Treatment of advanced myelodysplastic syndromes with recombinant interferon-alpha2b

Abstract: We examined the efficacy and toxicity of recombinant interferon-alpha2b (rIFN-α2b) in 10 previously untreated patients with advanced myelodysplastic syndromes. Morphological subtypes were refractory anaemia with excess of blasts (RAEB) in 4, RAEB in transformation (RAEB/T) in 3 and chronic myelomonocytic leukaemia (CMML) in 3 cases. IFN was administered subcutaneously at increasing doses of 1 to 3 times 10⁶ IU per day. The median duration of therapy was 6 months (range, 3 to 14). 2 patients, both with a diagnosis of CMML, achieved a complete and partial remission, respectively. In the complete responder, remission could be maintained for 9.5 months by daily administration of 1 times 10⁶ IU IFN. The other patients were classified as failures, although in 4 cases a decrease of bone marrow blasts was noted and none of the patients progressed to overt leukaemia while being treated with IFN. During the study, all patients with RAEB and RAEB/T showed a moderate to severe reduction in peripheral leukocyte and platelet counts, requiring premature termination of IFN therapy in 5 cases. Despite adequate supportive measures, 2 patients died of pneumococcal pneumonia and gastrointestinal bleeding, respectively. In 1 patient, IFN therapy had to be stopped because of neurologic toxicity (polyneuropathy). From these data we conclude that rIFN-α2b at the doses and schedule tried is not a useful treatment for advanced myelodysplastic syndromes. Patients with CMML, however, may be an exception and should further be considered as candidates for therapeutic trials with rIFN-α2b.     

Two types of acquired idiopathic sideroblastic anaemia (AISA): a time-tested distinction

In 1982, acquired idiopathic sideroblastic anaemia (AISA) was included by the French-American-British (FAB) Co-operative Group in their classification of myelodysplastic syndromes (MDS). However, the malignant potentiality of AISA has always been a matter of debate. In different series, median survival and rates of transformation into acute myeloid leukaemia (AML) varied extensively. On cytomorphological grounds, AISA can be divided into pure (dyserythropoietic) sideroblastic anaemia (PSA), in which dysplasia is confined to erythropoietic cells, and a true myelodysplastic form (RARS), which is characterized by additional dysplastic features of granulopoiesis and/or megakaryopoiesis. In a previous study, based on retrospective analysis of 94 patients with AISA, we found that both types of sideroblastic anaemia differed considerably in terms of survival and risk of AML transformation. Almost identical results have now been obtained through a prospective study of 232 new patients with AISA. The difference in survival between PSA and RARS remained significant over the whole period of follow-up (survival after 3 years being 77% vs. 56%; P = 0.003), and the incidence of AML did not increase with time in the PSA group, even in the long term. This prospective study strongly supported our conclusion that cytomorphological distinction between PSA and RARS provides valuable prognostic information.     

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.