Chronic Myelomonocytic Leukemia in Qatar, Single Institute Experience

Background Chronic myelomonocytic leukemia (CMML) is a rare de novo clonal hematopoietic stem cell disorder with overlapping features of myelodysplastic syndromes (MDS) and myeloproliferative neoplasms (MPN). The diagnosis is challenging and carrying risk for leukemic transformation. The median age at CMML diagnosis is ~71-73 years, with a male preponderance. According to the 2016 World Health Organization (WHO) classification of myeloid neoplasms, CMML is characterized by the presence of sustained (>3 months) peripheral blood (PB) monocytosis (≥1 × 109/L; monocytes ≥10% of white blood cell count) along with dysplastic features in the bone marrow (BM). < 20% blasts/blasts equivalent in the PB and BM. It has recommended categorization of CMML into "proliferative" (MPN-CMML) and "dysplastic" (MDS-CMML) sub-types; based on a total leukocytic count (TLC) (of ≥13 × 109/L for MPN-CMML). Also, based on PB and BM blast %, CMML can be sub-classified into three categories; (a) CMML-0 (<2% PB blasts including promonocytes and <5% BM blasts), (b) CMML-1 (2-4% PB blasts including promonocytes and 5%-9% BM blasts), and (c) CMML-2 (>5% PB blasts including promonocytes and 10%-19% BM blasts and/or when any Auer rods are present. Objective: To retrospectively analyze the cases of CMML diagnosed in the Hematology Department, National Center for Cancer Care and Research (NCCCR), Doha, Qatar from January 2013 to July 2020 with the assessment of risk and prognosis. Materials and methods: The results from flow cytometry, cytology, PB, and BM morphology, cytogenetics and molecular genetics were re-estimated. The CMML-specific prognostic scoring system (CPSS) was used for the risk stratification. Results:12 patients diagnosed as CMML were detected and included in the study, 10 males and 2 females, with a median age of 64 years. 3 Arabs and 9 non-Arabs. 10 patients were transfusion dependent. 6 patients had splenomegaly and 2 of them had massive splenomegaly (>20 cm in craniocaudal length). According to the TLC, 8 were myeloproliferative (CMML/MP) and 4 were myelodysplastic CMML. 4 of our patients were below 40 years (classified as young adults as per WHO) and all were of the proliferative type. The flow cytometry of PB and/or BM was done to 11 patients. The monocytic cells were characterized by co-expressing CD14 and CD64 and showed aberrant expression of CD56 on 5 patients. According to the morphology of the BM, one case was described as MDS/MPN or MPN, and the rest of the cases were diagnosed as MDS/MPN. According to WHO 2016 diagnostic criteria of CMML: one case was diagnosed as CMML0, one case was diagnosed as CMML1, 9 cases were diagnosed as CMML2 and one case was diagnosed as MPN/MDS -CMML2 or as MPN. The cytogenetic risk was high in 4 patients, intermediate in one patient, and low in 7 patients. According to CPSS, one patient was an intermediate risk I, 4 was intermediate-risk II, and 7 were high risk. Molecular analysis and NGS were done for 4 patients that were most recently diagnosed. One case showed NRAS in 30%, one case showed KRAS in 57%, one case showed DNMT3A and NPM1 each 42% and one case showed WT1 (36%), FLT3 (33%) and NPM1 (15%). Regarding management and supportive care, 10 out of 12 patients required transfusion support. 4 patients (3 Proliferative and one Dysplastic) were not eligible for active management and received only symptomatic treatment. 5 patients of the proliferative type were started on hydroxyurea. The other 3 patients were of dysplastic subtype who received hypomethylating agent +/- allogenic bone marrow transplant. 6 patients traveled back to their home country and lost follow up, 5 expired, and one patient still alive. Conclusion: CMML is a unique and rare hematopoietic neoplasm with complex biology and pathology. It is an aggressive rare disease that carries a dismal prognosis, with poor survival and a high risk of transformation. The therapeutic options are limited. In our clinic, for the 7 years period, CMML was confirmed only in 12 patients. The great majority of them were old males of the non-Arab nationality, transfusion-dependent, presented with TLC (> 13x10^3/ul Proliferative) of CMML2 subtype and high CPSS risk score. 33% of our patients were young adults (less than 40 years old) and were of the proliferative type. The combination of clinical, morphological, immunophenotyping, cytogenetic and molecular information is required to improve the accuracy of CMML prognostication. Disclosures No relevant conflicts of interest to declare.

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Spliceosome Mutations Involving SRSF2, SF3B1 and U2AF35 in World Health Organization Defined Chronic Myelomonocytic Leukemia; Prevalence, Clinical Correlates and Prognosis

Blood ◽

10.1182/blood.v120.21.1711.1711 ◽

2012 ◽

Vol 120 (21) ◽

pp. 1711-1711

Author(s):

Mrinal M. Patnaik ◽

Terra L Lasho ◽

Christy Finke ◽

Curtis A Hanson ◽

Janice M Hodnefield ◽

...

Keyword(s):

High Risk ◽

Chronic Myelomonocytic Leukemia ◽

Low Risk ◽

World Health ◽

Prognostic Impact ◽

Intermediate Risk ◽

Free Survival ◽

Clinical Correlates ◽

Significant Difference ◽

Myelomonocytic Leukemia

Abstract Abstract 1711 Background: Mutations in genes of the splicing machinery, such as SF3B1, SRSF2 and U2AF35 are common in patients with myelodysplastic syndromes [MDS] (Nature 2011;478:64) and chronic myelomonocytic leukemia [CMML] (Haematologica 2012;Epub). In MDS, SRSF2 gene mutations are an independent risk factor for shortened over-all (OS) and leukemia-free survival (LFS) (Blood 2012;119:3578). In MDS with ring sideroblasts (RS), SF3B1 mutations have a high prevalence (∼50%), but do not influence either, the OS or the LFS (Blood 2012;119:569). We carried out this study to evaluate the prevalence, clinical correlates and prognosis of the aforementioned spliceosome mutations in CMML. Methods: The study included 227 patients with WHO defined CMML who were seen at the Mayo Clinic from 1997 through 2007. All patients underwent bone marrow (BM) examination and cytogenetic evaluation at diagnosis. DNA was interrogated in the three most frequent spliceosome genes with somatic mutations; SRSF2, SF3B1 and U2AF35. Results I: Prevalence and clinical correlates Among the 227 study patients, 153 (67%) were male, median age was 71 years (range, 17–90 years) and 192 (85%) met the WHO criteria for CMML-1. Ninety (40%) patients had SRSF2 mutations (86% CMML-1), 13 (6%) had SF3B1 mutations (75% CMML-1) and 20 (9%) had U2AF35 mutations (95% CMML-1). One-hundred and twenty three (54%) patients had at least one of three spliceosome mutations (86% CMML-1). Mutational hot spots were P95 for SRSF2 (P95L-n=36/H-n=32/R-n=13/A-n=1), K700E (n=7) and H662Q (n=2) for SF3B1, and Q157 (Q157R-n=5/P-n=5/G-n=1) and S34F (n=7) for U2AF35. Seven patients (54%) with SF3B1 mutations had ≥1% RS, with 5 (38%) showing ≥15% RS. Mutations involving all three spliceosome genes were mutually exclusive. The cytogenetic distribution based on the Spanish risk stratification system (Haematologica 2011;96:375) was; SRSF2 mutations: 69 (77%) low risk, 11 (12%) intermediate risk, and 10 (11%) high risk (+8-n=3, del/monosomy 7-n=2, monosomal karyotype-n=5); SF3B1 mutations: 8 (62%) low risk and 5 (38%) intermediate risk; U2AF35 mutations: 15 (75%) low risk, 3 (15%) intermediate risk and 2 (10%) high risk (p=0.89). The distribution of mutations according to the MD Anderson prognostic scoring system [MDAPS] (Blood 2002;99:840) was; SRSF2 - low-n=41, intermediate-1-n=26, intermediate-2-n=18, high-n=5, SF3B1- low-n=7, intermediate-1-n=3, intermediate-2-n=2, high-n=1, and U2AF35- low-n=11, intermediate-1-n=5, intermediate-2-n=3, high-n=1 (p=0.73). There was no statistically significant difference, among the three mutation groups, in prognostically relevant parameters, including gender distribution, median age, hemoglobin values, platelet counts, peripheral blood (PB) and BM blast counts, absolute neutrophil counts (ANC) and absolute monocyte counts (AMC). The only notable difference was that patients with the SF3B1 mutation had a lower median white blood cell count (p=0.04) and a lower absolute lymphocyte count (p=0.045). Results II: Prognostic impact of spliceosome mutations At a median follow-up of 15 months, 166 (73%) deaths and 33 (14.5%) leukemic transformations were documented. Median survivals for patients with mutations involving SRSF2, SF3B1 and U2AF35 were 24, 17 and 12 months, respectively. In univariate analysis, the presence of SRSF2 (p=0.67), SF3B1 (p=0.96) or U2AF35 (p=0.49) mutations had no prognostic impact on OS. Similarly, none of the three spliceosome mutations affected LFS; corresponding p values were 0.55 for SRSF2, 0.9 for SF3B1 and 0.38 for U2AF35 mutations respectively. We then examined possible prognostic value of having none of these mutations (n=104) vs otherwise (n=123) and the results were once again negative (p=0.87). Conclusions: SRSF2 is the most frequently mutated spliceosome gene in CMML, but neither it nor SF3B1 or U2AF35 mutations affect overall or leukemia-free survival in CMML. Furthermore, the current study suggests limited genotype-phenotype association, save for the already established association between SF3B1 mutations and RS. Disclosures: No relevant conflicts of interest to declare.

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Short Survival and High Rates of Transformation Prevail in Chronic Myelomonocytic Leukemia Despite Hypomethylating Agent Therapy.

Blood ◽

10.1182/blood.v120.21.2800.2800 ◽

2012 ◽

Vol 120 (21) ◽

pp. 2800-2800

Author(s):

Emily J. Vannorsdall ◽

Vu H. Duong ◽

Xinyi Ng ◽

Dan P. Zandberg ◽

Michael L. Tidwell ◽

...

Keyword(s):

Bone Marrow ◽

Clinical Trials ◽

Research Funding ◽

Response Rates ◽

Chronic Myelomonocytic Leukemia ◽

World Health ◽

Free Survival ◽

Entire Cohort ◽

Myelomonocytic Leukemia

Abstract Abstract 2800 Background: Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic stem cell disorder categorized as a mixed myeloproliferative/myelodysplastic disorder in the World Health Organization classification system. Diagnostic criteria include a persistent peripheral blood monocytosis >1 × 109/L and bone marrow dysplasia. Our recent review of SEER Medicare data (ASH 2011 abstract 2784) demonstrated that CMML has a shorter overall survival (OS) and more frequent progression to acute myeloid leukemia (AML), compared to myelodysplastic syndromes (MDS). Due to the heterogeneity of this disease and its differences from MDS, efforts to identify prognostic factors have been ongoing. The MD Anderson prognostic score was previously validated, but was derived from patients treated prior to the availability of the hypomethylating agents (HMAs) azacitidine and decitabine. HMAs have now emerged as standard therapy, with reported response rates of 37–69%, but their impact on survival and AML transformation is unclear. The OS of CMML patients has been reported at 12–18 months and transformation rates have varied between 15–52%. We reviewed our own single-center experience with CMML over the past 12 years. Methods: We conducted a retrospective review of CMML patients evaluated at the University of Maryland Greenebaum Cancer Center between January 2000 and August 2012. Patient and disease characteristics, treatments, complications, progression to AML, and OS were recorded and analyzed. Descriptive statistics were used for baseline characteristics and Kaplan-Meier analysis was performed for all time-to-event data. Statistical analyses were performed using SPSS version 20.0. Results: We identified 35 patients with CMML, 71% were male and 71% white, with a median age of 69 (range 34–86) years; 75% had <10% bone marrow (BM) blasts and 68% had low-risk cytogenetic findings (normal karyotype or -Y). Most patients treated prior to 2005 received hydroxyurea and/or erythropoiesis-stimulating agents or were enrolled on clinical trials, while patients treated since 2005 received HMAs as primary therapy. The median OS of the entire cohort was 19.5 months, with 49% of patients progressing to AML with a median time to progression (TTP) of 16.9 months. Of the entire cohort, patients with <10% and ≥10% BM blasts had an estimated OS of 19.4 and 11.7 months respectively (p=.021). Patients with low-, intermediate-, and high-risk (complex karyotype, +8, or chromosome 7 abnormalities) cytogenetic findings had an estimated OS of 23.3, 16.5, and 12.0 months respectively (p<0.001). Twenty-two patients received HMAs. Their estimated OS was 16.5 months, compared to 23.0 months for patients who did not receive HMAs (p =.683); 50% of patients treated with HMAs had known progression to AML, with TTP varying from 3–28 months. AML-free-survival was 16 months in patients receiving HMAs, compared to 14 months in patients not treated with HMAs (p=0.960). The majority of patients receiving HMA therapy (63%) were treated with ≥ 6 cycles; 57% of these patients transformed to AML despite initial response, often in a sudden and unpredictable manner. Conclusions: Published trials using HMAs in CMML have been limited by small patient numbers, short median follow-up, and paucity of data on AML transformation. Our study had a median follow-up period of 41.1 months. We found a high rate of AML transformation and short OS even in patients who received HMAs. HMA treatment had no statistically significant impact on AML-free survival or OS. Although the results may be confounded by some selection bias, treatment with HMAs was largely based on the date of diagnosis rather than prognostic variables or performance status. Therefore, the favorable response rates previously reported with these agents, and also seen in our patients, do not appear to translate into an OS or AML-free-survival advantage. Our study underscores the continued need for novel agents and the need to prioritize clinical trials for this group of patients. Additionally, based on our data, early bone marrow transplantation should be strongly considered for CMML patients when feasible. Disclosures: Davidoff: Novartis: Research Funding; Celgene: Research Funding; GlaskoSmithKline: Research Funding. Baer:Novartis, Inc.: Research Funding; Celgene, Inc.: Research Funding.

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Successful Bone Marrow Transplantation with an Intensively Immunosuppressive Conditioning with Low Toxicity for High-Risk Chronic Granulomatous Disease Patients.

Blood ◽

10.1182/blood.v108.11.5354.5354 ◽

2006 ◽

Vol 108 (11) ◽

pp. 5354-5354 ◽

Cited By ~ 1

Author(s):

Mizuka Miki ◽

Teruyuki Kajiume ◽

Kazuhiro Nakamura ◽

Hiroshi Kawaguchi ◽

Takashi Sato ◽

...

Keyword(s):

Bone Marrow ◽

Flow Cytometry ◽

Bone Marrow Transplantation ◽

High Risk ◽

Chronic Granulomatous Disease ◽

Marrow Transplantation ◽

Mixed Chimerism ◽

Granulomatous Disease ◽

Hematopoietic Stem ◽

Low Toxicity

Abstract Chronic granulomatous disease (CGD) is an inherited disorder characterized by recurrent bacterial and fungal infections, often resulting in impaired quality of life and death. Allogeneic hematopoietic stem cell transplantation (HSCT) is the curative therapy for patients with CGD. HSCT in certain CGD patients is associated with a significant risk of therapy-related morbidity due to toxicity, rejection, GVHD, and/or infectious complications. Recently successful HSCT with nonmyeloablative conditioning for CGD patients has been developed. However, the results of HSCT in adult CGD patients have been insufficient in adult patients with CGD. In this study 5 patients with adult CGD underwent bone marrow transplantation after undergoing an intensive immunosuppressive regimen with reducing toxicity and optional donor lymphocyte infusion (DLI). All patients were diagnosed by the absence of oxidase activity and confirmed by the lack of the expression of 91phox using monoclonal antibody by flow cytometry. All patients were more than twenty years of age and suffered from critical and life-threatening infections, such as brain abscess, osteomyelitis, and granulomatous colitis at transplantation. Patients underwent a conditioning regimen consisting of cyclophosphamide (30 mg/Kg × 4), fludarabine (30 mg/m2 × 5), anti-lymphocyte globulin (15 mg/Kg × 4), and low-dose (3 Gy) of total body irradiation. Four of five patients were transplanted from HLA-identical siblings and one patient from HLA-haploidentical brother presenting microchimerism between donor and recipients. After transplantation prompt engraftment with mixed chimerism was observed without severe conditioning-related complications in all patients. Their infections were immediately improved within one month after transplantation during the period of mixed chimerism. The degree of chimerism was serially assessed by microsatellite DNA sequences and by the presence of 91phox-positive neutrophils using flow cytometry. Based on the chimerism assay, DLI was performed in two patients without developing GVHD. All patients have achieved complete chimerism without therapy-related complications. These results using an intensively immunosuppressive conditioning with low toxicity is a promising treatment modality for high-risk patients with CGD.

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Results of a Phase 2 Trial of the Monocyte-Targeted Histone Deacetylase Inhibitor Tefinostat (CHR-2845) in Chronic Myelomonocytic Leukemia (CMML) — the UK Monocle Study

Blood ◽

10.1182/blood-2018-99-110356 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 1818-1818 ◽

Cited By ~ 2

Author(s):

Steven Knapper ◽

Michael Dennis ◽

Mark W Drummond ◽

Robert K. Hills ◽

Richard James Dillon ◽

...

Keyword(s):

Bone Marrow ◽

High Risk ◽

Histone Deacetylase ◽

Clinical Benefit ◽

Chronic Myelomonocytic Leukemia ◽

Phase 2 ◽

Phase 2 Trial ◽

Phase 2 Study ◽

Myelomonocytic Leukemia ◽

Selective Activity

Abstract Background Chronic myelomonocytic leukemia (CMML) is a highly heterogeneous myeloid neoplasm with poor prognosis and limited therapeutic options. Tefinostat (CHR-2845) is a cell permeant ester that is converted to an active acid histone deacetylase (HDAC) inhibitor (CHR-2847) by human carboxylesterase 1 (hCE-1), an enzyme predominantly found in cells of monocyte lineage. Pre-clinical studies confirmed selective activity of tefinostat, correlating with hCE-1 expression and acetylation induction, in monocyte derived cell lines, primary CMML and AML (M4/M5) cells (1). A phase 1 study in refractory haematological malignancies showed tefinostat to be well tolerated, with complete remission reported in 1/2 CMML patients (2). Given the compelling rationale for selective activity in monocytoid malignancies, we conducted a phase 2 study to assess safety and efficacy of tefinostat in CMML. Methods MONOCLE was a single arm phase 2 trial conducted to a Bryant and Day 2-stage design with dual primary endpoints of safety and clinical efficacy. CMML-2 patients were included; additionally CMML-1 patients with symptomatic bone marrow failure or proliferative disease, symptomatic splenomegaly, extramedullary involvement, systemic symptoms or CMML-specific Prognostic Score (CPSS) int-2/high. Tefinostat was administered orally in continuous 28-day cycles starting at 360mg once daily, increasing to 480mg after 4 weeks if well tolerated. Concomitant hydroxycarbamide was permitted only with cycles 1-3. Clinical response was assessed according to International Consortium MDS/MPN Response Criteria (3); responding patients at cycle 6 were permitted to continue therapy. Toxicity was assessed according to CTCAE v4.0. Results In stage 1, 21 patients were enrolled at 9 centers (Jan-Sep 2017). 20 patients received tefinostat (median age 75 years [64-88], M/F 14/6) including 16 with CMML-1 (80%) and 4 CMML-2 (20%), 8 (40%) with myelodysplastic and 12 (60%) myeloproliferative CMML; respective proportions in CPSS low/int-1/int-2/high risk groups were 5/50/40/5%. Myeloid NGS analysis confirmed a molecularly relatively high risk population: 70% ASXL1 mutation frequency and median 4 (2-7) mutations per patient; other most commonly observed mutations being TET2 (65%), SRSF2 (50%), EZH2 (35%) and NRAS (35%). Prior therapy included azacitidine (3 patients) and hydroxycarbamide (7). 17/20 patients had high hCE-1 levels, assessed flow cytometrically at trial entry in monocytoid cells (vs bulk myeloid population). Median number of cycles of tefinostat received was 4 (1-15). Of 13 patients completing ≥3 cycles of tefinostat, 1 patient achieved clinical benefit (partial bone marrow response at cycle 6 with red cell transfusion independence sustained over 15 cycles of treatment), 9 had stable disease (of whom 1 had transient clinical benefit [MPN-SAF symptom reduction] which was not sustained to cycle 6) and 3 had progressive disease. Most frequent non-hematologic adverse events of any grade were raised creatinine (55% patients), fatigue (40%) and nausea/vomiting (30%). Grade ≥3 AEs judged potentially related to tefinostat included thrombocytopenia (3 patients), fatigue (2), raised creatinine (2), anorexia, AV block, nausea and neutropenia (1 each). Creatinine rises were in all cases reversible following tefinostat dose reduction/cessation. Induction of intracellular lysine acetylation in monocytes (a marker of HDAC inhibition) was observed in 50% of patients (including clinical responders), peaking between days 15-28 of cycle 1. While no clear relationship between baseline hCE-1 expression and clinical response was evident, reductions in marrow monocyte and myeloid blast fractions were seen in both clinical responders. Conclusion Following failure to achieve a pre-defined minimum number of clinical responses to tefinostat, patient recruitment was not continued into stage 2 of this phase 2 study. Drug tolerability was encouraging although observed renal effects will likely preclude dose escalation in this challenging, often frail patient group. Despite compelling scientific rationale and pre-clinical data favoring this monocyte targeted treatment approach we were unable to demonstrate a clinically significant single agent disease modifying effect in CMML. (1) Zabkiewicz J. Oncotarget 2016; 7: 16650-62 (2) Ossenkoppele G. Br J Haem 2013; 162: 191-201 (3) Savona M. Blood 2015; 125: 1857-65 Disclosures Knapper: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Other: Meeting and travel support; Jazz: Other: Meeting and travel support; Daiichi Sankyo: Other: Meeting and travel support; Chroma Therapeutics: Research Funding. Hills:Daiichi Sankyo: Consultancy, Honoraria. Dillon:Teva Pharmaceuticals UK: Consultancy, Honoraria; AbbVie UK: Consultancy, Honoraria. Pocock:Kent & Canterbury Hospital: Employment. Culligan:Pfizer: Honoraria; Takeda: Honoraria, Other: Support to attend conferences; JAZZ: Honoraria; Merck Sharp & Dohme (MSD): Honoraria; Abbvie: Other: Support to attend conferences; Celgene: Other: Support to attend conferences; Daiichi-Sankyo: Other: Support to attend conferences.

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Loss Of p53 Promotes Transformation Of Oncogenic Nras-Induced Chronic Myelomonocytic Leukemia To An Acute Phase

Blood ◽

10.1182/blood.v122.21.3790.3790 ◽

2013 ◽

Vol 122 (21) ◽

pp. 3790-3790

Author(s):

Jingfang Zhang ◽

Yangang Liu ◽

Guangyao Kong ◽

Yuan-I Chang ◽

Erik A. Ranheim ◽

...

Keyword(s):

Bone Marrow ◽

Median Survival ◽

Bone Marrow Cells ◽

Chronic Myelomonocytic Leukemia ◽

Self Renewal ◽

Hematopoietic Stem ◽

Myelomonocytic Leukemia ◽

Acute Myeloid ◽

Marrow Cells ◽

Myeloid Progenitors

Abstract Chronic myelomonocytic leukemia (CMML) primarily occurs in the elderly with the median age ranging from 65 to 75 years. As defined by WHO, CMML is characterized by persistent monocytosis in peripheral blood, hepatosplenomegaly, and the absence of BCR-ABL fusion gene. CMML is a devastating cancer for multiple reasons, one of which is that approximately 20% of CMML cases evolve into acute myeloid leukemia (AML) soon after their first diagnosis. However, little is known about the cellular and molecular mechanisms underlying this malignant transformation. Recently, our lab developed a CMML mouse model induced by oncogenic NrasG12D/+ expressed from its endogenous locus. Above 90% of recipient mice with NrasG12D/+ bone marrow cells developed CMML-like phenotypes with a median survival of ∼56 weeks. Interestingly, none of these mice spontaneously transform to AML. To identify the pathogenetic origins underlying CMML transformation to AML, we further deleted p53 expression in NrasG12D/+ bone marrow cells using p53fl/fl allele and Mx1-Cre because deletion of p53 is a common genetic event observed in oncogenic Ras-driven cancers. We found that ERK1/2 is significantly hyperactivated in NrasG12D/+; p53-/- hematopoietic stem/progenitor cells (enriched for myeloid progenitors) in the absence of cytokines or in the presence of low concentration of GM-CSF. Concomitantly, the mutant myeloid progenitors show significantly increased self-renewal in a serial replating assay in vitro. We transplanted NrasG12D/+, p53-/-, or NrasG12D/+; p53-/- bone marrow cells into lethally irradiated mice. Unlike recipients with p53-/- cells that died of a T-cell disease with 100% penetrance and a median survival of 24 weeks, ∼70% of recipients with NrasG12D/+; p53-/- cells died of AML or acute myeloid sarcoma with a median survival of 16 weeks. These malignant myeloid diseases are transplantable in secondary recipients. Interestingly, only mutant hematopoietic stem cells (HSCs) could initiate and maintain leukemia phenotypes in the NrasG12D/+ induced CMML model, whereas both NrasG12D/+; p53-/- HSCs and myeloid progenitors could initiate AML or acute myeloid sarcoma. Our results indicate that deletion of p53 cooperates with NrasG12D/+ mutation to transform CMML into an acute phase. This malignant transformation is initiated by mutant myeloid progenitors, which show increased self-renewal and potentially serve as leukemia initiating cells. Disclosures: No relevant conflicts of interest to declare.

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Correlation Of Outcomes Of Allogeneic Stem Cell Transplants For Chronic Myelomonocytic Leukemia With The Mayo Prognostic Model

Blood ◽

10.1182/blood.v122.21.5226.5226 ◽

2013 ◽

Vol 122 (21) ◽

pp. 5226-5226

Author(s):

Michelle T Patzelt ◽

Mark R. Litzow ◽

William Hogan ◽

Shahrukh K Hashmi ◽

Michelle Elliott ◽

...

Keyword(s):

Bone Marrow ◽

Stem Cell ◽

High Risk ◽

Univariate Analysis ◽

Disease Status ◽

Chronic Myelomonocytic Leukemia ◽

Prognostic Impact ◽

Cell Transplant ◽

Comorbidity Index ◽

Myelomonocytic Leukemia

Abstract Abstract 5226 Background Chronic myelomonocytic leukemia (CMML) is a clonal stem cell disorder with overlapping features between myelodysplastic syndromes and myeloproliferative neoplasms. Allogeneic stem-cell transplant (SCT) is considered to be a potentially curative option (Eur J Haematol. 2013; 90:355); with karyotype and comorbidity index (CI) being independent prognostic factors. The role of newer CMML prognostic models remains to be elucidated. We carried out this study to analyze the predictive value of the Mayo model (Leukemia 2013; 27:1504) in assessing transplant outcomes for patients with CMML. Methods After due IRB approval, 25 patients with WHO-defined CMML that underwent allo-SCT at Mayo Clinic from 1992 through 2013 were identified. All patients underwent bone marrow examination and cytogenetic evaluation at diagnosis. Clinical features including status at transplant, graft-versus-host disease (GVHD) prophylaxis, donor-recipient HLA-matching, donor-recipient blood types and CMV status were documented. Patients were evaluated for development of GVHD, disease relapse, remission status, and death from all causes. We evaluated the prognostic relevance of clinical and laboratory parameters including those previously identified by the MDAPS (Blood 2002;99:840), Spanish cytogenetic stratification (Haematologica 2011;96:375), and the recently described Mayo model Results Among 25 study patients, 14 (56%) were males and 15 (60%) had WHO defined CMML-1 (6-symptomatic/transfusion dependent, 3-monosomy 7). The median age at transplant was 51 years (range, 18-66 years). Graft sources included: 19 (76%) peripheral blood, 5 (20%) bone marrow, and 1 (4%) double umbilical cord blood. Ten (40%) patients received a reduced intensity conditioning. At last follow up, 15 (60%) deaths were documented while the remainders are alive and disease free. There were six (25%) post-transplant relapses all resulting in mortality. The 5-year OS was 42% and the 5-year non relapse mortality was 35%. Based on the Mayo model, 15 (60%) patients received a high-risk prognostication, 6 (24%) were intermediate and 3 (12%) were low. In an univariate analysis that included: demographics, blood counts at diagnosis and transplant, WHO classification (p=0.19), Spanish karyotypic stratification (p=0.67), prognostication according to the MDAPS (p=0.35) and Mayo model, disease status at transplant, SCT comorbidity index (p=0.06), graft sources, transplant conditioning regimens (p=0.08), development of acute (p=0.64) and chronic GVHD (p=0.06); thrombocytopenia at diagnosis (p=0.04), disease status at transplant (p=0.02), and a high risk prognostication using the Mayo model (p=0.01) were statistically significant. On a multivariable analysis only high risk prognostication by the Mayo model (p=0.02) retained its negative prognostic impact. In an univariate analysis for relapse-free survival, risk stratification by the Spanish cytogenetic system (p=0.04) and the Mayo model were prognostic (p=0.01), with the high risk prognostication by the Mayo model retaining its negative prognostic impact (p=0.01). Conclusions Allogeneic SCT remains a viable treatment option for patients with CMML. The Mayo model serves as a valuable tool, helping with the identification of high risk CMML patients. These patients seem to benefit from allo-SCT in comparison to non-transplant therapeutic options. Given the smaller sample size, validation in a larger patient cohort is needed. Disclosures: No relevant conflicts of interest to declare.

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Diagnostic Utility of Flow Cytometric Immunophenotyping in Chronic Myelomonocytic Leukemia

Blood ◽

10.1182/blood-2018-99-119689 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 5526-5526

Author(s):

Leonor Arenillas ◽

Ivonne Parraga ◽

Lourdes Florensa ◽

Sara Montesdeoca Romero ◽

Anna Puiggros ◽

...

Keyword(s):

Bone Marrow ◽

Flow Cytometry ◽

Peripheral Blood ◽

Conflicts Of Interest ◽

Chronic Myelomonocytic Leukemia ◽

Nonspecific Esterase ◽

Age Related ◽

Hla Dr ◽

Myelomonocytic Leukemia ◽

Classical Monocytes

Abstract INTRODUCTION The diagnosis of chronic myelomonocytic leukemia (CMML) according to WHO 2017 requires the presence of ≥1x109/L and ≥10% of monocytes in peripheral blood (PB). Establish an accurate diagnostic is difficult since many clinical situations present persistent monocytosis. The presence of dysplasia, mainly dysgranulopoiesis, is frequent but not always present in CMML. Cytogenetic aberrations are infrequent in this disease (20-25% of cases). Although 85-90% of CMML patients present at least one mutation in TET2, SRSF2 or ASXL1 genes, the use of NGS panels is not widespread. Furthermore, mutations in these genes are among the most frequently observed in age-related clonal hematopoiesis. Therefore, complementary techniques are required to support the diagnosis of this entity. The study of the peripheral monocyte subsets by flow cytometry (FC) has gained special interest due to a high sensitivity and specificity for the diagnosis of CMML (S = 90.6%, E = 95.1%, Selimoglu-Buet et al., Blood, 2015). An increase in the fraction of classical monocytes (Mo1) to >94% of total monocytes is an event frequently observed in CMML. There are no specific bone marrow (BM) FC panels for the diagnosis of CMML and very few have been validated for the diagnosis of MDS. "Ogata score", the only multicenter validated score in MDS, has not been applied in CMML. The aim of our study was to evaluate the usefulness of FC in PB and BM for the diagnosis of CMML. METHODS Twenty-two CMML were prospectively studied from 02/2016 to 04/2018. Patients' characteristics are summarized in Table 1. Diagnostic procedure consisted of morphological, cytochemical (Perls, myeloperoxidase, nonspecific esterase), cytogenetic and FC studies in BM, and morphological and FC studies in PB. "Ogata Score" was applied in BM samples (Table 2). Aberrant coexpression of CD2, CD7 and CD56 in BM monocytes was assessed. Immunophenotypic maturation profile of the monocytic elements in BM distinguishes: promonocytes (CD34-/CD117-/CD64++/CD14- or dim/CD45+/HLA-DR+++), mature monocytes (CD34-/CD117-/CD64++/CD14++/CD45++/HLA-DR++) and mature monocytes in terminal stage (CD300e+). In PB, the monocytes FC subsets (Mo1, Mo2 and Mo3) were studied, as well as the aberrant coexpression of CD2, CD7 and CD56 (Table 3). RESULTSThe presence of ≥2 aberrations in Ogata Score predicted properly the diagnosis of CMML in all patients analyzed (100% sensitivity). Due to the study design, we could not obtain results about specificity.An increase in Mo1 (classical monocytes) > 94% was detected in 18/20 patients (Table 3). This method predicted the diagnosis of CMML with a sensitivity of 91%, a result almost identical to the original study (Selimoglu-Buet et al., Blood, 2015).A good positive correlation was established between the percentage of BM promonocytes detected by morphology and by FC (Rho Spearman 0.61, P = 0.003).A negative correlation was found between the percentage of promonocytes by FC in MO and the expression of CD56 (Rho Spearman -0.612, P = 0.002). Similarly, CD56+ CMML presented a percentage of promonocytes by FC significantly lower than the CD56- CMML group (median: 24.5% (14-40) vs. 41% (23-71), P = 0.005). The expression of CD56 seems to be related to a more mature immunophenotypic profile of the monocytic population. On the other hand, the correlation between the percentage of CD56+ monocytes in BM and PB was almost perfect (Rho Spearman 0.928, P <0.001). CONCLUSION Our findings support the usefulness of flow cytometry in bone marrow and peripheral blood for the diagnosis of CMML. Disclosures No relevant conflicts of interest to declare.

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Impact of Bone Marrow Fibrosis and Early Response on Outcome after Azacitidine Therapy in 94 Patients with Myelodisplastic Syndromes, Chronic Myelomonocytic Leukemia and Acute Myeloid Leukemia

Blood ◽

10.1182/blood.v128.22.3187.3187 ◽

2016 ◽

Vol 128 (22) ◽

pp. 3187-3187

Author(s):

Gianluigi Reda ◽

Marta Riva ◽

Ramona Cassin ◽

Bruno Fattizzo ◽

Martina Pennisi ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

High Risk ◽

Myeloid Leukemia ◽

Chronic Myelomonocytic Leukemia ◽

Severe Neutropenia ◽

Bone Marrow Fibrosis ◽

Myelomonocytic Leukemia ◽

Marrow Fibrosis ◽

Acute Myeloid

Abstract Azacitidine (AZA) is effective in high risk myelodysplastic syndromes (MDS), chronic myelomonocytic leukemia type 2 (CMML-2) and low blast count acute myeloid leukemia (AML) patients not suitable for more intensive treatment. Factors that may influence response to AZA are still under investigation. Bone marrow fibrosis is a potentially negative prognostic marker on overall survival (OS), but its clinical significance in this setting of patients remains to be clarified. We evaluated clinical predictors of OS and overall response rate (ORR; complete/partial response CR/PR; stable/progressive disease SD/PD) to AZA in a real life cohort. We studied 94 consecutive patients, treated at two Institutions from June 2009 till February 2016 with AZA subcutaneously (5+2+2 schedule) every 28 days, outside clinical trials. We analyzed data from routine laboratory analysis, bone marrow histology, morphology and cytogenetics at diagnosis. OS was measured from the starting of AZA treatment. Table 1 shows the clinical characteristics pre- and post-AZA: most patients (68%) were AREB1 or AREB2, 13% RCUD/RCMD or MDS NOS according to WHO 2008 classification, 17% AML, 2% CMML. At the onset of AZA therapy the majority of MDS cases (68%) showed an intermediate-2 risk, according to the International Prognostic Scoring System (IPSS) and high/very high risk (78%) according to IPSS-revised. Secondary and de novo cases, as well as cytogenetics risk groups, were equally represented; 50% of patients were transfusion dependant and moderate to severe neutropenia or thrombocytopenia were present in roughly 50/70% of cases respectively. As expected, bone marrow biopsies pre-AZA showed hypercellularity in most patients (65%). Remarkably, 47,5% of cases showed bone marrow fibrosis of ≥1 grade before AZA initiation. These findings were mostly unchanged at post-AZA evaluation. On the whole, 93 patients receiving > 4 cycles of therapy were available for response evaluation according to International Working Group 2006 criteria. After a median of 6 cycles (4-44), ORR was 41.9% (CR 18.3%, PR 11.8%, SD with hematologic improvement HI 11.8%), SD was 21.5%, PD 10.7% and 25.8% failed to achieve a response. Thirteen percent of patients reached at least partial cytogenetic response and 50% a HI. ORR was not influenced by monocytosis, neutropenia or IPSS cytogenetic risk category. Interestingly, pre-AZA marrow blast percentage, cytogenetic risk, time from diagnosis to AZA and the interval from 1st to 6th cycle had no impact on response. As regards marrow characteristics, patients with MF-0 pre-AZA displayed significantly lower PD rate and higher ORR, SD and HI than those with any grade of fibrosis (21.4% vs 51.4% and 78.6% vs 48,6%, respectively p=0.006, Fig1). This observation was also confirmed at marrow evaluation after AZA (22% versus 48% for PD and 78% versus 52% for ORR/SD/HI, p=0.05, Fig1). Regarding cellularity pre- and post-AZA, higher ORR,SD and HI and lower PD were observed for patients with normo/hypo compared to those with hyper-cellularity (Fig1) although not significantly. Forty-one percent of cases presented a hematologic toxicity (33% neutropenia and 18% thrombocytopenia of any grade) occurring after a median of 2 (1-18) AZA cycles. Moreover 28.6% of patients had an infection during AZA treatment, not related to neutropenia degree. Of note, toxicities did not affect median time from the 1st to the 6th AZA cycle (170,115-240 days), nor ORR. Median OS from the beginning of therapy was 18.5 months (12.7-24.4, 95% CI). IPSS high category [HR 2.24 (1.19-4.20) p=0.01], poor cytogenetics [2.19 (1.27-3.78) p=0.005], and lower ORR [0.46 (0.26-0.80) p=0.006] significantly affected OS. Unexpectedly, a response obtained after less than 4 cycles negatively impact OS [HR 0.86 (0.80-0.92) p<0.0001]. Notably, cases with pre-AZA fibrosis ≥MF-1 showed lower OS [2.26 (1.28-3.99) p=0.005]. In conclusion we provide evidence of no relationship between neutropenia and infections and of no impact of toxicities on dose-density and ORR to AZA treatment. Moreover, high marrow fibrosis and hypercellularity may affect response to AZA therapy. Further studies are needed to disclose the clinical/biological significance of marrow fibrosis/cellularity in the era of hypomethylating agents. Disclosures Reda: Roche: Membership on an entity's Board of Directors or advisory committees; Gilead: Research Funding.

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Preclinical Characterization of KB003, a Novel Humaneered™ Monoclonal Anti-GM-CSF Antibody, Demonstrates That the GM-CSF Signaling Axis Is a Therapeutic Target in Chronic Myelomonocytic Leukemia (CMML)

Blood ◽

10.1182/blood.v120.21.3793.3793 ◽

2012 ◽

Vol 120 (21) ◽

pp. 3793-3793

Author(s):

Eric Padron ◽

Jeffrey S Painter ◽

Adam W Mailloux ◽

Kathy L. McGraw ◽

Jessica M. McDaniel ◽

...

Keyword(s):

Bone Marrow ◽

Flow Cytometry ◽

Therapeutic Target ◽

Mononuclear Cells ◽

Chronic Myelomonocytic Leukemia ◽

Bone Marrow Mononuclear Cells ◽

Gm Csf ◽

Signaling Axis ◽

Myelomonocytic Leukemia

Abstract Abstract 3793 Introduction: Chronic Myelomonocytic Leukemia (CMML) is a genetically diverse hematologic malignancy characterized by cytopenias with or without leukocytosis, marrow dysplasia, monocytosis, splenomegaly, and a propensity to transform to Acute Myeloid Leukemia (AML). It is among the most aggressive chronic myeloid malignancies with a three year overall survival approximating twenty percent. The current treatment armamentarium is generally ineffective and mostly derived from studies that focused on Myelodysplastic Syndromes (MDS). As has been well defined in Juvenile Myelomonocytic Leukemia (JMML), we previously reported that primary CMML bone marrow mononuclear cells exhibit GM-CSF-dependent pSTAT5 hypersensitivity. To determine whether this signaling pathway is a viable therapeutic target, we present the preclinical characterization of KB003 activity on primary CMML bone marrow mononuclear cells. Methods: KB003 was engineered and provided by KaloBios Pharmaceuticals. The ability of KB003 to neutralize GM-CSF was tested in two ways using doses that ranged from .01 to 10,000 ng/ml of KB003. First, 10 ng/ml of GM-CSF was used to induce IL-8 production by the U937 cell line as measured by ELISA. Second, the GM-CSF-dependent cell line, MO7e, was cultured in the absence and in the presence of 0.1, 1, and 10 ng/ml of GM-CSF with or without KB003. Apoptosis and viability was assessed by annexin and 4′,6-diamidino-2-phenylindole (DAPI) staining by flow cytometry. To determine anti-GM-CSF sensitivity in CMML, primary cryoperserved bone marrow samples from 10 patients were reconstituted in prewarmed StemSpan H3000 with 10% FBS and microcultured in a 96 well plate with increasing doses of GM-CSF and KB003. After a 48-hour incubation period, cells were stained with myeloid-specific antibodies (CD34, CD38, CD14, CD33) and measured by multi-color flow cytometry. DAPI was used to measure cell viability. MethoCult hematopoietic progenitor assays were used to quantify the expansion and differentiation of CMML mononuclear cells in the presence of GM-CSF and escalating concentrations of KB003 in those samples with sufficient cell number for analysis (n=7). Results: KB003 effectively neutralized GM-CSF-induced IL-8 secretion in U937 cells with an IC50 of 48.2 ng/ml, as shown in Figure 1a. A dose of 0.1, 1, and 10 ng/ml of GM-CSF was used to protect MO7e cells from apoptosis and a survival benefit was achieved at each dose tested (Fig 1b). In this assay, KB003 neutralized 0.1 ng/ml of GM-CSF, but was unable to neutralize GM-CSF at higher doses (10 ng/ml). Using CMML samples, doses ranging from 10 to 100 μg/ml of KB003 were tested in apoptosis and in colony formation assays. Using the gating strategy shown in Figure 2a, the percentage of mature (CD33+/CD14+) and immature (CD33+/CD14-) myeloid subpopulations within the viable gate after KB003 treatment was decreased (Figure 2b). As expected, KB003 had no effect on CD3+ T-cells in the mixed culture populations. In addition to myeloid subpopulations identified by CD14, the CD33+/CD38+ cells were also more sensitive than CD33+/CD38- or CD38+/CD34+ inhibition by KB003 (Figure 2c, p<0.05). As shown in Figure 2d, hematopoetic colony formation assays confirmed the viability results. Using a one way ANOVA, there was a dose dependent decrease in the number of hematopoietic colonies, coupled with less organized and more diffuse appearance of colonies after KB003 treatment (Figure 2d). Conclusion: GM-CSF neutralization using KB003 suppresses CMML progenitor survival in vitro. These preclinical data suggest that KB003 and other GM-CSF signaling axis inhibitors merit further investigation in CMML. A more committed myeloid precursor expressing CD38 may represent the progenitor population with enhanced GM-CSF dependence in CMML. This is consistent with the results showing CD38 to be a marker of GM-CSF-dependent pSTAT5 sensitivity in JMML and may prove to be predictive biomarker for anti-GM-CSF therapy in CMML. Disclosures: No relevant conflicts of interest to declare.

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Predictive Progenitor Profiling in Chronic Myelomonocytic Leukemia.

Blood ◽

10.1182/blood.v104.11.4739.4739 ◽

2004 ◽

Vol 104 (11) ◽

pp. 4739-4739

Author(s):

Catriona Jamieson ◽

Jason Gotlib ◽

Steve Coutre ◽

Kevin Li ◽

Irving Weissman

Keyword(s):

Stem Cells ◽

Bone Marrow ◽

Hematopoietic Stem Cells ◽

Chronic Myelomonocytic Leukemia ◽

Normal Bone Marrow ◽

Hematopoietic Stem ◽

Normal Bone ◽

Basic Biology ◽

Myelomonocytic Leukemia ◽

Myeloid Progenitors

Abstract Chronic myelomonocytic leukemia (CMML) is a unique myeloproliferative disease characterized by marrow dysplasia and an increase in monocytes. The median survival of patients with CMML is short, in part, because CMML is frequently resistant to therapy. In order to provide more effective CMML targeted therapies, a better understanding of the basic biology of CMML progenitors is required. We used FACS analysis and recently identified cell surface markers to identify phenotypic and functional differences between normal and CMML (n=14) bone marrow hematopoietic stem cells and myeloid progenitors. CMML marrow was typified by a reduction in CD34+CD38−CD90+(Thy1)Lin− hematopoietic stem cells and an expansion of CD34+CD38−CD90−Flk2+Lin- cells relative to normal bone marrow. In addition, there was a two-fold expansion in common myeloid progenitors (CMPs) and a corresponding decrease in megakaryocyte-erythroid progenitors (MEPs) suggesting that there was a skew in differentiation toward the myeloid lineage. In contrast to normal bone marrow derived CMPs, CMML CMPs gave rise to myeloid but not erythroid colonies. Moreover, real time quantitative RT-PCR analysis of highly purified FACS-sorted CMML CMPs demonstrated increased expression of two key regulators of myelomonocytic differentiation, PU.1 and c-jun, compared with normal bone marrow. A more detailed understanding of the basic biology of CMML myeloid progenitors and the genes that work in concert to expand them may aid in identifying novel molecular targets for CMML therapy.

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