Guidelines on the Principles of Good Distribution Practice for Active Substances for Medicinal Products for Human Use. There is a document out for consultation which describes requirements for distribution practices for APIs with requirements to ensure transparency, knowledge and control of the supply chain. While this Guideline specifically addresses APIs, the soon-to-be published Guideline on GDP, which will become part of Part III of the EU GMP Guideline more completely addresses drug product.
A copy of the proposal can be downloaded here: GDP consultation feb 2013