What is it? Why is it important?

A study can terminate prematurely because:

  • Participant recruitment is low and cannot reach the required number needed for the interpretation of the study
  • New research findings make the study obsolete
  • Based on an interim analysis results show:
    • Early-evidence of futility and / or the inability of the study to achieve its objectives (e.g. unable to achieve statistical significance)
    • The risk-benefit ratio is unacceptable (e.g. risks to participants outweighs expected benefits)
  • Inspection findings require that the study be stopped (e.g. due to the breach of safety laws, serious quality assurance deviations)


A study can also be terminated prematurely because;

  • Study termination criteria (e.g. number of recruited study participants) are met earlier than originally planned
  • An interim analysis shows evidence of an early benefit. Thus, the study hypothesis is proven before the end of the study


In an interim Analysis (IA), the treatment effect of an intervention is assessed before the data collection of the study is complete. The aim is to assess the safety, efficacy, and progress of the study, while the study is still ongoing.

What do I need to do?

As a SP-INV:

  • Ensure to comply with the:
    • Statistical analysis plan of the study (e.g. defined in the study protocol)
    • Any pre-defined interim analyses (e.g. data analysis prior to study completion)
    • Safety monitoring plan
  • If applicable, include a DSMB and define criteria for premature study termination
  • Report premature study termination to the Ethics Committee (EC) / RA (e.g. Swissmedic), participating study sites, and study participants


As a Site-NV:

  • Promptly inform study participants
  • As required, implement applicable therapies and follow-up of participants


It is unethical to:

  • Expose participants to new and added risks once these have been identified during study conduct (e.g. unacceptable toxicity)
  • Expose participants to less effective treatments after a treatment has proven to be effective (e.g. placebo controlled studies)
  • Postpone treatment in the medical community once it has been shown to be highly effective


In order to allow for an evaluation of study futility and/or its risk-benefit ratio, the DSMB will have access to un-blinded data (e.g. known treatment allocation). In the event that the study will want to continue, it is crucial that the study team remains blinded to any treatment allocation (e.g. SP-INV, Site-INV, respective study staff)

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

  • 1.25 Independent data-monitoring committee
  • 4.12 Premature Termination INV
  • 5.5.2 Trial management, data handling, and record keeping
  • 5.21 Premature Termination SP-INV

Declaration of Helsinki – see in particular principles

  • 16-18 Risks, burdens and benefits

ISO 14155:2020 Medical device (access liable to costs) – see in particular sections

  • 5.6.4 Continuing communication with the EC
  • 5.8.4 Information to be provided to the subject
  • 8.2 Suspension or premature termination of the clinical investigation

Swiss Law

ClinO – see in particular articles

  • Art. 38 Notification and reporting upon completion, discontinuation or interruption of a clinical trial
  • Art. 57 Transplant studies -notifications and reporting
  • Art. 62 Other studies - applicable provisions

ClinO-MD – see in particular article

  • Art. 36 Reporting the conclusion, termination or interruption of a clinical trial

HRO – see in particular article

  • Art. 22 Notification upon completion or discontinuation
  • ClinO – Clinical Trials Ordinance
  • ClinO-MD – Ordinance on Clinical Trials with Medical Devices
  • CTU – Clinical Trials Unit
  • DSMB – Data Safety Monitoring Board
  • EC – Ethics Committee
  • EC/RA – Ethics Committee / Regulatory Authorities
  • HRO – Human Research Ordinance
  • ICH GCP – International Council for Harmonisation - Good Clinical Practice
  • INV – Investigator
  • ISO – International Organization for Standardization
  • RA – Regulatory Authorities
  • Site-INV – Site Investigator
  • SP-INV – Sponsor Investigator
Conduct ↦ Ethics and Laws ↦ Premature Study Termination ↦ Rationale

Provides some background knowledge and basic definitions

Basic Monitoring
Basic Drug or Device

Starts with a study idea

Ends after having assessed and evaluated study feasibility

Concept Drug or Device

Starts with confidence that the study is feasible

Ends after having received ethics and regulatory approval

Development Drug or Device

Starts with ethics and regulatory approval

Ends after successful study initiation

Set-Up Ethics and Laws
Set-Up Quality and Risk
Set-Up Drug or Device

Starts with participant recruitment

Ends after the last participant has completed the last study visit

Conduct Drug or Device

Starts with last study visit completed

Ends after study publication and archiving

Completion Statistics
Completion Drug or Device
Current Path (click to copy): Conduct ↦ Ethics and Laws ↦ Premature Study Termination ↦ Rationale

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