Chronic immune thrombocytopenia purpura (ITP) in adults is a serious autoimmune disease in which platelets are prematurely destroyed, leaving the patient vulnerable to bruising and bleeding. Initial treatment is with corticosteroids. In patients who become resistant or intolerant to corticosteroids, the thrombopoietic agents (TPOs), consisting of romiplostim (ROM), eltrombopag (ELT) and avatrombopag (AVA) or the spleen tyrosine kinase inhibitor fostamatinib (FOS), are appropriate next lines of therapy. In this study, the comparative safety, effectiveness and cost of care between fostamatinib vs. the TPOs was evaluated in a real-world setting.
A retrospective analysis from 17 community hematology practices across the United States was conducted to identify adult ITP patients who received one of the four agents. Data collection consisted of patient demographics, disease characteristics, as well as number and type of prior treatments. From the first day until the end of treatment, data were also collected on platelet (PLT) counts, adverse events, the use of rescue IVIG, platelet transfusions and corticosteroids. Multivariable logistic regression analysis was used to compare PLT related endpoints between agents.
A sample of 179 ITP patients who had received at least one of the four agents was identified. This resulted in a final sample of 51, 87, 127 and 44 patients who received FOS, ELT, ROM or AVA respectively. At month six, there were no significant differences between FOS vs. the TPOs in terms of the proportion of patients with the PLT count being ≥ 30 x 103/μL, ≥ 50 x 103/μL as well as the proportion of patients whose PLTs levels doubled relative to baseline. The frequency of thromboembolic events (TEs) was 3.9% in FOS patients compared to 9.2%, 4.7% and 11.4% in the ELT, ROM and AVA groups. The mean cost per patient with FOS was $99,209 (95%CI: $59,595 to $115,074) compared to $92,341 (95:CI$68,331 to $115,519), $108,482 (95%CI: $84,782 to $132,182) and $131,050 (95%CI: $83,327 to $179,897) for ELT, ROM or AVA respectively.
In this real-world analysis, FOS was comparable to the TPOs in maintaining PLTs at clinically beneficial levels. Given these findings, the choice of therapy should be based on overall patient safety, preexisting risk factors for TEs and cost effectiveness.

The Author(s). Published by S. Karger AG, Basel.