Bioequivalence and Bioavailability Forum • Blind 2Stage

Blind 2Stage [Two-Stage / GS Designs]

posted by Astea – Russia, 2019-05-30 10:37 – Posting: # 20305
Views: 1,830

Dear Smart People!

Digging forum posts I've found this 9-year old question from Detlew. It turns out that the question can be now easily answered by the author after constructing Power2Stage.
But can you clarify me the meaning of blindness in BE trials?

I naively thought that blind interim analyses should not influence the type-one error. But
comparing power.tsd.ssr(n1=10,CV=0.1,blind=FALSE,theta0=1.25) and power.tsd.ssr(n1=10,CV=0.1,blind=TRUE,theta0=1.25) it turns out that blinding may even worse the situation (5.01% vs 7.36%, TIE). It is connected with the unknown PE (cause for BLIND=TRUE s20s<-mses), but isn't it contrintuitive?

Can it be true for parallel design also? Suppose we want to make a blind interim analyses after first stage with N subjects and recalculate sample size on fixed GMR=0.95 if total CV would be greater than initial suggestion. Will it cause any inflation? How to estimate it?

—
"We are such stuff as dreams are made on, and our little life, is rounded with a sleep"

Complete thread:

2-stage design with interim sample size estimation d_labes 2010-10-05 15:09 [Two-Stage / GS Designs]
- 2-stage design with interim sample size estimation Jack 2010-10-25 18:20
  - Null = bioINequivalence Helmut 2010-10-25 19:16
  - 2-stage design with interim sample size estimation d_labes 2010-10-26 13:28
    - 2-stage design with interim sample size estimation Jack 2010-10-26 18:26
      - Blind or not, Indecisions or Decisions d_labes 2010-10-27 16:01
        
        Blind or not, Indecisions or Decisions Jack 2010-10-27 18:14
        
        Blind ? Ohlbe 2010-10-27 23:37
        
        Blind ? Jack 2010-10-28 10:24
        
        Blind 2Stage Astea 2019-05-30 10:37
        
        Blind 2Stage Helmut 2019-05-30 12:56
        
        Blind 2Stage and an elephant Astea 2019-05-31 14:36
        
        Which elephant? Helmut 2019-06-02 20:14
        
        Blind interim in parallel design? Astea 2019-06-03 01:47
        
        Blind men d_labes 2019-06-05 12:23
        
        The Blind Leading the Blind Astea 2019-06-06 00:55