Old active ingredients in new medicinal products: is the regulatory path coherent with patients' expectations?

The rising costs of new medicinal products are a challenge to the economic sustainability of national healthcare systems in ensuring patients' access to therapies. European Union (EU) and US legislators have provided regulatory pathways aimed at simplifying Marketing Authorization (MA) applications for new medicinal products in cases when safety and efficacy profiles can be derived from the data of already-marketed products. In this review, we discuss the different regulatory pathways towards the MA of new medicinal products containing old drug substances and intended to improve the therapeutic value of a treatment, to obtain a new therapeutic indication (drug repositioning), or to ensure the same therapeutic value of a reference product at lower costs.