title: Bioequivalence between generic tacrolimus products marketed in Spain by adjusted indirect comparison.
abstract: OBJECTIVE
  The objective of the study was to investigate the relative bioavailability between the generic tacrolimus products that are presently authorized in Spain by adjusted indirect comparison. This was based on demonstration of bioequivalence with the reference product (Prograf, Astellas Pharma), which makes these generic tacrolimus products prescribable, switchable and therapeutically equivalent to the reference product; yet, according to Spanish legislation, only prescribers can switch tacrolimus-containing products.
  
  
  METHODS
  Data from independent bioequivalence studies that compare each generic product with the reference product were combined by adjusted indirect comparisons to investigate the relative bioavailability between generic drug products, since there is no direct bioequivalence study comparing generics to each other.
  
  
  RESULTS
  Eight generic tacrolimus products in the form of capsules are presently authorized in Spain, but only five are marketed. These eight products represent only three different generic product developments. One product is authorized with four different names/companies, while another is authorized under three different names/companies. The adjusted indirect comparisons between generic products show bioequivalence within the conventional 80-125 % confidence interval acceptance criteria for area under the curve (AUC) and maximum concentration (Cmax).
  
  
  CONCLUSIONS
  Not only are the generic products bioequivalent with the reference product, but also with each other.
authors.affiliation: División de Farmacología y Evaluación Clínica, Departamento de Medicamentos de Uso Humano, Agencia Española de Medicamentos y Productos Sanitarios, C/Campezo 1. Edificio 8, Planta 2 Oeste, 28022 Madrid, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Herranz
authors.forename: Susana
authors.initials: S
authors.lastname: Morales-Alcelay
authors.forename: Ma Teresa
authors.initials: MT
authors.lastname: Corredera-Hernández
authors.forename: José María
authors.initials: JM
authors.lastname: de la Torre-Alvarado
authors.forename: Antonio
authors.initials: A
authors.lastname: Blázquez-Pérez
authors.forename: Ma Luisa
authors.initials: ML
authors.lastname: Suárez-Gea
authors.forename: Covadonga
authors.initials: C
authors.lastname: Alvarez
authors.forename: Alfredo
authors.initials: A
authors.lastname: García-Arieta
mesh_terms: D016568:Drugs, Generic / Q000493:pharmacokinetics*; D006801:Humans; D015233:Models, Statistical; D013030:Spain; D016559:Tacrolimus / Q000493:pharmacokinetics*; D013810:Therapeutic Equivalency
chemical_list: D016568:Drugs, Generic; D016559:Tacrolimus