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We are putting together a protocol for dose optimization study for a
vaccine in micro grams. Can anyone provide an indication and
rationale regarding the steps for dose escalation e.g. two folds,
three folds or other, between one level to another?
Regulatory and Clinical Affairs Manager
BiondVax Pharmaceuticals Ltd.
Science Park, Building No. 14,
Rehovot 76326, Israel
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I don't think that vaccines behave like simple pharmacologically
active compounds. They have an all-or-none aspect due to activating a
relatively large immune response, so there tends to be a threshold
beneath which the vaccine is virtually inactive and then there is a
steep response once the threshold is exceeded. Also repeat doses
magnify the response, as we all know from booster inocculations, so
logically the safest design for this particular situation is probably
(say 3) repeated doses at a very low level for safety, probably at
least a week apart and measuring the antibody responses as you go.
If you hit the jackpot you get your intended response in one dose but
you need to know what happens on repeat anyway and the sooner you
know it the better.
My advice would be to talk to someone who actually uses vaccines in
the disease you are intending to prevent as they will know more about
the individual variations in response...which may well be a more
important factor than dose increments. I can introduce you to the
large vaccination centre associated with the University of Surrey,
UK, if that would help.
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