Bioequivalence and Bioavailability Forum • 0.760 or...

0.760 or... [🇷 for BE/BA]

posted by Helmut – Vienna, Austria, 2011-01-17 15:38 (4841 d 20:36 ago) – Posting: # 6429
Views: 29,091

Dear D. Labes!

❝ […] therefore the sample size is independent of the variability. […] For this reason the FDA has discussed 24 or32 subjects for scaled ABE. […] But don't know where these numbers exactly came from.

32 was FDA’s suggestion back in 2006 (see here). 24 is FDA’s current requirement (personal communication with Barbara Davit, Ljubljana, May 2010).

❝ if (CV>=0.3) theta1 <- exp(-0.760*CV2se(CVr)) else theta1 <- 0.8

❝ # change 0.76 to log(1.25)/CV2se(0.3) if you prefer higher precision

❝ # for the regulatory constant

❝

❝ Lets see what the results are:

❝ # Targetpower=0.8, theta0=0.95, alpha=0.05, design=2x3x3 partial replicate

❝ Regulatory body: EMA k=0.760

❝ CV theta1 theta2 Sample size Achieved power

❝ ---------------------------------------------------

❝ 0.300 0.800030 1.24995 30 0.820245 # limits not exact 0.8 - 1.25

Yes, we discussed that already in #5249pp. As the grumpy old man I am I was already lamenting in one of my lectures (slides 32-33). Though I have only used exact widened limits of 0.75 and 0.75^-1 in the past (not UL of 1.3333) I woudn’t bet on the acceptability of the exact value (which I will use anyway). As you mentioned in your commented code, one will get the ‘correct’ limits by calculating the regulatory constant based on a CV of 30%.

theta1 <- exp(-log(1.25)/CV2se(0.3)*CV2se(CVr))

    CV   theta1  theta2 Sample size Achieved power

---------------------------------------------------

 0.300 0.800000 1.25000          30       0.820400  # limits exactly 0.8 - 1.25

 0.325 0.785946 1.27235          30       0.833446

 0.350 0.772289 1.29485          27       0.802301

 0.400 0.746140 1.34023          27       0.818245

 0.450 0.721506 1.38599          27       0.829288

 0.500 0.698326 1.43200          27       0.837245

---------------------------------------------------

 0.550 0.698326 1.43200          30       0.811569

 0.600 0.698326 1.43200          36       0.826651

 0.650 0.698326 1.43200          39       0.802849

 0.700 0.698326 1.43200          45       0.812654

P.S.: Do you think that engineers would use 3.14 instead of π, because it’s written in a guideline? Bridges would collpase, trains derail, etc. :-D

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

The quality of responses received is directly proportional to the quality of the question asked. 🚮
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Complete thread:

Feature suggestion for bear and PowerTOST ElMaestro 2011-01-16 19:13 [🇷 for BE/BA]
- Sample size for widened scaled ABE limits d_labes 2011-01-17 13:19
  - 0.760 or...Helmut 2011-01-17 14:38
    - ... full precision is the question d_labes 2011-01-17 16:37
      - ... full precision is the question Helmut 2011-01-17 18:06
        
        OT: Number of horns on a unicorn d_labes 2011-01-18 08:32
        
        Goooogle Helmut 2011-01-18 11:44
  - Cadmium ElMaestro 2011-01-19 17:50
    - Never eaten Cadmium deliberately d_labes 2011-01-20 15:00
      - Never eaten Cadmium deliberately Helmut 2011-01-20 15:25
        
        Call of duty for simulants d_labes 2011-01-20 16:15
        
        Counterinuitive Helmut 2011-01-21 04:13
        
        Counterintuitive d_labes 2011-01-21 08:36
        
        Counterintuitive Helmut 2011-01-21 12:53
        
        Counterinuitive, but ... d_labes 2011-01-21 12:12
        
        Counterinuitive, but ... Helmut 2011-01-21 13:01
        
        Wow, Wow ... d_labes 2011-01-21 14:43
        
        Never eaten Cadmium deliberately ElMaestro 2011-01-21 12:59
        
        Simulants of the world, unite! Helmut 2011-01-21 14:05
        
        Simulants of the world, unite! ElMaestro 2011-01-21 14:52
        
        Hyslop, Howe, scaled ABE and that all d_labes 2011-01-21 15:28
        
        Hyslop, Howe, scaled ABE and that all ElMaestro 2011-01-21 15:45
        
        scABE and missings d_labes 2011-01-21 16:19
        
        Intuition Helmut 2011-01-21 18:41
      - Never eaten Cadmium deliberately ElMaestro 2011-01-20 15:34
        
        Use of Cadmium d_labes 2011-01-20 16:06
        
        Use of Cadmium ElMaestro 2011-01-20 16:52
        Use of Cadmium ElMaestro 2011-01-20 17:53