About randomization replacement

Sponsor users can replace subjects that have been withdrawn from a study with a new subject that is assigned to the same treatment arm.

In certain scenarios, your study design statistician may want to replace a subject that has been withdrawn early in order to maintain the balance of treatment arms. In this case, you can perform randomization replacement to replace withdrawn subjects with new subjects that are assigned the same treatment.

Required permissions

User administrators and unblinded sponsor users assigned the new Replace Randomization permission can update a study's settings to allow replacement randomization.

What sponsor users must know

As a sponsor user, be aware of the following when performing randomization replacement:

• On the Study Settings tab, in the Visit Settings section, the Allow Randomization Replacement option in the Randomization row is set to Off by default.

  When you enable this setting, you're prompted with additional selections:

  • Replacement Starting Prefix: This option requires you to add a prefix for the randomization replacement. The prefix increases by an integer of 1 for each replacement.

    Note:

    A maximum number of 9 digits for the prefix is allowed.
    For example:

    1. A randomization prefix is set to 995, and a subject with the randomization number 1000 is then marked for replacement.
    2. Randomization number 9951000 is added to the randomization list.
    3. The next randomized subject of the given treatment arm receives 9951000 and is also marked for replacement.
    4. The randomization number 9961000 would be added to the randomization list and assigned to the next subject that's marked for replacement randomization.
    5. If a study manager then updates the prefix to any other number, for example 888, before the next subject is randomized, the next randomized subject still receives the 9961000 number and is marked for replacement. The 888 prefix entered is not considered, and randomization 9971000 is added to the randomization list instead.
  • Set Max Replacements per Randomization Number: This option allows you to specify how many times a randomization number can be replaced. You are then required to add a quantity in the Max Replacements field.
• Enabling the Allow Randomization Replacement setting does not count withdrawn and replaced subjects, including withdrawn subjects that are not replaced, towards the following study totals:
  • Study randomization limits
  • Site randomization limits
  • Study cohort limits
• Blinded users cannot undo withdrawal when the Allow Randomization Replacement setting is selected in order to avoid unblinding. Additionally, undo withdrawal information does not display in the Subject History for a blinded user.
• Once a subject's randomization has been replaced, the option to undo withdrawal is not available for the replaced subject.

• Note:

  Be aware that if a subject is marked for randomization replacement, then a new randomization list is uploaded, that randomization replacement is discarded, and the new randomization list does not contain the replaced randomization number created for that subject.

  Additionally, if a subject is randomized in a list, and a second list is generated with the subject marked for randomization replacement, the new randomization number is included in the original list, even though it is no longer active.

• On the Subjects tab, in the Manage Subject drop-down menu, the Replace Randomization Number option is available when the Allow Randomization Replacement setting is enabled in the study settings. When Replace Randomization Number is selected for a subject, the subject's status updates to Withdraw / Rand Replaced in the Subjects list, and Replacement Randomization in the Subject History.

  Note:

  Only users with the Replace Randomization permission can perform replacement and view a replaced randomization.

For step-by-step instructions on replacing randomization, see Replace randomization for subjects.