As readers of this blog will know, a 505(b)(2) application is a US NDA where at least some of the information required for approval comes from studies not conducted by or for the applicant and for which the applicant has not obtained a right of reference. Under the right circumstances, either a new chemical entity (eg, a pro-drug of an approved drug) or a change to an approved drug (eg, oral to transdermal delivery) may be submitted as a 505(b)(2).

In Europe, there is a hybrid application that is somewhat analogous to the FDA’s 505(b)(2). The legal basis for a hybrid application is based on Article 10 of Directive 2001/83/EC which covers a generic, hybrid or similar biological application. In July 2008, a draft of “EMEA Procedural Advice for Users of the Centralized Procedure for Generic/hybrid Applications” was issued. This document states that:

“Hybrid applications under Article 10(3) of Directive 2001/83/EC as amended, differ from generic applications in that the results of appropriate pre-clinical tests and clinical trials will be necessary in the following 3 circumstances:

-where the strict definition of a ‘generic medicinal product’ is not met;

-where the bioavailability studies cannot be used to demonstrate bioequivalence;

-where there are changes in the active substance(s), therapeutic indications, strength, pharmaceutical form or route of administration of the generic product compared to the reference medicinal product

In such cases the results of tests and trials must be consistent with the data content standards required in the Annex to the Directive 2001/83/EC as amended by Directive 2003/63/EC. These applications will thus rely in part on the results of pre-clinical tests and clinical trials for a reference product and in part on new data.”

This European procedure covers some of the same situations that would qualify for 505(b)(2) applications in the US (such as changes in indication, pharmaceutical form, or route of administration). Note, however, the hybrid procedure encompasses some situations that would be handled in the US by an ANDA with a required clinical endpoint study (eg, generic drugs when bioavailability studies cannot be used to demonstrate bioequivalence). The EMEA hybrid scheme (Article 10b) also provides for fixed combinations of existing drugs.

Drugs approved through either the FDA 505(b)(2) pathway or the EMEA hybrid procedure cannot be marketed until the protection period (patent or exclusivity) of the reference product has expired.

The US and EMEA paths differ in respect to pediatric development.  As we have detailed before in this blog, 505(b)(2) applications are subject to PREA.  In contrast, the EMEA hybrids are not subject to that agency’s pediatric regulations.