Established singleagent oral chemotherapy

In patients who have CMML with a significant myelo-proliferative component, high WBC count, or organomegaly, treatment with single-agent chemotherapy has been the standard of care. Oral agents such as busulfan, 6-mercaptopurine, hydroxyurea, and oral etoposide have been used empirically with some success, but a prospective randomized study conclusively determined the superiority of hydroxyurea over etopo-side in terms of overall survival in patients with mostly advanced proliferative disease (i.e., splenomegaly, mild thrombocytopenia, and increased bone marrow blasts): 24 months for hydroxyurea versus 9 months for etoposide.10 This is the only prospective randomized study to date that has compared two treatment regimens in patients with CMML. Although neither regimen induced complete remission (CR) or affected the natural history of the disease, the results supported the idea of using hydroxyurea plus supportive care as the "standard-of-care" arm in any future randomized trials. No randomized study comparing "treatment" with supportive care has ever been reported in CMML.

Agents currently approved by the Food and Drug Administration for the management of CMML (defined as a subcategory of MDS by FAB classification) are 5-azacytidine (Vidaza®) and 2'-deoxy-5'-azacyti-dine (Dacogen®). One major reason for the lack of clinical trials specifically designed for CMML is the French-American British classification which recognized CMML as a subcategory of MDS, and guided the enrollment of patients with CMML into MDS trials. The identification of CMML as a separate disease entity,1 together with the availability of a prognostic risk assessment developed specifically for CMML,4 should facilitate future design of CMML-specific trials.

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