Bioequivalence and Bioavailability Forum

random repeated parallel FDA [Design Issues]

posted by d_labes  – Berlin, Germany, 2013-04-08 10:29 (4823 d 00:59 ago) – Posting: # 10366
Views: 9,327

Dear John,

❝ Proc mixed data=s1;

❝ class subject trt;

❝ model lcmax=trt / ddfm=satterth;

❝ lsmeans trt /pdiff cl alpha=.1;

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

Seems you are on the right path .
But I have the feeling that the ddfm option is only half of the truth. Your code gives still only one variance term. Try it.

I must confess that I never had worked out a mixed model to full detail which covers the 2-group parallel as special case. No need up to now.
But I think there had to be somefink like a random or repeated statement to specify different variabilities for test and reference.

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;

Complete thread:

• drugs of long half life Ken Peh 2013-03-31 06:43 
  • 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 FDAd_labes 2013-04-08 08:29
                • Proc Mixed: random repeated parallel FDA jag009 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