Switching between reference biologicals and biosimilars can be a contentious issue. A study from Italy, however, has found that this phenomenon is not limited to reference products and their biosimilars, but also often occurs between originator biologicals and other originator biologicals within the same category .
Carmen D’Amore and colleagues carried out a retrospective drug utilization study to investigate the occurrence of switching between different erythropoiesis stimulating agents in the Umbria region of Italy.
The study included 3,258 subjects who received their first epoetin prescription over the 4-year period between 1 July 2011 and 31 December 2014. Among the 2,896 patients with at least two prescriptions, 354 (12.2%) experienced one or more switches. The probability of switching depended on the duration of treatment: approximately 15% of users switched within 12 months of observation and 25% switched within 2 years.
Switching was not limited to reference and biosimilar epoetins and it affected patent and off-patent epoetins equally. When switched from the reference epoetin, the majority of subjects (61.8%) received another patented epoetin and 38.2% received a biosimilar epoetin. Initial users of other patented epoetins were mainly shifted to a different product within the same category (67.1%).
The authors found that the practice of switching mainly concerns drugs that have not undergone the direct comparability testing that is carried out before marketing a biosimilar. They therefore conclude that ‘when taken together with other sources of comparative evidence’ these data ‘may provide reassurance to physicians regarding the substitution of reference with biosimilar epoetins’.
Conflict of interest
The authors of the research paper  declared that there were no conflicts of interest.
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1. D’Amore C, Da Cas R, Rossi M, Traversa G. Switching between epoetins: a practice in support of biosimilar use. BioDrugs. 2016;30(1):27-32.