Active clinical trials for "Blood Platelet Disorders"

Study hypothesis: Desmopressin (DDAVP) can improve platelet function under influence of aspirin, hemodilution and mild hypothermia Mild hypothermia (34-35oC) is known to cause platelet dysfunction. This could lead to increased surgical bleeding and increased transfusion requirement during surgery. Although this hypothermia-induced platelet dysfunction seems to be reversible with warming, this is not always possible or desirable. Desmopressin (DDAVP) is a drug which has proven efficacy in improving platelet function in uraemic and cirrhosis patients, and in reducing blood loss in selected surgeries. In a recent study, we have found that subcutaneous injection of 1.5 mcg (1/10th the usual dose) is already sufficient to fully reverse the platelet dysfunction seen at 32oC. We have demonstrated in another study that prolongation of the bleeding time in a 20% hemodiluted sample predicts increased postoperative bleeding after total knee replacement. We have therefore designed this study as a follow up to our last two studies on DDAVP and hypothermia, to investigate whether hemodilution affects hypothermia induced platelet dysfunction and the response to DDAVP. In addition, another common cause of perioperative platelet dysfunction is the intake of COX inhibitors, particularly aspirin by patients. Therefor the effect of aspirin on hypothermia induced platelet dysfunction and the response to DDAVP, will also be investigated.

Inherited thrombocytopenias (ITs) are a heterogeneous group of disorders characterized by a reduced number of blood platelets and a consequent bleeding tendency that ranges from mild to life-threatening. Thrombocytopenia is caused by genetic mutations and therefore is present throughout life and can be transmitted to the progeny. Some patients with severely reduced platelet count present spontaneous bleeding, which represents a major clinical problem: in fact, bleeding diathesis exposes these subjects to the risk of severe hemorrhages, affects their quality of life and often requires hospitalization and/or transfusions. Conversely, other patients with ITs have absent or mild spontaneous bleeding tendency. However, even these patients are at risk of major bleeding on the occasion of surgery or other invasive procedures. Therefore, the potential for hemorrhages on the occasion of invasive procedures represent a clinical problem for all patients affected by ITs. Eltrombopag is a drug, available in tablets, which stimulates the production of platelets by the bone marrow. A previous study demonstrated that a short course of eltrombopag was effective in increasing platelet count in most patients with the MYH9-related disease (MYH9-RD), the most frequent form of IT. Eltrombopag was given for 3 to 6 weeks to 12 patients with MYH9-RD and platelet counts lower than 50 x10e9/L. Eleven patients responded to the drug and 8 of them obtained platelet counts higher than 100 x10e9/L or three times the baseline value. Remission of spontaneous bleeding was achieved by 8 of 10 patients and treatment was well tolerated in all the cases. Based on these findings, short-term eltrombopag courses have been successfully used for preparing for major surgery two patients with MYH9-RD and less than 20 x10e9 platelets/L. The present study has two main objectives. - To verify if eltrombopag is effective in transiently increasing platelet count over 100 x 10e9/L and abolishing bleeding tendency in patients with different forms of IT. To this end, eltrombopag will be given for 3-6 weeks to patients with different forms of IT. Eltrombopag will be administered at the dose of 50 mg/day for 3 weeks. After 3 weeks of treatment, the patients who will obtain a platelet count higher than 100 x10e9/L and complete remission of bleeding tendency will stop therapy. In the other cases, patients will be treated with eltrombopag at a higher dose (75 mg/day) for 3 additional weeks. This treatment schedule is called "Phase 1" of the study. If the study will achieve this goal, short-term eltrombopag could be potentially used in the future to prepare these patients for surgery or other invasive procedures - To verify if eltrombopag can be used to stably reduce spontaneous bleeding tendency for long periods of time in patients with clinically significant spontaneous hemorrhages. To this end, patients with clinically significant spontaneous bleedings at baseline and who had their bleeding tendency reduced during the Phase 1 of the study without severe side effects, will be admitted to the "Phase 2" of the study. During the Phase 2, patients will be treated with eltrombopag for 16 weeks. In order to determine the lowest dose of eltrombopag that is able to reduce or abolish their bleeding tendency, patients will start treatment with eltrombopag 25 mg/day for 4 weeks. Then, every 4 weeks, patients will be re-evaluated and the dosage of eltrombopag will be adjusted according to bleeding tendency and platelet count. The dosages of eltrombopag that can be used in the Phase 2 range from 12.5 to 75 mg/day. Other objectives of the study are: to evaluate safety and tolerability of Eltrombopag in patients affected with ITs. to identify the dosages of Eltrombopag required for achieving the primary endpoints of Phases 1 and 2. to study the effects of Phase 2 treatment on patients' health-related quality of life (HR-QoL); to study the effects of treatment on some laboratory parameters related to platelet production and function. All patients will be undergo a follow-up visit 30 days after completion of treatment. Patients will be treated as outpatients. The evaluation of patients at enrollment and at each subsequent on-treatment and post-treatment visits includes: medical history; physical examination; evaluation of bleeding tendency according to WHO bleeding scale; CBC and differential; platelet count by phase-contrast microscopy; peripheral blood smear examination; plasma transaminases, bilirubin, and creatinine; urine analysis; ophthalmic assessment (only at some visits); measurement of serum thrombopoietin level; evaluation of HR-QoL (only at baseline and during Phase 2); evaluation of in vitro platelet aggregation in response to ADP, collagen and ristocetin whenever platelet count is over 100 x 10e9/L.

The term MYH9-related disease (MYH9RD) includes four genetic disorders: May-Hegglin anomaly, Sebastian syndrome, Fechtner syndrome, and Epstein syndrome. All these disorders derive from mutation of a unique gene, named MYH9, and they have been recognized as different clinical presentations of a single illness that was named MYH9RD. All patients affected by MYH9RD present since birth with thrombocytopenia, which can result in a variable degree of bleeding diathesis; some of them subsequently develop additional clinical manifestations, such as renal damage, sensorineural hearing loss, and/or presenile cataracts. Eltrombopag is an oral thrombopoietin receptor agonist that stimulates proliferation and differentiation of megakaryocytes, the bone marrow cells that produce blood platelets. This drug is effective in increasing platelet count in healthy volunteers, as well as in patients affected by some acquired thrombocytopenias, such as idiopathic thrombocytopenic purpura and HCV related thrombocytopenia. The purpose of this study is to determine if eltrombopag, administered orally at the dose of 50 or 75 mg/daily for up to 6 weeks, is effective in increasing platelet count of patients affected by MYH9RD. Further aims of this study are to test if eltrombopag is effective in reducing bleeding tendency of MYH9RD patients; to evaluate safety and tolerability of eltrombopag in patients with MYH9RD; to evaluate in vitro function of platelets produced during therapy in patients responding to this drug.

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Study rationale is based on the data that in previous clinical studies of eltrombopag in ITP there are some patients who have been reported as non responders at the maximal approved dose of 75 mg daily. The trend in both normal volunteers and in patients with ITP suggest and increasing response rate with increased doses of eltrombopag up to a dose of 75mg. Previously published data has shown no overt increase in toxicity in normal volunteers, oncology patients and aplastic anemia patients treated with escalated doses as high or higher than those proposed in this study. It therefore seems possible that in ITP patients who did not respond to a dose of 75mg daily, eltrombopag could be more effective at a higher dose. We propose a double blind randomized controlled trial in ITP patients who have been defined as non-responders at the maximum dose (75mg) of eltrombopag, assessing efficacy and toxicity at higher daily doses (100mg, 125 mg, 150 mg)

The purpose of this study is to test the safety and effectiveness of Humate-P® to prevent bleeding in patients with von Willebrand Disease who are undergoing surgery.

Patients admitted for coronary artery bypass surgery taking antiplatelet medicine have an increased risk for bleeding. Present study aims to compare the platelet function in two patient groups using different types of heart-lung machine methods. It is assumed that one of the methods is superior verified by sensitive methods of testing platelet function.

Rationale: Cardiac surgery with extracorporeal circulation (ECC) triggers platelets. Minimal extracorporeal circulation system (minimal-ECC) has several advantages compared with conventional ECC amongst less platelet activation. Platelet function can be analysed with thromboelastography (TEG) and multiple electrode aggregometry (MEA). Objective: The use of minimal ECC leads to less platelet dysfunction compared with conventional ECC in coronary artery bypass grafting (CABG) analysed with TEG and MEA Study design: Single center, prospective, randomized, pilot study Study population: Group 1: 20 patients undergoing CABG using minimal ECC. Patients continued the use of acetylsalicylic acid and discontinued the use of clopidogrel minimal 5 days preoperative. Group 2: 20 patients undergoing CABG using conventional ECC. Patients continued the use of acetylsalicylic acid and discontinued the use of clopidogrel minimal 5 days preoperative. Intervention: Group 1: CABG using minimal ECC Group 2: CABG using conventional ECC Main study parameters/endpoints: Results of TEG and MEA, see detailed description Per operative blood loss and total blood loss 24 hours after CABG Total amount of transfused platelet units during CABG and 24 hours after CABG

Platelets play pivotal role in atherosclerosis and acute cardiovascular events. Platelet hyperreactivity and increase platelet-monocyte aggregate (PMA) formation are found in HIV infected patients, which may contribute to the excess cardiovascular risk. Low level of vitamin D has been associated with the presence of cardiovascular diseases. The aim of our study is to determine the effect of vitamin D supplementation on platelet activation, platelet reactivity and platelet-leukocyte complex formation in asymptomatic HIV-infected patients treated with ART

The goal of this study is to identify the platelet defect responsible for the bleeding in families from our inherited platelet disorders Israeli-Palestinian registry. The investigators plan to characterize platelet proteome expression after removing high abundance proteins. The investigators will compare the proteome of sick and healthy members of families with inherited platelet disorders, and identify and validate structural proteins, signaling cascades and biomarkers for detection and diagnosis of unknown platelet disorders. The investigators expect to discover new key findings that allow better understanding of human platelet function and allow better diagnosis and treatment of patients with inherited platelet function disorders.