JOI
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Brazil,
2011-11-16 12:57
(4538 d 21:10 ago)

Posting: # 7676
Views: 5,437
 

 Pre Treatment drug levels [Study As­sess­ment]

Dear all

We found in one of the study subjects, drug levels above LLOQ at the pre-dose sample of the first study period.
This came out on both analytes under study (ethinyl estradiol and gestodene), somehow confirming this was not an artifact.

Since levels were below 5% of the Cmax, our first approach was to include this subject in the analysis anyway.
It was also noticed that the statistical analysis shows a significant sequence effect (p ~= 0,048)

Sequence effect does not show up taking this subject out of the analysis. I think this is just a coincidence since the pk profile for this subject is almost coincident for both ref and test drugs. (Cmax 325.46 vs 315.95 pg/mL and AUC 0-t 2859 vs 3017 [pg x hr]/mL, for ethinyl, for example).

I'm wondering what would be the "best" approach to report the final results - including or excluding this volunteer - since our regulators usually "don't like" volunteer exclusions.
By the way, BE results are the same (bioequivalent) including or excluding this volunteer from the BE analysis.

Thanks in advance for your comments


Edit: Category changed. [Helmut]
Helmut
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Vienna, Austria,
2011-11-16 14:59
(4538 d 19:08 ago)

@ JOI
Posting: # 7677
Views: 4,698
 

 Pre Treatment drug levels

Dear Jaime!

❝ We found in one of the study subjects, drug levels above LLOQ at the pre-dose sample of the first study period.

❝ This came out on both analytes under study (ethinyl estradiol and gestodene), somehow confirming this was not an artifact.


❝ Since levels were below 5% of the Cmax, our first approach was to include this subject in the analysis anyway.

  • Noncompliance of the subject with an exclusion criterion (=intake of the respective combination contraceptive)? Ask the subject again.
  • If the value was <5 % of Cmax, but reasonably close to the LLOQ, the result may be pure chance.

❝ It was also noticed that the statistical analysis shows a significant sequence effect (p ~= 0,048)


Is ANVISA still asking for that? To be honest I have given up to fix the many broken links in the Guidance page. Do you have a working URL?

❝ Sequence effect does not show up taking this subject out of the analysis. I think this is just a coincidence since the pk profile for this subject is almost coincident for both ref and test drugs. (Cmax 325.46 vs 315.95 pg/mL and AUC 0-t 2859 vs 3017 [pg x hr]/mL, for ethinyl, for example).


❝ I'm wondering what would be the "best" approach to report the final results - including or excluding this volunteer - since our regulators usually "don't like" volunteer exclusions.


What have you stated in the protocol?

❝ By the way, BE results are the same (bioequivalent) including or excluding this volunteer from the BE analysis.


Lucky you! I would submit whatever you have stated in the protocol as primary analysis and show the data after exclusion as a sensitivity analysis (supportive).

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JOI
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Brazil,
2011-11-16 18:11
(4538 d 15:56 ago)

@ Helmut
Posting: # 7678
Views: 4,702
 

 Pre Treatment drug levels

Dear Helmut

Thank you for your swift reply

  • Noncompliance of the subject with an exclusion criterion (=intake of the respective combination contraceptive)? Ask the subject again.

  • If the value was <5 % of Cmax, but reasonably close to the LLOQ, the result may be pure chance.

Unfortunately, maybe due to any cultural reason, it is difficult to get a positive return from some of the volunteers in these cases. But we are quite sure this was the case, since levels are almost 5% of the Cmax, which is compatible with taking a pill from 3 to 7 days earlier.
Anyway, as you said, lucky me to have no influence on the study outcome.

❝ ... To be honest I have given up to fix the many broken links in the Guidance page. Do you have a working URL?


I'll have a look, hoping to provide you the correct links nowadays.


Many thanks,

Jaime
Helmut
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Vienna, Austria,
2011-11-16 19:11
(4538 d 14:56 ago)

@ JOI
Posting: # 7679
Views: 4,749
 

 Protocol Deviation

Dear Jaime!

❝ Unfortunately, maybe due to any cultural reason, it is difficult to get a positive return from some of the volunteers in these cases.


I think that this is not due to cultural differences. Subjects rarely ‘confess’ that they have violated study’s restrictions fearing they will never be included again (not without a cause…).

❝ But we are quite sure this was the case, since levels are almost 5% of the Cmax, which is compatible with taking a pill from 3 to 7 days earlier.


Even if you don’t get a positive response from the volunteer I would include this reasoning in the report.

❝ ❝ ... To be honest I have given up to fix the many broken links in the Guidance page. Do you have a working URL?


❝ I'll have a look, hoping to provide you the correct links nowadays.


THX, would be nice. I asked colleagues from ANVISA personally and by e-mail numerous times. They all agreed to help, but actually never did… :-D

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