Investigational Medicinal Product [IMP]

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An investigational medicinal product is an active ingredient or placebo that has been pharmaceutically formulated (prepared) for human use which is being tested, or used as a comparator, in a clinical trial.

Typically IMPs have not yet received marketing authorisation, however in some circumstances they may be products that have been authorised:

    • when they have been made using a different formulation than that which is authorised (e.g. different dose),


    • when the authorised product is to be used as the test substance or comparator in a clinical trial,


    • when used for an unapproved indication (off-label), or


    • when used to gain further information about an approved use.


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