Drug utilization of biological drugs in the treatment of chronic Immune-Mediated Inflammatory Diseases (IMIDs): an observational study on Italian patients

Analisi di Farmacoutilizzazione dei Trattamenti Biologici Nelle Malattie Infiammatorie Immunomediate Croniche: I Risultati di Uno Studio Osservazionale Retrospettivo Condotto in un Centro Ospedaliero del Centro Italia

Abstract

Objectives The aim of this analysis was to provide an estimate of drug utilization indicators (dose escalation and dose tapering) related to biologic drugs in the chronic treatment of adult patients with Immune-Mediated Inflammatory Diseases (IMIDs). Methods We conducted an observational retrospective cohort analysis using the Policlinico di Tor Vergata (PTV) database. We considered all biologic drugs dispensed by the PTV hospital pharmacy between January 2010 and December 2015:abatacept, adalimumab, certolizumab, etanercept, golimumab, infliximab (originator and biosimilar), tocilizumab, and ustekinumab were included. Drug dose escalation and dose tapering were calculated and compared with their Defined Daily Dose (DDD). Results A total of 1803 patients with IMID and biologic drug prescription were analyzed (male: 51.2%). The majority of patients were in the class 36-50 years (n = 612). The median follow-up was 33.8 months (IQR 14.43-56.20). Dermatology was the ward with the largest number of patients (n = 882; 48.9%), followed by rheumatology (n = 619; 34.3%) and gastroenterology (n = 302; 16.8%). Dose escalation was observed in 406 patients (22.5%). Infliximab biosimilar (n = 51) was the biological drug with the highest dose escalation rate (86.3%), followed by infliximab originator (n = 28; 60.3%) and ustekinumab (37.8%). Etanercept was the biological drug with the lowest dose escalation rate (7.4%), followed by golimumab (12.2%) and adalimumab (13.8%). In 677 patients (37.5%) a dose tapering was observed. Etanercept showed the highest rate of patients with dose tapering (41.6%), followed by adalimumab (33.6%). Conclusions The results of this analysis show that dose modification is quite common in PTV clinical practice. Considering the strong focus on the pharmaceutical expenditure and the need of cost containment, it is also important to take into account the effect of dose modifications in order to assess the actual treatment cost for biological drugs.