Primary versus Secondary Immune Thrombocytopenia (ITP): A Meeting Report from the 2023 McMaster ITP Summit.

The McMaster Immune Thrombocytopenia (ITP) Summit, held on October 27, 2023, was an educational seminar from leading experts in immune thrombocytopenia and related disorders geared toward hematologists, internists, immunologists, and clinical and translational scientists. The focus of the Summit was to review the mechanisms, diagnosis, and treatment of primary versus secondary ITP. Specific objectives were to describe the unique features of secondary ITP, and to review its mechanisms in the context of autoimmune disease and infection.

Inhibition of FcRn with rozanolixizumab in adults with immune thrombocytopenia: Two randomised, double-blind, placebo-controlled phase 3 studies and their open-label extension.

Primary immune thrombocytopenia (ITP) is an antiplatelet-antibody-mediated disorder with accelerated platelet clearance and decreased platelet production. Rozanolixizumab, a monoclonal IgG4 anti-FcRn antibody, blocks IgG recycling and decreases IgG levels. We report efficacy and safety of rozanolixizumab in adults with persistent/chronic ITP in 24-week phase 3 studies (TP0003; TP0006), and their 52-week open-label extension (OLE).

Nipocalimab in Early-Onset Severe Hemolytic Disease of the Fetus and Newborn.

Background: In early-onset severe hemolytic disease of the fetus and newborn (HDFN), transplacental transfer of maternal antierythrocyte IgG alloantibodies causes fetal anemia that leads to the use of high-risk intrauterine transfusions in order to avoid fetal hydrops and fetal death. Nipocalimab, an anti-neonatal Fc receptor blocker, inhibits transplacental IgG transfer and lowers maternal IgG levels.

Methods: In an international, open-label, single-group, phase 2 study, we assessed treatment with intravenous nipocalimab (30 or 45 mg per kilogram of body weight per week) administered from 14 to 35 weeks' gestation in participants with pregnancies at high risk for recurrent early-onset severe HDFN.

Familial autoimmunity and risk of developing immune thrombocytopenia and Evans syndrome.

Background: Immune thrombocytopenia (ITP) and Evans syndrome (ES) are manifestations of immune dysregulation. Genetic variants in immune-related genes have been identified in patients with ITP and especially ES. We aimed to explore familial autoimmunity in patients with ITP and ES to understand possible contributions to chronicity.

Unexpected diagnosis of WHIM syndrome in refractory autoimmune cytopenia.

WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis) syndrome is a rare primary immunodeficiency predominantly caused by heterozygous gain-of-function mutations in the C-terminus of the gene CXCR4. These CXCR4 variants display impaired receptor trafficking with persistence of the CXCR4 receptor on the surface, resulting in hyperactive downstream signaling after CXCL12 stimulation. In turn, this results in defective lymphoid differentiation, and reduced blood neutrophil and lymphocyte numbers.

Immune thrombocytopenia (ITP) in pregnancy.

Immune thrombocytopenia (ITP) in pregnancy is challenging for both mother and fetus. Understanding the pathophysiology, treatments, and risks to the mother and fetus leads to proper management resulting in successful pregnancy and delivery in almost all cases. ITP in a pregnant woman has many similarities to ITP not in pregnancy although gestational thrombocytopenia can be confused with ITP.

The highs and lows of cyclic thrombocytopenia.

Cyclic thrombocytopenia (CTP) is characterized by periodic platelet oscillation with substantial amplitude. Most CTP cases have a thrombocytopenic background and are often misdiagnosed as immune thrombocytopenia with erratically effective treatment choices. CTP also occurs during hydroxyurea treatment in patients with myeloproliferative diseases.

Treatment of immune thrombocytopenia during pregnancy with thrombopoietin receptor agonists.

The introduction of thrombopoietin receptor agonists (TPO-RAs) led to a paradigm shift in the management of immune thrombocytopenia (ITP). However, TPO-RAs are not approved for use during pregnancy due to the absence of evidence and concerns for possible effects on the fetus due to their expected transplacental transfer. This comprehensive review examines the safety and efficacy of TPO-RA in 45 pregnancies of women with ITP (romiplostim n = 22; eltrombopag n = 21; both in the same pregnancy n = 2).

Efficacy and safety of the neonatal Fc receptor inhibitor efgartigimod in adults with primary immune thrombocytopenia (ADVANCE IV): a multicentre, randomised, placebo-controlled, phase 3 trial.

Background: Primary immune thrombocytopenia is an autoimmune disorder mediated partly by platelet autoantibodies, resulting in thrombocytopenia, bleeding, and constitutional symptoms. Efgartigimod, a first-in-class novel human IgG1 Fc fragment, binds the neonatal Fc receptor with high affinity and thus reduces serum IgG concentrations, including autoantibodies. The objective of this study was to evaluate the efficacy and safety of efgartigimod in adults with persistent and chronic primary immune thrombocytopenia.

The role of genetics in refractory immune thrombocytopenia.

Patients with refractory immune thrombocytopenia (rITP) have increased morbidity and mortality. Currently, there is limited understanding of the cause of refractoriness and no markers to help direct novel treatment options. Understanding the reason(s) for refractoriness is crucial to determining novel treatment options.

Early initiation of second-line therapy in primary immune thrombocytopenia: insights from real-world evidence.

To compare patients with primary immune thrombocytopenia (ITP) prescribed early (within 3 months of initial ITP treatment) second-line treatment (eltrombopag, romiplostim, rituximab, immunosuppressive agents, splenectomy) with or without concomitant first-line therapy to those who received only first-line therapy. This real-world retrospective cohort study of 8268 patients with primary ITP from a large US-based database (Optumde-identified Electronic Health Record [EHR] dataset) combined electronic claims and EHR data. Outcomes included platelet count, bleeding events, and corticosteroid exposure 3 to 6 months after initial treatment.

Overuse of corticosteroids in patients with immune thrombocytopenia (ITP) between 2011 and 2017 in the United States.

Corticosteroids (CSs) are standard first-line therapy for immune thrombocytopenia (ITP). Prolonged exposure is associated with substantial toxicity; thus guidelines recommend avoidance of prolonged CS treatment and early use of second-line therapies. However, real-world evidence on ITP treatment patterns remains limited.

Maintenence rituximab following induction in autoimmune cytopenias.

About 50% of immune thrombocytopenia (ITP) patients respond to rituximab induction, but most relapse. The effectiveness of rituximab maintenance remains untested. This study included autoimmune cytopenia patients who had previously responded to rituximab induction but subsequently relapsed.