neethu
☆    

2008-07-31 13:44
(5719 d 18:12 ago)

Posting: # 2116
Views: 9,279
 

 Period and sequence effects [General Sta­tis­tics]

hello,

I want to know the resons for the period effect and subject nested in sequence in a BA/BE study?


Thanks&regards
Neethu
Research Assistant-Biostatistics

--
Edit: Category and unspecific subject line changed. Please see here. [Helmut]

Thanks & Regards
Nees
ElMaestro
★★★

Denmark,
2008-07-31 14:15
(5719 d 17:41 ago)

@ neethu
Posting: # 2117
Views: 8,089
 

 Period and sequence effects

Dear Neethu,

a period effect could arise when the washout period was too short. In that case you might see positive (non-zero) pre-dose levels period 2.
Subject effect is a little different. Generally, not two people on this planet are identical (neither in looks, nor in PK, nor in ...) etc. But we need to bear in mind that the subj effect is evaluted by F being the between-MS divided by within-MS. When F is significant (large) then the between-MS is larger than the within-MS. This gives you joy and happiness in your evaluation of the 90% Conf. interval.

EM.
neethu
☆    

2008-07-31 15:12
(5719 d 16:44 ago)

(edited by Jaime_R on 2008-08-01 09:06)
@ ElMaestro
Posting: # 2118
Views: 8,041
 

 Period and sequence effects

Dear Em,
Thanks for ur reply. If the wash out period is for 10 days for the test drug. then how the period effect is occuring?

--
Edit: Full quote removed. Please see this post! [Jaime]

Thanks & Regards
Nees
ElMaestro
★★★

Denmark,
2008-07-31 15:58
(5719 d 15:58 ago)

@ neethu
Posting: # 2120
Views: 8,079
 

 Period and sequence effects

Dear Neethu,

no one knows what the chance is of getting a period effect even if there is none. It happens and one must be aware of this. Is it significant for both AUCt, Aucinf and Cmax?

Second, try and look at the LSMeans for period1 and period2: how different are they? Which one is higher?

What type of API are you working with?

BREM.
neethu
☆    

2008-08-01 08:16
(5718 d 23:40 ago)

(edited by Jaime_R on 2008-08-01 09:10)
@ ElMaestro
Posting: # 2123
Views: 8,011
 

 Period and sequence effects

Dear EM,

The period effect is significant for the AUCt,AUCinf and Cmax for the test drug.bt for the refernce drug AUCt,AUCinf and Cmax the period effect is not significant.

--
Edit: Full quote removed. Please see this post! ...and this one also. [Jaime]

Thanks & Regards
Nees
ElMaestro
★★★

Denmark,
2008-08-01 10:45
(5718 d 21:11 ago)

@ neethu
Posting: # 2124
Views: 7,989
 

 Period and sequence effects

Hi Neethu,

You wrote:

❝ The period effect is significant for the AUCt,AUCinf and Cmax for the test drug.bt for the refernce drug AUCt,AUCinf and Cmax the period effect is not significant.


This sounds confusing to me; what design has been used, and are you sure you are not confusing unequal carry-over with period effect? Could you paste the ANOVA table here, along with the period means? And please provide info on the api.
BR
EM.
neethu
☆    

2008-08-01 14:04
(5718 d 17:52 ago)

@ ElMaestro
Posting: # 2126
Views: 8,000
 

 Period and sequence effects

The design used is a 2x2 cross over design.
In the ANOVA table the P-value of period for the test drug for AUCt is 0.0492.for AUCinf is0.0304 nad for Cmax is 0.0020.
The P-value for the refernce drug for AUCt is 0.1577,AUCinf is 0.1018 and for Cmax is 0.3919.

--
Edit: Full quote removed. Please see this post! ...and this one also. [Jaime]

Thanks & Regards
Nees
Jaime_R
★★  

Barcelona,
2008-08-01 14:55
(5718 d 17:00 ago)

@ neethu
Posting: # 2129
Views: 7,955
 

 Period and sequence effects

Dear Neehtu!

❝ The design used is a 2x2 cross over design.

❝ [...] P-value of period for the test drug for AUCt is 0.0492 [...]

❝ for the refernce drug for AUCt is 0.1577.


I'm as confused as ElMastro. In a 2x2 cross-over it's simply not possible to distinguish between treatment-/period-/sequence-effects separated for treatment (there's just one period effect in ANOVA; not 'PE for test' and 'PE for reference'). Where do you get this numbers from?
Can you please come up with a table here (columns: subject, period, sequence, AUCt - one row per subject), or provide a link to a text-file for download.
If you decide posting it here, please don't use tabulators to separate columns (see here how to format tables).

Regards, Jaime
shankar
★    

India,
2008-07-31 16:01
(5719 d 15:55 ago)

@ neethu
Posting: # 2121
Views: 8,034
 

 Period and sequence effects

Dear Neethu,

Please note that as per FDA recommendation "more than 5 half lives of the moieties to be measured" for washout period.

Period effect may due to posture, conditions, formulation effect and gastric empting time of individuals.

Thanks,

Shankaranarayanan
neethu
☆    

2008-08-01 14:07
(5718 d 17:48 ago)

@ shankar
Posting: # 2128
Views: 8,007
 

 Period and sequence effects

Hai,
The period effect for the test drug for AUCt,AUCinf and Cmax are significant.But the period effect for the reference drug is not significant for any of these parameters...

--
Edit: Full quote removed. Please see this post! [Jaime]

Thanks & Regards
Nees
ElMaestro
★★★

Denmark,
2008-08-01 15:21
(5718 d 16:34 ago)

@ neethu
Posting: # 2130
Views: 7,949
 

 Period and sequence effects

Dear Neethu,

Think of your design: 2 treaments, two periods, two sequences. Each subject is assigned to either sequence TR (P1: test; P2: ref) or RT (p1: Ref; P2:test). Not TT and/or RR. Therefore, you are not able to acquire any data that indicate that there is a period effect for the test but not for the ref etc.

Best regards
EM.
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