Bioequivalence and Bioavailability Forum • OT: A choice between

OT: A choice between [Design Issues]

posted by Helmut – Vienna, Austria, 2024-10-23 13:58 (39 d 06:31 ago) – Posting: # 24247
Views: 1,835

Hi BEQool,

❝ Regarding the choice of alpha level of 0.05 or 0.1 - every sponsor would probbaly choose 0.05 in order to decrease the chance of detecting an interaction?

Sure – though I still hold that the entire idea of such a test is crap.

Let’s see again what ICH M13A says:

The statistical model should take into account the multi-group nature of the BE study, e.g., by using a model including terms for group, sequence, sequence × group, subject within sequence × group, period within group and formulation. The group × treatment interaction term should not be included in the model. However, applicants should evaluate potential for heterogeneity of treatment effect across groups and discuss its potential impact on the study data, e.g., by investigation of group × treatment interaction in a supportive analysis and calculation of descriptive statistics by group.

What should we point out in the discussion? That a significant group × treatment interaction is to be expected at the level of test? What might be meant by »calculation of descriptive statistics by group«? Geometric means of PK metrics (irrespective of treatment), separately for the treatments, or PEs by model 3 (i.e., the conventional one with any group terms)? What would an assessor conclude from any of those? Even if they would calculate the CI of groups separately, likely they would overlap. So what?

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Helmut Schütz

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Complete thread:

Possible reasons for group effect GM 2019-07-20 07:36 [Design Issues]
- Group “effect” Helmut 2019-07-20 14:02
- Possible reasons for group effect ElMaestro 2019-07-20 19:20
  - Possible reasons for group effect GM 2019-07-23 06:23
    - “Group-by-Treatment Interaction” Helmut 2019-07-23 10:32
      - “Group-by-Treatment Interaction” BEQool 2024-10-22 12:39
        
        “Group-by-Treatment Interaction” Helmut 2024-10-22 12:47
        
        OT: A choice between mittyri 2024-10-22 16:03
        
        OT: A choice between BEQool 2024-10-23 11:02
        
        OT: A choice betweenHelmut 2024-10-23 11:58
        
        OT: A choice between BEQool 2024-10-23 13:17
        
        OT: A choice between Helmut 2024-10-23 13:22
        Groups: Overlapping CIs Helmut 2024-11-03 11:36
        
        Groups: Overlapping CIs BEQool 2024-11-05 09:14
        
        Groups: Overlapping CIs Helmut 2024-11-05 10:12
        
        Groups: Overlapping CIs BEQool 2024-11-06 07:44
        
        Groups: (Hardly‽) overlapping CIs Helmut 2024-11-21 13:20
        
        Groups: (Hardly‽) overlapping CIs BEQool 2024-11-22 12:32
        
        Groups: (Hardly‽) overlapping CIs Helmut 2024-11-22 12:58
        Multiplicity? Helmut 2024-11-23 13:05
        
        Groups BEQool 2024-11-26 08:15