Roberto Stasi

Standardization of terminology, definitions and outcome criteria in immune thrombocytopenic purpura of adults and children: report from an international working group

Diagnosis and management of immune thrombocytopenic purpura (ITP) remain largely dependent on clinical expertise and observations more than on evidence derived from clinical trials of high scientific quality. One major obstacle to the implementation of such studies and in producing reliable meta-analyses of existing data is a lack of consensus on standardized critical definitions, outcome criteria, and terminology. Moreover, the demand for comparative clinical trials has dramatically increased since the introduction of new classes of therapeutic agents, such as thrombopoietin receptor agonists, and innovative treatment modalities, such as anti-CD 20 antibodies. To overcome the present heterogeneity, an International Working Group of recognized expert clinicians convened a 2-day structured meeting (the Vicenza Consensus Conference) to define standard terminology and definitions for primary ITP and its different phases and criteria for the grading of severity, and clinically meaningful outcomes and response. These consensus criteria and definitions could be used by investigational clinical trials or cohort studies. Adoption of these recommendations would serve to improve communication among investigators, to enhance comparability among clinical trials, to facilitate meta-analyses and development of therapeutic guidelines, and to provide a standardized framework for regulatory agencies.

International consensus report on the investigation and management of primary immune thrombocytopenia

Previously published guidelines for the diagnosis and management of primary immune thrombocytopenia (ITP) require updating largely due to the introduction of new classes of therapeutic agents, and a greater understanding of the disease pathophysiology. However, treatment-related decisions still remain principally dependent on clinical expertise or patient preference rather than high-quality clinical trial evidence. This consensus document aims to report on new data and provide consensus-based recommendations relating to diagnosis and treatment of ITP in adults, in children, and during pregnancy. The inclusion of summary tables within this document, supported by information tables in the online appendices, is intended to aid in clinical decision making.

The efficacy and safety of B‐cell depletion with anti‐CD20 monoclonal antibody in adults with chronic immune thrombocytopenic purpura

Because of its B‐cell depleting effect, rituximab has entered clinical trials in several autoimmune conditions. This study assesses the efficacy and safety of rituximab in 57 adults with chronic immune thrombocytopenic purpura (ITP). All patients had platelet counts <30 × 109/l, all had received two or more previous ITP treatments and 31 had undergone splenectomy. Patients received rituximab 375 mg/m2 weekly for 4 weeks. Thirty‐one patients (54%) responded, achieving a platelet count >50 × 109/l: 18 achieved a complete response (CR: platelet count >150 × 109/l) and 13 a partial response (PR: platelet count 50–150 × 109/l). Twenty‐nine responses occurred within 8 weeks of the first infusion. Sixteen of 18 CR patients (28% overall), including eight who had failed splenectomy, continued in CR after a median of 72·5 weeks; 15 of 16 are >1 year from the first infusion. Only two of 13 maintained a PR. Thirty‐three patients experienced grade 1–2 adverse events and one a grade 3 event, but they all completed treatment. Circulating B cells fell to <0·03 × 109/l. No changes in immunoglobulin levels or infectious complications were seen. In summary, rituximab was well tolerated with no immediate complications and induced a lasting, substantial response in 32% of adults with chronic ITP.

Analysis of regulatory T-cell changes in patients with idiopathic thrombocytopenic purpura receiving B cell–depleting therapy with rituximab

The effects of B-cell depletion with rituximab on regulatory T cells (Tregs) have not been determined. We investigated Tregs in patients receiving rituximab for chronic idiopathic thrombocytopenic purpura (ITP). The peripheral blood Tregs, identified as CD4+FOXP3+ T cells, were measured by flow cytometry prior to and after the immunotherapy. In addition, Tregs were analyzed for their usage of the T-cell receptor (TCR) beta-variable (VB) region gene as well as their regulatory function as assessed by cell proliferation assays. Pretreatment data revealed a reduced number and a defective suppressive capacity of Tregs in ITP patients compared with control individuals. In addition, Tregs showed a polyclonal spectratype. Patients, particularly responders, showed restored numbers of Tregs as well as a restored regulatory function upon treatment with rituximab. These results indicate that patients with active ITP have a defective T regulatory cell compartment that can be modulated by a B cell-targeted therapy.

Effects of eradication of Helicobacter pylori infection in patients with immune thrombocytopenic purpura: a systematic review

Whether the eradication of Helicobacter pylori infection can increase the platelet count in patients with immune thrombocytopenic purpura (ITP) is still a controversial issue. To provide evidence-based guidance, we performed a systematic review of the literature published in English, selecting articles reporting 15 or more total patients. We identified 25 studies including 1555 patients, of whom 696 were evaluable for the effects of H pylori eradication on platelet count. The weighted mean complete response (platelet count > or = 100 x 10(9)/L) and overall response (platelet count > or = 30 x 10(9)/L and at least doubling of the basal count) were 42.7% (95% confidence interval [CI], 31.8%-53.9%) and 50.3% (95% CI, 41.6%-59.0%), respectively. In 222 patients with a baseline platelet count less than 30 x 10(9)/L, the complete response rate was 20.1% (95% CI, 13.5%-26.7%) and the overall response rate was 35.2% (95% CI, 28.0%-42.4%). The response rate tended to be higher in countries with a high background prevalence of H pylori infection and in patients with milder degrees of thrombocytopenia. These findings suggest that the detection and eradication of H pylori infection should be considered in the work-up of patients with seemingly typical ITP.

Idiopathic thrombocytopenic purpura: current concepts in pathophysiology and management.

Idiopathic thrombocytopenic purpura (ITP) is characterized by a low platelet count, which is the result of both increased platelet destruction and insufficient platelet production. Although the development of autoantibodies against platelet glycoproteins remains central in the pathophysiology of ITP, several abnormalities involving the cellular mechanisms of immune modulation have been identified. Conventional treatments for ITP aim at reducing platelet destruction, either by immunosuppression or splenectomy. Two new thrombopoietic agents, AMG 531 and eltrombopag, have been used in clinical trials to stimulate platelet production in ITP patients not responsive to standard treatments. These new molecules bear no structural resemblance to thrombopoietin, but still bind and activate the thrombopoietin receptor. This review will focus on the pathophysiology and treatment of ITP in adults, highlighting recent advances in both fields.

Outcomes 5 years after response to rituximab therapy in children and adults with immune thrombocytopenia.

Treatments for immune thrombocytopenic purpura (ITP) providing durable platelet responses without continued dosing are limited. Whereas complete responses (CRs) to B-cell depletion in ITP usually last for 1 year in adults, partial responses (PRs) are less durable. Comparable data do not exist for children and 5-year outcomes are unavailable. Patients with ITP treated with rituximab who achieved CRs and PRs (platelets > 150 × 10(9)/L or 50-150 × 10(9)/L, respectively) were selected to be assessed for duration of their response; 72 adults whose response lasted at least 1 year and 66 children with response of any duration were included. Patients had baseline platelet counts < 30 × 10(9)/L; 95% had ITP of > 6 months in duration. Adults and children each had initial overall response rates of 57% and similar 5-year estimates of persisting response (21% and 26%, respectively). Children did not relapse after 2 years from initial treatment whereas adults did. Initial CR and prolonged B-cell depletion predicted sustained responses whereas prior splenectomy, age, sex, and duration of ITP did not. No novel or substantial long-term clinical toxicity was observed. In summary, 21% to 26% of adults and children with chronic ITP treated with standard-dose rituximab maintained a treatment-free response for at least 5 years without major toxicity. These results can inform clinical decision-making.

Management of Immune Thrombocytopenic Purpura in Adults

Primary immune thrombocytopenic purpura (ITP), also referred to as idiopathic thrombocytopenic purpura, is an organ-specific autoimmune disorder in which antibody-coated or immune complex-coated platelets are destroyed prematurely by the reticuloendothelial system, resulting in peripheral blood thrombocytopenia. The disease is heterogeneous with regard to its severity and clinical course and is unpredictable in its response to therapy. Although the basic underlying pathophysiology of ITP has been known for more than 50 years, current treatment guidelines are based on expert opinion rather than on evidence because of a lack of high-quality clinical trials and research. The only patients for whom treatment is clearly required are those with severe bleeding and/or extremely low platelet counts (< 10 x 10(9)/L). Treatment of patients with ITP refractory to corticosteroids and splenectomy requires careful evaluation of disease severity, patient characteristics related to risk of bleeding, and adverse effects associated with treatment. Clinical trials with numerous new agents are under way, which we hope will add more effective and targeted strategies to our therapeutic armamentarium. We describe a logical and structured approach to the clinical management of ITP in adults, based on a literature review and our personal experience.

Daunorubicin versus mitoxantrone versus idarubicin as induction and consolidation chemotherapy for adults with acute myeloid leukemia: the EORTC and GIMEMA groups study AML-10

PURPOSE To compare the antitumor efficacy of three different anthracyclines in combination with cytarabine and etoposide in adult patients with newly diagnosed acute myeloid leukemia (AML). PATIENTS AND METHODS We randomly assigned 2,157 patients (age range, 15 to 60 years) to receive intensive induction-consolidation chemotherapy containing either daunorubicin, idarubicin, or mitoxantrone. After achieving complete remission (CR), patients were assigned to undergo either allogeneic or autologous stem-cell transplantation (SCT), depending on the availability of a sibling donor. RESULTS The overall CR rate (69%) was similar in the three groups. Autologous SCT was performed in 37% of cases in the daunorubicin arm versus only 29% and 31% in mitoxantrone and idarubicin, respectively (P < .001). However, the disease-free survival (DFS) and survival from CR were significantly shorter in the daunorubicin arm: the 5-year DFS was 29% versus 37% and 37% in mitoxantrone and idarubicin, respectively. The proportion of patients who underwent allogeneic SCT (22%) was equivalent in the three treatment groups, and the outcome was similar as well. The [corrected] 5-year overall survival rates were 31%, 34%, and 34%, [corrected] respectively. CONCLUSION In adult patients with AML who do not receive an allogeneic SCT, the use of mitoxantrone or idarubicin instead of daunorubicin enhances the long-term efficacy of chemotherapy.

Pathobiology of Secondary Immune Thrombocytopenia

Primary immune thrombocytopenic purpura (ITP) remains a diagnosis of exclusion both from nonimmune causes of thrombocytopenia and immune thrombocytopenia that develops in the context of other disorders (secondary immune thrombocytopenia). The pathobiology, natural history, and response to therapy of the diverse causes of secondary ITP differ from each other and from primary ITP, so accurate diagnosis is essential. Immune thrombocytopenia can be secondary to medications or to a concurrent disease, such as an autoimmune condition (eg, systemic lupus erythematosus [SLE], antiphospholipid antibody syndrome [APS], immune thyroid disease, or Evans syndrome), a lymphoproliferative disease (eg, chronic lymphocytic leukemia or large granular T-lymphocyte lymphocytic leukemia), or chronic infection, eg, with Helicobacter pylori, human immunodeficiency virus (HIV), or hepatitis C virus (HCV). Response to infection may generate antibodies that cross-react with platelet antigens (HIV, H pylori) or immune complexes that bind to platelet Fcγ receptors (HCV), and platelet production may be impaired by infection of megakaryocyte (MK) bone marrow–dependent progenitor cells (HCV and HIV), decreased production of thrombopoietin (TPO), and splenic sequestration of platelets secondary to portal hypertension (HCV). Sudden and severe onset of thrombocytopenia has been observed in children after vaccination for measles, mumps, and rubella or natural viral infections, including Epstein-Barr virus, cytomegalovirus, and varicella zoster virus. This thrombocytopenia may be caused by cross-reacting antibodies and closely mimics acute ITP of childhood. Proper diagnosis and treatment of the underlying disorder, where necessary, play an important role in patient management.