The purpose of this study is to investigate the drug interaction between fostamatinib and digoxin by comparing the safety, tolerability and plasma concentration of digoxin when administered alone and with fostamatinib in healthy subjects.

Inclusion Criteria:

• Provision of informed consent prior to any study specific procedures
• Male or female subjects aged 18 to 45 years (inclusive)
• Minimum weight of 50 kg and body mass index (BMI) between 18 and 30 kg/m2 (inclusive)
• Female subjects must have a negative pregnancy test at screening and on Day -1,must not be lactating, and must be of non-childbearing potential

Exclusion Criteria:

• History or presence of gastrointestinal, hepatic, or renal disease or any other condition known to interfere with the absorption, distribution, metabolism, or excretion of drugs (except for cholecystectomy)
• Any clinically significant illness, medical/surgical procedure or trauma within 4 weeks of the first administration of the investigational product
• Subjects who smoke more than 5 cigarettes or the equivalent in tobacco per day
• Absolute neutrophil count of <2500/mm3 or 2.5 x 109/L
• Previous treatment with fostamatinib or digoxin in the present study