Bioequivalence and Bioavailability Forum • “Type 1” slightly higher power than “Type 2” for the same adj. α

“Type 1” slightly higher power than “Type 2” for the same adj. α [Two-Stage / GS Designs]

posted by Helmut – Vienna, Austria, 2017-02-18 11:51 (1427 d 15:06 ago) – Posting: # 17081
Views: 11,435

Hi BE-proff,

I agree with ElMaestro.

» 2) Why Method C is considered "better" for sponsors than Method B?

Unfortunately there is an „inflation” of letters denoting methods.
Therefore, I suggested* to use “Type 1” (B, E, …) and “Type 2” (C, D, C/D, F, …) instead.

“Type 1”

[image]

“Type 2”

[image]

In “Type 2” TSDs the conventional (unadjusted) α 0.05 may be used in the first stage (dependent on interim power). Hence, under certain conditions you have a decent chance to stop already in the first stage with no sample size penalty (due to the mandatory adjusted α in “Type 1” TSDs).

Potvin et al. recommended Method C over B due to its higher power. Examples (power by the noncentral t-approximation):

n1 CV (%) B C 12 10 0.97697 0.98858 24 20 0.88046 0.90882 36 30 0.83704 0.84676 48 40 0.82901 0.82838 60 50 0.82477 0.82405

Schütz H. Two-stage designs in bioequivalence trials. Eur J Clin Pharmacol. 2015;71(3):271-81. doi:10.1007/s00228-015-1806-2

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Helmut Schütz

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Complete thread:

Data for 2nd stage of Potvin’s designs BE-proff 2017-02-18 06:40
- Data for 2nd stage of Potvin’s designs ElMaestro 2017-02-18 10:20
  - Data for 2nd stage of Potvin’s designs BE-proff 2017-02-18 13:29
    - GMR = fixed! Helmut 2017-02-18 16:23
- “Type 1” slightly higher power than “Type 2” for the same adj. αHelmut 2017-02-18 11:51
  - “Type 1” slightly higher power than “Type 2” for the same adj. α BE-proff 2017-02-18 13:31
    - Terminology Helmut 2017-02-18 16:27
      - Terminology Yura 2017-02-20 11:28
        
        Which GMR to plug in ElMaestro 2017-02-20 11:46
        
        Which GMR to plug in BE-proff 2017-02-21 11:35
        
        Which GMR to plug in ElMaestro 2017-02-21 11:47
        
        Validated frameworks; observed GMR not relevant Helmut 2017-02-22 12:03
        
        Validated frameworks; observed GMR not relevant Silva 2017-03-09 01:26
        
        GMR, theta 0 and that all d_labes 2017-03-09 09:21
        
        GMR, theta 0 and that all Silva 2017-03-09 12:38
        
        GMR, theta 0 and that all ElMaestro 2017-03-09 12:56
        GMR, theta0 and that all d_labes 2017-03-09 13:55
        
        GMR, theta0 and that all Silva 2017-03-09 18:01
  - “Type 1” slightly higher power than “Type 2” for the same adj. α BE-proff 2017-02-21 11:31