Very-low-dose cytarabine for myelodysplastic syndromes and acute myeloid leukaemia in the elderly

Low dose Ara-C for myelodysplastic syndromes: is it still a current therapy?

The myelodysplastic syndromes (MDS) are characterized by hemopoietic insufficiency associated with severe cytopenias, leading to serious morbidity, and acute leukemia development. MDS typically occur in elderly people, with a median age at diagnosis ranging between 60 and 75 years. The patients' prognosis, estimated according to the International Prognostic Scoring System, age and performance status should be considered before choosing among the various treatment options. A therapeutic dilemma exists in MDS, due to the multifactorial pathogenetic features of the disease, the heterogeneous stage and the elderly age of patients at diagnosis. This is underlined by the absence of a Food and Drug Administration-approved agent with an indication for this disease. The therapeutic end-points vary from symptom management (using low-intensity treatment with biological targeted agents, or only supportive therapy), to attempts to change the natural history of the disease (generally using high intensity treatment, including intensive chemotherapy and hemopoietic stem cell transplantation). The main goal of low-intensity therapies is generally to induce hematological improvements and is mainly used for low-risk disease. On the other hand, high-intensity therapies generally aims to alter the disease's natural history (improving survival, and decrease progression to acute myeloid leukemia), and are mainly used for high-risk disease. This review will focus on the current role of low-dose Ara-C therapy in the management of MDS. In fact, there is evidence that low-dose chemotherapy with Ara-C can induce responses in patients with MDS. In particular, the use in combinations with growth factors, such as G-CSF or M-CSF, looks promising, suggesting further investigations about this old new therapeutic tool.

In vitro release of cytarabine from swellable matrices of CnEmCn triblock copolymers

Matrices loaded with cytarabine were prepared by compression of the tailor made triblock copolymers C17E227C17 and C17E454C17 (where C=methylene and E=oxyethylene). Observations of the swelling characteristics of copolymer matrices on immersion in distilled water indicated an increase in the thickness of the gel layer around the matrices following ingress of water into the matrices. The in vitro release of cytarabine was characterised from matrices of different molar mass and with different known drug loadings. The release of cytarabine from the copolymer matrices was predominantly by a Fickian diffusion mechanism; the release rate was dependent on drug loading and independent of copolymer molar mass.

Disseminated Mycobacterium avium-intracellulare infection in a patient with myelodysplastic syndrome (refractory anemia)

A 31-year-old woman presented with fever and arthralgia. Despite treatment with antimicrobials and corticosteroids, her symptoms persisted. A diagnosis of myelodysplastic syndrome (MDS)-refractory anemia (RA) was made by pancytopenia, dysplasia, and trisomy 8. Cultures of bone marrow, blood, and gastric juice showed Mycobacterium avium-intracellulare (MAI). She was treated with antimycobacterial drugs and recombinant human G-CSF/M-CSF and showed an initial response, but spike fever recurred and pancytopenia progressed. Hepatosplenomegaly and marked retroperitoneal lymphadenopathy were revealed, indicating further dissemination of MAI. Treatment with recombinant human GM-CSF and very-low-dose cytosine arabinoside, was started but was not effective. This case showed significant reduction in peripheral blood T-lymphocytes, especially the CD4+ population, and low immunoglobulin levels. Immunodeficiency state associated with long-term steroid therapy and MDS seemed to contribute to the development of the disseminated infection with MAI.

A randomized phase II trial of low-dose aclarubicin vs very low-dose cytosine arabinoside for treatment of myelodysplastic syndromes

We performed a randomized phase II trial comparing low-dose aclarubicin (LC-ACR) with very low-dose cytosine arabinoside (VLD-AC) in 39 consecutive untreated patients with myelodysplastic syndromes (MDS), including refractory anemia (RA), RA with excess of blasts (RAEB) and RAEB in transformation (RAEB-t). Nineteen patients received the VLD-AC therapy; 2 good responses (GR) and 2 partial responses (PR) were obtained in 11 patients with RAEB and RAEB-t, while 2 PR were obtained in 8 RA patients. Eighteen patients received the LD-ACR therapy; 2 GR and 4 PR were obtained in 11 RAEB/RAEB-t patients while 2 PR in 7 RA patients. There was no significant difference in the therapeutic effects and survival between these two groups of patients. These observations suggest that the LD-ACR therapy is effective in some patients with MDS and can be used as an alternative to the low-dose Ara-C therapy.

Maintenance with low-dose cytarabine for acute myeloid leukemia in complete remission

Thirty-four patients with acute myeloid leukemia (AML) in complete remission (CR), 30 of them aged over 60, received maintenance therapy scheduling four courses of low-dose cytarabine (LDA) 20 mg/m2/day in two subcutaneous injections for 3 weeks every 6 weeks. Each course was stopped when hematologic toxicity occurred, and doses of LDA were subsequently reduced by 50% for the following courses. During the first course of LDA, 15 patients needed blood and four patients platelet transfusions. Overall, 28 patients received four courses of LDA: 11 did not require any dose reduction, while 14 required one dose reduction and three needed two successive dose reductions. Two patients were hospitalized during maintenance. Median disease-free survival (DFS) is 308 days, with 16% of patients surviving at 5 years. Seven patients relapsed during the 168 days of maintenance, while ten of the 27 patients remaining at risk on day 169 relapsed during the 168 days following maintenance. We conclude that in AML in CR, the maximal dose of LDA tolerated by ambulatory patients is 10 mg/m2/day for 3 weeks. LDA seemed to delay relapse; however, precise assessment of the efficacy of this approach would require a randomized trial.

The role of low-dose chemotherapy in myelodysplastic syndromes

Aggressive chemotherapy of myelodysplastic syndromes is rarely feasible because these disorders predominantly occur in elderly patients who often have concurrent illnesses. Alternative treatment modalities must therefore be evaluated. This review summarizes the results that have been obtained with low-dose chemotherapy, especially with low-dose cytosine arabinoside (Ara-C). Overall response rates to treatment with low-dose Ara-C are about 40%, with some 20% of patients achieving a complete remission. Transition of MDS to AML does not reduce the probability of response. The therapeutic outcome cannot be reliably predicted by clinical or experimental parameters. Hematological toxicity is substantial, with approximately 10-25% treatment-related deaths. Duration of response is short and rarely exceeds one year. In terms of overall survival, low dose Ara-C does not appear to be superior to supportive care only. Other cytotoxic agents have not been studied in detail, but data available do not suggest an appreciable advantage over Ara-C. Before denying low-dose chemotherapy a helpful role in MDS, randomized studies should concentrate on those patients who can be expected to derive the greatest benefit. Because of their short survival, patients with RAEBt or those transformed to overt leukemia are such candidates.

Interleukin 4 suppresses the spontaneous growth of chronic myelomonocytic leukemia cells

We studied the effects of IL-4 on the spontaneous proliferation of chronic myelomonocytic leukemia (CMMoL) cells in vitro. IL-4 (100 U/ml) suppressed the spontaneous DNA synthesis by approximately 50% in 5 of 8 cases examined. IL-4 (100 U/ml) also inhibited the spontaneous colony formation by CMMoL cells in a methylcellulose culture by 50-97% in all of the 10 cases in which spontaneous colonies were formed. This IL-4-mediated suppression of the growth of CMMoL cells was completely abolished by the addition of anti-IL-4 neutralizing antibodies. The spontaneous CMMoL colonies were substantially suppressed by the addition of either anti-IL-6 or anti-granulocyte/macrophage colony-stimulating factor (GM-CSF) antibodies to the colony assay system: the addition of both anti-IL-6 and anti-GM-CSF antibodies resulted in greater than 80% inhibition of the colony formation by CMMoL cells. On the other hand, none of anti-IL-1-beta, anti-granulocyte-CSF, anti-macrophage-CSF, or anti-tumor necrosis factor-alpha antibodies affected the CMMoL colony formation. In the supernatants from 24-h cultures of CMMoL cells, high levels of IL-6 and GM-CSF were demonstrated in 9 of 9 and 2 of 9 cases examined, respectively. IL-4 (100 U/ml) almost completely inhibited the secretion of IL-6 and GM-CSF by CMMoL cells. These observations suggest that IL-4 suppresses the spontaneous proliferation of CMMoL cells by inhibiting their production of IL-6 and/or GM-CSF, both of which could act in vitro as an autocrine growth factor for CMMoL cells.

Myelodysplastic syndromes

A cure for MDS has yet to be found. The aim of therapy is to attempt to restore normal hematopoiesis and prevent evolution to acute leukemia. The major trend is supportive care. Blood counts and bone marrow aspirations are taken to evaluate the disease, and transfusions of blood products and antibiotics are given when necessary. A new encouraging modality of therapy is the use of hematopoietic growth factors to reverse cytopenias. As there is no curative treatment for MDS, the patient is likely to be offered investigational drugs either singly or in combination. Future trends in the treatment of MDS will be combinations of agents including biological agents with retinoic acid or vitamin D, low-dose Ara-C, the interferons, and colony-stimulating factors.

Treatment of myelodysplastic syndrome and atypical leukemia with low-dose aclarubicin

To study the therapeutic effect of low-dose aclarubicin (ACR), we carried out comparative treatment of 15 patients with myelodysplastic syndrome (MDS) and atypical leukemia using this drug. Complete remission (CR) was achieved in three patients with RAEB-t and one patient with AML, partial remission was obtained in one patient with RAEB and hematological improvement in one patient with refractory anemia (RA). Interestingly, prolonged CR for more than 26 months with persistent chromosomal abnormalities was observed in a case of AML, which progressed from RA. Myelosuppression caused by low-dose ACR was milder than that caused by low-dose Ara-C. Furthermore, in vitro studies indicated that ACR induced differentiation of bone marrow cells from one patient with MDS. From these observations, it is suggested that low-dose ACR may be an alternative to low-dose Ara-C for treatment of MDS, and that the in vivo effect of ACR may be mediated by the differentiation of abnormal hemopoietic clones.

The role of low-dose cytosine arabinoside and aggressive chemotherapy in advanced myelodysplastic syndromes

The efficacy of low-dose cytosine arabinoside (Ara-C) and aggressive chemotherapy was assessed in 67 patients with advanced myelodysplastic syndromes (MDS). In most cases, treatment was started because of worsening peripheral cytopenia, increase in bone marrow blasts, or transition of MDS to acute myeloid leukemia (AML). Of 51 patients (age range, 18-82 years) receiving low-dose Ara-C by subcutaneous bolus injection (10 mg/m2 every 12 hours) or continuous intravenous infusion (20 mg/m2/day), nine (18%) entered complete remission (CR) and four (8%) had a partial response (PR). Duration of CR varied from 4 to 25+ months. Overall survival of patients treated with Ara-C was not superior to that of a historical control receiving supportive care only. Hematologic toxicity of low-dose Ara-C was considerable, with 12 patients (24%) dying of hemorrhage or infection during the initial treatment course. Sixteen patients (age range, 17-65 years) who presented with a Karnofsky score of more than 80% were chosen for aggressive chemotherapy using standard AML protocols. In this group, nine CR and two PR were obtained. Early death from pneumonia occurred in two patients, and three patients had refractory disease. The factors most strongly associated with successful remission induction were (1) presence of Auer rods in granulocyte precursors, and (2) a comparatively low medullary blast count (less than 30%) at the start of treatment. Median duration of bone marrow aplasia for patients entering CR was 21 days (range, 6-51). Prolonged remissions (22+, 27+, and 29 months, respectively) could be achieved in three of four patients receiving consolidation and maintenance chemotherapy after induction of CR. From these data we conclude that aggressive chemotherapy should not generally be considered contraindicated in advanced MDS. In patients with a good Karnofsky score, this form of treatment may be more advantageous than the currently favored low-dose Ara-C, which is also myelotoxic, but induces remissions in only a minority of patients.

Low-dose cytosine arabinoside in acute non-lymphoblastic leukemia

Eighteen previously untreated patients with acute non-lymphoblastic leukemia (ANLL) were treated with cytosine arabinoside (Ara-C) in low doses (10 mg/m2 every 12 hours) subcutaneously for 3 weeks. Complete remission (CR) was achieved in four patients (22.2%), and myelosuppression was observed in nearly all of them. Thrombocytopenia (20 X 10(3)/microliters) was pronounced in the third week of treatment and six patients (33.3%) needed platelet support. Contrary to earlier claims, our experience suggests that treatment with low-dose Ara-C is associated with significant cytopenias. Ara-C does not obviate the need for intensive supportive care and CR rates are no longer better. Low-dose Ara-C does not seem to be a choice in previously untreated ANLL patients who otherwise have a high probability of achieving a CR with standard multidrug chemotherapy protocols.

Differentiation induction therapy of myelodysplastic syndromes

Myelodysplastic syndromes are a heterogenous group of haemopoietic stem cell disorders characterized by dysplastic haematopoiesis and a defective maturation of a slowly expanding or sometimes of a stable population of haemopoietic progenitors. Defective maturation, which may involve one or more of the marrow cell lineages is regarded as the central pathophysiological feature of myelodysplastic syndromes. Patients with myelodysplastic syndromes respond poorly to conventional cytotoxic chemotherapy, frequently developing a prolonged marrow aplasia. The alternative and more appropriate form of therapy is differentiation induction therapy. The results of few preliminary clinical studies in myelodysplastic patients showed that a combination of differentiating agents is superior to single agent differentiation therapy. An extensive pre-clinical screening of the response of fresh cells from myelodysplastic patients in primary culture is needed to establish the optimal doses and conditions for significant synergies between various differentiating agents followed by large controlled randomized clinical trials based on differentiation induction therapy for patients with myelodysplastic syndromes.

The management of leukaemia in the elderly

Leukaemia is relatively common in the elderly compared to the general population, with over half of all cases of leukaemia occurring in patients aged 65 and over. Special problems are associated with treating patients in this age group. The leukaemias may be intrinsically different, in part because of the high incidence of preceding myelodysplasia. There is increased likelihood of coincident disease. There is lower tolerance to toxic complications, such as infection and bleeding, associated with a decreased resilience of normal haematopoiesis. There is more difficulty in obtaining intravenous access in elderly patients. These problems render patients ineligible for marrow transplants. Myelodysplastic syndromes occur predominantly in the elderly. There are a number of myelodysplastic syndromes now identified, each with its characteristic natural history. Management decisions are based on accurate diagnosis of the specific syndrome, consideration of prognostic features, a period of observation, and conservative treatment principles. More than half the cases of acute myeloblastic leukaemia also occur in the elderly. Prognostic factors must be examined and the literature carefully scrutinized for results pertinent to the elderly patient. In some patients treatment may be justifiably withheld, others may benefit from low dose cytosine arabinoside and some patients should receive aggressive combination chemotherapy. Management of the chronic leukaemias in the elderly is a less controversial area. Chronic lymphocytic leukaemia is the most common of the leukaemias in this age group. Prognostic factors can be determined using staging criteria. observation alone is indicated in many patients. Chlorambucil and prednisone are the most widely used drugs for symptomatic disease. Aggressive combination chemotherapy may benefit a few patients with advanced or refractory CLL. Hairy cell leukaemia is a rare disorder but many of the patients are over age 65. The elderly male patient may have a particularly benign course and require no therapy. Splenectomy is the standard first line of therapy, but recombinant alpha-interferon is sufficiently effective and non-toxic that it should be the treatment of choice in some patients. Deoxycoformycin is also effective in preliminary trials and may soon be routinely indicated. It is not often appreciated that half of all patients with chronic myelogenous leukaemia are aged 65 and over.(ABSTRACT TRUNCATED AT 400 WORDS)