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Modernization Transition Top Questions

Responses to top questions about the modernized ClinicalTrials.gov website and transition to the modernized Protocol Registration and Results System (PRS) are provided below.

Modernized ClinicalTrials.gov

When was the classic version of ClinicalTrials.gov retired?

The classic ClinicalTrials.gov was retired on June 25, 2024. At that time, the classic application programming interface (API), a tool to help researchers and developers access the data in ClinicalTrials.gov study records, was also retired.

Is there a new API available to replace the classic API?

Yes. A modernized API(https://clinicaltrials.gov/data-api/about-api) has replaced the classic API, which was retired on June 25, 2024. An API migration guide(https://clinicaltrials.gov/data-api/about-api/api-migration) is available to help users understand the differences between the classic API and the modernized API. Additional support materials include documentation on the Study Data Structure(https://clinicaltrials.gov/data-api/about-api/study-data-structure) and Search Areas(https://clinicaltrials.gov/data-api/about-api/search-areas) pages of the modernized ClinicalTrials.gov.

As background, the application programming interface, or API, is a tool to help researchers and developers access the data in ClinicalTrials.gov study records. The ClinicalTrials.gov API version 2.0 for the modernized website was finalized in February 2024 and has been updated several times since then.

I bookmarked pages on the classic ClinicalTrials.gov website. Will my bookmarks still work?

Although the classic ClinicalTrials.gov has been retired, many bookmarks for pages on the classic site are being redirected to the modernized site. Most of the regulatory and other informational content was migrated from the classic website to the modernized site, and users who try to view that information using links to the classic site are automatically redirected to the equivalent information on the modernized website. Some of this content was reorganized or restructured, but all the essential information is there. Because there may occasionally be broken links, it is important to update your bookmarks to go directly to the relevant pages on the modernized site.

If you used the expert search feature on the classic website and bookmarked results of searches that involved a complex search expression, you may still be able to use those bookmarks. When you visit the bookmarked page, the modernized ClinicalTrials.gov will interpret the expression and redirect you to the search results page on the modernized site. If these search results look different from the search results on the classic website, it may be because the modernized ClinicalTrials.gov does not support some of the filters from your complex search. If this is the case, an information alert will be displayed above the search results. Check the Focus Your Search sidebar to see which filters were applied and update them as needed.

What happened to my saved studies on the classic ClinicalTrials.gov website?

You will have to recreate your list of saved studies on the modernized ClinicalTrials.gov website. You can do this by entering the NCT Numbers of the studies of interest in the Other terms field or the Study IDs field under “Focus Your Search.” Then follow these instructions for saving studies(https://clinicaltrials.gov/find-studies/how-to-use-search-results#save-studies). You can also use any of the Focus Your Search fields to conduct new searches.

Are the search results on the modernized ClinicalTrials.gov the same as on the classic website?

As a result of improvements to the ClinicalTrials.gov search function, search results are not the same on the modernized website; the modernized website’s search results are more targeted and refined. This is due to differences in the search algorithm for the new website, resulting in a different number of results being returned for the same search. Examples of the differences in the search logic include the following:

  • Synonym recognition is more precise using the modernized site’s search logic.
  • If a location and distance are specified on the modernized site’s search form, the search results will be biased by proximity to the closest location for every study.

We created a Search Areas(https://clinicaltrials.gov/data-about-studies/search-areas) page that describes the ClinicalTrials.gov search logic and provides more examples like these.

Now that the classic ClinicalTrials.gov website has been retired, when will I see my favorite features on the modernized ClinicalTrials.gov website?

Most of the features of the classic website are available on the modernized website. These include the search function, study record details, the record history version comparison, the ability to download study results in different formats, a modernized API, the ability to save studies, and the ability to create an RSS feed to save searches. We will continue to improve the features of the modernized site and, potentially, add new ones. User feedback and usage information will inform decisions about which additional features will be completed and in what order. To learn about features that may be added to the modernized ClinicalTrials.gov, please visit the Planned Features on ClinicalTrials.gov(https://clinicaltrials.gov/about-site/planned-features) page.

Yes. The modernized ClinicalTrials.gov provides an RSS feed, which allows users to save a search from the search results page. You can also save and download individual studies from your searches. Another way to save a search is to bookmark the search results page. To learn more about creating RSS feeds, see these detailed instructions(https://clinicaltrials.gov/find-studies/rss).

Will the information about the Final Rule (42 CFR Part 11) that was located at https://prsinfo.clinicaltrials.gov continue to be available?

Most of the information and documents found on the Final Rule (42 CFR Part 11) Information page (prsinfo.clinicaltrials.gov) have been incorporated into the modernized ClinicalTrials.gov website for convenience and ease of acces. This includes resources on formatting and submitting studies and results, information about PRS accounts, regulatory information, and the protocol registration and results data element definitions. Since June 25, 2024, users have been automatically redirected from prsinfo.clinicaltrials.gov to the relevant pages on the modernized website. Please make sure to update your bookmarks and links to reflect the new URLs.

If you created a complex search expression using the classic website’s expert search feature and bookmarked the search results, you may still be able to use that bookmark. When you visit the bookmarked page, the modernized ClinicalTrials.gov will interpret the expression and redirect you to the search results page on the modernized site. Your search results may be different from the search results on the classic website because the modernized ClinicalTrials.gov may not support some of the filters from your complex search. If this is the case, an information alert will be displayed above the search results. Check the Focus Your Search sidebar to see which filters were applied and update them as needed.

If you saved the text of a complex search expression that you created using the classic site’s expert search, you can paste it in the Other terms field under Focus Your Search on the modernized site and conduct the search again. In most cases, ClinicalTrials.gov will be able to interpret the complex search expression and return search results. If you receive an error due to unsupported operators, review the Constructing Complex Search Queries(https://clinicaltrials.gov/find-studies/constructing-complex-search-queries) page and update your search expression.

Modernized PRS (PRS Beta)

What features are available in the Modernized PRS?

Currently, users can complete the entire protocol registration process and submit the Protocol Section of a study record to ClinicalTrials.gov for review using the Modernized PRS. Users can email others with record access directly from the Record List. They can also control who can access a record and copy and download the Protocol Section from the Record Summary page. PRS Administrators can access the Planning View and Public Site View to manage records, and reviewers can add, edit, and delete comments on protocol registration records.

If I’m working in the classic version of the PRS, will my updates also appear in the Modernized PRS?

Yes. Any information entered and saved in one version of the PRS will be available in the other, so your work will be accessible in either version and will not be lost. For example, you can make changes to a record using the Modernized PRS, and those changes will also be saved in the Classic PRS. We encourage data submitters to use the Modernized PRS to work on real study records as much as possible.

Can PRS users switch between the Modernized PRS and the Classic PRS?

Yes, users can switch between the Modernized PRS and the Classic PRS. To access any functionalities that are not yet available in the Modernized PRS, users will need to return to the Classic PRS. Any changes made using either the Classic or Modernized PRS will appear in both. Please note that users should save their work before switching between the two versions of the PRS.

When will the Modernized PRS be completed?

Development of the Modernized PRS is continuing into 2025 as we build tools such as those needed to submit study results and manage accounts. We will communicate the progress made on the Modernized PRS as those tools are released through the Release Notes(https://register.clinicaltrials.gov/prs/beta/public/release-notes-prod) page, the Hot Off the PRS!(https://public.govdelivery.com/accounts/usnlmocpl/subscriber/new?topic_id=usnlmocpl_30) e-bulletin, and other channels.

How soon will the Modernized PRS become the primary site?

The Modernized PRS will become the primary system for completing and submitting the Protocol Section of a study record in August, 2024. Users will be able to submit protocol registrations using the Modernized PRS, but they will need to return to the Classic PRS to complete results submissions and to use other features. Please note that study records with results, delayed results, or study documents will open only in the Classic PRS.

When will the Classic PRS be retired?

The Classic PRS will remain available until all components of the Modernized PRS have been built and are fully functional. The timeline for retiring the Classic PRS has not been determined yet, but retirement will not occur before 2025.

Can I practice using the Modernized PRS before using it to submit my study record?

Features of the Modernized PRS are first deployed in PRS Test, a sandbox environment where users can explore features and practice registering a clinical trial. PRS Test is for training purposes only, and any changes made in PRS Test will not affect the actual PRS. We encourage users to explore and become familiar with the Modernized PRS using the PRS Test environment. To obtain a PRS Test account, please contact us at register@clinicaltrials.gov.

I'm currently using XML uploads to create and update my records in the PRS. What will happen to this feature when the Modernized PRS becomes the primary interface for registering studies?

The XML upload feature of the Modernized PRS is still under development, but options to upload records using XML and to upload records from the National Cancer Institute Clinical Trials Reporting Program (NCI CTRP) can be found in the Records menu on the Record List page of the Modernized PRS. Currently, clicking on either of these options will return you to the Classic PRS to complete those actions.

Does the Problems column on the Record List page of the Modernized PRS list the same problems as the Classic PRS?

Any errors associated with the Results Section, Document Upload module, or Delayed Results module of a study record will not be included in the Record Has Errors count in the Modernized PRS because those parts of the system are still under development. Also, the Record Has Errors count will not include errors for studies with a Study Start Date before January 17, 2017. For an accurate count of errors for these types of records, users should switch to the Record List in the Classic PRS.

What should I do if I notice differences between the information displayed in the Modernized PRS and the Classic PRS?

If you notice differences between the information displayed on the Modernized PRS and the Classic PRS, please use the yellow Feedback button in the bottom, right-hand corner of the website to notify us. Provide as much detail about the discrepancy as possible and continue your work using the Classic PRS. The Classic PRS should be considered the source of truth and will have the most up-to-date information. Our team will investigate and resolve all reported discrepancies as soon as possible.

Last updated on October 02, 2024