BE study designs [Design Issues]

posted by Helmut Homepage – Vienna, Austria, 2006-01-16 16:39 (7024 d 06:48 ago) – Posting: # 54
Views: 28,986

Dear Essar,

in order to continue with the nomenclature generally used in BE studies I have re-aranged your table. Periods (P1-P3) in columns, and Sequences/Groups (S1-S3) in rows:
┌────┬────────────┐
│    │ P1  P2  P3 │
├────┼────────────┤
│ S1 │ T1  T2  R  │
│ S2 │ T2  R   T1 │
│ S3 │ R   T1  T2 │
└────┴────────────┘

❝ Now, please let me know whether my design is right? Is it approprirate to name this study as "3-treatment, 3-period, 3-sequence crossover Bioequivalence study"?


Question #1: no
Question #2: yes

❝ Can there be other designs to compare T1 and T2 with R in a single BE study?


Yes, explanations following:
Your design is not balanced in respect to all effects in the model, in other words, 3 combinations of treatments are missing. The chance of regulatory acceptance of a 3×3 is close to zero.
The plainest design you may apply is a Williams' design (3-treatment, 3-period, 6-sequence):
┌────┬────────────┐
│    │ P1  P2  P3 │
├────┼────────────┤
│ S1 │ T1  T2  R  │
│ S2 │ T2  R   T1 │
│ S3 │ R   T1  T2 │
│ S4 │ T1  R   T2 │
│ S5 │ T2  T1  R  │
│ S6 │ R   T2  T1 │
└────┴────────────┘

If you want to extract paired comparisons (e.g., for the nonparametric method) you will fail with your design (3×3), but succeed with the given one (6×3).

Since we are leaving the novice's level now, I would suggest you some further reading (not cheap, but every cent worth):

❝ Also, please let me know how you calculate the no of subjects required for this type of a study.


Have a look at


RP Qu
Sample Size and Power Calculation for High Order Crossover Design
Bio/Pharma Quarterly 9(1), 9-14 (March 2003)
which is available online (277kB PDF).


Good Luck!

Complete thread:

UA Flag
Activity
 Admin contact
23,422 posts in 4,927 threads, 1,671 registered users;
21 visitors (0 registered, 21 guests [including 7 identified bots]).
Forum time: 00:28 CEST (Europe/Vienna)

To know the history of science is to recognize the mortality
of any claim to universal truth.    Evelyn Fox Keller

The Bioequivalence and Bioavailability Forum is hosted by
BEBAC Ing. Helmut Schütz
HTML5