Bioequivalence and Bioavailability Forum

PowerTOST and Sample size estimation for R-SABE [RSABE / ABEL]

posted by mittyri  – Russia, 2015-06-25 12:43 (3610 d 16:48 ago) – Posting: # 14986
Views: 14,467

Dear Astea,

I completely agree with the Detlew's post above.
Let me explain some additional issues.

❝ As far as I know SampleN.scABEL simulates studies to get the target power so it would be erroneously just to calculate sample size using SampleN.TOST and scale thetha1 and theta2, wouldn't it?

Absolutely!
Please compare the results:
sampleN.scABEL(theta0=0.90, CV=0.5, targetpower=0.8, design="2x2x4")
and
sampleN.TOST(alpha=0.05, targetpower=0.8, theta0=0.9, theta1=0.6984, theta2=1.4319, CV=0.50, design="2x2x4")

❝ It doesn't fit in my head because there exist replicate studies completed with more than 50 subjects... It turns that it was redundantly?

That's not so easy...
When you performed first study with replicate design in Russia, the Sponsor wasn't sure - is it possible to wide the limits or not. Even after "the carving in red book"...
AFAIK now we can use all advantages of replicate designs in our studies, experts already approved some protocols with scABEL.

From then onward no full replicate studies with 60 subjects for sartans
The most illustrative graph you can find in the Helmut's lecture (slide 98)

Complete thread:

• Sample size calculation for R-SABE Lucas 2014-02-07 11:41 
  • EMA’s ABEL Helmut 2014-02-07 14:21
    • EMA’s ABEL Lucas 2014-02-07 16:49
      • Carry-over Helmut 2014-02-07 17:12
        • Carry-over Lucas 2014-02-07 17:42
          • Carry-over Shuanghe 2014-02-10 17:11
  • PowerTOST and Sample size estimation for R-SABE d_labes 2014-02-07 14:37
    • PowerTOST and Sample size estimation for R-SABE kumarnaidu 2014-04-18 13:38
      • PowerTOST and Sample size estimation for R-SABE Dr_Dan 2014-04-18 19:29
        • PowerTOST and Sample size estimation for R-SABE kumarnaidu 2014-04-19 06:04
    • PowerTOST and Sample size estimation for R-SABE Astea 2015-06-25 01:14
      • Sample size for scABEL/RSABE vs. conventional ABE d_labes 2015-06-25 09:19
      • PowerTOST and Sample size estimation for R-SABEmittyri 2015-06-25 10:43
        • PowerTOST and Sample size estimation for R-SABE Astea 2015-06-25 13:54
          • Scaled ABE d_labes 2015-06-25 14:04