Bone marrow transplantation for myelodysplasia in adults and children: when and who?

Recent progress in the treatment of myelodysplastic syndrome in adult patients

Peripheral blood cytopenias and dysplastic hematopoietic progenitors characterize the myelodysplastic syndrome. Patients suffer from the consequences of chronic cytopenias or progression to acute myelogenous leukemia. Although allogeneic hematopoietic stem cell transplantation is a potentially curative option, the standard of care for most patients with myelodysplastic syndrome continues to be supportive care, with blood product transfusion and antibiotics for infectious complications. Many patients with myelodysplastic syndrome are not candidates for allogeneic hematopoietic stem cell transplantation because of advanced age, comorbid illnesses, and lack of a histocompatible donor. Increased rates of apoptosis in hematopoietic progenitors, altered production of inflammatory cytokines, neoangiogenesis, and autoreactive T lymphocytes have all been shown to contribute to the phenotype of myelodysplastic syndrome. These recent insights into the pathophysiology of myelodysplastic syndrome have been translated into therapeutic trials of noncytotoxic agents for this disorder. Although clinical responses have been seen with these novel agents, the critical biologic targets have not yet been clearly defined.

Low-dose 5-aza-2'-deoxycytidine, a DNA hypomethylating agent, for the treatment of high-risk myelodysplastic syndrome: a multicenter phase II study in elderly patients

PURPOSE

5-Aza-2'-deoxycytidine (decitabine; DAC) is a DNA hypomethylating agent that has shown a 50% response rate in a small phase II study in elderly patients with high-risk myelodysplastic syndrome. We performed a second, multicenter phase II study in a larger group of patients to confirm our findings and to study the toxicity of DAC.

PATIENTS AND METHODS

Between June 1996 and September 1997, 66 patients (median age, 68 years) from seven centers received DAC 45 mg/m(2)/d for 3 days every 6 weeks. For patients in whom a complete response (CR) was reached after two courses, two further cycles were administered as consolidation therapy. In case of a stable disease situation, improvement, or a partial response (PR), a maximum of six cycles was administered. The primary end points were response rate and toxicity. The secondary end points were response duration, survival from the start of therapy, and overall survival.

RESULTS

The observed overall response rate was 49%, with a 64% response rate in the patients with an International Prognostic Scoring System (IPSS) high-risk score. The actuarial median response duration was 31 weeks, with a response duration of 39 weeks and 36 weeks for patients who reached a PR or CR, respectively. The actuarial median survival time from the time of diagnosis was 22 months and from the start of therapy was 15 months. For the IPSS high-risk group, the median survival time was 14 months. The median progression-free survival time was 25 weeks. Myelosuppression was rather common, and the treatment-related mortality rate was 7% and was primarily associated with pancytopenia and infection. Significant responses were observed with regard to megakaryopoiesis, with increases in platelet counts having already occurred after one cycle of DAC therapy in the majority of the responding patients.

CONCLUSION

We were able to confirm our previous observation that DAC therapy was effective in half of the studied patients with high-risk myelodysplastic syndrome and is especially active in the patients with the worst prognoses. Myelosuppression was the only major adverse effect observed.

Long-term blood product transfusion support for patients with myelodysplastic syndromes (MDS): cost analysis and complications

Patients with myelodysplastic syndromes (MDS) frequently become dependent on blood transfusions. We analyzed the total transfusion support required, and its complications and cost, following the diagnosis of MDS (total period = 79.7 patient-years) in 50 patients followed at the Minneapolis VA Medical Center. From diagnosis of MDS to transformation to AML or death (the MDS phase), 41 patients (82%) required transfusions. The median numbers of transfused blood products per patient per year of follow-up in the MDS phase were: packed red blood cells (pRBC), 11.1 (range, 0-91.3) units, random donor platelets (RDP), 6.8 (range, 0-581) units, and single donor apheresis platelet packs (SDP): 0 (range, 0-40) collections. In the AML phase (time from diagnosis of secondary AML to death or last follow-up), median transfusion requirements per patient (n = 5) were 24 (range, 8-88) units pRBC, 94 (range, 24-480) units RDP and 3 (range, 0-19) collections of SDP. Overall, 80% of patients required either special processing or selection of blood products, had reactions to blood products or required premedications (specified/complicated transfusions); 94% of all pRBC and 97% of all platelet transfusions were specified/complicated. The median cost of transfusions per patient was $4048 (range, $0-73210) during the MDS phase and $13210 (range, $5288-59010) during the AML phase. During the MDS phase, the median cost was $4877 (range, $0-67050) per patient-year of follow-up; the major proportion of this cost was for pRBC transfusions. Long-term support with frequent transfusions for MDS usually requires specially selected or processed blood products, and is associated with a high incidence of transfusion reactions. This study provides baseline data on the costs of transfusion support for MDS, and can be used for comparing resource utilization and costs of long-term transfusion support (supportive care) with growth factor therapy or disease-modifying modalities such as allogeneic transplantation.