Your Easy Guide to Clinical Studies

A Placebo or Comparator is used as a control in interventional studies.

 

A placebo is:

• A product that does not contain an active substance and thus expected to be harmless (e.g. sugar pill, saline/water solution).

A comparator corresponds:

• To a treatment, management, or clinical practice that is routinely accepted and used for patients with the condition under study. A common comparator is the current Standard of Care (SOC)

 

The aim of using a:

• Placebo is to confirm that any observed safety or efficacy differences between the placebo and the intervention group can be attributed to the intervention (e.g. placebo has no effect)
• Comparator is to confirm a potential superiority, similarity, or inferiority effect of the interventional product

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As a SP-INV, when planning a placebo/comparator study, ensure:

• The placebo product is manufactured in accordance with GMP, and undistinguishable from the interventional product (e.g. size, texture, viscosity, colour)
• Both placebo and the interventional product is coded and labelled in a manner that complies with regulatory requirements and – if needed - protects blinding
• A diligent planning. As placebo/comparator studies requires additional resources (e.g. production of the placebo product, handling and management of the placebo/comparator and the interventional product, expertise of study staff)

 

To guarantee that placebo/comparator groups are comparable with the treatment group:

• Plan for treatment and placebo/comparator allocation to be randomized
• Consider whether it is possible and appropriate to conceal treatment allocation from study participants, investigators (e.g. SP-INV, Site-INV), outcome assessors (e.g. statistician), or other study personnel by implementing study blinding

References

ICH GCP E6(R3) – see in particular guidelines

• Glossary: Definition comparator
• Glossary: Definition interventional product
• 3.15.2 Manufacturing, packaging, labelling, and coding investigational product(s)
• Appendix B. Clinical trial protocol: B.4.2 Description of trial design / B.4.9 Accountability procedures for the placebo

ICH Topic E8(R1) General considerations for clinical studies - see in particular

• 5.3 Choice of control group

ICH E10 – Choice of control group in clinical trials - see in particular guideline

• 1.3 Types of controls

ISO 14155:2026 Medical device (access liable to cost) – see in particular section

• 3.12 Comparator definition
• 3.15 Control group
• 3.50 Subject

Swiss Law

HRA – see in particular article

• Art. 13 Placebo

ClinO – see in particular article

• Art. 2b Definition of intervention
• Art. 2h Definition of placebo

ClinO-MD – see in particular

• Art 2a Definition performance study
• Art. 2b Definition conformity-related clinical trials