DiarioFarma. One of the therapeutic areas in which biosimilars have had the greatest impact in recent times is Rheumatology, where patients with diseases such as rheumatoid arthritis, psoriatic arthritis or ankylosing spondylitis have new valuable alternatives from the emergence of the first biological medicines. To analyze the impact that these products have had on people's health, and on the occasion of the tenth anniversary of the launch of the first biosimilar, José Luis Andreu, president of the Spanish Rheumatology Society (SER) and specialist at the Puerta de Hierro Hospital (Majadahonda), explains to Diariofarma what his vision is as well as the position of the SER in controversial aspects such as the substitution or interchangeability of the original biologics with their biosimilars, taking into account that the latter are key to fitting the pieces of the puzzle called sustainability.