James M. Rossetti

Activity of azacitidine in chronic myelomonocytic leukemia

Hypomethylating drugs are useful in the management of myelodysplastic syndrome (MDS). Two of these drugs, azacitidine and decitabine, have received FDA approval for the treatment of MDS and chronic myelomonocytic leukemia (CMML). However, phase 2 and 3 studies that assessed these agents in MDS included only a small number of patients with CMML. The objective of this study was to evaluate the efficacy and safety of azacitidine in the treatment of CMML.

Treatment of acute myelogenous leukemia with outpatient azacitidine

Patients older than 55 years of age with acute myelogenous leukemia (AML) are less likely to achieve complete remission and more likely to experience toxicity with conventional induction chemotherapy than younger patients. Azacitidine administered in the outpatient setting is well tolerated and can induce complete hematological remission in patients with myelodysplastic syndromes (MDS). At higher doses, azacitidine has activity in AML.

Azacitidine in the management of patients with myelodysplastic syndromes.

Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal hematopoeitic disorders characterized by ineffective hematopoiesis and potential transformation to acute myeloid leukemia (AML). For decades, the mainstay of treatment for MDS was supportive care, including transfusion of blood products and growth factors. Further understanding of disease biology led to the discovery of a high prevalence of hypermethylation of tumor suppressor genes in high-risk MDS and secondary leukemias. Hence, the role of irreversible DNA methlytransferase inhibitors such as azacitidine was investigated with promising outcomes in the treatment of MDS. Azacitidine was initially approved in the USA by the Food and Drug Administration (FDA) in 2004 for the treatment of all subtypes of MDS and was granted expanded approval in 2009 to reflect new overall survival data demonstrated in the AZA-001 study of patients with higher-risk MDS. Azacitidine has demonstrated significant and clinically meaningful prolongation of survival in higher-risk patients with MDS and has changed the natural history of these disorders. The agent maintains a relatively safe toxicity profile, even in older patients. The role of azacitidine has been explored in the treatment of AML and chronic myelomonocytic leukemia and has also been studied in the peritransplant setting. Azacitidine has been combined with other novel agents such as lenalidomide, histone deacetylase inhibitors and growth factors in the hope of achieving improved outcomes. Currently, both intravenous and subcutaneous forms of azacitidine are approved for use in the USA with the oral form being granted fast track status by the FDA.

The role of azacitidine in the treatment of myelodysplastic syndromes.

Myelodysplastic syndromes (MDS) are a heterogeneous group of hematopoietic disorders characterized by ineffective hematopoiesis and potential transformation to acute myeloid leukemia. Supportive care including transfusions and growth factors remained the mainstay of treatment for decades; however, further understanding of the biology behind these diseases led to the investigation of novel agents. As hypermethylation of tumor suppressor genes, such as p15, was believed to play a key role in the pathogenesis of these diseases, hypomethylating agents were investigated. Azacitidine is one of two hypomethylating agents used in the treatment of MDS, and the first approved by US FDA. In preclinical studies, azacitidine demonstrated hypomethylating/differentiating activity with low concentration, whereas high concentration was associated with cytotoxic effects. In clinical trials, azacitidine not only improved the cytopenias associated with MDS but also delayed leukemic transformation, improved quality of life and improved overall survival in many patients so treated. Azacitidine was the first agent noted to change the natural history of the disease. Further studies are underway evaluating the role of azacitidine pre- and post-transplantation, in combination with other agents, as well as in treatment of acute myeloid leukemia patients who are not good candidates for intensive chemotherapy. Azacitidine is also likely to be studied in the treatment of other malignant conditions. Although both subcutaneous and intravenous administrations have been approved, oral azacitidine is presently under investigation.

Viability and Potency of Hematopoietic Progenitor Cells after Prolonged Cryopreservation at –80°C

Peripheral blood HPC were collected from 28 donors at our institution between April 1994 and June 2002 using the Baxter CS-3000 blood cell separator. Patient characteristics are shown in table 1 . Only 3 donors of the HPC products were alive at the time of analysis of the products (UPN 947, UPN 1,000 and the normal unrelated donor); the recipient of the unrelated-donor HPC product was deceased at the time of analysis. On the day of the third transplant, the UPN 947 sample was taken directly from the HPC product infused at the bedside. The UPN 1,000 sample was obtained from a remaining unit stored in the same cassette as the infused product and analyzed 231 days after the third transplant. Patients provided inPeripheral blood hematopoietic progenitor cells (HPC) collected by apheresis and cryopreserved constitute the major source of stem cells for autologous transplantation, which is widely used to treat hematological malignancy [1, 2] . Controlled-rate freezing, using dimethyl sulfoxide (DMSO), with or without hydroxyethyl starch (HES) as cryoprotectant, and storage of products in liquid nitrogen (LN) is the most widely used method of cryopreservation and storage of HPC [3, 4] . The method requires specialized equipment, a constant supply of LN and carries the risk of cryogenic injury to laboratory personnel. An alternative method of cryopreservation with 5% DMSO, 6% HES and 4% human serum albumin (HSA) was described by Stiff et al. [5] , utilizing non-controlledrate freezing and storage in a mechanical freezer at –80 ° C. HPC cryopreserved by this method provided sustained engraftment in 68 of 72 patients after high-dose chemotherapy [6] . However, the effect of storage on HPC activity for 1 5 years under these conditions has not been examined. We examined the viability and hematopoietic colony-forming activity of HPC products stored in DMSO/HES/HSA at –80 ° C between 7.1 and 14.9 years. The mean number of days of storage of the HPC product at –80 ° C was 4,254 (range 2,582–5,433, standard deviation 563). Received: November 25, 2010 Accepted after revision: March 10, 2011 Published online: May 17, 2011

Erythroid variant of chronic myelogenous leukemia.

1 Pearson TC. Evaluation of diagnostic criteria in polycythemia vera. Semin Hematol 2001; 1 (Suppl 2): 21–24. 2 Westerman D, Juneja S. Reply to authors: ‘re: essential thrombocythemia in young individuals: frequency and risk factors for vascular events and evolution to myelofibrosis in 126 patients. Alvarez-Larrán A et al. Leukemia 2007; 21: 1218–1223’, Leukemia 2007. 3 Alvarez-Larrán A, Cervantes F, Bellosillo B, Giralt M, Juliá A, Hernández-Boluda JC et al. Essential thrombocythemia in young individuals: frequency and risk factors for vascular events and evolution to myelofibrosis in 126 patients. Leukemia 2007; 21: 1218–1223.