-recs/faq#fr_23. Published November 2018. Accessed March 13, 2019.
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