title: Drug reformulations and repositioning in the pharmaceutical industry and their impact on market access: regulatory implications.
abstract: BACKGROUND
  Repurposing has become a mainstream strategy in drug development, but it faces multiple challenges, amongst them the increasing and ever changing regulatory framework. This is the second study of a series of three-part publication project with the ultimate goal of understanding the market access rationale and conditions attributed to drug repurposing in the United States and in Europe. The aim of the current study to evaluate the regulatory path associated with each type of repurposing strategy according to the previously proposed nomenclature in the first article of this series.
  
  
  METHODS
  From the cases identified, a selection process retrieved a total of 141 case studies in all countries, harmonized for data availability and common approval in the United States and in Europe. Regulatory information for each original and repurposed drug product was extracted, and several related regulatory attributes were also extracted such as, designation change and filing before or after patent expiry, among others. Descriptive analyses were conducted to determine trends and to investigate potential associations between the different regulatory paths and attributes of interest, for reformulation and repositioning cases separately.
  
  
  RESULTS
  Within the studied European countries, most of the applications for reformulated products were filed through national applications. In contrast, for repositioned products, the centralized procedure was the most frequent regulatory pathway. Most of the repurposing cases were approved before patent expiry, and those cases have followed more complex regulatory pathways in the United States and in Europe. For new molecular entities filed in the United States, a similar number of cases were developed by serendipity and by a hypothesis-driven approach. However, for the new indication's regulatory pathway in the United States, most of the cases were developed through a hypothesis-driven approach.
  
  
  CONCLUSIONS
  The regulations in the United States and in Europe for drug repositionings and reformulations allowed confirming that repositioning strategies were usually filed under a more complex regulatory process than reformulations. Also, it seems that parameters such as patent expiry and type of repositioning approach or reformulation affect the regulatory pathways chosen for each case.
authors.affiliation: University of Lyon, University Claude Bernard Lyon I, UFR d'Odontologie, 11 rue Guillaume Paradin, 69372, Lyon, Cedex 08, France; Lundbeck SAS, 37-45, Quai du Président Roosevelt, 92445 Issy-les-Moulineaux, Cedex, Paris, France.
authors.forename: Susana
authors.initials: S
authors.lastname: Murteira
authors.affiliation: Creativ-Ceutical S.A., 215, rue du Faubourg St-Honoré 75008, Paris, France.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Millier
authors.affiliation: Creativ-Ceutical S.A., 215, rue du Faubourg St-Honoré 75008, Paris, France.
authors.forename: Zied
authors.initials: Z
authors.lastname: Ghezaiel
authors.affiliation: University of Lyon, University Claude Bernard Lyon I, UFR d'Odontologie, 11 rue Guillaume Paradin, 69372, Lyon, Cedex 08, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Lamure
keywords: market access; reformulation; regulation; regulatory; repositioning; repurposing