Bioequivalence and Bioavailability Forum • Numerical example

Numerical example [Two-Stage / GS Designs]

posted by ElMaestro – Denmark, 2011-10-26 18:49 (4987 d 21:24 ago) – Posting: # 7550
Views: 18,712

Dear d_labes,

❝ Using the famous :cool: R-package PowerTOST we obtain:

That package is a great resource.

❝ power.TOST(alpha=0.005, CV=0.2, theta0=0.95, n=24) -> 0.5489

❝ power.TOST(alpha=0.048, CV=0.2, theta0=0.95, n=24) -> 0.8919

❝

❝ sampleN.TOST(alpha=0.005,CV=0.2,theta0=0.95) -> 36

❝ sampleN.TOST(alpha=0.048,CV=0.2,theta0=0.95) -> 20

Hmmmm I get really uncertain now. I think you will hafta go with the 0.5489 value and procced to st. 2 with n=36 then?!?
I guess the real answer should come from a simulation of the scenario.

❝ If you use alpha₁ in all steps except stage 2 BE evaluation you end in an study with n=36, highly overpowered.

Power 0.8919 is not so bad; it certainly looks within the range of commonly accepted values by ethics committees. Did you sim and check final power. It will be a little lower, won't it?

This isn't simple :confused:

. Why don't we discuss method C in stead where the authors make a clear discussion between alpha1 and alpha2; it is for many practical purposes performing just like method B anyway, at least under the conditions tested by Potvin :-D

.

And yeah, what the heck is wrong with the Danish people? What are they, nuts?

best regards,
em.

Complete thread:

2-stage design - power evaluation d_labes 2011-10-12 11:10 [Two-Stage / GS Designs]
- No opinions out there? d_labes 2011-10-26 09:14
  - Opinion yes, answer no ElMaestro 2011-10-26 11:15
    - Decision scheme without (?) power check d_labes 2011-10-26 13:00
      - Decision scheme without (?) power check ElMaestro 2011-10-26 13:20
        
        Decision scheme 'without' power check d_labes 2011-10-26 14:51
        
        Decision scheme 'without' power check ElMaestro 2011-10-26 15:24
        
        Numerical example d_labes 2011-10-26 16:28
        
        Numerical exampleElMaestro 2011-10-26 16:49
        
        Potvin C with unsymmetrical alphas d_labes 2011-10-27 14:54
        
        Potvin B, C, or D? Helmut 2011-10-27 22:52
        Two-stage (classical Pocock) and the FDA Helmut 2011-10-31 02:36
- Weirdo paper ElMaestro 2011-11-30 18:04
  - Weirdo paper Helmut 2011-11-30 23:45
    - Weirdo paper ElMaestro 2011-12-01 07:16