Treatment Approach for Chronic Myelomonocytic Leukemia (CMML)

Initial Disease Classification and Treatment Strategy

The European Hematology Association recommends that treatment of CMML must be stratified based on two critical factors: the hematologic phenotype and the bone marrow blast percentage, with a classification that determines the treatment strategy 1, 2
Before initiating therapy, the European Hematology Association suggests performing bone marrow aspiration and biopsy with cytogenetic analysis, and obtaining HLA typing for patients under 65 years of age, to guide treatment decisions 1
The European Hematology Association recommends measuring serum erythropoietin in all patients with low red blood cell count, to assess the need for erythropoietic stimulating agents 1

For myelodysplastic CMML with low blast count, the European Hematology Association recommends managing with supportive therapy aimed at correcting low blood cell counts, with a focus on reducing symptoms and improving quality of life 1, 2
For myelodysplastic CMML with high blast count, the European Hematology Association suggests integrating supportive therapy with hypomethylating agents, such as azacitidine or decitabine, to reduce blast counts and improve survival 1, 2
For myeloproliferative CMML with low blast count, the European Hematology Association recommends initiating cytoreductive therapy with hydroxyurea, to control proliferative myelomonocytic cells and reduce organomegaly 1, 2
For myeloproliferative CMML with high blast count, the European Hematology Association suggests administering blastolytic therapy with polychemotherapy, followed by allogeneic stem cell transplantation when feasible, to achieve a potentially curative treatment 1, 2

The European Hematology Association recommends considering allogeneic stem cell transplantation for intermediate to high-risk patients who are eligible, as it remains the only potentially curative treatment for CMML 2
Reduced-intensity conditioning transplant has demonstrated improved outcomes compared to myeloablative conditioning, according to the European Hematology Association 2

The International Working Group recommends applying different response criteria based on disease phenotype, with specific criteria for myelodysplastic and myeloproliferative CMML, to assess treatment response and guide further management 3
Responses must last at least 4 weeks, according to the International Working Group, to be considered a true response to treatment 3

The European Hematology Association recommends not delaying treatment in symptomatic patients or those with high blast counts, as the median overall survival for CMML is less than 36 months, with progression to acute myeloid leukemia being inevitable in most cases 2
The European Hematology Association suggests not using intensive chemotherapy in elderly patients or those with significant comorbidities without considering transplant eligibility, as most CMML patients present in the 7th decade of life with high comorbidity burden 2
The European Hematology Association recommends not failing to recognize disease evolution from myelodysplastic to myeloproliferative CMML, and performing hematologic and cytogenetic re-evaluation when significant changes occur, to guide treatment decisions 3, 2