High-Dose Dexamethasone Displays The Ability To Reduce Elevated Interleukin-16 Levels In Adult Immune Thrombocytopenia Patients
In this study, researchers investigated interleukin-16 (IL-16), a signaling molecule which promotes intercommunication of T-cells, B-cells, and dendrite cells, to determine the significance of the role IL-16 may play in ITP. Previous studies have focused on the effect of IL-16 on T helper cells, which helps to stimulate B cells to secrete antibodies and activate killer T cells to attack infected or defective cells. This leads to an increase in immune response, which could cause increased platelet destruction in patients with ITP.
Preliminary findings found that IL-16 displayed elevated expression in both the bone marrow and circulating blood plasma for ITP patients compared to healthy controls. To explore the importance of IL-16 in the pathogenesis of ITP, this experiment examined how IL-16 levels were altered in patients treated with high-dose dexamethasone.
When ITP patients treated with high-dose dexamethasone displayed a positive response to treatment (an increased platelet count), IL-16 expression was found to revert back to normal levels, i.e. the cross-communication between immune cells normalized. These finding indicate that IL-16 may play an important part in the pathogenesis of ITP and may indicate pathways to develop alternative therapies to treat ITP. However, further investigations are needed in order to determine the precise mechanism by which IL-16 promotes ITP.
An Open-Label Phase 3 Extension Study Examines The Effects Of Long-term Fostamatinib (TavalisseTM) Treatment On Adult ITP Patients
This ongoing phase 3 open-label extension study examines the safety and efficacy of long-term fostamatinib (Tavalisse™) treatment for adult ITP. 146 patients who previously participated in a randomized, double-blind, placebo-controlled phase 3 fostamatinib study were enrolled into this study. Fostamatinib, a spleen tyrosine kinase signaling inhibitor, has been FDA approved as a second-line treatment and works by suppressing antibody‐mediated platelet destruction in adults with immune thrombocytopenia (ITP). Unlike the previous studies, this open-label extension study ensured that all patients knowingly receive fostamatinib treatment and also allowed for patients who achieved a response in the previous study to continue treatment.
This study found very similar response rates to the previous randomized study including when looking at those patients who had been on placebo in the first study and now were receiving fostamatinib for the first time, including 44% of the patients treated with fostamatinib achieving a significant response in platelet count. In addition to treatment response, this study also analyzed the durability and long-term effects of fostamatinib treatment. So far, this ongoing study has found that the extended use of fostamatinib has not resulted in the loss of a response or in the development of new or more frequent side effects. After 28 months of treatment, the most common adverse events were mild/moderate including diarrhea, hypertension, nausea, epistaxis, and abnormal liver function tests. Fortunately, most adverse events were easily managed by dose reduction, temporary interruption, or using medications such as imodium.