semaxinib and Myelodysplastic-Syndromes

The vascularization is a very important part of a structure of each tissue both normal, including bone marrow stroma, and pathologically changed. Neoplastic tissues secure supplying in necessary substances for growth and expansion through regulated by its own cells neovasculation. Key role in multipotential cell's differentiation to endothelial cells plays regulatory system consisted of vascular-epithelial growth factor's family (VEGF B, C, D), receptors VEGFR-1, -2, -3, and system Tie2/angiopoetins. Stimulation and importance of angiogenesis for expansion of neoplastic diseases is a current problem in oncology. It is pointed to importance of neovascularization in pathogenesis of acute and chronic leukemias, lymphomas and multiple myeloma. The knowledge of the importance ofvascularization of neoplastic tissues is availing in therapy (researching of substances inhibiting angiogenesis--semaxinib, SU6668, ZD 6474, thalidomid, cetuximab, gefitinib, interferon-alpha, irradiation and others), in diagnostics as a monitoring of a success of the therapy, and in prognosis. Inhibitors ofangiogenesis are antineoplastic drugs with relatively lower toxicity, and lower risk of drug-resistance than conventional chemotherapy what has the importance especially during prolong administration, so they can be an alternative way of therapeutic process. During qualification for antiangiogenic therapy it is necessary to have a consciousness of its limited efficiency.

Topics: Angiogenesis Inducing Agents; Angiogenesis Inhibitors; Angiopoietin-1; Angiopoietin-2; Hematologic Neoplasms; Humans; Indoles; Leukemia, Lymphocytic, Chronic, B-Cell; Leukemia, Myeloid, Acute; Multiple Myeloma; Myelodysplastic Syndromes; Neoplasm Metastasis; Neovascularization, Pathologic; Oxindoles; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Propionates; Pyrroles; Receptor, TIE-2; Receptors, Vascular Endothelial Growth Factor; Vascular Endothelial Growth Factors

Increased bone marrow angiogenesis and vascular endothelial growth factor (VEGF) levels are adverse prognostic features in patients with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDSs). VEGF is a soluble circulating angiogenic molecule that stimulates signaling via receptor tyrosine kinases (RTKs), including VEGF receptor 2 (VEGFR-2). AML blasts may express VEGFR-2, c-kit, and FLT3. SU5416 is a small molecule RTK inhibitor (RTKI) of VEGFR-2, c-kit, and both wild-type and mutant FLT3. A multicenter phase 2 study of SU5416 was conducted in patients with refractory AML or MDS. For a median of 9 weeks (range, 1-55 weeks), 55 patients (33 AML: 10 [30%] primary refractory, 23 [70%] relapsed; 22 MDS: 15 [68%] relapsed) received 145 mg/m2 SU5416 twice weekly intravenously. Grade 3 or 4 drug-related toxicities included headaches (14%), infusion-related reactions (11%), dyspnea (14%), fatigue (7%), thrombotic episodes (7%), bone pain (5%), and gastrointestinal disturbance (4%). There were 11 patients (20%) who did not complete 4 weeks of therapy (10 progressive disease, 1 adverse event); 3 patients (5%) who achieved partial responses; and 1 (2%) who achieved hematologic improvement. Single agent SU5416 had biologic and modest clinical activity in refractory AML/MDS. Overall median survival was 12 weeks in AML patients (range, 4-41 weeks) and not reached in MDS patients. Most observed toxicities were attributable to drug formulation (polyoxyl 35 castor oil or hyperosmolarity of the SU5416 preparation). Studies of other RTKI and/or other antiangiogenic approaches, with correlative studies to examine biologic effects, may be warranted in patients with AML/MDS.

Topics: Acute Disease; Adult; Aged; Antineoplastic Agents; Apoptosis; Bone Marrow Cells; Bone Marrow Examination; Humans; Indoles; Leukemia, Myeloid; Middle Aged; Myelodysplastic Syndromes; Necrosis; Pharmacokinetics; Protein-Tyrosine Kinases; Pyrroles; Remission Induction; Salvage Therapy