9. Subject with known history of human immunodeficiency virus (HIV) or if known seropositive for hepatitis C virus (HCV) or hepatitis B virus (HBV). HIV-positive patients on combination antiretroviral therapy are ineligible because of the potential immunosuppressive effects of and the potential for pharmacokinetic interactions with fostamatinib. In addition, these patients are at increased risk of lethal infections when treated with marrow-suppressive therapy.