Spontaneous subdural hematoma in a patient with Philadelphia chromosome-positive acute lymphoblastic leukemia with normal platelet count after dasatinib treatment

Intracerebral hemorrhage as a rare complication of imatinib in a Philadelphia chromosome positive acute lymphoblastic leukemia pediatric patient

Imatinib is a BCR-ABL tyrosine kinase inhibitor used for the treatment of a variety of diseases including Philadelphia chromosome positive (Ph+) leukemia. We report a 15 year old male patient presenting with symptomatic acute intracerebral hemorrhage (ICH) in midbrain while on imatinib more than three years after completion of therapy for Ph + B-ALL. The patient denied recent trauma history and consumption of other medication. Laboratory findings did not show any signs of relapse, coagulopathy nor thrombocytopenia. Under the impression of imatinib related ICH, imatinib was discontinued and with conservative management the patient recovered without neurologic sequalae. This case demonstrates the first pediatric case of spontaneous ICH as a rare complication of imatinib.

Recurrent Gastrointestinal Hemorrhage in Children with Philadelphia-Positive B-Cell Acute Lymphoblastic Leukemia Treated with Dasatinib: Case Reports

Dasatinib, a second-line tyrosine kinase inhibitor (TKI), has been widely used in chronic myeloid leukemia (CML) and Philadelphia-positive B-cell acute lymphoblastic leukemia (Ph + B-ALL). Although dasatinib has been well tolerated, side effects including hemorrhage are not rare. Cases of bleeding disorders ultimately result in thrombocytopenia, but platelet aggregation dysfunction induced by dasatinib has also been demonstrated in Ph + B-ALL and CML patients. We report three Chinese children with Ph + B-ALL who received a combination treatment of chemotherapy and dasatinib and developed gastrointestinal bleeding several months later. The platelet count and clotting tests were normal, and these patients presented with dasatinib-induced platelet dysfunction. These findings reveal that physicians should be aware of and carefully monitor for side effects, including bleeding disorders.

Acquired platelet antagonism: off-target antiplatelet effects of malignancy treatment with tyrosine kinase inhibitors

Platelets can contribute to tumor progression and metastasis. Cancer patients are at increased risk of thrombosis, and advanced stages of cancer are associated with thrombocytosis or increased platelet reactivity. Tyrosine kinase inhibitors (TKIs) are widely used as a targeted strategy for cancer treatment, with the aim of prolonging progression-free survival of the patients. Because of their broad kinase target spectrum, most TKIs inevitably have off-target effects. Platelets rely on tyrosine kinase activity for their activation. Frequently observed side effects are lowering of platelet count and inhibition of platelet functions, whether or not accompanied by an increased bleeding risk. In this review, we aim to give insights into: (i) 38 TKIs that are currently used for the treatment of different types of cancer, either on the market or in clinical trials; (ii) how distinct TKIs can inhibit activation mechanisms in platelets; and (iii) the clinical consequences of the antiplatelet effects of TKI treatment. For several TKIs, the knowledge on affinity for their targets does not align with the published effects on platelets and reported bleeding events. This review should raise awareness of the potential antiplatelet effects of several TKIs, which will be enhanced in the presence of antithrombotic drugs.

Cardiovascular Toxicity and Management of Targeted Cancer Therapy

The advent of effective oral, molecular-targeted drugs in oncology has changed many incurable malignancies such as chronic myeloid leukemia into chronic diseases similar to coronary artery disease and diabetes mellitus. Oral agents including monoclonal antibodies, kinase inhibitors and hormone receptor blockers offer patients with cancer incremental improvements in both overall survival and quality of life. As it is imperative to recognize and manage side effects of platelet inhibitors, beta blockers, statins, human immunodeficiency virus drugs and fluoroquinolones by all healthcare providers, the same holds true for these newer targeted therapies; patients may present to their generalist or other subspecialist with drug-related symptoms. Cardiovascular adverse events are among the most frequent, and potentially serious, health issues in outpatient clinics, and among the most frequent side effects of targeted chemotherapy. Data support improved patient outcomes and satisfaction when primary care and other providers are cognizant of chemotherapy side effects, allowing for earlier intervention and reduction in morbidity and healthcare costs. With the implementation of accountable care and pay for performance, improved communication between generalists and subspecialists is essential to deliver cost-effective patient care.

Subdural Hematoma Associated with Dasatinib and Intrathecal Methotrexate Treatment in Philadelphia Chromosome-positive Acute Lymphoblastic Leukemia

Dasatinib has been associated with an increased risk of bleeding, with the most prominent risk noted in patients with advanced-stage chronic myeloid leukemia and thrombocytopenia. We herein report two cases of Philadelphia chromosome-positive acute lymphoblastic leukemia in which a subdural hematoma developed in association with low-dose (40-50 mg/day) dasatinib treatment and lumbar puncture for intrathecal methotrexate injection. Both patients were in complete remission, with normal platelet counts and coagulation status. We suggest that dasatinib, even at a low dose, may impair platelet aggregation and that lumbar puncture may increase the risk of a subdural hematoma (occasionally bilateral) in patients receiving dasatinib.