Interchangeability is the medical practice consisting of changing a medicinal product for another that is expected to obtain the same clinical effect in a particular clinical picture, and in any patient, at the discretion of the prescribing doctor. (1) It is therefore possible to exchange one biological medicinal product for another, as long as the decision is made by the prescribing doctor and with the agreement and knowledge of the patient, within the framework of the doctor-patient ferencelationship.
Substitution (automatic) is the practice of dispensing one medicine instead of another equivalent and interchangeable medicine at pharmacy level without consulting the prescriber. (2)
Some also differentiate between changing or switching to refer to the one-off occurrence of switching from an original treatment to the biosimilar, from a biosimilar to the original, or from a biosimilar to another biosimilar. (2)
Most interchangeability data refer to the first biosimilar for infliximab. Three studies that analysed whether the practice of interchangeability affects the efficacy and safety of the treatment with infliximab and etanercept biosimilars are discussed below.
- In the PLANETRA (3) and PLANETAS (4) studies, which involved patients with rheumatoid arthritis or ankylosing spondylitis, respectively, who received original infliximab in the closed part of the study and were then changed to biosimilar infliximab and monitored for an additional year, the efficacy and safety remained similar in all patient groups.
- The NOR-SWITCH study, sponsored by the Norwegian Ministry of Health, was a randomised, double-blind, 52-week, non-inferiority study, which included 482 patients treated with reference infliximab who were stable for at least six months, where half of the patients continued with the same product and the other half were changed to biosimilar infliximab at the same dose. The results showed that the option to switch to biosimilar infliximab was not inferior in terms of efficacy or safety to the option to continue with original infliximab. No immunogenicity differences were observed between the two groups during the study.(6)
The results available of etanercept biosimilar for two years of period extension, suggest that the change from the reference medicine to the biosimilar medicine has not any effect in the effectiveness, side effects profile ad immunogenicity.(5)
The results obtained after switching from an original medicinal product to its biosimilar are reassuring. To date, published studies of the highest quality have not been able to demonstrate a negative impact on interchangeability. (7)
- Estudio informativo de consenso 2013. Lo que debe saber sobre los medicamentos biosimilares. Proceso sobre Responsabilidad Corporativa en el ámbito de las farmacéuticas. Acceso a los medicamentos en Europa. Guía de medicamentos biosimilares para médicos BIOSIM abril 2017
- Yoo DH, Prodanovic N, Jaworski J, et al. Efficacy and safety of CT-P13 (biosimilar infliximab) in patients with rheumatoid arthritis: comparison between switching from reference infliximab to CT-P13 and continuing CT-P13 in the PLANETRA extension study. Ann Rheum Dis. 2017;76:355-363.
- Park W, Yoo DH, Miranda P, et al. Efficacy and safety of switching from reference infliximab to CT-P13 compared with maintenance of CT-P13 in ankylosing spondylitis: 102-week data from the PLANETAS extension study. Ann Rheum Dis. 2017;76:346-354.
- Burness CB, Duggan ST. Etanercept (SB4): A Review in Autoimmune Inflammatory Diseases. BioDrugs. 2016;30:371-8.
- Jørgensen KK, Olsen IC, Goll GL, et al. Switching from originator infliximab to biosimilar CT-P13 compared with maintained treatment with originator infliximab (NOR-SWITCH): a52-week, randomised, double-blind, non-inferiority trial. Lancet. 2017 May 11. pii: S0140-6736(17)30068-5. doi: 10.1016/S0140-6736(17)30068-5. [Epub ahead of print]
- Libro blanco de los medicamentos biosimilares en España: Innovación y sostenibilidad. Fundación Gaspar Casal. 2017