Bioequivalence and Bioavailability Forum • Proc Mixed: random repeated parallel FDA

Proc Mixed: random repeated parallel FDA [Design Issues]

posted by jag009 – NJ, 2013-04-08 17:36 (4458 d 15:01 ago) – Posting: # 10370
Views: 8,107

Hi Detlew,

❝ The following code seems to work (gives 2 variance parameters) but has to be verified / validated:

❝ Proc mixed data=s1;


❝   class subject trt;

❝   model lcmax=trt / ddfm=satterth;

❝   repeated trt / group=trt;

❝   estimate 'T vs R' trt 1 -1/ cl alpha=0.1;

❝ run;

Enlight me guru. Why the need for a repeated trt/group=trt statement though?
We are looking at a parallel study design whereby two groups of subjects are given either T or R in the 1 study period.

Personally I don't see what additional variability(ies) one can extract from a parallel study other than inter-subject CV since we don't give the drugs to the same person twice. The use of total variability (intra and inter) to compute the sample size I guess is just to cover all ground and increase the level of comfort (My old friend always told be liberal on sample size estimation, but then be rational)... Maybe I am wrong and still need to understand more...

Thanks
John

Complete thread:

drugs of long half life Ken Peh 2013-03-31 06:43 [Design Issues]
- drugs of long half life jag009 2013-04-02 15:17
  - drugs of long half life Helmut 2013-04-02 15:34
    - drugs of long half life jag009 2013-04-02 16:01
      - drugs of long half life Helmut 2013-04-02 16:40
        
        parallel FDA d_labes 2013-04-04 08:33
        
        parallel FDA jag009 2013-04-05 18:01
        parallel FDA jag009 2013-04-05 21:10
        
        random repeated parallel FDA d_labes 2013-04-08 08:29
        
        Proc Mixed: random repeated parallel FDAjag009 2013-04-08 15:36
        
        Proc Mixed: parallel groups with different variabilities d_labes 2013-04-08 16:41
        
        Proc Mixed: parallel groups with different variabilities jag009 2013-04-08 20:22
  - drugs of long half life Ken Peh 2013-04-04 15:03
    - drugs of long half life jag009 2013-04-05 17:45