The Global. The president of the Spanish Society of Rheumatology, José Luis Andreu, has assured, in an interview held at the Wecare-u headquarters, that biosimilar medicines will be able to "improve the efficiency of the National Health System" allowing to treat "patients lower cost." However, Andreu recalled that Spanish legislation prevents the substitution of a biological by its biosimilar. In this sense, he has insisted on the importance that "the introduction of the biosimilar is done with the express authorization of the doctor and the patient, because it will ensure that it is a reasonable introduction, and that the patient knows that he is going to be treated with a determined agent.