This open-labelled study will evaluate the safety and preliminary efficacy of dexpramipexole for reducing the number of eosinophils in the peripheral blood and in improving nasal polyp score when administered to 20 subjects with chronic sinusitis with nasal polyps and eosinophilia.~Subjects will received dexpramipexole for up to 6 months and will have safety tests performed monthly and will have efficacy evaluations performed at month 1, month 3, and month 6 after beginning study drug.
Phase 2, open-label, multi-center study to evaluate the clinical effects of oral administration of dexpramipexole for 6 months in subjects with chronic sinusitis with nasal polyps and eosinophilia.