Automated clinical databases are an important data source for drug utilization studies but often they do not capture prescriptions for drugs such as biological agents and other data sources are required. We describe how a feasibility evaluation (FE) was designed and implemented for a drug utilization study (DUS) of RTX, a biological agent approved for the treatment of rheumatoid arthritis, granulomatosis with polyangiitis and microscopic polyangiitis, and administered in specialized infusion centers (ICs). There is some evidence of RTX use in additional conditions, e.g. systemic lupus erythematosus, but the extent of this use is unclear. RTX prescriptions are usually not captured in hospital or population prescription databases. The FE goal was to evaluate if a single study conducted in ICs across 5 European countries (France, Germany, Italy, Spain, and The UK) could achieve the following operational goals: to collect estimates of treated patients by clinical indication; to learn about counseling practices and workflow at the ICs; to assess the feasibility of conducting both a medical record abstraction to characterize clinical use and a patient self-administered survey to evaluate the counseling practices at the ICs. A feasibility questionnaire was sent to a total of 65 ICs and 30 completed it (overall response rate, 46%; range by country, 22%-75%). Results were heterogeneous across the 5 countries regarding response rates of ICs, number of eligible patients, ICs characteristics, clinical use of RTX, and infusion waiting times. Countries were more homogeneous regarding ICs operations and counseling practices, availability of variables for chart abstraction, infusion duration, and interest to participate in the future study. In conclusion, DUSs can be performed when usual data sources are not available but it is recommended to conduct FEs to guide the study design and confirm feasibility, especially when the study is conducted in several countries with different health care systems and prescribing practices.