Low dose cytosine arabinoside used to induce remission in acute myelofibrosis

Changes in Chemosensitivity of K 562 Leukemia Cells after Induction of Erythroid Differentiation by Hemin

The human leukemia cell line K 562, when treated with subcytotoxic doses of hemin, undergoes reversible erythroid commitment, as shown by the increased synthesis of hemoglobin. Hemin-treated cells maintain replicative capabilities, although perturbations in cell cycle kinetics are induced. K 562 cells were used to investigate changes in antitumor drug sensitivity as a consequence of cell differentiation induced by hemin treatment. K 562 leukemia cells, cultured in the presence of 20 μM hemin for 12 days, were treated with non-phase-specific (adriamycin, 4-OOH-cyclophosphamide, mitomycin C, bleomycin, cis-diamminedichloro platinum) and phase-specific (vincristine, methotrexate and 5-fluorouracil) antitumor drugs. The results obtained by chemosensitivity tests showed a generalized decrease in chemosensitivity of the K 562 cells to all the drugs tested as a consequence of the hemin-induced differentiation.

Danazol therapy combined with intermittent application of chemotherapy induces lasting remission in myeloproliferative disorder (MPD): an alternative for the elderly with advanced MPD

There is no good alternative therapy available for elderly patients with advanced myeloproliferative disorders (MPD) who failed on conventional therapies and are not candidates for bone marrow transplant. We report here an effective therapy that induced exceptionally long-lasting remissions and improved quality of life. Eighteen elderly patients (mean age: 70·6 years) (16 myelofibrosis and 2 thrombocythemia) who had failed on conventional therapies were treated. Danazol was administered daily at 200-800 mg throughout the study. Chemotherapy was applied intermittently as needed to reduce spleen size and blood counts. Busulfan (2-4 mg/day) was used most often and 6-mercaptopurine (6-MP) (50-100 mg/day) and/or cytarabine (100-200 mg/m(2)) if the white blood cell (WBC) count rose rapidly. When MPD stabilized, chemotherapy was discontinued and dosage of danazol was reduced. Therapy was well tolerated. Overall, 61% of patients responded with unexpectedly long-lasting remissions and improved quality of life. Three (17%) had excellent (E) response, defined by normalization of blood counts and non-palpable spleen, while eight (44%) had good (G) response, defined by rise of Hct by ≥7% and ≥50% reduction of spleen. Mean duration of remission was 45 months (10-78 months) in E responders and 11 months in G responders (2-22 months). This regimen offers a safe and effective alternative for advanced MPD in the elderly.

Trisomy 13 is associated with poor prognosis in idiopathic myelofibrosis with myeloid metaplasia

We report a case of idiopathic myelofibrosis with trisomy 13 as the sole clonal aberration, as demonstrated by metaphase cytogenetics. The clinical course was especially poor in this case, with death in blast crisis occurring within two weeks from diagnosis. The dismal outcome bears striking similarity to two previous cases of idiopathic myelofibrosis and trisomy 13 reported in the literature. Therefore trisomy 13 may be a predictor of a rapidly fatal outcome in this otherwise indolent disease. Fluorescence in situ hybridisation (FISH) with a chromosome 13 specific probe may enhance the detection of this aberration, since only 50% of cases of idiopathic myelofibrosis are karyotyped successfully using conventional techniques.

Idiopathic myelofibrosis--an update with particular reference to clinical aspects and prognosis

Idiopathic myelofibrosis (IMF) is characterized by excessive accumulation of connective tissue in the bone marrow as part of a clinical syndrome which in its classical form is featured by leukoerythroblastic anemia and huge splenomegaly at the time of diagnosis. An acute variant of the disease exists being featured by pancytopenia, nor or minimal splenomegaly and a rapidly fatal clinical course. This review describes the relationship of IMF to other chronic myeloproliferative disorders and highlights current concepts of the pathogenesis of bone marrow fibrosis, implicating the intramedullary release of various growth factors, including platelet-derived growth factor beta. In a subgroup of patients bone marrow fibrosis may develop consequent to autoimmune bone marrow damage. The clinical and laboratory findings in some of the larger series of patients are presented and the reasons for the highly variable clinical presentation and prognosis are critically discussed. It is proposed that studies on prognosis in IMF are based upon simple prognostic staging systems, which should include the Hb-concentration, platelet count, spleen size and the presence/absence of osteomyelosclerosis on X-ray. Using these parameters the patients are easily categorized into three prognostic groups with highly different survival times.

Aggressive polychemotherapy for acute myelofibrosis

Acute myelofibrosis is a rare and still ill-defined disease. Based on morphological observation, immunophenotyping and ultrastructural analysis, we support the assumption that acute myelofibrosis is a malignant disorder mainly of the megakaryocytic lineage and is closely related to acute megakaryocytic/blastic leukaemia. Consequently, the 11 patients reported here were treated with aggressive polychemotherapy with combinations including daunorubicin and cytosine arabinoside and 6-thioguanin or VP16-213. 4 complete remissions, 2 partial remissions and 1 minor response were observed. Duration of aplasia was not significantly prolonged. These findings indicate that the use of aggressive polychemotherapy is feasible in acute myelofibrosis and results in a significant number of remissions.

Myelofibrosis: a review of clinical and pathologic features and treatment

The purpose of this review is to discuss and clarify the current understanding of the pathogenesis, clinical manifestations, and treatment of MF. MF may be either a primary or secondary disorder. It is characterized by an increased deposition of bone marrow collagen, fibronectin, and laminin. Present evidence indicates that MF may be mediated by platelet or megakaryocyte growth factors, decreased prostaglandin mediated stem cell inhibition, immune complex deposition, and both fibroblast and endothelial cell proliferation. Recently acute MF has been recognized to be identical to acute megakaryocytic leukemia. Secondary MF usually responds to appropriate treatment of the underlying disease. Primary MF is usually treated by blood product support, but may be responsive to androgens, splenectomy, splenic irradiation, chemotherapy, or bone marrow ablation with marrow reconstitution.

Myelofibrosis: a concise review of clinical and pathologic features and treatment

This paper reviews and clarifies the current understanding of the clinical and pathologic features and treatment of MF. Recent investigations indicate that MF may be mediated by platelet- and megakaryocyte-derived growth factors, impaired prostaglandin-mediated stem cell growth inhibition, or excessive endothelial cell and fibroblast proliferation. Immunologic disorders have been associated with MF. MF may be either a primary or a secondary phenomenon. Secondary MF often regresses with appropriate treatment of this underlying disorder. Primary MF may require androgen therapy, splenectomy, splenic irradiation, bone curettage, chemotherapy, or bone marrow transplantation.

Low-dose Ara-C can cause complete remission of acute non-lymphocytic leukemia: differentiation induction?

Fourteen patients with acute nonlymphocytic leukemia were treated with low-dose arabinosylcytosine (LDAC). Thirteen patients received subcutaneous injections at a dose of 10 mg/M2 every 12 h. One patient received 25 mg intramuscularly daily. All cases received one to three courses with each course lasting 10-60 days (median 19). Complete remission was achieved in 6 (or 43%) of the patients. Three patients had only cytoreduction and 5 patients did not respond. During the therapy severe thrombocytopenia occurred in all patients while prominent other cytopenias occurred in 10. Two-thirds of the patients achieving a remission had significant myelosuppression. There was one treatment-related death. During therapy 11 patients demonstrated a decrease in leukemia cells with an associated increase in differentiated granulocytes. This included 3 of the 4 complete remitters, and 3 of the 5 nonresponders. These results seem to suggest that the therapeutic effect of low-dose Ara-C may result from a combination of differentiation induction, cytotoxicity and unusual sensitivity of the leukemic cells to this agent.