Bioequivalence and Bioavailability Forum • Relevant: The PK metric with highest CV

Relevant: The PK metric with highest CV [Power / Sample Size]

posted by Helmut – Vienna, Austria, 2018-05-23 10:40 – Posting: # 18802
Views: 1,544

Hi libaiyi,

» I want to ask about power calculation. In BE, Cmax, AUCt, and AUCinf are all needed for power consideration. […] But AUCinf and AUCt are highly correlated,

AUC and C_max are (highly?) correlated as well.

» […] so could I […] only consider about AUCt and Cmax for the power setting?

If you think about sample size estimation I would go a step further and consider only the PK metric with the highest variability, which generally* is the one of C_max (see this thread, linked other posts, and references). You could use function power.2TOST() of the R-package PowerTOST to explore various correlations (ρ). This issue is a little bit academic because ρ is rarely known.

An early truncated partial AUC can be highly variable as well.

—
Cheers,
Helmut Schütz

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Complete thread:

Power decrease for the highly correlation of AUCt and AUCinf libaiyi 2018-05-23 08:40
- Relevant: The PK metric with highest CV Helmut 2018-05-23 10:40
  - Relevant: The PK metric with highest CV libaiyi 2018-05-24 10:02
    - Power of 2 independent TOSTs ≈ 2 simultaneous TOSTs with ρ=0 Helmut 2018-05-24 12:54
      - Power of 2 independent TOSTs ≈ 2 simultaneous TOSTs with ρ=0 libaiyi 2018-05-30 03:24