An Evaluation of the Effectiveness of Risk Minimization Measures for Tigecycline in the European Union

Background: Risk minimization measures (RMM) were implemented from February 2011 in the European Union to address risks of superinfection, off-label use and lack of efficacy associated with tigecycline. The objective of this study was to evaluate RMM effectiveness by describing prescription patterns among adults and children treated with any dose of tigecycline for any indication pre- and post-RMM implementation; incidence proportions of superinfection and lack of efficacy among adults treated with approved doses of tigecycline for complicated intra-abdominal infection and complicated skin and soft tissue infection were also evaluated. Methods: This was an observational, retrospective chart-abstraction study, including charts from 777 patients (399 pre-RMM, 378 post-RMM) at 13 sites across Austria, Germany, Italy, Greece and the United Kingdom (UK). Potential superinfection and lack of efficacy cases among those using tigecycline for on-label indication, age, dose, and duration were adjudicated. The distribution of indications for tigecycline was analyzed overall (i.e. across both study periods) and stratified by study period. Numbers and incidence proportions of superinfection and lack of efficacy cases (potential and adjudicated) were calculated overall and by study period. Results: Off-label use (indication or age) decreased from 54.2% [95% confidence interval (95% CI): 49.0, 59.3%] pre-RMM to 35.7% (95% CI 30.4, 41.2%) post-RMM. Overall, 45.7% (95% CI 41.9, 49.5%) of patients were prescribed tigecycline off-label; the most commonly reported off-label indications were characterized as “other” (25.5%), hospital acquired pneumonia (8.2%), other pneumonia (6.3%), bacteremia (5.2%) and diabetic foot infection (1.5%). Across study periods, incidence proportions of definite or probable superinfection and lack of efficacy in adults treated for approved indications, authorized treatment doses and duration were 4.5% (95% CI 2.1, 8.4%) and 5.5% (95% CI 2.8, 9.7%), respectively. Conclusions: Off-label use of tigecycline decreased following RMM implementation. Overall incidence proportions of definite or probable superinfection and lack of efficacy were low. EU PAS register number: EUPAS3674.