Retrospective, multicenter study in patients with hemophilia B. This study will be placed at
20 to 50 hemophilia treatment centers in North America and the EU, and is designed to
estimate the frequency of Class II and III allergic reactions in association with the
administration of any FIX concentrate.
Following informed consent and eligibility, historical patient information including
demographics, allergy history, hemophilia history, frequency and severity of allergic
reaction(s), number of exposure days with products causing allergic reactions, exposure days
to blood products including FIX concentrates, treatment for allergic reaction(s), outcome of
event(s), any other adverse event(s) occuring within 48 hours of onset of allergic
reaction(s), rechallenge and outcome, switch to another FIX product (if applicable) and
outcome, current status of patient, and results of any special studies (eg, skin or RAST
testing, alloantibody analyses, ect) will be collected.