What is it? Why is it important?

Interim database locks (IL) are performed before all data has been collected due to required:

  • Interim evaluation(s) of the study based on specification given in the study protocol (e.g. safety and efficacy concerns)
  • Data cleaning processes during long term studies

Timing of data cleaning and query resolution should be planned both:

  • Prior to an IL as the data will be used for statistical analysis and study interim evaluation
  • After an IL lock with checks on an ongoing basis in order to detect incorrect and missing data


Database locks and evaluations during study conduct must always be based on specifications and rationales given in the study protocol (e.g. e.g. safety and efficacy concerns). Requests for an interim analysis during study conduct might also be forwarded by the DSMB and/or EC.

Data analysis not based on specifications in the study protocol carries the risk of corrupting the study, as the researcher is no longer an independent bystander of the study but become biased as to study outcome.

What do I need to do?

  • Follow the timeline of interim database locks as defined in the study protocol
  • As applicable, ensure data cleaning and query resolution are finalised before any IL
  • Inform stakeholders of an upcoming IL including the expected lock duration
  • Follow database lock procedures
  • For the interim evaluation follow:
    • Defined data export procedures for transfer to a statistical software system
    • If applicable, ensure data remains blinded to the SP-INV and statistician during data evaluation


Database locks during study conduct can put increased pressure on site staff and people involved in data collection and management. Still, in order to ensure data quality and be prepared for upcoming locks, train and remind the staff to enter data consistently and regularly.

Safety and efficacy information provided by the interim analysis will help to determine whether the study should be continued, adapted or terminated.

Where can I get help?

Your local CTU can support you with experienced staff regarding this topic


ICH GCP E6(R2) – see in particular guidelines

  • 5.5. Trial Management, data handling, and record-keeping
  • CTU – Clinical Trials Unit
  • DSMB – Data Safety Monitoring Board
  • IL – Interim Lock
  • SP-INV – Sponsor Investigator
Conduct ↦ Data Handling ↦ Data Handling ↦ Interim Lock

Provides some background knowledge and basic definitions

Basic Protocol
Basic Statistics
Basic Monitoring
Basic Drug or Device
Basic Biobanking

Starts with a study idea

Ends after having assessed and evaluated study feasibility

Concept Protocol
Concept Statistics
Concept Drug or Device
Concept Biobanking

Starts with confidence that the study is feasible

Ends after having received ethics and regulatory approval

Development Protocol
Development Statistics
Development Drug or Device
Development Biobanking

Starts with ethics and regulatory approval

Ends after successful study initiation

Set-Up Protocol
Set-Up Ethics and Laws
Set-Up Statistics
Set-Up Quality and Risk
Set-Up Drug or Device
Set-Up Biobanking

Starts with participant recruitment

Ends after the last participant has completed the last study visit

Conduct Protocol
Conduct Statistics
Conduct Drug or Device
Conduct Biobanking

Starts with last study visit completed

Ends after study publication and archiving

Completion Protocol
Completion Statistics
Completion Drug or Device
Completion Biobanking
Current Path (click to copy): Conduct ↦ Data Handling ↦ Data Handling ↦ Interim Lock

Please note: the Easy-GCS tool is currently under construction.