Bioequivalence and Bioavailability Forum • drugs of long half life

drugs of long half life [Design Issues]

posted by Helmut – Vienna, Austria, 2013-04-02 17:34 (4464 d 09:50 ago) – Posting: # 10328
Views: 8,171

Hi John!

❝ The sample size for parallel design (I think Helmut mentioned this to me before, right Helmut? :-) ) is based on the total CV (intersubject CV and intrasubject CV).

Yessir.

❝ 90% CI computation will be done using the intersubject CV

Nope. The residual variance in a parallel design is also the total. What Niazi writes:

The width of the conﬁdence interval is determined by the within-subject variance (between-subject variance for parallel group studies) and the number of subjects in the study.

is wrong (or another example of sloppy terminology). In a parallel design between-subject variance is not accessible – only total (or pooled if you prefer).

@Ken:

❝ The comparator product […] reported in their product insert an elimination half-life of 18 days. To fulfill the washout period of 5 half-life, the washout period will be about 90 days.

Don’t fall into the trap of basing you design on a reported mean value. Take the variability into account (i.e., conservatively assume a longer half life). Does the SmPC contain data on the variability (±SD)?

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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 lifeHelmut 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 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