Diagnosis Of Chronic Myelomonocytic Leukemia Research Articles

Diagnosis of chronic myelomonocytic leukaemia (CMML) in adults

No abstract available

Preliminary Results of a Phase 2 Study of IMM01 Combined with Azacitidine (AZA) As the First-Line Treatment in Adult Patients with Chronic Myelomonocytic Leukemia (CMML)

Background: Patients with Chronic Myelomonocytic Leukemia (CMML) have poor prognosis and an inherent risk for transformation to acute myeloid leukemia. IMM01 is a recombinant signal regulatory protein α (SIRPα) IgG1 fusion protein that exerts anti-tumor activity via blocking “Don't eat me” signal and activating the “Eat me” signal to induce strong antibody-dependent cellular phagocytosis (ADCP). Furthermore, IMM01 activated macrophages could process and present tumor antigen to T cells and elicit long-last tumor-specific T cell immune response. Methods : This is an open-label, multi-center, phase 2 study (NCT05140811) that evaluated safety and efficacy of IMM01 in combination with AZA as the first-line treatment in patients with newly diagnosed CMML. We enrolled patients aged 18 years or older with the diagnosis of CMML, including subtypes CMML-1 and 2, not eligible for stem cell transplant. Patients with treatment-naive CMML were administered intravenous IMM01 at a dosage of 2.0mg/kg/week and subcutaneous AZA at a dosage of 75 mg/m 2 on D1-7 per 28-day cycle. Safety was assessed by CTCAE V5.0 and efficacy by IWG 2006 (MDS) criteria. Results : Between August 4, 2022 and July 7, 2023, 24 patients were enrolled: median age was 62 years, 15 (62.5%) males, 18(75.0%) ECOG≥1. Additionally, 1(4.2%), 7(29.2%) and 16(66.7%) patients were intermediate risk(IR)-1, IR-2 and high risk(HR) by CPSS-mol classification, respectively. According to World Health Organization (WHO) classification of CMML, patients enrolled included CMML-1(50.0%) and CMML-2(50.0%). Majority of patients had poor baseline hematologic conditions with a median Hb of 69.5 (32, 132) g/L and a median PLT of 73.5 (5, 667)×10 9/L. By the data cut-off date of July 7, 2023, the median follow-up for the study was 4 months (95%CI:3.3-4.8). Among the 16 efficacy evaluable patients who received initial treatment ≥3 months, overall response rate (ORR) was 87.5% (14/16), including 25.0% (4/16) complete response (CR), 18.8% (3/16) marrow CR (mCR) with hematologic improvement (HI), 6.3% (1/16) HI and 37.5% (6/16) mCR alone. Among the 9 efficacy evaluable patients who received initial treatment ≥4 months, ORR was 88.9% (8/9), including 44.4% (4/9) CR, 11.1% (1/9) mCR with HI and 33.3% (3/9) mCR alone. The CR rate of IMM01 combined with AZA is increasing with longer treatment duration. The median duration of response (DoR) was not reached. NGS analysis of bone marrow collected from responders were included in this study. The most frequent treatment related adverse events (TRAEs) (≥20%) were lymphopenia (70.8%), leukopenia (70.8%), neutropenia (70.8%), thrombocytopenia (58.3%), infusion related reaction (33.3%), anemia (25.0%), pyrexia (25.0%), pneumonia (25.0%), constipation (20.8%), nausea (20.8%), vomiting (20.8%) and leukocytosis (20.8%). The most common ≥Grade 3 TRAEs (≥10%) included lymphopenia (66.7%), neutropenia (54.2%), leukopenia (54.2%), thrombocytopenia (54.2%), anemia (20.8%) and pneumonia (16.7%), all of which were commonly reported in AZA monotherapy studies for treatment naive MDS/CMML patients in China. The study is ongoing. Conclusions: Preliminary data showed that IMM01 (without a low-dose priming) combined with AZA were well tolerated. The combo, when compared to the historical data of AZA alone, showed exciting efficacy result for patients with treatment-naive CMML1-2.

Clinical Characteristics and Outcomes of Therapy-Related Chronic Myelomonocytic Leukemia: Analysis of a Large Cohort

Introduction: Therapy-related myeloid neoplasms are associated with a previous exposure to cytotoxic agents or ionizing radiation, and account for 10-20% of all myeloid neoplasms. They are associated with a worse outcome, usually with high risk genetic abnormalities and poor response to therapies. Chronic myelomonocytic leukemia (CMML) is a rare myeloid neoplasm with persistent monocytosis, bone marrow dysplasia and an inherent risk of acute myeloid leukemia (AML) transformation. Due to its rarity, it is difficult to establish the specific impact of previous therapy in CMML. We previously reported the characteristics and outcomes of patients with therapy-related CMML (tCMML). Herein we report an update, including molecular characteristics, being the largest tCMML cohort reported to date. Methods: We retrospective evaluated a cohort of patients diagnosed with CMML from 2005 to 2022. Data regarding previous exposure to treatment was captured and tCMML diagnosis was established for patients with a documented prior history of radiation therapy or cytotoxic chemotherapy due to an antecedent malignancy prior to the diagnosis of CMML. Those non-tCMML were defined as de novo CMML (dnCMML). Overall survival (OS) was calculated from diagnosis to death, and leukemia-free survival (LFS) was calculated from diagnosis to death or AML transformation. Results: A total of 532 patients with CMML were included in the study, of whom 71 (13%) were tCMML. When comparing tCMML with dnCMML, there were no differences in median age (73 vs 70 years old) or sex (67% vs 69% male). No differences were noted in white blood cell count, absolute monocyte count, hemoglobin or platelet count. According to the WHO 2016 classification, 38% vs 44% were CMML-0, 40% vs 36% were CMML-1, and 22% vs 20% were CMML-2, for patients with dnCMML and tCMML, respectively. According to the FAB classification, 42% vs 52% were dysplastic and 58% vs 49% were proliferative, for patients with dnCMML and tCMML, respectively. Chromosome 7 abnormalities where more common among tCMML compared to dnCMML (14% vs 4%, p=0.006), with no differences in frequency of complex karyotype (8% vs 3%, p=0.1). In tCMML patients, 35% received only radiotherapy, 31% only chemotherapy and 34% both. In patients that received chemotherapy, the most common therapies were alkylating agents (45%), agents targeting microtubules (37%) and antimetabolite agents (35%). The median latency from therapy to tCMML was 6.5 years (range, 0.1-24). Most common neoplasms prior to the diagnosis of tCMML were prostate (25%), lymphoma (23%) and breast cancer (14%). Most frequently detected mutations at diagnosis were TET2 (55% vs 61%, p=0.5), ASXL1 (44% vs 53%, p=0.3), and SRSF2 (43% vs 30%, p=0.1), in patients with dnCMML and tCMML, respectively. Patients with tCMML had a lower incidence of NRAS (22% vs 6%, p=0.007) and CBL (18% vs 5%, p=0.04) mutations compared to dnCMML, but these mutations were present at a higher median VAF among patients with tCMML (48% vs 18% [p=0.04] for NRAS and 91% vs 20% [p=0.02] for CBL) (Figure 1). TP53 mutations were more frequent in the tCMML although differences were not significant (12% vs 4%, p=0.06). Among all patients, 352 patients received treatment and were evaluable for response (305 patients with dnCMML and 47 patients with tCMML). More than 90% of patients received an hypomethylating agent-based therapy, with an ORR of 59% for dnCMML and 60% for tCMML. The median follow-up was 58 months, and the median OS and LFS for the entire cohort were 36 and 29 months, respectively. No differences in OS (36 vs 35 months, p=0.3) or LFS (29 vs 28 months, p=0.8) were observed between dnCMML and tCMML, However, when comparing by risk groups according to CPSS-Mol, patients with tCMML classified as intermediate-1 (Int-1) risk had a significant lower OS (38 vs 88 months, p=0.02) and LFS (38 vs 85 months, p=0.03), compared to Int-1 dnCMML (Figure 2). In a multivariate model for OS including CPSS-mol, tCMML stratified by type of therapy and age, patients with tCMML with a previous exposure to chemotherapy had a hazard ratio of 1.76 (1.07-2.89, p=0.03). Conclusion: Patients with tCMML have a higher proportion of chromosome 7 abnormalities and a lower incidence of NRAS and CBL mutations. Although responses to HMA were similar, patients with tCMML with a previous exposure to chemotherapy are associated with a lower survival, especially patients classified as CPSS-Mol intermediate-1.

Molecular Classification of Chronic Myelomonocytic Leukemia: Results of the Analysis of an International Cohort of 2,471 Patients

Background. Chronic myelomonocytic leukemia (CMML) is a rare myeloid neoplasm that shares both dysplastic and proliferative features and includes patients with highly heterogeneous clinical manifestations and prognosis. Despite known co-mutation patterns that are suggesting of a CMML diagnosis such as TET2 and SRSF2 mutations, the current diagnosis and classification schemes rely solely on morphological criteria that fail to capture the genomic heterogeneity of the disease. Here we perform an unsupervised analysis using only genomic features to generate a novel classification schema of CMML patients with unique clinical features. Methods. A cohort of 2,471 CMML patients defined according to WHO 2016 criteria from European and US centers was analyzed. Bayesian network analysis and hierarchical Dirichlet processes were used to identify genomic associations and subgroups as a basis to define a molecular classification of CMML. Bayesian networks allow to infer the structure of conditional dependencies among mutations. Dirichlet processes were applied to define clusters capturing broad dependencies among all gene mutations and cytogenetic abnormalities. Multivariate logistic regression analysis was applied to compare clinical and hematological characteristics among different groups. ( JCO 2021 39:11, 1223-1233) Results. Baseline clinical and molecular characteristics are summarized in Table 1. We identified 11 clusters defined according to specific genomic features (Table 2). Two clusters were primarily defined by the presence of mutations in splicing genes SRSF2 and ZRSR2, frequently associated with TET2 mutations. Patients assigned to these clusters showed myelodysplastic features according to French American British (FAB) criteria, had a low rate of peripheral blood cytopenias, and low blast counts. Additionally, two clusters were characterized by the same mutations in splicing genes (i.e., SRSF2 or ZRSR2 with associated TET2), together with co-mutations in genes that correlate with a more aggressive phenotype ( RUNX1, ASXL1, EZH2). These groups showed overlapping myelodysplastic and myeloproliferative features by FAB, intermediate-risk per prognostic scores, and decreased survival as compared with the first 2 clusters. A distinct cluster was characterized by SF3B1 gene mutations (frequently associated with TET2 or DNMT3A). The SF3B1 cluster was marked by a dysplastic phenotype and more severe anemia (with a high rate of transfusion-dependence) with respect to the other genomic groups. Four clusters (27.8% of the overall population) were characterized by the presence of mutations in signal transduction and tyrosine kinase pathways genes ( NRAS/KRAS, CBL, JAK2 and SETBP1 often associated with ASXL1/TET2, respectively). Patients within these groups showed a mostly proliferative phenotype and intermediate survival. The presence of JAK2 mutations appeared to confer a better prognosis compared with other proliferative clusters. A minority of patients (4.6%) were assigned to two high-risk clusters, defined by TP53 mutations (often biallelic) with complex karyotype, and AML-like mutations ( NPM1, IDH1/2, FLT3), respectively. Patients in these clusters were predominantly dysplastic by FAB, had a high prevalence of severe cytopenias, higher blast counts, and a dismal outcome. Finally, we identified a cluster of patients defined by the absence of gene mutations and chromosomal abnormalities (4.5%). The majority of patients assigned to this cluster were characterized by a dysplastic phenotype, had low absolute monocyte counts, and favorable outcome. A subset of patients (18.9%) could not be assigned to a specified cluster in this preliminary analysis. An independent validation of this molecular classification is currently being conducted on a US prospective cohort (n=650). Conclusion. Our results provide proof of concept for a molecular classification of CMML based on the identification of homogeneous genomic signatures and associated clinical features. 15% of patients showed clear overlapping features with other myeloid neoplasms, thus providing the rational to refine the boundaries among different clinical entities. A molecular classification of CMML may provide a basis to define a next-generation prognostic tool and improve clinical decision-making.

Chronic Myelomonocytic Leukemia Patients With Lysozyme Nephropathy and Renal Infiltration Display Markers of Severe Disease

Chronic myelomonocytic leukemia (CMML) is a hematologic disorder that is an overlap syndrome between myelodysplastic syndromes and myeloproliferative neoplasms, and can be associated with autoimmune and inflammatory diseases. This study aimed to describe kidney involvement in patients with CMML, their treatments, and outcomes. We conducted a French and American multicenter retrospective study in 15 centers, identifying patients with CMML with acute kidney injury (AKI), chronic kidney disease (CKD), and urine abnormalities. Sixteen patients (males, n= 14; median age 76.5 years [71.9-83]) developed a kidney disease 6 months [1.6-25.6] after the diagnosis of CMML. At the time of kidney disease diagnosis, median urinary protein-to-creatinine ratio was 2 g/g [1.25-3.4], and median serum creatinine was 2.26 mg/dl [1.46-2.68]. Fourteen patients (87.5%) underwent a kidney biopsy, and the 2 main pathological findings were lysozyme nephropathy (56%) and renal infiltration by the CMML (37.5%). Ten patients received a new treatment following the CMML-associated kidney injury. Among patients with monitored kidney function, and after a median follow-up of 15 months [9.9-34.9], 4 patients had CKD stage 3, 4 had CKD stage 4, 1 had an end-stage kidney disease. In our patient series, 2 patients evolved to an acute myeloid leukemia (AML), and 5 died. Compared with 116 CMML controls, patients who had a kidney involvement had a higher monocyte count (P< 0.001), had more CMML-1 (P= 0.005), were more susceptible to develop an AML (P= 0.02), and were more eligible to receive a specific hematologic treatment, with hydroxyurea, or hypomethylating agents (P< 0.001), but no survival difference was seen between the 2 groups (P= 0.6978). In this cohort of patients with CMML with a kidney injury, the 2 most frequent renal complications were lysozyme-induced nephropathy and renal infiltration by the CMML. Kidney involvement should be closely monitored in patients with CMML.

What’s New in the Classification, Diagnosis and Therapy of Myeloid Leukemias

Myeloid leukemias are a broad group of hematological disorders, characterized by heterogeneous clinical and biological features. In recent years, unprecedented genetic discoveries and clinical–biological correlations have revolutionized the field of myeloid leukemias. The most relevant changes have specifically occurred in acute myeloid leukemia (AML), chronic myelomonocytic leukemia (CMML), chronic myeloid leukemia (CML) and myeloid neoplasms (MNs) with eosinophilia. The recently published International Consensus Classification (ICC) of myeloid neoplasms has addressed these changes, providing an updated framework and revised diagnostic criteria for such entities. This is also the aim of the 5th edition of the WHO classification of hematopoietic tumors, whose preliminary version was published in 2022. Parallel to this, new therapeutic options and novel molecular targets have changed the management of many myeloid entities, including AML and CML. This review aims to address the most relevant updates in the classification and diagnosis of AML, CMML, CML and MNs with eosinophilia. The state of the art of treatment and future therapeutic options for such disorders are also discussed.

Multiple adult xanthogranuloma as the first sign of chronic myelomonocytic leukaemia.

We report the case of a 69-year-old woman with multiple adult xanthogranuloma that developed before a diagnosis of chronic myelomonocytic leukaemia. There are few reports in the literature of multiple adult xanthogranuloma and to the best of our knowledge, this is the first report of chronic myelomonocytic leukaemia associated with multiple adult xanthogranuloma.

Optimization of monocyte gating to quantify monocyte subsets for the diagnosis of chronic myelomonocytic leukemia.

The presence of >94% classical monocytes (MO1, CD14++/CD16-) in peripheral blood (PB) has an excellent performance for the diagnosis of chronic myelomonocytic leukemia (CMML). However, the monocyte gating strategy is not well defined. The objective of the study was to compare monocyte gating strategies and propose an optimal one. This is a prospective, single center study assessing monocyte subsets in PB. First, we compared monocyte subsets using 13 monocyte gating strategies in 10 samples. Then we developed our own 10 color tube and tested it on 124 patients (normal white blood cell counts, reactive monocytosis, CMML and a spectrum of other myeloid malignancies). Both conventional and computational (FlowSOM) analyses were used. Comparing different monocyte gating strategies, small but significant differences in %MO1 and percentually large differences in %MO3 (nonclassical monocytes) were found, suggesting that the monocyte gating strategy can impact monocyte subset quantification. Then, we designed a 10-color tube for this purpose (CD45/CD33/CD14/CD16/CD64/CD86/CD300/CD2/CD66c/CD56) and applied it to 124 patients. This tube allowed proper monocyte gating even in highly abnormal PB. Computational analysis found a higher %MO1 and lower %MO3 compared to conventional analysis. However, differences between conventional and computational analysis in both MO1 and MO3 were globally consistent and only minimal differences were observed when comparing the ranking of patients according to %MO1 or %MO3 obtained with the conventional versus the computational approach. The choice of monocyte gating strategy appears relevant for the monocyte subset distribution test. Our 10-color proposal allowed satisfactory monocyte gating even in highly abnormal PB. Computational analysis seems promising to increase reproducibility in monocyte subset quantification.

Assessment of Dysgranulopoiesis By Optical Cytology Compared to Distribution of Monocyte Subsets By Flow Cytometry in Peripheral Blood for Predicting the Diagnosis of CMML

Introduction The diagnosis of chronic myelomonocytic leukemia (CMML) according to the WHO 2017 requires the presence of absolute (≥ 1x109/L) and relative (≥ 10%) monocytosis. Optical cytology represents the basis for its diagnosis and is essential to evaluate dysmyelopoiesis and to identify promonocytes and blasts. Although dysplasia is not a specific finding, its presence along with a persistent monocytosis is highly suggestive of CMML. In this sense, dysgranulopoiesis is an almost constant finding in CMML. The study of monocyte subsets distribution in peripheral blood (PB) by multiparametric flow cytometry (MFC) has proven to be a very useful tool, since the presence of >94% of classical phenotype monocytes (MO1) allows to predict the diagnosis of CMML with a sensitivity and specificity greater than 90% (Selimoglu-Buet et al. Blood 2015). The aim of this study was to evaluate the predictive capacity of morphological evaluation of PB smears for the diagnosis of CMML in a series of patients with absolute and relative monocytosis. Additionally, these results were compared with the analysis of monocyte subsets distribution in PB by MFC. Methods 162 patients with absolute and relative monocytosis were studied. 114 PB smears were available for morphological assessment and 160 MFC analysis of monocyte subsets distribution. The final diagnosis for these patients was: CMML (n=76), Phi negative chronic myeloproliferative neoplasia (MPN) (n=9) and reactive monocytosis (n=77). Genomic information (cytogenetics and NGS) was available in 66 CMML and all of MPN. After anonymizing PB smears, a cytological assessment was performed without additional clinical or analytical data (eg.: age, blood counts, biochemistry). This way we tried to compare the predictive capacity for the diagnosis of CMML of both techniques without the influence of additional data other that the known absolute and relative monocytosis. The cytological evaluation of PB smears consisted fundamentally of a qualitative evaluation of dysgranulopoiesis: nuclear hyposegmentation, chromatin hypercondensation and/or cytoplasmic hypo-degranulation. The sensitivity, specificity, Youden index, positive predictive value (PPV) and negative predictive value (NPV) of both techniques were analyzed. The Youden index allows to evaluate the balance between sensitivity and specificity ([sensitivity + specificity] -100). The capacity for diagnostic prediction of CMML for both techniques was assessed using the C-index. Finally, Cohen's Kappa index was used to evaluate the concordance between both techniques. Results Table 1 shows the results of sensitivity, specificity, Youden index, PPV, NPV and C-index of both techniques. The Kappa index showed a very good degree of agreement (K=0.715; p<0.001) between both techniques. Conclusions The presence of >94% MO1 had a better balance between sensitivity and specificity than the assessment of dysgranulopoiesis in PB. It also had a high sensitivity, demonstrating that it can be very useful screening tool. Despite this, the specificity and PPV of the assessment of dysgranulopoiesis were higher than those of the MFC, demonstrating that the identification of morphological dysplasia would allow the diagnosis of CMML to be predicted with a higher degree of certainty in the initial workup of absolute and relative monocytosis. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Chronic Myelomonocytic Leukemia Diagnosis By Flow Cytometry: An Italian Center Experience

Chronic myelomonocytic leukemia (CMML) is a myeloid neoplasm characterized by dysplasia, abnormal production of monocytes, and an increased risk of leukemic evolution. According to WHO, CMML patients show a persistent (≥3 months) absolute PB monocytosis (≥1×109/L) and relative monocytosis (≥10% of PB leukocytes), with the exclusion of Chronic Myeloid Leukemia (CML), Myeloproliferative Neoplasms, and a blast cell count <20% in PB and/or BM. In addition, morphological and/or histopathological evidence for diagnostic dysplasia ≥1 of the three major BM cell lineages must be present. If dysplasia is absent or not diagnostic (<10%), the presence of cytogenetic or molecular alterations or flow cytometry (FC) abnormalities may be utilized as co-criteria for the diagnosis of CMML. FC is helpful in confirming the monocyte and blast cell counts. In addition, FC is useful for confirming the presence of distinct monocyte populations. Based on the expression of CD14 and CD16, monocytes are classified into classical (MO1) (CD14+/CD16−), intermediate (MO2) (CD14+/CD16+) and non-classical (MO3) (CD14-/CD16+). FC analysis of PB monocytes was proposed as a quick and efficient tool for distinguishing CMML from reactive monocytosis by highlighting an increase in the MO1 fraction above 94% and a decrease in the percentage of MO3. Using FC, we evaluated 25 patients with a confirmed diagnosis of CMML in BM and PB samples, as well as 11 patients with other malignancies (MPN-monocytosis), and 28 patients with reactive monocytosis only in PB samples. Among these patients, 21/25 (84%) of CMML patients displayed MO1 ≥94%, while in patients with reactive monocytosis, MO1≥94% was observed in 11/28 (39%) and 2/11 (18%) in patients with MPN-monocytosis. Then we analyzed the MO3 fraction, which was <1.13% in 18/25 (72%) CMML patients, only one patient with MO1 lower than 94% resulted in an M3 fraction >1.13%. The evaluation of SLAN positivity in this fraction MO3 was always lower than 1.7%. The patient with MO1<94% and MO3 > 1.13% had an active ureteral carcinoma and, at NGS evaluation, had TET2, JAK2, and ZRSR2 mutations. In BM and PB samples from MPN patients, the MO3 fraction was in 2/11 <1.13%, the same patients with MO1> 94%, the diagnosis was a CML in one patient and a PMF triple negative in the other patient. PB samples from reactive monocytosis MO3 fraction were in 11/28 (39%) <1.13%, the same patients with MO1> 94%. The evaluation of SLAN positivity in this fraction MO3 in MPN and reactive monocytosis was always superior at 1.7% (range 4.9-60%). BM samples from CMML and MPN patients reflected the percentage of MO1 and MO3 of PB. Commonly PB and BM monocytes in CMML display aberrant expression of CD56. Furthermore, it was detectable a fraction of non-maturing neutrophils (CD66b+/CD11b-) in nearly half of CMML patients. In conclusion, our real-life experience of routinely FC study on PB and BM CMML samples is similar to the studies described in the literature. It confirms the comparable percentages of monocyte subpopulations in both samples, suggesting that PB samples can be used for diagnostic FC in these patients.

The Use of Avapritinib in Advanced Systemic Mastocytosis: Report of an Open-Label Compassionate Use Program in the United Kingdom

Background: Advanced systemic mastocytosis (AdvSM) is a rare haematological neoplasm occurring due to clonal proliferation of mast cells in extracutaneous organs. In up to 95% of cases, the driver mutation is KIT D816V. AdvSM encompasses aggressive SM (ASM), mast cell leukaemia and SM with an associated haematological neoplasm (SM-AHN). In this latter, the AHN component often dictates the clinical course, being most frequently associated with chronic myelomonocytic leukaemia (CMML). Treatment for AdvSM has evolved recently with the introduction of targetted tyrosine kinase inhibitors (TKI). Avapritinib, a highly selective inhibitor for KIT and PDGFRA, produced robust responses in measures of mast cell/disease burden in the PATHFINDER trial, leading to approval in USA and Europe. We report the clinical experience of AdvSM patients who have received avapritinib at 11 centers in the United Kingdom via an open-label compassionate use program. Methods: Avapritinib was commenced in AdvSM patients with progressive disease-related symptoms and end-organ damage. The initial dose was adjusted according to tolerability and kept continuously until disease progression or unmanageable toxicity. Results: In a cohort of 13 patients, with an age average of 68.8 years (range 57-76), 11 patients (84.6%) were diagnosed with SM-AHN; 81.8% with a concomitant diagnosis of CMML. 2 patients (15.4%) were diagnosed with ASM. All patients harbored the D816V mutation and 8 patients (61.5%) presented with additional mutations; 5 with SRSF2 and 1 with ASXL1. On application of prognostic scores; International Prognostic Scoring system for Mastocytosis (IPSM) 10 patients (76.9%) were classified as AdvSM-3/4 and Mutation-Adjusted Risk Score for Advanced Systemic Mastocytosis (MARS) 7 patients (53.8%) were stratified as high risk. Treatment: 10 patients (76.9%) received avapritinib as a first-line regime, and 9 patients (69.2%) started at a dose of 200 mg od. Three patients were previously treated with other regimes - one patient with midostaurin, one with cladribine and one with azacytidine. Response: Median duration of treatment was 503.7 days (range 75 - 1168 days). Baseline median blood parameters for this cohort were tryptase level of 168 ng/mL (range 91-811), alkaline phosphatase (ALP) of 437 IU/L (range 127-1235), albumin of 34.5 g/L (range 24-48) and a spleen size of 16.4 cm (range 12-26), measured by radiologically. At response evaluation, 9 patients (69.2%) had a tryptase level <20 ng/mL and 11 patients (84.6%) had normalised their ALP and albumin levels. None of the patients had a clinically enlarged spleen, with 9 patients (69.2%) having a normal spleen size on abdominal ultrasound. 8 patients had a complete pathological remission. The overall response rate (using the modified IWG-ECNM-MRT criteria) was 76.9% with a complete response (CR) or CR with partial haematologic recovery in 53.8% of patients. At the last follow-up, 3 patients (23.1%) died; 1 from SM progression, 1 from haematemesis and 1 due to progression of the AHN component but had a partial response of the SM with avapritinib. Toxicities:10 patients (76.9%) had haematological toxicities. Bleeding was reported in 4 patients (30.8%); 3 patients with grade 1/2 (1 mucocutaneous and 2 mild gastrointestinal bleeds), and 1 fatal gastrointestinal bleed. No intracranial bleeds were reported. Fluid retention was noted in 3 patients (23.1%). Less frequent side effects noted were nausea/vomiting (2 patients) and skin/hair discoloration (1 patient). 11 patients (84.6%) needed dose reduction of avapritinib due to haematological toxicity with 8 patients (72.7%) remaining at 100 mg od. 4 patients (36.4%) had to intermittently stop treatment until haematological recovery. Avapritinib was stopped in 2 patients (15.4%) due to disease progression or unmanageable toxicity. Conclusion: This small cohort of patients reflects the clinical heterogeneity of AdvSM and mirrors the PATHFINDER trial outcomes in 'real world 'experience in the UK. Avapritinib as 1st line was tolerated, producing sustained clinical and pathological responses in the majority of this group of non-selected patients with AdvSM with high risk disease. Dose adjustments due to anticipated myelosuppression were made, with 72.2% of patients maintained on 100mg Avapritinib od. 2 patients with SM-AHN are referred for HSCT as a curative treatment as a result of achieving a CR with Avapritinib.

Efficacy and Safety of Ruxolitinib for Treatment of Symptomatic Chronic Myelomonocytic Leukemia (CMML): Results of a Multicenter Phase II Clinical Trial

Introduction CMML is a myelodysplastic/myeloproliferative neoplasm (MDS/MPN) with poor overall survival (OS). Like primary myelofibrosis, a large subset of CMML patients suffer from disease-related symptoms and splenomegaly that contribute to morbidity. We have demonstrated that CMML is molecularly characterized by hematopoietic stem and progenitor cell hypersensitivity to granulocyte-macrophage colony-stimulating factor (GM-CSF). As the sentinel kinase required for GM-CSF signaling, JAK2 represents a rational therapeutic target in CMML and pharmacologic inhibition has demonstrated activity in preclinical models and in a phase I/II clinical trial. The overall response rate in that trial was 38% by MDS/MPN IWG criteria and 43% of patients (pts) with baseline splenomegaly achieved a spleen response by palpation. However, that clinical trial did not systematically or objectively measure symptom burden or radiographic splenomegaly. Here, we report results of our second phase II clinical trial with ruxolitinib for treatment of CMML objectively measuring spleen responses and symptom improvement. Methods This was a phase II prospective multicenter study. Key eligibility criteria included confirmed diagnosis of CMML and having either symptomatic splenomegaly and/or a myeloproliferative neoplasms symptom assessment form (MPN-SAF) total score (TSS) >17, ANC ≥ 250/ul, and platelets ≥35,000 u/l. Ruxolitinib was administered at 20 mg po BID at the previously identified RP2D. Dose adjustments/holding occurred for both hematological and non-hematological parameters. The primary endpoint was clinical benefit or better response per International Working Group (IWG) criteria for MDS/MPNs and symptom improvement was assessed using the MPN-SAF TSS. Pts were treated at least for 16 weeks if no clear progression and those deriving a clinical benefit could continue on study. Serial blood counts, chemistry and bone marrow assessment were conducted to assure safety and assess efficacy. Spleen volume was measured by CT imaging and the percentage of spleen volume reduction (SVR) was captured. Daily measurements of the MPN-SAF were performed for up to 17 weeks while on study. Results A total of 29 pts were enrolled at 4 centers (Moffitt, John Hopkins, Cleveland Clinic and Dana Farber) between September 2019 and June 2022. The median age was 74 (63-87) years. The majority were white (93%) and male (62%) consistent with the known demographics of CMML. Most pts had CMML-0 (62%) and proliferative CMML (69%) by the French American British group criteria. Fifty nine percent were high risk by the Mayo Clinic CMML risk model. Two patients had prior hypomethylating agent treatment and two had prior hydroxyurea. The most common somatic mutations at baseline were TET2 (79%), SRSF2 (68%) and ASXL1(48%). NRAS (21%), CBL (37%), and JAK2 (21%) were seen at higher proportions than previously reported likely due to study inclusion criteria. The median duration of follow up was 16 months and at the data cut off 8 pts remains on treatment. The median duration on treatment was 4 mo (.5-23 mo). Treatment-related adverse events and reasons for discontinuation are similar to that reported in the initial phase 1/2 study. The overall response rate by MDS/MPN IWG criteria was 17%: 10% (3) partial response and 7% (2) marrow response; 69% (20) had stable disease and 14% (4) were not yet evaluable. In addition, a clinical benefit was achieved in 66% of pts (19/29). Among 20 pts evaluable for spleen response, 30% (6/20) achieved ≥ 35% SVR measured by CT scan and 10/20 (50%) had 10% or more SVR (Figure 1a). Fifty four percent of patients achieved MPN-SAF TSS >50% reduction at 60 days and all but four patients demonstrated an improvement in MPN-SAF TSS (Figure 1b). The estimated median overall survival was 24 months (95% CI 9-39). Conclusions Ruxoltinib demonstrated meaningful clinical activity in CMML patients with splenomegaly and/or high disease symptom burden. Two thirds of patients achieved clinical benefit, 33% had ≥ 35% SVR, and 54% had a reduction in TSS>50%. The overall survival compares favorably to historical data among higher risk CMML and the magnitude of symptomatic benefit is similar to that observed in primary myelofibrosis. Collectively, our data suggests that ruxolitinib is a viable therapeutic for patients with symptomatic CMML. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Treatment Outcomes and Prognostic Factors in 66 Patients with Chronic Myelomonocytic Leukemia (CMML) in a Single Center.

Chronic myelomonocytic leukemia (CMML) is a rare hematological malignancy bearing of both myelodysplastic syndrome and myeloproliferative neoplasm characteristics. Despite the low incidence, the clinical diagnosis of CMML was difficult and the survival was poor. The optimal first-line therapy for CMML still remains a matter of debate. We retrospectively analyzed the clinical characteristics of 66 CMML patients in a single center during the past 10 years and studied the survival status of CMML patients in the real world and the influence of treatment methods on the prognosis of patients. For the 66 CMML patients, the median age was 60 years old (IQR 47.0-67.0), and an approximately 1.6:1.0 male-to-female ratio was found. CMML-0, CMML-1 and CMML-2 accounted for 13.7% (9/66), 43.9% (29/66) and 42.4% (28/66), respectively. The chromosome abnormality rate was 27.2% (18/66). Gene mutation was detected in 60 patients by sequenced in first-generation with 51.1% (22/43) gene mutations and in NGS with 82.3% (14/17) gene mutations. The top three mutation genes were ASXL1MT (11/60, 18.3%), TET2MT (10/60, 16.7%), and SRSF2 MT (9/60, 15.0%). There were 27 patients in supportive therapy group, and 39 patients in chemotherapy group including patients undergoing HSCT. Patients in chemotherapy group showed better OS than those in the supportive group before and after PSM analysis with p < 0.05. Patients with blast cell in bone marrow ≥10% or WHO CMML-2 benefited more from chemotherapy treatment achieving better OS. Multivariate analysis showed that supportive therapy and intermediate-2/high in CPSS were independent risk factors for OS after PSM. Chemotherapy including hypomethylating agents prolonged overall survival of CMML patients, especially in patients with blast cell ≥10% in bone marrow or WHO CMML-2 comparing with supportive therapy. Sequencing may provide direct insight into the molecular mechanism by detection of gene mutation, enabling personalized treatment in the future.

Efficacy of Oral Decitabine/Cedazuridine (ASTX727) in the CMML Subgroup from the Ascertain Phase 3 Study

Abstract text:Background/Introduction:Chronic Myelomonocytic Leukemia (CMML) is an uncommon MDS/MPN overlap syndrome that has historically been included under the umbrella of myelodysplastic syndromes (MDS) for clinical trial and treatment. As a result, DNA methyltransferase inhibitors (DNMTi) such as decitabine or azacitidine have been the established standard of care for the treatment of CMML. The oral bioavailability of these agents has been limited due to rapid degradation by cytidine deaminase (CDA) in the gut and liver so treatment has required intravenous infusion or subcutaneous injections daily for 5-7 days every month (m) adding significant burden to older cancer patients due to daily time commitment and travel to treatment centers. In the context of pandemic SARS-CoV-2, parenteral therapy also increases contact with medical settings with increased infection risk. Oral decitabine 35 mg/cedazuridine 100 mg (ASTX727) is an oral fixed dose combination of decitabine and the CDA inhibitor cedazuridine that produced equivalent exposure (99%; 90% CI 93% to 106%) to IV decitabine 20 mg/m 2 in a randomized cross-over study (Garcia-Manero et al, ASH 2019), and Median overall survival (mOS) for the entire study population in the ASCERTAIN study was approximately 32 months (Savona, 2021). Here, we present outcome data for this study for the enrolled subpopulation of patients with CMML.Methods:We used a randomized cross over design in which patients were randomized in the first 2 cycles 1:1 to either Sequence A: (decitabine 35 mg/ cedazuridine 100 mg in Cycle 1 followed by IV decitabine at 20 mg/m 2 in Cycle 2), or Sequence B: (IV decitabine in Cycle 1 followed by oral decitabine/cedazuridine in Cycle 2). We conducted an intra-patient comparison of decitabine PK (primary PK endpoint: decitabine AUC equivalence over 5 days of dosing). Cycles were repeated every 28 days (unless delays were needed). All patients received oral decitabine/cedazuridine in Cycles 3 and above until disease progression or unacceptable toxicity. Patients were eligible per the FDA-approved label of IV decitabine (MDS patients by FAB classification including CMML, or MDS IPSS Intermediate-1, 2 or high-risk patients). Clinical endpoints were best response according to International Working Group (IWG) 2006 response criteria, transfusion independence for at least 8 or 16 consecutive weeks, overall survival, and safety. Adverse events (AEs) were graded by Common Terminology Criteria for Adverse Events (CTCAE) v 4.03.Results:Of the 133 patients enrolled and treated in ASCERTAIN, 16 (12%) had a diagnosis of CMML with demographics and as follows: median age 71.5 years, 69% Male/31% Female, median weight 87kg (range 65-124), 25% ECOG 0, 75% ECOG 1. Population disease characteristics were: 19% poor or intermediate risk cytogenetics, with median baseline hemoglobin 90 g/L, neutrophils 1.27 X 10 9/L, platelets 84 x 10 9/L, bone marrow blasts 5%, with 38% RBC transfusion dependent. Patients received a median of 7 cycles of therapy (range 3-24). Treatment-emergent adverse events of CTCAE Grade 3 or higher in > 10% of patients, independent of relationship to ASTX727, were cytopenias (neutropenia [69%], thrombocytopenia [63%], anemia [56%], leukopenia [19%]), febrile neutropenia (31%), fatigue (13%). Two patients (12.5%) had Complete Responses (CR), 8 (50%) had marrow CR ([mCR], including 3 (19%) with hematologic improvement (HI); Overall Response rate (ORR) [CR + PR+ mCR + HI] was 75%. Of six patients with baseline RBC transfusion dependence 3 (50%) became transfusion independent. Leukemia-free survival was 28.2 months and after a median follow up of more than 33 months, median overall survival had not been reached. Two patients (13%) went on to Hematopoietic Stem Cell Transplant (HCT).Conclusions:In the overall study, oral decitabine/cedazuridine delivered equivalent PK exposure to 5 days of IV decitabine 20mg/m 2 with a resultant clinical activity safety and efficacy profile in CMML patients consistent with the published literature (e.g Zeidan, et al 2017) and the Phase 2 experience. The use of oral decitabine/cedazuridine is a reasonable approach in CMML patients.

Real-World Study of CPX-351 Treatment Outcomes for Acute Myeloid Leukemia (AML) in England

Introduction: CPX-351 (US: Vyxeos ®; Europe: Vyxeos ® Liposomal) is a dual-drug liposomal encapsulation of daunorubicin and cytarabine in a synergistic 1:5 molar ratio. Since November 2018, the National Institute for Health and Care Excellence (NICE) has recommended its use for adults with newly diagnosed, therapy-related AML (t-AML) or AML with myelodysplasia-related changes (AML-MRC) due to either prior myelodysplastic syndrome (MDS)/chronic myelomonocytic leukemia (CMML) or de novo AML with myelodysplasia-related cytogenetic changes. The key aims of this study were to utilize the Cancer Analysis System (CAS) database available through the National Cancer Registration and Analysis Service (NCRAS) to describe the demographics and clinical characteristics of adults with AML in England who have received CPX-351, as well as to estimate overall survival (OS) and survival within stratifications of interest.Methods: The NCRAS systematically collects and curates population-level data about cancer diagnoses, treatments, and outcomes across England. Adults (aged ≥18 years) diagnosed with AML and treated with CPX-351 were included in this study. A diagnosis of t-AML or AML-MRC between January 2013 and March 2020 was determined either directly using International Classification of Diseases for Oncology, Third Edition (ICD-O-3) codes or indirectly using non-specific ICD-O-2, ICD-O-3, or ICD-10 AML codes in combination with either prior systemic anticancer therapy or radiotherapy (t-AML) or a prior diagnosis of MDS or CMML (AML-MRC; other AML-MRC subtypes could not be specifically identified and are included within the de novo AML subgroup). OS was measured from the date of diagnosis; a separate analysis of OS landmarked from the date of hematopoietic cell transplant (HCT) was also performed. Within this preliminary analysis, no OS adjustments have been made to account for any COVID-19-related deaths.Results: A total of 172 patients with AML who were treated with CPX-351 were identified: 37 (22%) had t-AML, 57 (33%) had AML-MRC, and 78 (45%) had de novo AML. At diagnosis, the mean (standard deviation) age was 62.8 years (10.1), with 49/172 (28%) patients aged <60 years; 66% of patients were male; 87% were white; and most had an Eastern Cooperative Oncology Group performance status of 0 or 1 (68%). Six (3%) patients had received azacitidine treatment for a prior malignancy. To date, 43/172 (25%) patients had undergone HCT overall, including 43/97 (44%) patients with ≥3 months of follow-up.The cut-off date for OS was December 31, 2020, giving a median (interquartile range) follow-up of 11.2 months (3.6, 16.9). Overall, 91 patients had died, with an estimated median OS (95% confidence interval [CI]) of 16.6 months (11.0, not estimable) and probability of survival (95% CI) at 1 and 2 years of 0.54 (0.47, 0.62) and 0.39 (0.30, 0.50), respectively (Figure 1). Early mortality rates were 7% at 30 days and 15% at 60 days. When OS was landmarked from the date of HCT, median OS was not reached, with a probability of survival (95% CI) at 1 year of 0.74 (0.62, 0.89; Figure 2). When stratified by age, estimated median OS (95% CI) was not reached for patients aged <60 years and 12.8 months (8.9, 17.6) for patients aged ≥60 years. In a treatment patterns analysis that evaluated second-line treatments after CPX-351, 68 patients died without salvage therapy and 64 were alive without receiving subsequent therapy by the end of the study period. The most common salvage treatments were fludarabine, cytarabine, idarubicin, and granulocyte-colony stimulating factor (FLAG-Ida; n = 15), daunorubicin plus cytarabine (DA)-based therapy (n = 6), and azacitidine alone (n = 7). Of the 43 patients who received an HCT, 6 (14%) underwent HCT following salvage therapy.Conclusions: This is the largest study to date examining the real-world outcomes for patients with AML who were treated with CPX-351. The estimated median OS of 16.6 months is consistent with reported real-world outcomes for CPX-351 in French and Italian studies. Median OS has not been reached in patients aged <60 years or when landmarked from the date of HCT. Once the CAS database has been updated, these analyses will be repeated to increase follow-up and patient numbers and to determine the impact of COVID-19 on OS following CPX-351 treatment. [Display omitted] DisclosuresLegg: Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Doubleday: IQVIA Inc., which was contracted by Jazz Pharmaceuticals for the conduct of this analysis: Current Employment. Reich: IQVIA Inc., which was contracted by Jazz Pharmaceuticals for the conduct of this analysis: Current Employment. Lambova: IQVIA Inc., which was contracted by Jazz Pharmaceuticals for the conduct of this analysis: Current Employment. Medalla: Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company.

MDS-083: Huntsman Cancer Institute Survival Analysis of Genetic Mutations in Patients with Chronic Myelomonocytic Leukemia

Context: Chronic myelomonocytic leukemia (CMML) is a rare hematopoietic stem cell disorder that predominantly affects the elderly. Previous genetic analysis supports the presence of mutations including ASXL1, TET2, spliceosome components (SF3B1, SRSF2, U2AF1, and ZRSR2), and the oncogenic RAS pathway (NRAS, KRAS, CBL, PTPN11, and NF1). Objective: As part of a precision cancer surveillance to increase our basic, translational, and clinical understanding of rare diseases at the Huntsman Cancer Institute, we identified a cohort of patients with CMML treated at our institution. This report reports their clinical and molecular characteristics based on standard of care molecular profiling with myeloid next-generation sequencing. We also describe the overall survival of patients with molecular profiles of interest. Design: We extracted data from 57 CMML patients from the Huntsman Cancer Institute electronic health record system. We categorized the patients using their first bone marrow myeloid malignancy panel diagnosis between October 2009 and September 2020. We reviewed their charts for the following information elements: date of birth, sex, vital status, bone marrow biopsy, CMML diagnosis, and date of death or last follow-up. Our analysis was performed by producing Kaplan-Meier survival curves. Results: We identified a total of 34 gene mutationstal Saint-Louis, Paris, France

MDS-308: Mutational Profile of Patients Diagnosed with Myelodysplastic Syndromes, First Experiences in a Center of Argentina

Context: Myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML) are heterogeneous myeloid malignant clonal disorders. Different mutations can be associated with higher risks of these diseases, specific characteristics, and responses to certain treatments. Molecular findings obtained through next-generation sequencing (NGS) have gained importance in myeloid neoplasms, but local access is limited. We recently incorporated NGS technology in our center that will seek to identify mutations. Objective: To describe the mutational landscape of patients diagnosed with MDS and CMML locally. Design: We designed a prospective observational cohort study from July 2019 to July 2020 in adult patients diagnosed with MDS and CMML who underwent bone marrow biopsy with NGS at a private university reference hospital, Hospital Italiano, in Buenos Aires. Results: 24 adult patients with MDS and CMML diagnosis were included, 18 MDS and 6 CMML. The median age was 74 years (IQR: 60–78.25), 54% male. All patients were classified with IPSS-R. NGS was performed in all patients; 86.9% had at least one mutation. Among the most frequent genes were TET2, SRSF2, DNMT3A, and RUNX1. Five of six patients with CMML had a normal karyotype; all obtained at least three mutations, and SRF2 mutation was the most frequent. The most common mutational pathways involved in patients with adverse cytogenetics were DNA repair and transcription pathways (p = 0.019). The number of mutations in patients with high-risk IPSS-R was 3.5 vs 2 mutations in low-risk patients, which was not statistically significant. The mean Hb value in patients with 2 mutations or fewer was 10.3 mg/dl vs 9 mg/dl in patients with > 3 mutations (p = 0.069). Treatment was required in 50% of patients with 1–2 mutations and in 86% of patients with 3 mutations or more (p = 0.016). Conclusions: As described in the literature, most of our patients had mutations, the most frequent being epigenetic regulators and signal translation genes. The number of mutations was statistically correlated with the degree of anemia and with treatment indication. Recognizing mutations is crucial for clinical decisions, diagnosis, prognosis, and treatment. Although we have evaluated few patients, our data are comparable to those published and encourage us to continue working to improve the care of our patients.

Prognostic Factors and Survival Outcomes in Blast Transformed Chronic Myelomonocytic Leukemia: A Mayo Clinic-MD Anderson Cancer Center Study of 171 Cases

Background:Blast transformed (BT) chronic myelomonocytic leukemia (CMML); defined by ≥20% blood or bone marrow (BM) blasts, occurs in 15-30% of patients and is a major cause of mortality. Reported risk factors include high risk karyotype, circulating blast count, circulating immature myeloid cells (IMC), CMML morphological subtype, and the presence of ASXL1 mutations. In the current study, we reviewed consecutive cases of BT CMML from the Mayo Clinic, MN, and the MD Anderson Cancer Center, Texas, USA, with the intent to examine i) prognostic factors, ii) survival trends, and iii) treatment outcomes.Methods:Diagnoses of CMML and BT-CMML were according to the 2016 WHO criteria. Treatment response in BT-CMML patients was assessed according to standard AML response criteria. Statistical analyses considered clinical and laboratory data collected at the time of BT. Survival was calculated from the date of BT to the date of death or last contact.Results:171 cases of BT CMML were identified from the Mayo Clinic (n=84) and MDACC (n=87). The median age at BT was 69 years and 64% were male. Eight one (49%) had received prior hypomethylating agent (HMA) therapy (Decitabine 50, 5-azacitidine 31), with 30% having achieved a complete remission (CR) prior to BT. CMML patients that received prior HMA therapy were more likely to have thrombocytopenia (p=0.03), higher LDH levels (p=0.007), lower frequency of TET2 mutations (p=0.04) and higher risk stratification by the Mayo prognostic model (p=0.009). The two institutional cohorts were comparable with regards to variables, both at CMML diagnosis and BT.Patient characteristics at time of BT: The median time from CMML diagnosis to BT was 12 months (range, 1-36). At BT, 16 (10%) presented with extramedullary disease, 81 (63%) with an abnormal karyotype, 41 (34%) with cytogenetic clonal evolution, with the following mutational distribution; TET2 50%, ASXL1 39%, NRAS 39%, FLT3 ITD 20%, NPM1 6%, RUNX1 6%, and 5% each for IDH1/2, EZH2 and JAK2 . Molecular clonal evolution was seen in 4 (22%) of 18 evaluable cases.Survival trends: After a median follow-up of 4.4 months (range 0-122), 141 (82%) deaths were recorded. Median overall survival (OS) was 6 months with 1- and 3-year survival rates of 25% and 9%, respectively; survival trends were similar (p=0.4) for patients diagnosed prior to and after the year 2006 (figure 1A).Treatment and response rates: Specific treatment for BT-CMML was documented in 157 cases and included induction chemotherapy (n=61), induction chemotherapy followed by stem cell transplant (HCT, n=18), HCT alone (n=3), HMA (n=18), novel therapeutic agents (n=18), and best supportive care (BSC, n=39). Treatment response was assessable in 113, including 76 treated with induction chemotherapy, 18 with HMA and 16 with novel therapeutics; with respective CR rates of 24%, 0% and 41%; with an additional 24%, 16% and 16% of patients achieving CR with incomplete blood count recovery (CRi), with a survival similar to those with CR (figure 1B). HCT was reported in 25 patients, 17 myeloablative and 8 reduced intensity, with a median OS of 7 months.Predictors of survival in BT-CMML: In univariate analysis of variables recorded at time of BT, risk factors adversely impacting survival included older age, lower hemoglobin, PB blast %, adverse cytogenetics at BT, prior exposure to HMA, not receiving induction chemotherapy, not achieving CR or CRi and not receiving HCT; all of these risk factors remained significant when analysis was adjusted for age. In multivariable analysis, lack of prior HMA exposure (p=0.001, HR 5.1; 95% CI 1.9-14.1) and the achievement of CR/CRi (p=0.02, HR 1.4; 95% CI 1.2-3.4) remained significant while HCT lost its significance (p=0.09). Gene mutations, including FLT3 ITD, cytogenetic and molecular clonal evolution at the time of BT did not impact survival. The 3-year survival rates for BT patients receiving induction chemotherapy, induction chemotherapy followed by HCT, HMA, novel agents and BSC were 8%, 20%, 12%, 3% and 0% respectively (figure 1C).Conclusions: Survival in patients with BT- CMML is dismal (≈6 months) and is adversely impacted by prior exposure to HMA and by the failure to achieve CR/CRi. After BT, the use of HMA therapy is largely ineffective (0% CR), with intensive therapies such as induction chemotherapy with or without HCT, failing to achieve durable remissions. [Display omitted] DisclosuresJabbour:Amgen: Research Funding; Novartis: Research Funding; Pfizer: Research Funding; Takeda Oncology: Research Funding. Kantarjian:Amgen: Research Funding; Delta-Fly Pharma: Research Funding; ARIAD: Research Funding; Novartis: Research Funding; Pfizer: Research Funding; Bristol-Meyers Squibb: Research Funding.

Multicentric Validation of the “Monocyte Assay” for Chronic Myelomonocytic Leukemia Diagnosis By Flow Cytometry

Introduction:Accumulation of classical monocytes (MO1:CD14++CD16-) ≥94% of total peripheral blood monocytes analyzed by flow cytometry (FCM) was demonstrated to be a specific and sensitive tool that distinguishes chronic myelomonocytic leukemia (CMML) from reactive monocytosis (Selimoglu-Buet D et al, Blood 2015). The 94% threshold was further validated in an independent study (Talati C et al, Blood 2017) and is increasingly used as a diagnostic marker of CMML. Since this “monocyte assay” has been largely adopted by French diagnosis laboratories, we evaluated its performance in a multicentric evaluation.Methods: A short survey was sent by personalized emails between July and September 2016 to 48 French laboratories performing routinely FCM diagnosis of myeloid neoplasms. Afterwards, a few selected centers were asked to send their raw data files as well as the corresponding MO1 percentage evaluation in order to perform a centralized blind analysis using Kaluza® Software (Beckman Coulter®). Biological and clinical data were also provided when available.Results: We obtained a comprehensive reply to the survey with a 100% rate of response. Thirty of 48 centers (63%) use routinely the “monocyte assay”: apart from the three centers that participated to the initial study and keep using it, 27 centers spontaneously implemented it, most often following the initial publication and/or a meeting presentation. Eighteen out of 27 (67%) centers use at least the published exclusion panel for non-monocyte mature blood cells (i.e. CD2 and CD56 for T lymphocytes and NK cells, CD24 for B lymphocytes and granulocytes). Ten centers use at least one exclusion marker while two use no one. Nine centers perform 1 to 2 tests per month, fifteen 3 to 6, three 6 to 10 and three more than 10 tests. All the surveyed cytometrists consider the “monocyte assay” useful for CMML diagnosis. Among the 18 centers that do not use the “monocyte assay”, 8 intend to develop it soon, the 10 remaining centers not excluding a possible implementation.In a second step, five centers (named A to E) were selected according to their frequency of use and their antibody panel, excluding the three centers which were part of the initial study. They provided 329 FCM raw data files with the corresponding MO1 percentage. All these files were reanalyzed in a blind fashion. This centralized analysis compared to the MO1 percentage determined by the centers showed an excellent correlation (r=0.93; p<0.0001, Figure 1A) without any major bias (Center A: r = 0.93; B: r=0.97; C: r=0.89; D: r=0.93, E: r=0.93; p<0.0001). As the cut-off value of 94% MO1 is the most relevant parameter in the “monocyte assay”, we compared the patients with MO1 percentage ≥94% by centralized analysis (i.e. suspected of being diagnosed as CMML) and found an excellent concordance between both analyses (matching for 110 analyses/ 115 (95.7%), Figure 1B). Conversely, of the 214 patients with a fraction of MO1 <94% by the centralized analysis, 201 (93.5%) displayed MO1 percentage <94% in the original center. In most of the 18 divergent cases, the difficulty in drawing MO1 gate was related to an insufficient number of classical monocytes analyzed. Hence, we decided to exclude all the files showing MO1 event number below 10,000 (Figure 1C), thereby improving the correlation (r=0.94) and the concordance for the 245 remaining files (total matching files: 95%). Among these latter files, we collected clinical data for 84 patients for whom an overt diagnosis was made, namely 46 CMML, 24 reactive monocytosis and 14 non-CMML malignancies. MO1 accumulation ≥94% determined by centralized analysis was observed in 43 of the 46 CMML (Figure 1D), indicating a sensitivity of 93.5% in accordance with previous results. A specificity of 86.8% was calculated as 5 of the 38 “non-CMML” patients displayed MO1 <94% determined by centralized analysis. Interestingly, using these data we established a new Receiver Operator Curve (ROC) and obtained yet again a 94% cut-off value.Conclusion: This study demonstrates a strong adhesion of the French laboratories to the “monocyte assay” for CMML diagnosis set-up in 2015, with 30 user centers so far. We also demonstrate that this FCM test requires the acquisition of a minimum of 10,000 events. Finally, we observed a low variability of the MO1 percentage quantification between centers and validated the published 94% cut-off value with a 93.5% sensitivity and a 86.8% specificity. [Display omitted] DisclosuresFenaux:Celgene: Honoraria, Research Funding; Astex: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Astex: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Janssen: Honoraria, Research Funding. Wagner Ballon:Alexion: Consultancy, Honoraria.

Extramedullary Manifestations in World Health Organization-Defined Chronic Myelomonocytic Leukemia: Clinical, Molecular and Prognostic Correlates

Background:Chronic myelomonocytic leukemia (CMML) is an aggressive myeloid neoplasm with overlapping myeloproliferative and myelodysplastic features. Extramedullary manifestations (EMM) include splenomegaly, hepatomegaly, lymphadenopathy, leukemia cutis, gingival infiltrates, central nervous system (CNS) and testicular involvement and myeloid sarcomas. We carried out this study to i) define clinical and laboratory correlates of EMM in CMML, ii) to assess the prognostic impact of EMM, and iii) to document survival outcomes.Methods:Four hundred and fifty-two patients with WHO-defined CMML were included in the study. All morphological and cytogenetic assessments at baseline were performed at the Mayo Clinic, MN. Bone marrow (BM) DNA at diagnosis was available in 229 (50%) patients and was subjected to a 29 gene panel next generation sequencing analysis. EMM for the purpose of this study were defined as: palpable splenomegaly, palpable hepatomegaly, palpable lymphadenopathy, clinical/radiological or biopsy proven leukemia cutis, gingival infiltrates, testicular involvement, CNS involvement, and myeloid sarcomas. EMM were included if present either at the time of CMML diagnosis, or within six months of stable disease following diagnosis. Standard statistical tests and measures were utilized.Results:Three hundred and seventy-three (82%) patients had an exam documented at the time of diagnosis, or within six months of diagnosis, and were included in the analysis. The median age was 69 years (range, 18-95), 66% were male and 176 (47%) had a “proliferative CMML phenotype.”1. Clinical correlates:One hundred and nineteen (32%) patients had at least one EMM at diagnosis. This included; palpable splenomegaly 91 (76%), hepatomegaly 48 (40%), lymphadenopathy 19 (15%), leukemia cutis 7 (6%), gingival infiltrates 4 (3%), myeloid sarcomas 2 (2%), and 1 each with testicular and CNS involvement (1%). Thirty two (27%) had non hepatosplenic EMM, 102 (86%) had palpable hepato and/or splenomegaly, whereas 54 (45%) and 11 (9%) had isolated palpable splenomegaly and hepatomegaly. In comparison to CMML patients without EMM, those with, were more likely to be younger (p <0.0001), have a higher leukocyte count (WBC, p <0.0001), higher absolute neutrophil count (ANC, p <0.0001), higher absolute monocyte count (AMC, p <0.0001), have circulating immature myeloid cells (IMC, p <0.0001), have mutations involving ASXL1 (p 0.03), CBL (p 0.04), and CSF3R (p 0.02), lack SF3B1 (p 0.009) and ZRSR2 (p 0.03) mutations and have a higher risk stratification by the Mayo Molecular Model (MMM, p<0.0001) and the GFM model (p=0.004).2. Prognostic impact:At last follow up (median 14 months), 249 (67%) deaths and 69 (18%) leukemic transformations were documented. Median survival (OS) was 13 months for patients with non hepatosplenic EMM, 13.2 months for those with palpable hepatosplenomegaly, and 25 months for those without EMM (Figure 1). On univariate analysis, survival was adversely affected by, male sex (p 0.03), low hemoglobin (p <0.0001), high WBC (p 0.0005), high AMC (p <0.0001), presence of IMC (p 0.002), circulating blast % (p <0.0001), high LDH (p 0.0004), presence of EMM (p <0.0001), palpable hepatosplenomegaly (p=0.0008), leukemia cutis (p=0.02), proliferative CMML phenotype (p <0.0001), adverse cytogenetics (p 0.003), absence of TET2 (p 0.0004) and the presence of DNMT3A (p 0.002), IDH1 (p 0.013), ASXL1 (p 0.03), and Tp53 (p 0.014) mutations. Non-hepatosplenic EMM, palpable lymphadenopathy, CNS, testicular involvement and the presence of myeloid sarcomas did not impact OS. On multivariate analysis, only male sex (p= 0.009, HR 1.6, 95% CI 1.1-2.3), low hemoglobin (p <0.0001, HR 1.74, 95% CI 1.3-2.3), palpable hepatosplenomegaly (p 0.0005, HR 1.8, 95% CI 1.04-2.2), absence of TET2 mutations (p 0.023, HR 0.7, 95% CI 0.5-0.95), and the presence of DNMT3A mutations (p 0.013, HR 2.3, 95% CI 1.2-4.3) retained an independent negative prognostic impact. Palpable hepatosplenomegaly retained prognostic significance when assessed in the context of the MMM (p=0.03) and the GFM (p=0.04) models. EMM had no impact on leukemia-free survival.Conclusion:The current study demonstrates a prognostically-relevant frequent occurrence of hepatosplenomegaly in CMML; the study also provides the spectrum and frequency of extramedullary manifestations and correlations with mutations. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.