Efficacy and Safety Study of Fostamatinib Tablets to Treat B-cell Lymphoma

Inclusion Criteria: 1. Patients must be \> 18 years old. 2. Patients must be willing and able to give written informed consent by signing an IRB-approved Informed Consent Form prior to admission to this study and must fully understand the requirements of the study and be willing to comply with all study visits and assessments. 3. Patients with relapsed/refractory B-cell malignancy, (DLBCL, follicular lymphoma, mantle cell lymphoma, MALT lymphoma, marginal zone lymphoma, CLL or SLL), who have failed at least one prior treatment regimen and for whom no standard therapy exists; patients who are intolerant of standard therapy or who are not candidates for available standard therapy may also be included. 4. Patients must have measurable disease. 5. Patients may be male or female. Men, if sexually active, must agree to use at least one medically acceptable form of birth control for the duration of the study and for 30 days thereafter. Sexually active women of childbearing potential must have a negative serum pregnancy test, and agree to use two independent methods of birth control for the duration of the study and for 30 days thereafter. Exclusion Criteria: 1. Patients with T-cell lymphoma or primary CNS lymphoma 2. Patients with a history of malignancy other than lymphoma, except basal cell carcinoma of the skin and in situ cervical carcinoma, if \< 2 years since curative treatment 3. Chemotherapy within 4 weeks of Day 1 of treatment (6 weeks for mitomycin C and nitrosoureas) 4. Antibody therapy or lymphoma vaccine therapy within 6 weeks of Day 1 5. Radiotherapy within 2 weeks of Day 1, 4 weeks if to marrow-bearing sites (sternum, pelvis) 6. Any other investigational therapy within 4 weeks of Day 1 7. Significant gastrointestinal disease (Crohn's or ulcerative colitis) or major gastric or small bowel surgery 8. Difficulty swallowing or malabsorption 9. Patients with bone marrow impairment: Hgb \< 9.0 g/dL; ANC \< 1500/μL; platelets \< 75,000/μL 10. Patients with impairment of renal function: creatinine \> 2.0 g/dL 11. Patients with abnormal liver function: AST/ALT \> 3x ULN (up to 5x ULN with liver involvement); bilirubin \> 1.5 mg/dL 12. Patients who have been treated with a CYP3A4 inducer/inhibitor within 1 week prior to Day 1 or who are expected to require treatment with CYP3A4 inducer/inhibitor during the course of the study (Appendix IV) 13. Patients with Karnofsky performance status \< 60% (Appendix I) 14. Patients whose life expectancy is \< 3 months 15. Patients who are known to be HIV positive 16. Patients who have a history of any other significant medical or physical condition that might impair the patient's well being or preclude full participation in the study 17. Pregnant or nursing females 18. Patients receiving systemic or chronic inhaled steroids, with the exception of intermittent dexamethasone for the treatment of emesis or intermittent steroid inhalers for exacerbations of asthma