Therapy-related myelodysplastic syndromes deserve specific diagnostic sub-classification and risk-stratification-an approach to classification of patients with t-MDS.

In the current World Health Organization (WHO)-classification, therapy-related myelodysplastic syndromes (t-MDS) are categorized together with therapy-related acute myeloid leukemia (AML) and t-myelodysplastic/myeloproliferative neoplasms into one subgroup independent of morphologic or prognostic features. Analyzing data of 2087 t-MDS patients from different international MDS groups to evaluate classification and prognostication tools we found that applying the WHO classification for p-MDS successfully predicts time to transformation and survival (both p < 0.001). The results regarding carefully reviewed cytogenetic data, classifications, and prognostic scores confirmed that t-MDS are similarly heterogeneous as p-MDS and therefore deserve the same careful differentiation regarding risk. As reference, these results were compared with 4593 primary MDS (p-MDS) patients represented in the International Working Group for Prognosis in MDS database (IWG-PM). Although a less favorable clinical outcome occurred in each t-MDS subset compared with p-MDS subgroups, FAB and WHO-classification, IPSS-R, and WPSS-R separated t-MDS patients into differing risk groups effectively, indicating that all established risk factors for p-MDS maintained relevance in t-MDS, with cytogenetic features having enhanced predictive power. These data strongly argue to classify t-MDS as a separate entity distinct from other WHO-classified t-myeloid neoplasms, which would enhance treatment decisions and facilitate the inclusion of t-MDS patients into clinical studies.

Intrapatient functional clonality deconvoluted by coupling intracellular flow cytometry and next-generation sequencing in human leukemia.

The interplay between tumor heterogeneity and microenvironmental factors is a critical mechanism for clonal selection in leukemia. Evidence of unique clonal capacities to engraft within patient-derived xenograft (PDX) models suggests that intrapatient genetic architecture may be defined by functional differences at the clonal level. However, methods to detect functional differences assigned to genetically defined clones remain limited. Here, we describe a scalable method to directly measure the functional properties of clones within the same leukemia patient by coupling intracellular flow cytometry and next-generation sequencing (NGS). We provide proof of concept utilizing primary chronic myelmonocytic leukemia (CMML) samples and granulocyte-macrophage colony stimulating factor (GM-CSF) to elucidate the interaction between tumor heterogeneity and microenvironmental factors. Mixtures of human leukemia cell lines, with known response to GM-CSF, were used to validate the accuracy of our methodology. Using this approach, we confirm that our method is capable of discriminating GM-CSF sensitive cell lines, identifies somatic variants in primary leukemia samples, and resolves functional clonal architecture in an illustrative patient. Taken together, our data describes a novel method to determine intrapatient functional clonal heterogeneity and provides proof-of-concept for future investigation aimed at elucidating the clinical relevance of functional clonal differences.

Short- and long-term benefits of lenalidomide treatment in patients with lower-risk del(5q) myelodysplastic syndromes.

The treatment of patients with myelodysplastic syndromes (MDS) begins with assessment of karyotype and risk. Lenalidomide is approved for the treatment of patients who have transfusion-dependent anemia due to lower-risk MDS with chromosome 5q deletion (del(5q)) with or without additional cytogenetic abnormalities, and isolated del(5q) only in the European Union. Mounting evidence suggests that lenalidomide is effective not only in reducing red blood cell (RBC) transfusion burden, but also in modifying the disease natural history by suppressing the malignant clone. Data discussed here from the pivotal phase 2 (MDS-003) and phase 3 (MDS-004) studies of lenalidomide demonstrate that lenalidomide treatment was associated with both short- and long-term benefits. These clinical benefits included high rates of RBC-transfusion independence (TI) with prolonged durations of response, high rates of cytogenetic response (CyR) associated with achievement of durable RBC-TI, no significant difference in rates of progression to acute myeloid leukemia (AML), and improvements in health-related quality of life (HRQOL). Achievement of RBC-TI and CyR with lenalidomide treatment was associated with extended survival and time to AML progression. Achievement of RBC-TI and hemoglobin response was additionally associated with HRQOL benefits. Recent data describing the impact of TP53 mutations and p53 expression on the prognosis of patients with del(5q) and the impact on response to lenalidomide are also discussed. The authors provide practical recommendations for the use of lenalidomide in patients with lower-risk del(5q) MDS.

An international data set for CMML validates prognostic scoring systems and demonstrates a need for novel prognostication strategies.

Since its reclassification as a distinct disease entity, clinical research efforts have attempted to establish baseline characteristics and prognostic scoring systems for chronic myelomonocytic leukemia (CMML). Although existing data for baseline characteristics and CMML prognostication have been robustly developed and externally validated, these results have been limited by the small size of single-institution cohorts. We developed an international CMML data set that included 1832 cases across eight centers to establish the frequency of key clinical characteristics. Of note, we found that the majority of CMML patients were classified as World Health Organization CMML-1 and that a 7.5% bone marrow blast cut-point may discriminate prognosis with higher resolution in comparison with the existing 10%. We additionally interrogated existing CMML prognostic models and found that they are all valid and have comparable performance but are vulnerable to upstaging. Using random forest survival analysis for variable discovery, we demonstrated that the prognostic power of clinical variables alone is limited. Last, we confirmed the independent prognostic relevance of ASXL1 gene mutations and identified the novel adverse prognostic impact imparted by CBL mutations. Our data suggest that combinations of clinical and molecular information may be required to improve the accuracy of current CMML prognostication.

Mayo prognostic model for WHO-defined chronic myelomonocytic leukemia: ASXL1 and spliceosome component mutations and outcomes.

We evaluated the prognostic relevance of several clinical and laboratory parameters in 226 Mayo Clinic patients with chronic myelomonocytic leukemia (CMML): 152 (67%) males and median age 71 years. At a median follow-up of 15 months, 166 (73%) deaths and 33 (14.5%) leukemic transformations were documented. In univariate analysis, significant risk factors for survival included anemia, thrombocytopenia, increased levels of white blood cells, absolute neutrophils, absolute monocyte count (AMC), absolute lymphocytes, peripheral blood and bone marrow blasts, and presence of circulating immature myeloid cells (IMCs). Spliceosome component (P=0.4) and ASXL1 mutations (P=0.37) had no impact survival. On multivariable analysis, increased AMC (>10 × 10(9)/l, relative risk (RR) 2.5, 95% confidence interval (CI) 1.7-3.8), presence of circulating IMC (RR 2.0, 95% CI 1.4-2.7), decreased hemoglobin (<10 g/dl, RR 1.6, 99% CI 1.2-2.2) and decreased platelet count (<100 × 10(9)/l, RR 1.4, 99% CI 1.0-1.9) remained significant. Using these four risk factors, a new prognostic model for overall (high risk, RR 4.4, 95% CI 2.9-6.7; intermediate risk, RR 2.0, 95% CI 1.4-2.9) and leukemia-free survival (high risk, RR 4.9, 95% CI 1.9-12.8; intermediate risk, RR 2.6, 95% CI 1.1-5.9) performed better than other conventional risk models and was validated in an independent cohort of 268 CMML patients.