Therapeutic aspects of myelodysplastic syndromes in chronic phase

Effect of Diagnosis (Refractory Anemia With Excess Blasts, Refractory Anemia With Excess Blasts in Transformation, or Acute Myeloid Leukemia [AML]) on Outcome of AML-Type Chemotherapy

In current medical practice, patients with refractory anemia with excess blasts in transformation (RAEB-t), and especially patients with RAEB, receive chemotherapy regimens (AML Rx) administered to patients with acute myeloid leukemia (AML) less often than do patients with AML. These entities are distinguished primarily by marrow blast percentage (5% to 19% RAEB, 20% to 29% RAEB-t, and ≥30% AML). The poor prognosis of many RAEB or RAEB-t patients, if untreated, led us to give them AML Rx using the same plan as for AML. The purpose of this analysis was to see if diagnosis (RAEB, RAEB-t, or AML) affected outcome. We treated 372 patients with AML (acute promyelocytic leukemia [APL] excluded), 106 with RAEB-t, and 52 with RAEB. AML Rx produced a 62% complete remission (CR) rate in RAEB, essentially identical to the rates in RAEB-t and AML, but event-free survival (EFS) from CR and from start of treatment (start of Rx), as well as overall survival, were poorer in RAEB than in AML or RAEB-t, with AML and RAEB-t being identical. However, patients with RAEB or RAEB-t were more likely to have poor prognostic characteristics, in particular complex abnormalities involving chromosomes 5 and/or 7. Multivariate analyses indicated that, when considered together with cytogenetics and other patient characteristics, a diagnosis of RAEB rather than AML or RAEB-t had no effect on EFS from start of Rx, EFS from CR, survival, or achievement of CR. These analyses suggested a trend for patients with RAEB-t to have better EFS from start of Rx than patients with AML or RAEB (P = .08; relative risk, 0.80; 95% confidence interval, 0.62 to 1.03), but there were no differences with respect to the other outcomes. Our data suggest that the propriety of administering AML Rx to patients with RAEB or RAEB-t who have poor prognosis without treatment is identical to the propriety of treating AML in this fashion. Deterrents to standard AML Rx in these patients could justifiably include cytogenetics, age, etc, but not a diagnosis of RAEB or RAEB-t per se.

A sequential erythropoietin and GM-CSF schedule offers clinical benefits in the treatment of anaemia in myelodysplastic syndromes

In order to reduce anaemia in patients with myelodysplastic syndromes (MDS) a stepwise treatment protocol including erythropoietin (EP) and granulocyte-macrophage colony-stimulating factor (GM-CSF) was designed. Thirty-seven MDS patients (stages I-III) with symptomatic anaemia were first given EPO 10,000 U s.c. 3 times weekly for 6 weeks. Those not responding, i.e. increased their haemoglobin levels > 15 g/l, proceeded into the second phase of the study where GM-CSF (200 micrograms/d. s.c. on weeks 1-6) was combined with EPO (10,000 U s.c. 3 times weekly on weeks 5-14). Following the initial EPO treatment phase, 14 of the 37 patients (38%) responded with increased haemoglobin levels. Responders were significantly different from non-responders in that their pre-treatment values of s-EPO, s-LDH and bone marrow blast cell counts were lower, their baseline haemoglobin levels higher and their transfusion dependency less pronounced. Eighteen of the 23 non-responders proceeded into the second phase, 13 of those were evaluable having completed the entire schedule. Three of the 13 initially EPO resistant patients (23%) responded to the GM-CSF/EPO combination with increased haemoglobin levels, suggesting a positive synergy between the two cytokines. Thus, the overall response rate to the present protocol was 46% (17 of 37 cases), but only a limited subset of the patients did clearly benefit from the combined GM-CSF/EPO administration. Therefore, we believe this step-wise approach to multiple growth factor treatment in MDS, starting with EPO alone and reserving the combination for refractory cases, has considerable advantages, taking into account both medical and socio-economical aspects.

Low-dose ARA-C consistently induces hematologic responses in the clinical 5q- syndrome

Five patients with the classical clinical syndrome associated with a deletion of the long arm of chromosome 5, i.e., anemia, macrocytosis, and thrombocytosis, or a normal platelet count, were treated successfully with subcutaneous low-dose cytosine arabinoside (LDARA-C). Prior therapy with other drugs had failed in four of the five patients. A total of nine complete and one partial hematologic responses were induced in five patients. Duration of the first hematologic response ranged from 3 to 30+ months. Two patients (cases 3 and 4) continue in their first hematologic response at 29 and 30 months. Upon relapse, up to three responses could be reinduced in two patients. Duration of the subsequent hematologic responses in case 1 was 16, 8, and 10 months and case 2 achieved two responses of 15 and 18+ months duration. LDARA-C therapy was associated with mild to severe neutropenia and moderate to severe thrombocytopenia. Thus, subcutaneous LDARA-C is highly effective in the treatment of patients with myelodysplasia associated with deletion of the long-arm of chromosome 5 (5q-).