Phasing Out the Classic PRS: Timeline, Features, and User Support

The National Library of Medicine (NLM) has completed the multi-year modernization effort for the Protocol Registration and Results System (PRS) and the public website, ClinicalTrials.gov. The Modernized PRS is now the primary system for protocol registration and results submission, and NLM continues to add new features and make improvements based on user feedback.

Because most of the features found on the classic website are now available on the modernized website, the timeline for phasing out the Classic PRS has been established. The timeline below outlines the plan of events and highlights recent and upcoming enhancements to the Modernized PRS.

The Transition to the Modernized PRS

NLM has been closely monitoring the adoption of the Modernized PRS. Features of the Classic PRS will be phased out as adoption thresholds are reached. User feedback plays a central role in this process by directly shaping enhancements to the Modernized PRS and helps support users as they transition from one website to the other. As of April 2026, more than 80% of users register new records in the Modernized PRS instead of the Classic PRS.

• August 2024 - The Modernized PRS became the primary system for protocol registration.
• September 2025 - The Modernized PRS became the primary system for creating, editing, and viewing the Study Documents and Results Sections.
• July 2026 - Users will no longer be able to create a new record in the Classic PRS. Users who navigate to the classic website to register a new record will be redirected to the Modernized PRS.
• Fall 2026 - All protocol submissions must be completed in the Modernized PRS.
• 2027 (target) - The Classic PRS Results Section modules and XML upload feature will be phased out as adoption thresholds are met. NLM will continue to provide updates on the timeline to the full retirement of the Classic PRS.

During the process of phasing out the Classic PRS, NLM will keep users informed through alerts, banners, and the PRS Release Notes. For example, starting this month, any users going to the Classic PRS to register a new record will see a pop-up informing them of the planned phase out, and can navigate to the Modernized PRS to complete their work.

Modernized PRS Updates and New Features

As the Classic PRS is phased out, the Modernized PRS will continue to expand its functionality to match and build on what users relied on before. Highlights of updated and upcoming features are discussed below.

Users of the Modernized PRS can now use XML upload for a single study record with both Protocol Registration and Results data, in addition to a record with the Protocol Section alone. This update eliminates the need for users to fill in each data field individually. The ability to use XML upload for partial record data (e.g., for the Results Section) is planned for release this summer.

Columns were added to the Record List from the Record Information Download page of the Classic PRS that expand the functionality of the Record List for PRS administrators.

The Record Summary page was redesigned to make it easier for users to identify the current status of a record, as well as the next step in the record process.

Figure 1. The redesigned Record Summary page

Modernized PRS users will also notice that the Status Dashboard now provides a unified view of the record modules and the corresponding number of system validations and review comments. A single-click dashboard filtering was added to enable users to narrow their focus to only the modules with issues.

Figure 2. The Status Dashboard

The Delayed Results module of the Results Section was recently released. Updated features of this module include the addition of improved on-screen guidance and the dynamic presentation of relevant fields depending on whether a certification or extension is chosen. Future release plans include the addition of the administrative features for record management.

User support

The Modernized PRS includes updated instructional content both on-screen and in the Modernized PRS Guided Tutorials. The tutorials have been updated for Protocol Registration, and updates to content for the Results modules are in progress. Please continue to provide us with feedback using the button on the lower right-hand corner of the website.

Editor's Note: "API" was removed from the "2027 (target)" bullet. API features will remain in place.