[The role of real-world evidence for the study of rare diseases epidemiology and the post-marketing evaluation of orphan drugs]

In Europe, diseases are defined as "rare" when they have a prevalence of less than 0.05% in the general population. When available, drugs used to treat such diseases often fall into the category of orphan drugs, i.e. drugs used for the diagnosis, prevention and treatment of rare diseases. Generating evidence about the efficacy and safety of orphan drugs in the pre-marketing phase is challenging due to critical issues related to the rarity of these diseases. This highlights the need to generate robust post-marketing evidence to fill the evidence gap in the pre-marketing phase, with the aim to more accurately define the benefit-risk profile and the cost-effectiveness of orphan drugs in the real-world setting. Real-world data (i.e., the data relating to patient health status and/or the delivery of health care routinely collected from a variety of sources) has significantly increased over the last years and their use is increasingly proposed, including by regulatory agencies, to generate evidence to support the regulatory authorization processes of orphan drugs and to study rare diseases. In this article, the authors describe the main sources of real-world data and their role to support the regulatory authorization processes of orphan drugs.