Bioequivalence and Bioavailability Forum • CVintra # CVinter # CVtotal

CVintra # CVinter # CVtotal [Regulatives / Guidelines]

posted by Helmut – Vienna, Austria, 2008-11-29 11:14 (6401 d 19:55 ago) – Posting: # 2833
Views: 9,010

Dear Muneesh,

❝ Case-1: [...] intra-subject CV of 0.5363 and observed %T/R ratio of 0.9148. The sample size calculated is 175 for two-way cross-over pivotal study as programmed.

OK, confirmed your calculations (actually 176...) in two programs.

❝ I want to use the replicate (four-way cross-over) study design,

Why?

❝ in that case can I do the pivotal four-way cross-over study with at least half the number of subjects i.e. 88?

Yes, but you should:

accept that both the T/R and CV from the pilot study are not natural constants like the speed of light. Allow for a safety margin!
If you go with a replicate design, your safety margin should be even higher (more drop-outs are likely due to the doubled number of periods).

❝ Case-2: […] parallel design […] total CV of 0.16 and observed %T/R ratio of 112.08. The sample size calculated is 27 for two-way cross-over study as programmed. In that case can I do the pivotal parallel study with at least double the number of subjects i.e. 54?

What? Your sample size is 27 per group in parallel study (no X-over!), or 54 in total. Remember: in a parallel design, any differences in the two groups will be treated as a treatment effect - be cautious!

—
Dif-tor heh smusma 🖖🏼 Довге життя Україна!
Helmut Schütz

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Complete thread:

sample size for BA/BE studies drmuneesh 2008-10-18 09:17 [Regulatives / Guidelines]
- sample size for BA/BE studies shankar 2008-10-18 11:47
  - sample size for BA/BE studies drmuneesh 2008-10-18 12:18
    - sample size for BA/BE studies Ohlbe 2008-10-18 13:32
      - sample size for BA/BE studies drmuneesh 2008-10-19 10:42
      - sample size for BA/BE studies drmuneesh 2008-11-17 14:10
        
        sample size for BA/BE studies ElMaestro 2008-11-17 14:32
        
        sample size for BA/BE studies drmuneesh 2008-11-18 10:34
        sample size for BA/BE studies drmuneesh 2008-11-28 07:50
        
        sample size for BA/BE studies Helmut 2008-11-17 15:47
        
        sample size for BA/BE studies drmuneesh 2008-11-18 07:44
        
        sample size for BA/BE studies ElMaestro 2008-11-18 08:49
        
        sample size for BA/BE studies drmuneesh 2008-11-18 09:31
        
        sample size for BA/BE studies ElMaestro 2008-11-18 09:59
        
        sample size for BA/BE studies drmuneesh 2008-11-18 10:27
        
        sample size for BA/BE studies drmuneesh 2008-11-19 10:14
        
        sample size for BA/BE studies ElMaestro 2008-11-19 10:48
        
        sample size for BA/BE studies drmuneesh 2008-11-20 08:30
        
        CVintra # CVinter # CVtotal Helmut 2008-11-20 11:18
        
        Circulus vitiosus d_labes 2008-11-20 13:57
        
        Sterne! Helmut 2008-11-20 18:11
        
        CVintra # CVinter # CVtotal drmuneesh 2008-11-28 10:37
        
        CVintra # CVinter # CVtotalHelmut 2008-11-29 10:14
        
        CVintra # CVinter # CVtotal drmuneesh 2008-11-30 07:18
        
        is something fishy in case 2? ElMaestro 2008-11-29 15:42
        
        is something fishy in case 2? drmuneesh 2008-11-30 07:17
        
        SAS and sample size d_labes 2008-11-19 11:33
        
        SAS and sample size drmuneesh 2008-11-20 08:31