Assessment of oxidative/nitrative modifications of plasma proteins, selected ROTEM parameters and kinetics of fibrinogen polymerization in patients with multiple myeloma at diagnosis.

Patients with multiple myeloma (MM) are at increased risk of thrombosis. Growing evidence indicates that oxidative and nitrative modifications of proteins, including fibrinogen, may lead to changes in hemostasis. The study compares samples from patients with MM at diagnosis and healthy volunteers with regard to the oxidative/nitrative modifications of proteins, ROTEM and thrombin-catalyzed fibrin polymerization. The content of carbonyl groups in plasma proteins of patients with MM was significantly higher than in controls (2.981 vs. 1.807 nmol/mg of protein, p = 0.005), while no differences were seen in the concentrations of nitrated proteins. Maximum clot firmness readings were significantly higher in the samples of patients than in controls according to FIBTEM test (23.5 vs. 15 mm, p = 0.006). The lag time of the fibrin polymerization process and the velocity of clot lysis (V Lys) were found to be significantly higher in the group of MM patients than controls. In contrast, no marked differences were identified between studied groups in reference to maximal velocity of fibrin polymerization process (V max), maximal absorbance (A max) and plasmin amidolytic activity values. In conclusion, our study demonstrates that at the time of diagnosis, patients with MM demonstrated greater oxidative stress than healthy volunteers, which is reflected in a higher amount of carbonylated proteins. Some prothrombotic features found in ROTEM tests in MM patients were not confirmed by turbidimetry.

JAK inhibitors: pharmacology and clinical activity in chronic myeloprolipherative neoplasms.

The Janus family kinases (JAKs), JAK1, JAK2, JAK3, and TYK2, are involved in cell growth, survival, development, and differentiation of a variety of cells, particularly immune cells and hematopoietic cells. They form a subgroup of the non-receptor protein tyrosine kinases. Activating mutations within each of the JAKs is associated with malignant transformations; the most common are mutations of JAK2 in polycythemia vera (PV) and other myeloproliferative neoplasms (MPN). Identification of the V617F mutation of the JAK2 gene (JAK2 V617F) led to an important breakthrough in the understanding of MPN disease pathogenesis. The JAK2 V617F mutation is present in the majority of PV patients, and about 50% of patients with essential thrombocythemia (ET) and primary myelofibrosis (PMF) are affected. This mutation leads to hyperactivation of JAK2, cytokine-independent signaling, and subsequent activation of downstream signaling networks. JAK2 ATP-competitive inhibitors that indirectly inhibit the JAK-STAT pathway are new candidates for the treatment of MPN. JAK2 inhibitors in development for the treatment of MPN have demonstrated clinical activity with minimal toxicity. These agents consistently alleviate constitutional symptoms and reduce spleen size in PMF and other MPN. However, some of these inhibitors have additional unique effects. Ruxolitinib causes a significant reduction in the level of pro-inflammatory cytokines. Another inhibitor, CYT387, improves anemia. Many other JAK2 inhibitors such as TG101348 or SAR302503, SB1518, CEP701 and LY2784544 are now under investigation for MPN development. In contrast tasocitinib, a predominantly JAK3 inhibitor, is being evaluated in a number of inflammatory and immunological diseases, including rheumatoid arthritis, psoriasis, ulcerative colitis, dry eye disease and in kidney transplant patients. In conclusion the use of JAK inhibitors in MPN and some of the immune-mediated disorders is a promising new strategy for therapy. However, definitive data from ongoing and future preclinical and clinical trials will aid in better defining the status of these drugs in the treatment of these diseases.

Clinical assessment of Optivate®, a high-purity concentrate of factor VIII with von Willebrand factor, in the management of patients with haemophilia A.

Factor VIII (FVIII) concentrates have revolutionized the treatment of patients with haemophilia A. Concerns over the transmission of viral infections through these products have been addressed through stringent, donor-screening procedures and robust antiviral manufacturing steps. Bio Products Laboratory has developed a high-purity FVIII product with von Willebrand factor, Optivate(®). Its safety, tolerability and efficacy as prophylaxis and treatment of bleeds have been established in long-term studies. Seventy previously treated patients with severe haemophilia A, with ≥ 20 exposure days, were recruited into two long-term, multicentre, open-label studies. The protocols were virtually identical. Patients received Optivate(®) either prophylactically or on-demand. A mean of 159.0 EDs were experienced over 11,320 infusions. Under both conditions, Optivate(®) was well tolerated. Only 10% of patients experienced a treatment-related adverse event; the most commonly reported were headache (4% of patients) and dizziness (3% of patients). The mean number of bleeds/patient over the 2 year treatment period was 23.5 during prophylactic use and 70.4 during on-demand use. In patients treated prophylactically, clinical responses to breakthrough bleeds were rated by physicians as excellent or good and as very helpful or helpful by patients in 95% of bleeds. Clinical responses for on-demand patients were rated as excellent or good by physicians and helpful or very helpful by the patients for 91% of bleeds. There were no viral transmissions or inhibitors. The studies confirm the clinical efficacy and safety of Optivate(®) in both prophylactic and on-demand management of patients with haemophilia A.

Pharmacokinetics of Optivate(®), a high-purity concentrate of factor VIII with von Willebrand factor, in patients with severe haemophilia A.

Optivate(®) is a high purity factor VIII/von Willebrand factor (FVIII/VWF) concentrate, which is manufactured using two antiviral processes: solvent/detergent and terminal dry heating (80 °C for 72 h). A multicentre, non-randomized open-label study in 15 patients was conducted to test the pharmacokinetics (PK) of Optivate(®). PK variables were analysed for the patients' prior FVIII product (PK1), their first dose of Optivate(®) (PK2) and at 3 months therapy (PK3). Mean non-compartmental half-lives (h) were 14.1, 12.4 and 12.1, respectively (P = 0.45), mean clearances (mL h(-1) kg(-1)) were 3.6, 3.2 and 3.1, respectively (P = 0.051), MRTs (h) were 19.0, 17.3 and 17.4, respectively (P = 0.39) and mean AUC(0-48h) (h IU mL(-1)) were 14.3, 15.4 and 16.6, respectively (P = 0.051) and mean AUC(0-∞) (h IU mL(-1)) were 15.9, 16.4 and 17.9, respectively (P = 0.18). The recovery data from this PK study was aggregated with recovery data collected from another study, with similar design but devoid of the other PK measurements. A total of 309 recoveries were conducted in 70 patients. The overall mean recovery per subject across 27 Optivate(®) batches was 2.7 IU dL(-1) per IU kg(-1). There were no clinical differences between Optivate(®) and other FVIII products, and except for volume of distribution (Vd), no statistically significant differences were seen with respect to any of the other PK variables, or in recovery between weeks 0 and 12. Therefore, the PK of FVIII is not affected by the processes used to manufacture Optivate(®), which can be expected to be effective in the management of patients with haemophilia A.

Assessment of coagulation disorders and cancer procoagulant activity in patients with myelodysplastic syndromes.

Hemostatic disorders mainly due to thrombocytopenia represent an important clinical problem in patients with myelodysplastic syndromes (MDS). Much less is known about the possible coagulation abnormalities. Thirty patients with MDS were studied. Activity of cancer procoagulant (CP), concentrations of activation markers of coagulation and fibrinolysis such as thrombin-antithrombin complexes (TAT), prothrombin fragment 1+2 (F1+2) and D-dimers (DD) as well as standard coagulation tests were determined. Coagulation abnormalities concerned mainly patients with RAEB and RAEB-t. In this group the mean values of TATand F1+2 concentrations were significantly higher than in control indicating chronic coagulation activation similar to that observed in acute leukemias. CP activity in MDS patients did not differ from the control group.

Assessment of coagulation disorders in patients with acute leukemia before and after cytostatic treatment.

Coagulation disorders are often the reason for fatal bleeding in acute promyelocytic leukemia. Their occurrence as well as pathogenesis and prognostic significance in other subtypes of acute myelogenous leukemia and acute lymphoblastic leukemia is less known. Tests were carried out in 70 patients including 49 with AML and 21 with ALL. In all patients thrombin-antithrombin complexes (TAT), D-dimer (DD) and plasmin-antiplasmin complexes (PAP), antithrombin III activity, fibrinogen/fibrin degradation products, APTT and PT were determined. The tests were performed on diagnosis and after cytostatic treatment. The level of TAT, DD and PAP was elevated in 83% of the patients on diagnosis and in 90% after treatment. The highest values were observed in AML M3 patients. Among leukemic patients with normal levels of TAT, DD and PAP at diagnosis, cytostatic treatment had a negligible effect on the level of these markers. During remission the levels of these markers returned to the normal values while in patients without remission they were either elevated or returned to normal values. No correlation between the levels of activation markers and remission rate was reported. DIC was diagnosed in 13 patients including three after chemotherapy. The DIC was acute or subacute in AML and chronic in ALL patients. In the majority of acute leukemia patients there were already changes on diagnosis indicating coagulation activation. Except for AML M3, these usually had a subclinical course. The TAT, DD and PAP tests are not reliable markers of remission in acute leukemias.

[Anagrelide--new antiplatelet drug]. / Anagrelide--nowy lek przeciwplytkowy.

Anagrelide is a quinazoline compound developed as a potent inhibitor of platelet aggregation. During studies in human it has produced rapid and selective thrombocytopenia and has therefore been evaluated for use in conditions associated with thrombocythaemia. Anagrelide significantly inhibits human megakaryocyte colony development in vitro by preventing full megakaryocyte maturation, and inhibits platelet aggregation as a result of potent inhibition of cyclic adenosine monophosphate (cAMP) phosphodiesterase activity. In 60 to 93% of patients with essential or myeloproliferative thrombocythaemia anagrelide produces sustain reductions in platelet counts and also reduces the incidence of disease-related symptoms. Most adverse effects are related to its vasodilatory or positive inotropic properties. This new agent appears promising in the treatment of thrombocytosis in patients with chronic myeloproliferative diseases, especially in younger persons in whom the risk of leukaemogenic transformation with some alternative drugs is of particular concern.