Bioequivalence and Bioavailability Forum

Non-informative “profiles” [General Sta­tis­tics]

posted by Helmut  – Vienna, Austria, 2014-03-11 18:22 (4064 d 12:37 ago) – Posting: # 12600
Views: 10,152

Hi Fabrice,

❝ The context is the following:

❝ – Phase IIa multiple-dose placebo-controlled study, so only one active treatment

❝ – Oral inhalation, resulting in quite high inter- and intra-patient PK variability

This was one of the possibilities I suspected. Let’s see whether our specialist for OIPs (ElMaestro) will join the party…

❝ The study is thus not at risk from a PK point of view.

❝ But I was nevertheless interested on what would be the suggestions to best handle such a situation from a pure statistical point of view.

OK, I think cards are stacked against you if you want to stick to NCA only. PK modeling (or even PopPK/PD if you are courageous) with censored data might be helpful if you face a lot of missing data.

❝ For PK, the potential impact is on the steady-state vs single dose comparison, but you can also simply consider the computation of the descriptive geometric mean Cmax and AUC... how to best deal with a zero value?

Too bad that ln(0) is undefined…

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


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Complete thread:

• Log-transformation of "null" PK para­meters fno 2014-03-11 12:18 [General Sta­tis­tics] 
  • Non-informative “profiles” Helmut 2014-03-11 13:29
    • Non-informative “profiles” Ohlbe 2014-03-11 13:47
      • Non-informative “profiles” Helmut 2014-03-11 14:04
        • Non-informative “profiles” fno 2014-03-11 15:52
          • Non-informative “profiles”Helmut 2014-03-11 17:22
            • Non-informative “profiles” ElMaestro 2014-03-11 18:50
              • OT: log(0) - NaN, NA or what d_labes 2014-03-12 08:59
                • OT: log(0) - NaN, NA, ‘.’, –∞, or empty Helmut 2014-03-12 15:31
              • Non-informative “profiles” fno 2014-03-12 11:18
                • Non-informative “profiles” nobody 2014-03-12 13:18