eswar lal
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Hyderabad,
2006-11-01 13:57
(6357 d 02:26 ago)

Posting: # 354
Views: 4,120
 

 regarding the deadlines for intake of volunteer into study [Design Issues]

Dear sir,

some CROs are following the deadline of 15 or 21 days for intake of selected healthy volunteer into the study after screening date.is there any requirement mentioned by any authority? if may i know the reason behind this 15 or 21 days limit concept. please clarify me sir.
Helmut
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Vienna, Austria,
2006-11-01 16:29
(6356 d 23:54 ago)

@ eswar lal
Posting: # 356
Views: 3,452
 

 Lenght of screening period

Dear Eswar!

❝ some CROs are following the deadline of 15 or 21 days for intake of selected healthy volunteer into the study after screening date. is there any requirement mentioned by any authority?


As far as I know, there is no regulation...

❝ if may i know the reason behind this 15 or 21 days limit concept.


OK, the maximum interval between start of screening and the first treatment I have seen in the last 25 years in Europe was 14 days.
The longer the time interval between screening and inclusion of healthy subjects and the first treatment, the higher the chance that a subject gets sick—just simple flu is enough ;-)

Therefore many CROs (driven by cautious sponsors) set the limit to a much shorter interval. One pretty large CRO performs the screening routinely 1 day (!) before the first treatment.

In my experience (from a European perspective) a 21 days screening period has a fairly high chance of rejection from the local ethics committee.
Short interval:
Pro: You can be quite sure that subjects are really healthy at start.
Con: Recruitment is rather strenous since you will have to screen a lot of subjects in order to start the study with the planned size (actually some healthy subjects will be sent home without participation).
Long interval:
Pro: Easier recruitment; lower number of subjects acting as a 'reserve' at start.
Con: You never can be sure that subjects are healthy (rejection by IEC?)...

The tight interval demanded by some sponsors is a little bit hypocritical, since only in two out of the 500+ studies I performed, the sponsor wanted a full screening prior to the second treatment period. :lol3:

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