How much are biosimilars used in southern Italy?: a retrospective analysis of epoetin utilization in the local health unit of Messina in the years 2010-2011.

Background: Epoetins are one of the three biologics for which biosimilars are available in Italy. So far, there is a lack of Italian national/regional longitudinal data about epoetin use.

Objective: The aim of this study was to evaluate the prescribing pattern of epoetins (reference products and biosimilars) in a Local Health Unit (LHU) of Southern Italy in recent years.

Methods: A retrospective drug utilization study was conducted during the period 1 January 2010 - 31 May 2011. The data source was the dispensing database of the Messina LHU, which contains anonymized data about dispensed drugs (including epoetins) that are prescribed by specialists to the residents in the catchment area. Indication of use and prescribed dosage of epoetins were derived by the therapeutic plans filled in by specialists and linked to drug dispensing records. Prevalence of epoetin use in the province of Messina (653 810 inhabitants) in 2010 was calculated. Furthermore, frequency analyses by sex, age, indication of use of epoetin users, as well as measurement of volume of use (defined daily dose [DDD]/1000/day) and expenditure of epoetins in 2010 were also performed. Analysis of the switching pattern between different reference products and biosimilar epoetins was performed.

Results: Overall, 4288 patients were treated with epoetins during the study period (mean age  ± SD: 74.2 ± 13.7; females: 52%). Darbepoetin alpha and reference product epoetin alpha accounted overall for 79.8% of epoetin users, while biosimilars of epoetin alpha accounted for 0.9%. Among 1247 epoetin users for whom the therapeutic plan was revised, 1065 (85.4%) were treated because of anemia due to chronic kidney disease and 158 (12.6%) because of chemotherapy-induced anemia. In 2010, prevalence of epoetin use was 5.5 (95% CI 5.3, 5.7) per 1000 inhabitants in the province of Messina. The volume of use and related expenditure for epoetins was 3.58 DDD/1000 inhabitants/day and Euro 5 572 457 (about Euro 8.50 per capita/day) in 2010. Switching between different epoetins was very frequent (21.8% of users) but switching from reference products to biosimilars was very rare.

Conclusions: Epoetins are frequently dispensed to residents in the province of Messina, mainly for the treatment of chronic kidney disease-related anemia, with a relevant impact on the pharmaceutical expenditure covered by the National Health System. Use of biosimilar products is very low in both naïve patients and in those who switch from other reference product epoetins.