Contemporary treatment of immune thrombocytopenia

Treatment of Children with Persistent and Chronic Idiopathic Thrombocytopenic Purpura: 4 Infusions of Rituximab and Three 4-Day Cycles of Dexamethasone

OBJECTIVES

To assess initial and long-term outcome of children with persistent/chronic idiopathic thrombocytopenic purpura (ITP) treated with 4 infusions of rituximab and three 4-day cycles of dexamethasone (4R+3Dex) including cohorts with most benefit and/or treatment associated toxicity.

STUDY DESIGN

All pediatric patients with ITP at Weill-Cornell who received 4R+3Dex were included in this retrospective study. Duration was median time from first rituximab infusion to treatment failure. Patient cohort included 33 children ages 1-18 years with persistent/chronic ITP; 19 were female, 10 of whom were adolescents. Every patient had failed more than 1 and usually several ITP treatments.

RESULTS

Children were treated with rituximab, 375 mg/m² weekly for 4 weeks and three 4-day courses of dexamethasone 28 mg/m² (40 mg max). Average age of nonresponders was 7.75 years, and initial responders averaged 12.7 years (P = .0073); 30% maintained continuing response at 60 months or last check-up. Eight of the 10 patients who underwent remission were female with ITP <24 months prior to initiating 4R+3Dex. All responding male patients except 2 relapsed.

CONCLUSIONS

Durable unmaintained ITP remission after 4R+3Dex was seen almost exclusively in female adolescents with <24 months duration of ITP. This provides a new therapeutic paradigm for a subpopulation with hard-to-treat chronic ITP. The pathophysiology of ITP underlying this distinction requires further elucidation.

Beyond immune thrombocytopenia: the evolving role of thrombopoietin receptor agonists

Since its discovery, the thrombopoietin (TPO) pathway has been an important pharmaceutical target for the treatment of thrombocytopenia. The first generation of TPO mimetics included peptide agents sharing homology with endogenous TPO, but these introduced a risk of antibody formation to endogenous TPO and were not successful. However, second-generation TPO mimetics or TPO receptor agonists (RAs) are currently being used to treat thrombocytopenia associated with a number of conditions, such as immune thrombocytopenia (ITP), severe aplastic anaemia (SAA), and hepatitis C virus-associated chronic liver disease. Accumulating efficacy and safety data suggest that the role of TPO-RAs in the treatment of thrombocytopenia may evolve in the near future with broader use of these agents in ITP and SAA, as well as approval in other indications, potentially including myelodysplastic syndromes, chemotherapy-associated thrombocytopenia, and post-transplant thrombocytopenia. This review provides an overview of clinical data on the efficacy and safety of TPO-RAs, emphasising recent findings that may expand their clinical utility.

A practical guide to the use of eltrombopag in children with chronic immune thrombocytopenia

INTRODUCTION

Pediatric immune thrombocytopenia (ITP) may be associated with significant burden on children and their parents/caregivers. Thrombopoietin (TPO) receptor agonists (RAs) have been used to treat adult patients with chronic ITP (cITP) for nearly a decade and following pediatric studies Eltrombopag has been recently approved for pediatric cITP in the United States and Europe. TPO-RA s may help reduce the risk of bleeding and the need for conventional ITP therapies.

REVIEW

In this review, the clinical data demonstrating the efficacy and safety of TPO-RAs in pediatric ITP are evaluated, key recommendations regarding safe administration of eltrombopag are provided, and potential future directions in management of pediatric ITP are discussed.

Initial Experience with the Use of Thrombopoetin Receptor Agonists in Patients with Refractory HIV-Associated Immune Thrombocytopenic Purpura: A Case Series

HIV-associated immune thrombocytopenic purpura (ITP) has decreased in incidence 10-fold since the advent of highly active antiretroviral therapy (HAART). For patients with detectable HIV viral loads, first-line treatment approaches involve optimizing HAART followed by standard ITP options used to treat those without HIV infection. In the general population, the thrombopoetin receptor agonists (TRAs), eltrombopag and romiplostim, are effective when used as salvage ITP therapy. In addition, eltrombopag has been used effectively in patients with thrombocytopenia secondary to hepatitis C--a virus seen commonly in HIV-infected patients, especially in those who also have a history of intravenous drug use. There are, however, few reports or studies of TRAs use in those with HIV infection. Herein, we describe 5 cases of refractory HIV-associated ITP managed with TRAs. Although platelet counts improved for all patients, 2 patients succumbed to thromboembolic complications. Our initial experience, as well as our findings from a Medline review, supports the potential utility of TRA as salvage therapy in the treatment of HIV-related ITP; however, we recommend caution in the use of these agents in those who are at highest risk of thrombosis. Additional studies are needed to determine the efficacy and, more importantly, the safety of TRAs in treatment of HIV-associated ITP.