Europe – Draft guideline on quality and equivalence of topical products

The guideline relates to locally applied and locally acting medicinal products for cutaneous use and is also relevant for other medicines e.g. preparations for auricular or ocular use. Specific guidance is provided:
On the quality of topical products not covered by other guidelines.
On equivalence testing of topical products in lieu of therapeutic equivalence clinical trials.
Existing guidelines state that, for topical products, changes in formulation, dosage form,
method of administration or manufacturing process may significantly influence the efficacy
and/or safety. Clinical therapeutic equivalence studies are in principle necessary, but other
models may be used or developed.
Guidance is provided on other models and studies that may be used to independently
determine equivalence with respect to (i) quality, (ii) efficacy, and (iii) safety that taken
together support a claim of therapeutic equivalence, when the method of administration is the same and risks of inequivalence to the patient are minimal.
Guidance is provided on situations where therapeutic equivalence clinical trials will be
expected.
Scope, limitations and acceptance criteria of this approach are described.
The guidance should be used to develop and justify topical product-specific equivalence
protocols.
In addition, equivalence test protocols are provided for:
*  in vitro release
*  in vitro human skin permeation
*  in vivo stratum corneum sampling (tape stripping)
*  in vivo vasoconstriction assay for corticosteroids
The quality guidance applies to new marketing authorisation applications and post approval changes.
The equivalence guidance is applicable to certain cases of demonstration of equivalence of a new topical medicinal product with an existing medicinal product.