Bioequivalence and Bioavailability Forum

Coming soon ... [Power / Sample Size]

posted by d_labes  – Berlin, Germany, 2013-02-08 12:57 (4879 d 01:21 ago) – Posting: # 9992
Views: 12,881

Dear Helmut, dear Anu,

❝ As Detlew already pointed out there is no analytical solution for RSABE due to the GMR-restriction (+ the 50% CV cap for EMA). Either you use the tables or you set up your own simulations.

No need to set up your own simulations. Just let PowerTOST do the job :

sampleN.scABEL(CV=0.4, theta0=1.16, design="2x3x3", regulator="FDA")

+++++++++++ scaled (widened) ABEL +++++++++++
            Sample size estimation
---------------------------------------------
Study design:  2x3x3
log-transformed data (multiplicative model)

alpha = 0.05, target power = 0.8
CVw(T) = 0.4; CVw(R) = 0.4
Null (true) ratio = 1.16
PE constraints    = 0.8 ... 1.25
Regulatory body: FDA
- CVswitch =  0.3, no cap on ABEL
- Regulatory constant = 0.8925742

Sample size search
 n     power
36   0.717989
39   0.744064
42   0.768658
45   0.789295
48   0.807810

And the best of all: computational time for each step approx. 1-2 sec for 1E+06 sims, believe it or not .

But ...
Cave 1: Only functions with PowerTOST V1.1-00. Distribution via CRAN may take some time.

Cave 2: PowerTOST is doing the sample size estimation only for balanced designs since the break down of the total subject number in case of unbalanced sequence groups is not unique. Moreover the formulas used are only for balanced designs. That may give different sample sizes compared to the two Laszlos.

Cave3: In case of regulator="FDA" the sample size is only approximate since the BE decision method via widened BE limits is not exactly what is expected by the FDA. But the two Laszlos state that the scABEL method should be 'operational' equivalent to the FDA method. Thus the sample size should be comparable.

Complete thread:

• Sample size for RSABE Anu 2013-02-01 07:01 
  • Sample size for RSABE d_labes 2013-02-01 09:46
    • Sample size for RSABE Anu 2013-02-07 06:58
      • No analytic solution! Helmut 2013-02-07 12:32
        • Coming soon ...d_labes 2013-02-08 11:57
          • Wow! Helmut 2013-02-08 12:19
            • Wow! Anu 2013-02-09 09:20
              • read… Helmut 2013-02-09 09:35
            • Bigamist d_labes 2013-02-09 18:11
              • Some testing (Part I) Helmut 2013-02-10 18:35
              • Some testing (Part II) Helmut 2013-02-11 01:00
                • Power testing d_labes 2013-02-11 12:03
                  • the unknown x Helmut 2013-02-11 14:40
                • Unequal CVs d_labes 2013-02-15 08:47
                  • Typo Helmut 2013-02-15 13:01