Ponatinib Exerts an Inhibitory Effect on Collagen-induced Platelet Aggregation and Generation of Coated-Platelets.

BACKGROUND/AIM: BCR-ABL tyrosine kinase inhibitors (TKIs) are exceptionally effective drugs in the treatment of chronic myeloid leukemia, nevertheless, TKIs have also an effect on platelets. We aimed to investigate the effect of a third-generation TKI, ponatinib on platelet functions. MATERIALS AND METHODS: Collagen-induced platelet aggregation and coated-platelet formation were examined using in vitro and in ex vivo samples of patients on ponatinib therapy. RESULTS: In platelet rich plasma of healthy volunteers, ponatinib at a supra-therapeutic concentration (1,000 nM) significantly impaired collagen induced platelet aggregation (p≤0.01) and reduced the formation of coated-platelets at 150 nM ponatinib concentration (p≤0.05). In addition, upon glycoprotein VI (GPVI) receptor activation, a significantly lower percentage of PAC1 binding platelets (p≤0.05) was observed at 1,000 nM final concentration of ponatinib. Platelets, isolated from patients on ponatinib therapy showed impaired collagen elicited aggregation response, already in pre-dose samples compared to healthy donors. CONCLUSION: The therapeutic concentration of ponatinib impairs platelet activation processes elicited by GPVI receptor agonists.

Practical management of side effects of tyrosine kinase inhibitor therapy in chronic myeloid leukemia / A krónikus myeloid leukaemia tirozin-kináz-gátló kezelésének mellékhatásai és azok gyakorlati ellátása.

Összefoglaló. A krónikus myeloid leukaemia ritka, klonális ossejt eredetu betegség. A myeloid sejtsor kóros muködését a 9-es és 22-es kromoszómák reciprok transzlokációja következtében kialakuló fúziós gén (BCR/ABL1) által kódolt patológiás (fokozott) aktivitású tirozin-kináz jelátviteli fehérje okozza. A tartós, gyakran élethosszig tartó BCR/ABL1 specifikus tirozin-kináz-gátló (TKI-) kezelés a betegek jelentos hányadában az egészséges populáció túlélését eléro teljes gyógyulást biztosít, melyhez folyamatos, a mindenkori szakmai ajánlásoknak megfelelo onkohematológiai ellenorzés szükséges. Az igen hatékony TKI-kezelés mellett azonban nemkívánatos mellékhatások jelentkezhetnek, melyek - számos szervrendszert érintve - a krónikus myeloid leukaemiás beteg kezelését multidiszciplináris együttmuködéssé szélesítik ki. Jelenleg Magyarországon ötféle TKI érheto el, melyek mellékhatásprofilja igen eltéro. A kezelés elindításakor, illetve terápiamódosítás esetén beteg- és kórképspecifikus szempontokat mérlegelve kell kiválasztani az adott TKI-kezelést. Tekintettel a tartós kezelés mellett elérheto kiváló túlélési eredményekre, egyre gyakoribb azoknak a krónikus myeloid leukaemiás betegeknek a száma, akiknél változó súlyosságú nemkívánatos mellékhatások jelentkeznek, melyek miatt a betegek sokszor nem a hematológus szakorvosnál jelentkeznek. A leggyakrabban észlelt szövodmények ismertetését saját beteganyagunk részletes elemzése kapcsán a mindennapi klinikai gyakorlatban is bemutatjuk. Igen fontos, hogy a társszakmák (háziorvos, belgyógyász, kardiológus, angiológus, diabetológus, tüdogyógyász, gasztroenterológus stb.) gyakorlói is tisztában legyenek az adott TKI-kezelés lehetséges mellékhatásaival, azok megelozésével, idoben történo felismerésével és hatékony kezelésével. Szakmai közremuködésük révén így segíthetik a klinikai hematológust a megfelelo terápia megtervezésében, valamint a betegek folyamatos kezelése kapcsán gyakran szükségessé váló szakmaspecifikus gondozásában is. Orv Hetil. 2021; 162(30): 1198-1207. Summary. Chronic myeloid leukemia is a rare clonal stem cell disorder. The pathological overproduction of the myeloid cell line is caused by abnormal function of a tyrosine kinase encoded by a fusion gene (BCR/ABL1) which is formed upon a reciprocal translocation of chromosomes 9 and 22. Long-term, often lifelong treatment with BCR/ABL1-specific tyrosine kinase inhibitors provides excellent disease control and overall survival rates close to the general survival of a healthy population in a significant proportion of patients. These patients require continuous oncohematological monitoring in accordance with the current diagnostic and treatment guidelines. However, undesirable side effects may occur that extend the treatment of the patients to a multidisciplinary approach involving a number of nonhematological specialities. Currently, five types of tyrosine kinase inhibitors are available in Hungary, with very different side effect profiles. At the start of treatment or in the event of a change in therapy, patient- and leukemia-specific assessments should be taken to select the most proper tyrosine kinase inhibitors treatment. Given the excellent survival outcomes achieved with long-term tyrosine kinase inhibitor treatment, there is an increasing number of patients who might experience adverse events of different kind or severity, which often results in patients ending up in different, nonhematological medical situations. The description of the most frequently observed complications in connection with a detailed cross-sectional analysis of our own patient cohort is also presented here resembling everyday clinical practice. It is very important that practitioners of other medical professions (general practitioner, internist, cardiologist, angiologist, diabetologist, pulmonologist, gastroenterologist, etc.) should be aware of the possible side effects of specific tyrosine kinase inhibitor therapies. They can help to assist the clinical hematologist in planning the appropriate tyrosine kinase inhibitor therapy as well as in professional caretaking of these patients. Orv Hetil. 2021; 162(30): 1198-1207.

Imidazo[1,2-b]pyrazole-7-Carboxamide Derivative Induces Differentiation-Coupled Apoptosis of Immature Myeloid Cells Such as Acute Myeloid Leukemia and Myeloid-Derived Suppressor Cells.

Chemotherapy-induced differentiation of immature myeloid progenitors, such as acute myeloid leukemia (AML) cells or myeloid-derived suppressor cells (MDSCs), has remained a challenge for the clinicians. Testing our imidazo[1,2-b]pyrazole-7-carboxamide derivative on HL-60 cells, we obtained ERK phosphorylation as an early survival response to treatment followed by the increase of the percentage of the Bcl-xlbright and pAktbright cells. Following the induction of Vav1 and the AP-1 complex, a driver of cellular differentiation, FOS, JUN, JUNB, and JUND were elevated on a concentration and time-dependent manner. As a proof of granulocytic differentiation, the cells remained non-adherent, the expression of CD33 decreased; the granularity, CD11b expression, and MPO activity of HL-60 cells increased upon treatment. Finally, viability of HL-60 cells was hampered shown by the depolarization of mitochondria, activation of caspase-3, cleavage of Z-DEVD-aLUC, appearance of the sub-G1 population, and the leakage of the lactate-dehydrogenase into the supernatant. We confirmed the differentiating effect of our drug candidate on human patient-derived AML cells shown by the increase of CD11b and decrease of CD33+, CD7+, CD206+, and CD38bright cells followed apoptosis (IC50: 80 nM) after treatment ex vivo. Our compound reduced both CD11b+/Ly6C+ and CD11b+/Ly6G+ splenic MDSCs from the murine 4T1 breast cancer model ex vivo.

Dasatinib Inhibits Procoagulant and Clot Retracting Activities of Human Platelets.

Tyrosine kinase inhibitors (TKI) such as the BCR-ABL inhibitor dasatinib and nilotinib are highly effective therapies for chronic myeloid leukemia (CML). However, several lines of evidence suggest that dasatinib can induce bleeding which may be due to impaired collagen-induced platelet adhesion, aggregation, and secretion. Sarcoma family kinases (SFK) play central role in the GPVI-induced signaling pathway. We aimed to investigate whether and how dasatinib can modulate SFK-mediated platelet procoagulant activity in a purified system and in dasatinib/nilotinib treated CML patients. In platelet rich plasmas of healthy volunteers, dasatinib dose-dependently reduced convulxin-induced phosphatidylserine exposure and attenuated thrombin formation. Similarly to these changes, integrin activation and clot retraction were also significantly inhibited by 100 nM dasatinib. Platelets isolated from dasatinib treated patients showed a significantly lower phosphatidylserine expression upon convulxin activation compared to premedication levels. In these samples, thrombin generation was significantly slower, and the quantity of formed thrombin was less compared to the trough sample. Western blot analyses showed decreased phosphorylation levels of the C-terminal tail and the activation loop of SFKs upon dasatinib administration. Taken together, these results suggest that dasatinib inhibits the formation of procoagulant platelets via the GPVI receptor by inhibiting phosphorylation of SFKs.

Dasatinib inhibits coated-platelet generation in patients with chronic myeloid leukemia.

Since the introduction of tyrosine kinase inhibitors, the overall survival of patients with chronic myeloid leukemia has markedly improved. However long term use of these drugs results in various adverse events. Treatment with second generation dasatinib is often complicated by hemorrhagic events. Previous lumi-aggregometry studies have shown impaired platelet function in patients on dasatinib therapy. Dual agonist activated platelets (coated-platelets) are also sensitive indicators of platelet function. We hypothesized that dual activation with convulxin and thrombin of platelets in a flow cytometric assay could be a more sensitive method for detecting platelet dysfunction as compared to single agonist studies used in lumi-aggregometer. Platelets of healthy volunteers incubated with dasatinib as well as platelets from patients on dasatinib therapy were investigated. Low therapeutic plasma level dasatinib concentrations at which a considerable reduction in coated-platelet generation was observed in vitro, did not cause detectable change in platelet aggregation response. Coated-platelet assay and lumi-aggregometry were also investigated at 0, 1 and 4 hours after drug administration in dasatinib treated CML patients. Significant decrease was observed at 1 hour in maximal aggregation by collagen. Although the aggregation curves became normalized by 4 hours, coated-platelet generation was still inhibited in dasatinib treated patients. Nilotinib, another second generation tyrosine kinase inhibitor, had no effect on aggregation and on coated-platelet formation neither in vitro nor in ex vivo samples. At therapeutic plasma levels coated-platelet assay is more sensitive than lumi-aggregometry studies for the demonstration of the inhibitory effect of dasatinib on platelet function.

[Drug treatment of acute myelogenous leukaemia. Current options and future perspectives]. / Az akut myeloid leukaemia gyógyszeres kezelése. Jelenlegi lehetoségek, jövobeli kilátások.

Acute myelogenous leukemia is a heterogeneous disease. Recent molecular mutational analysis techniques have shed more light on different, genetically well characterised types of the disease. Treatment approach is uniform except for acute promyelocytic leukemia. Application of the "3 + 7" induction treatment has been the gold standard in the past 40 years. While the dose of cytarabine has not been changed, escalating daunorubicine dose in younger (<60 years) patients with good performance status to 90 mg/m(2) had a positive impact on overall survival. High dose chemotherapy is tolerated poorly in patients older than 60 years of age and, as treatment is not curative in the elderly, improvement of overall survival and quality of life remains the main goal of management in these patients. Low intensity treatment is beneficial and can provide additional advantage over supportive care. Innovative and targeted therapy approaches might give promise to better management of patients with acute myelogenous leukemia.

[Changes in hematologic and hemostatic parameters after transjugular intrahepatic portosystemic shunt (TIPS) implantation]. / Hematológiai és haemostasisparaméterek változása transjugularis intrahepaticus portosystemas shunt hatására.

BACKGROUND: The pathogenesis of thrombocyte- and leukopenia associated with liver cirrhosis is far from being understood. Hypersplenism is considered to play a major role in this hematologic complication. The effect of transjugular intrahepatic portosystemic shunt (TIPS) implantation--a more recent technique in portal decompression--on platelet count is controversial in the literature. One of the main problems related to TIPS is the frequent occurrence of shunt malfunctions. There have been no reports on consistent clinical or biochemical parameters being able to predict the occlusive and rebleeding episodes after TIPS implantation. AIM AND METHOD: Platelet counts, white blood cell counts and different haemostatic data (prothrombin time, activated partial thromboplastin time and fibrinogen level) of the 24 patients undergoing TIPS placement were analyzed retrospectively prior to the procedure, after one month, after 3 months and 3 monthly thereafter for 18 months. RESULTS: The portal pressure gradient decreasing below the desired 12 mmHg after TIPS placement seems to be the only factor, which can result in moderate but significant increase in platelet counts. There was no significant alteration in white blood cell counts during the follow-up period. The different haemostatic parameters scattered in a wide range, no real tendency was demonstrable. Patients in whom recurrent variceal bleeding occurred, the platelet count at the 3rd month was significantly lower compared to the basal platelet count. The decrease in the platelet count preceded shunt malfunction detected with color-Doppler or the appearance of the clinical symptoms. CONCLUSION: Monitoring platelet count may be of prognostic interest in the assessment of the shunt function and the risk of imminent variceal rebleedings during the follow-up period.