Frequently Asked Questions

Contents

• General
  • Is there a charge for listing studies on ClinicalTrials.gov?
  • My study is not yet approved by a human subjects review board (ethics review committee, institutional review board). Can I enter it on ClinicalTrials.gov?
  • Why can't I find my study on ClinicalTrials.gov?
  • When will the NCT Number for my study be assigned?
  • Can I register a study after it has started, has closed to recruitment, or has completed?
  • How do I contact ClinicalTrials.gov if I have a question about my study record?
• Protocol Registration System (PRS) Accounts
  • Can an organization have multiple users in a single account?
• Uploading Study Data to ClinicalTrials.gov
  • Can protocol information be uploaded electronically to ClinicalTrials.gov?
• Results
  • Am I required to submit the results to ClinicalTrials.gov of a clinical trial that is not an Applicable Clinical Trial?
  • How do I submit results information if the trial is terminated (that is, stopped prematurely) and no data were collected for one or more outcome measures?

Additional questions about managing study records may be sent to ClinicalTrials.gov staff (register@clinicaltrials.gov).

General

Is there a charge for listing studies on ClinicalTrials.gov?

No, there is no charge for listing studies on ClinicalTrials.gov. ClinicalTrials.gov is a free service of the National Institutes of Health, provided through the National Library of Medicine.

My study is not yet approved by a human subjects review board (ethics review committee, institutional review board). Can I enter it on ClinicalTrials.gov?

Most trials require approval from a human subjects review board. If your study requires approval, you may register your study on ClinicalTrials.gov prior to getting approval if the Overall Recruitment Status of the study is "Not yet recruiting." See Overall Recruitment Status data element on ClinicalTrials.gov .

If a study requires human subjects review board approval, approval must be obtained before the study's Overall Recruitment Status is changed to Recruiting. When board approval is obtained, please update the protocol section of the study record in the Protocol Registration System (PRS) and release the study for processing.

See How to Register Your Study and How to Edit Your Study Record for more information.

Why can't I find my study on ClinicalTrials.gov?

It might not have been released (that is, submitted) to ClinicalTrials.gov for processing. After a record has been entered into PRS (or has been modified) and marked as Complete, it must be Approved and Released by the Responsible Party (see Responsible Party data element on ClinicalTrials.gov )

It might be undergoing review. After the Responsible Party releases (submits) information to ClinicalTrials.gov, that information undergoes a manual review to identify possible errors, deficiencies, or inconsistencies that are not detected automatically during data entry. The Responsible Party will be notified of any necessary corrections, usually within a few days after release of the protocol information. The review of results information may take longer (up to 30 days), depending on the quantity and complexity of information submitted.

See How to Register Your Study and How to Submit Your Results for more information.

When will the NCT Number for my study be assigned?

The NCT Number, also called the ClinicalTrials.gov Identifier, is assigned after the protocol information has been released (that is, submitted) by the Responsible Party and passed review by ClinicalTrials.gov staff. At that time an e-mail notification with the NCT Number is sent. The record, including its NCT Number, will typically be available on ClinicalTrials.gov within 2–5 business days after it is released.

See How to Register Your Study for more information.

Can I register a study after it has started, has closed to recruitment, or has completed?

Yes, you can register a study on ClinicalTrials.gov at any time. Please note that, in general, Section 801 of the Food and Drug Administration Amendments Act (FDAAA 801) requires Applicable Clinical Trials to be registered within 21 days of enrollment of the first participant. In addition, the International Committee of Medical Journal Editors and other journals require registration of clinical trials prior to enrollment of the first participant.

See FDAAA 801 Requirements for more information.

How do I contact ClinicalTrials.gov if I have a question about my study record?

If you have questions or need assistance with how to update your record, you may email ClinicalTrials.gov staff (register@clinicaltrials.gov). If the question is about a specific study record, please provide the NCT Number or the Unique Protocol ID (if an NCT Number is not yet assigned). Please include sufficient information about the issue so that we may better assist you. We generally respond to all emails within one business day.

Protocol Registration System (PRS) Accounts

Can an organization have multiple users in a single account?

Yes. When sponsors or their representatives register to become PRS data providers, they will be given information on using PRS, including instructions for creating additional user accounts.

See How to Apply for an Account for more information.

Uploading Study Data to ClinicalTrials.gov

Can protocol information be uploaded electronically to ClinicalTrials.gov?

Yes. This option is available in PRS as an HTTP upload of an Extensible Markup Language (XML) formatted file. After obtaining a PRS account, login to PRS and refer to the User's Guide for information on XML upload.

See How to Apply for an Account for help with obtaining a PRS account.

Results

Am I required to submit the results to ClinicalTrials.gov of a clinical trial that is not an Applicable Clinical Trial?

Results submission is not required under FDAAA 801 for a clinical trial that is not an Applicable Clinical Trial (for example, a phase 1 trial studying a Food and Drug Administration (FDA)-regulated investigational new drug). If a Responsible Party chooses to voluntarily submit results for such a trial, however, the Voluntary Submissions (PDF) provision of FDAAA 801 may apply.

Under the Voluntary Submissions (PDF) provision, a Responsible Party who submits results for such a clinical trial must submit complete clinical trial results information and must also submit results for each Applicable Clinical Trial that is required to be submitted to FDA under Section 505, 510(k), 515, 520(m) of the Federal Food, Drug, and Cosmetic Act or Section 351 of the Public Health Service Act for the same use studied.

How do I submit results information if the trial is terminated (that is, stopped prematurely) and no data were collected for one or more outcome measures?

If no participants were ever enrolled in the trial, set the Overall Recruitment Status to "Withdrawn", and no further results information needs to be submitted.

For a trial that was terminated after participants were enrolled, provide any available data. If no data are available for any of the Outcome Measures, specify zero ("0") for the Number of Participants Analyzed in each Arm/Group, and leave the data fields blank. In this case, provide an explanation in the Analysis Population Description for why zero participants were analyzed and, if appropriate, provide information in the Limitations and Caveats module. Even if data are not entered for Outcome Measures, submit the available data for the enrolled participants in the Participant Flow, Baseline Characteristics, and Adverse Events modules.