Bioequivalence and Bioavailability Forum • Proc Mixed FA0(1) for partial replicate

Proc Mixed FA0(1) for partial replicate [RSABE / ABEL]

posted by d_labes – Berlin, Germany, 2013-08-05 17:59 (4300 d 00:45 ago) – Posting: # 11206
Views: 10,103

Dear Wolfgang,

❝ For highly variable drugs, the reference-scaled average bioequivalence method is suggested by FDA. They request that a "conventional approach" analysis be done with some specific code, containing a random statement for SAS Proc Mixed,

❝ random tmt / sub=subject type=FA0(2);

❝ But, in the case of a partially replicated design (RRT/RTR/TRR), this model is overspecified, which can lead to various error messages from SAS, to non-convergence, and to unstable results.

Welcome to the club. We had some discussions about that topic here in the forum.
Look here or here or here for instance. But no satisfactory solution.

❝ Has anyone thought about using type=FA0(1) instead? Which in this case amounts to the same model but correctly specified.

Interesting! Can you please a bit more specific:

Why do you think that it is the same model?
Why do you think it is correctly specified? Seems to me a logical trap: same models, one correct, the other overspecified.

❝ What would FDA's attitude be towards this?

Duno since never had that idea :-D

. Also no experience with the FDA.
But I guess your proposal will be accepted if straight justified. The statisticians at FDA are those who :cool:

—
Regards,

Detlew

Complete thread:

RSAB model overspecified Wolfgang 2013-08-05 14:37
- RSAB model overspecified jag009 2013-08-05 15:35
- Proc Mixed FA0(1) for partial replicated_labes 2013-08-05 15:59
  - Proc Mixed FA0(1) for partial replicate Wolfgang 2013-08-05 16:24
    - Proc Mixed FA0(1) for partial replicate ElMaestro 2013-08-05 17:19
      - Proc Mixed FA0(1) for partial replicate Wolfgang 2013-08-06 08:35
        
        Proc Mixed FA0(1) for partial replicate ElMaestro 2013-08-06 10:34
    - Proc Mixed FA0(1) for partial replicate d_labes 2013-08-06 10:30
      - FA0(1) for partial replicate in Phoenix Helmut 2013-08-07 15:13
        
        FA0(1) for partial replicate in SAS d_labes 2013-08-08 09:42
        FA0(1) for partial replicate in Phoenix lhughes 2013-08-30 15:17
        
        FA0(1) in PHX: works (& more questions) Helmut 2013-08-30 17:07