Fostamatinib in the Treatment of Chronic Active Antibody Mediated Rejection

Inclusion Criteria * Signed informed consent prior to any study specific screening procedures. * Male or female, at least 18 years of age * Females must be either post-menopausal, surgically sterile (hysterectomy, bilateral salpingectomy or bilateral oophorectomy), or, if of child-bearing potential, must not be pregnant or lactating. * Patients must be established on tacrolimus maintenance immunosuppression * A pre-study renal biopsy obtained within 3 months prior to Baseline (Visit 1) will be reviewed by a renal pathologist to ensure subjects meet the following Banff histologic entry criteria: If C4d positive: Microcirculation inflammation score (g+ptc) ≥1 If C4d negative: Microcirculation inflammation score (g+ptc) ≥2 Chronic glomerulopathy (cg) score ≥1b or significant Peritubular Capillary Basement Membrane Multilayering (PTCBML) Chronic tubulo-interstitial scarring ≤50% Glomerular global obsolescence ≤50% Sample must contain at least 7 glomeruli and 1 artery * Otherwise in stable health as determined by the Investigator based on medical history and laboratory tests during the screening period. See Exclusion Criteria for specific exclusions. * In the Investigator's opinion, understand the duration of the study (up to 52 weeks), including the requirements for renal biopsies, and has the ability to understand the nature of the study and any hazards of participation and to communicate satisfactorily with the Investigator. Exclusion Criteria: * Co-existing Banff Category 4…