Puzzle: Estimation of half life [Surveys]
Dear D. Labes!
According to our Master the average time for assessing a BE report is one hour – therefore, nothing.
Me not either.
Right. Actually the sponsor wants to perform another study and felt that they had too many data points in the previous one (little bit tricky, three drug combo). First I asked for spaghetti plots. Nil. Next for raw data. Received an M$-DOC (actually part of the Appendix to the study report) containing SAS-output like the following (one page per profile):
Really handy to be imported into PK software. Next: An Excel-file converted from the SAS-binary. Finally something to work with.
Last three data-points. t½ 8.00 h, R² 0.751 (R with 0.867 below the CRO’s cut-off 0.95). Before I start to fit individuals I use to have a look at spaghetti plots. Subjects with higher concentrations consistently showed such a slow phase (t½ >6 h). The quality of fits was sometimes pretty good (R²adj 0.998) and mainly >0.9… Taking the overall-PK into account, I would say that the bad fit of this subject is still justified (haha – I don’t have a R-cutoff…).
I this study residual AUCs were not an issue, but I’m concerned about careless fitting – which might tweak residual AUCs to <20%.
❝ The more interesting question is: What do regulators think?
According to our Master the average time for assessing a BE report is one hour – therefore, nothing.
❝ I never have seen deficiency questions […]
Me not either.

❝ Although I find the fit a little bit strange, […]
Right. Actually the sponsor wants to perform another study and felt that they had too many data points in the previous one (little bit tricky, three drug combo). First I asked for spaghetti plots. Nil. Next for raw data. Received an M$-DOC (actually part of the Appendix to the study report) containing SAS-output like the following (one page per profile):
Plasma
Age/ Actual Blood concentration
Site/ Sex/ Sample time vol. (ng/mL)
Subject Race Per. Treat. Sched. taken (hh:mm) (mL) XXXX YYYY Comment
-------------------------------------------------------------------------------------
AA/BBBB 22/M/Ca 1 Tablet pre Yes 07:37 10.0 BLQ BLQ
[…]
16 h pd Yes 23:54 10.0 121.33 12.10 late sampl.
[…]
Really handy to be imported into PK software. Next: An Excel-file converted from the SAS-binary. Finally something to work with.
❝ BTW: What is Your eyeball solution for this curve?
Last three data-points. t½ 8.00 h, R² 0.751 (R with 0.867 below the CRO’s cut-off 0.95). Before I start to fit individuals I use to have a look at spaghetti plots. Subjects with higher concentrations consistently showed such a slow phase (t½ >6 h). The quality of fits was sometimes pretty good (R²adj 0.998) and mainly >0.9… Taking the overall-PK into account, I would say that the bad fit of this subject is still justified (haha – I don’t have a R-cutoff…).
I this study residual AUCs were not an issue, but I’m concerned about careless fitting – which might tweak residual AUCs to <20%.
The only people who see the whole picture
are the ones who step out of the frame. Salman Rushdie
—
Dif-tor heh smusma 🖖🏼 Довге життя Україна!![[image]](https://static.bebac.at/pics/Blue_and_yellow_ribbon_UA.png)
Helmut Schütz
![[image]](https://static.bebac.at/img/CC by.png)
The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes
Dif-tor heh smusma 🖖🏼 Довге життя Україна!
![[image]](https://static.bebac.at/pics/Blue_and_yellow_ribbon_UA.png)
Helmut Schütz
![[image]](https://static.bebac.at/img/CC by.png)
The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes
Complete thread:
- Puzzle: Estimation of half life Helmut 2011-07-26 16:03 [Surveys]
- Puzzle: Estimation of half life ElMaestro 2011-07-27 10:58
- Puzzle: Estimation of half life Helmut 2011-07-27 15:10
- Puzzle: Estimation of half life d_labes 2011-07-28 08:44
- Puzzle: Estimation of half lifeHelmut 2011-07-28 11:38
- Puzzle: Estimation of half life ElMaestro 2011-07-28 10:24
- Puzzle: Estimation of half life Helmut 2011-07-28 11:53
- Puzzle: Estimation of half life ElMaestro 2011-07-27 10:58