Complex Clinical Trials

Complex Clinical Trials (e.g. Umbrella-, Basket- Platform design)

There are differences between complex clinical trials and conventional clinical trials, particularly with regards to clinical trial applications (CTAs) and requests for substantial amendments. The Clinical Trials Facilitation and Coordination Group (CTFG) highlights these differences in the Recommendation Paper on the Initiation and Conduct of Complex Clinical Trials published 12.02.2019. These recommendations should be read in conjunction with current legislation regulating clinical trials.
For the assessment of clinical trial applications of studies with complex designs, Swissmedic relies on the recommendation paper of the CTFG.

Swissmedic suggests you to read the publication of the CTFG and asks you to communicate with us according to the language used in this publication.

Before you submit a clinical trial with complex design,

you may apply for a pre-assessment of the project. Depending on the pre-assessment, Swissmedic will decide whether the project qualifies for a complex clinical trial or not, and whether Swissmedic accepts the project as one single trial or not.

Thus the following has to be done:

  1. Send an E-mail to with the reference “Pre-assessment clinical trial with complex design”.
  2. Use File Transfer to send us the following documents or attach them to your e-mail:
    a. Protocol synopsis
    b. Study Flow Chart that shows the following elements: master protocol, sub-protocol, indication(s), IMPs and indicate which trial design is used. For this, choose the possibilities of either Umbrella-, Platform-, Basket-Design or other.
  3. If you were not invited to File Transfer already earlier, please send an e-mail to with the reference “Request for File Transfer”. You will receive an invitation to upload your files.

Submission of a Clinical Trial Application (CTA) for a clinical trial with complex design

The submission dossier must contain the following documents:

  1. The CTA dossier according to the CTA-Guideline on our web page for conventional clinical trials, using the same CTA-Form.
  2. The pre-assessment of Swissmedic for the clinical trial with complex design.

Scientific advice:

The Swissmedic Clinical Trials division cannot provide any scientific advice on study design, statistics or applications for marketing authorisation. It is, however, possible to discuss issues relating to the submission of a complex clinical trial in a conference call. If you would like a telephone conference, please already specify this in the above-mentioned "Pre-assessment – clinical trial with complex design" e-mail. You will then receive an invitation with various suggestions for calling times.

Questions on complex clinical trials with transplant products, gene therapy and/or GMO must be addressed directly to the Transplants Unit (Swissmedic home page> Human medicines > Special categories > Transplant products).

Last modification 18.12.2019

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