Risk Prediction for Clonal Cytopenia: Multicenter Real-World Evidence.

Clonal cytopenia of undetermined significance (CCUS) represents a distinct disease entity characterized by myeloid-related somatic mutations with a variant allele fraction of ≥2% in individuals with unexplained cytopenia(s) but without a myeloid neoplasm (MN). Notably, CCUS carries a risk of progressing to MN, particularly in cases featuring high-risk mutations. Understanding CCUS requires dedicated studies to elucidate its risk factors and natural history. Our analysis of 357 CCUS patients investigated the interplay between clonality, cytopenia, and prognosis. Multivariate analysis identified 3 key adverse prognostic factors: the presence of splicing mutation(s) (score = 2 points), platelet count <100×109/L (score = 2.5), and ≥2 mutations (score = 3). Variable scores were based on the coefficients from the Cox proportional hazards model. This led to the development of the Clonal Cytopenia Risk Score (CCRS), which stratified patients into low- (score <2.5 points), intermediate- (score 2.5-<5), and high-risk (score ≥5) groups. The CCRS effectively predicted 2-year cumulative incidence of MN for low- (6.4%), intermediate- (14.1%), and high- (37.2%) risk groups, respectively, by Gray's test (P <.0001). We further validated the CCRS by applying it to an independent CCUS cohort of 104 patients, demonstrating a c-index of 0.64 (P =.005) in stratifying the cumulative incidence of MN. Our study underscores the importance of integrating clinical and molecular data to assess the risk of CCUS progression, making the CCRS a valuable tool that is practical and easily calculable. These findings are clinically relevant, shaping the management strategies for CCUS and informing future clinical trial designs.

Venetoclax plus hypomethylating agents in DDX41-mutated acute myeloid leukaemia and myelodysplastic syndrome: Mayo Clinic series on 12 patients.

Venetoclax (VEN) is an FDA-approved selective inhibitor of B-cell leukaemia/lymphoma-2 (BCL-2), used for treating elderly or unfit acute myeloid leukaemia (AML) patients unable to undergo intensive chemotherapy. Combining VEN with hypomethylating agents (HMAs) has shown impressive response rates in high-risk myelodysplastic syndromes (MDS) and relapsed/refractory AML. However, the efficacy of VEN and HMAs in treating DDX41-mutated (mDDX41) MDS/AML patients remains uncertain. Despite the favourable prognostic nature of mDDX41 MDS/AML patients, there is a lack of clinical experience regarding their response to different treatment regimens, leading to an unknown optimal therapeutic approach.

TP53 variant allele frequency and therapy-related setting independently predict survival in myelodysplastic syndromes with del(5q).

Among 210 patients with myelodysplastic syndromes (MDSs) with del(5q), molecular information was available at diagnosis or at least 3 months before leukaemic transformation in 146 cases. Multivariate analysis identified therapy-related setting (p = 0.02; HR 2.3) and TP53 variant allele frequency (VAF) ≥22% (p < 0.01; HR 2.8), but not SF3B1 mutation (p = 0.65), as independent risk factors for survival. Median survival was 11.7 versus 4 years (5/10-year survival 73%/52% vs. 42%/14%) in the absence (N = 112) versus presence (N = 34) of ≥1 risk factors; leukaemia-free survival was affected by TP53 VAF ≥22% (p < 0.01). Such information might inform treatment decision-making in MDS-del(5q) regarding allogeneic stem cell transplant.

Cardiac events in newly diagnosed acute myeloid leukaemia during treatment with venetoclax + hypomethylating agents.

Among 301 newly diagnosed patients with acute myeloid leukaemia receiving venetoclax and a hypomethylating agent, 23 (7.6%) experienced major cardiac complications: 15 cardiomyopathy, 5 non-ST elevation myocardial infarction and/or 7 pericarditis/effusions. Four patients had more than one cardiac complication. Baseline characteristics included median age ± interquartile range; 73 ± 5 years; 87% males; 96% with cardiovascular risk factors; and 90% with preserved baseline ejection fraction. In multivariate analysis, males were more likely (p = 0.02) and DNMT3A-mutated cases less likely (p < 0.01) to be affected. Treatment-emergent cardiac events were associated with a trend towards lower composite remission rates (43% vs. 62%; p = 0.09) and shorter survival (median 7.7 vs. 13.2 months; p < 0.01). These observations were retrospectively retrieved and warrant further prospective examination.

Prognostic relevance of clonal hematopoiesis in myeloid neoplastic transformation in patients with follicular lymphoma treated with radioimmunotherapy.

While novel radioisotope therapies continue to advance cancer care, reports of therapy-related myeloid neoplasms (t-MN) have generated concern. The prevalence and role of clonal hematopoiesis (CH) in this process remain to be defined. We hypothesized that: (i) CH is prevalent in relapsed follicular lymphoma and is associated with t-MN transformation, and (ii) radiation in the form of radioimmunotherapy (RIT) plays a role in clonal progression. In this retrospective cohort study, we evaluated the prevalence and prognostic impact of CH on clinical outcomes in 58 heavily pre-treated follicular lymphoma patients who received RIT. Patients had been given a median of four lines of therapy before RIT. The prevalence of CH prior to RIT was 46%, while it was 67% (P=0.15) during the course of RIT and subsequent therapies in the paired samples. Fourteen (24%) patients developed t-MN. Patients with t-MN had a higher variant allele fraction (38% vs. 15%; P=0.02) and clonal complexity (P=0.03) than those without. The spectrum of CH differed from that in age-related CH, with a high prevalence of DNA damage repair and response pathway mutations, absence of spliceosome mutations, and a paucity of signaling mutations. While there were no clear clinical associations between RIT and t-MN, or overall survival, patients with t-MN had a higher mutant clonal burden, along with extensive chromosomal abnormalities (median survival, afer t-MN diagnosis, 0.9 months). The baseline prevalence of CH was high, with an increase in prevalence on exposure to RIT and subsequent therapies. The high rates of t-MN with marked clonal complexities and extensive chromosomal damage underscore the importance of better identifying and studying genotoxic stressors accentuated by therapeutic modalities.

FLT3 inhibitors potentially improve response rates in acute myeloid leukemia harboring t(6;9)(DEK::NUP214): The Mayo Clinic experience.

Not available.

Genetic landscape and clinical outcomes of patients with BCOR mutated myeloid neoplasms.

The BCL6-corepressor (BCOR) is a tumor-suppressor gene located on the short arm of chromosome X. Data are limited regarding factors predicting survival in BCOR-mutated (mBCOR) acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). We evaluated 138 patients with mBCOR myeloid disorders, of which 36 (26.1%) had AML and 63 (45.6%) had MDS. Sixty-six (47.8%) patients had a normal karyotype while 18 (13%) patients had complex karyotype. BCOR-mutated MDS/AML were highly associated with RUNX1 and U2AF1 co-mutations. In contrast, TP53 mutation was infrequently seen with mBCOR MDS. Patients with an isolated BCOR mutation had similar survival compared to those with high-risk co-mutations by European LeukemiaNet (ELN) 2022 criteria (median OS 1.16 vs. 1.27 years, P=0.46). Complex karyotype adversely impacted survival among mBCOR AML/MDS (HR 4.12, P<0.001), while allogeneic stem cell transplant (alloSCT) improved survival (HR 0.38, P=0.04). However, RUNX1 co-mutation was associated with an increased risk of post-alloSCT relapse (HR 88.0, P=0.02), whereas melphalan-based conditioning was associated with a decreased relapse risk (HR 0.02, P=0.01). We conclude that mBCOR is a high-risk feature across MDS/AML, and that alloSCT improves survival in this population.

Prognostic impact of SF3B1 mutation and multilineage dysplasia in myelodysplastic syndromes with ring sideroblasts: a Mayo Clinic study of 170 informative cases.

The revised 4th edition of the World Health Organization (WHO4R) classification lists myelodysplastic syndromes with ring sideroblasts (MDS-RS) as a separate entity with single lineage (MDS-RS-SLD) or multilineage (MDS-RS-MLD) dysplasia. The more recent International Consensus Classification (ICC) distinguishes between MDS with SF3B1 mutation (MDS-SF3B1) and MDS-RS without SF3B1 mutation; the latter is instead included under the category of MDS not otherwise specified. The current study includes 170 Mayo Clinic patients with WHO4R-defined MDS-RS, including MDS-RS-SLD (N=83) and MDS-RSMLD (N=87); a subset of 145 patients were also evaluable for the presence of SF3B1 and other mutations, including 126 with (87%) and 19 (13%) without SF3B1 mutation. Median overall survival for all 170 patients was 6.6 years with 5- and 10-year survival rates of 59% and 25%, respectively. A significant difference in overall survival was apparent between MDS-RS-MLD and MDS-RS-SLD (P<0.01) but not between MDS-RS with and without SF3B1 mutation (P=0.36). Multivariable analysis confirmed the independent prognostic contribution of MLD (hazard ratio=1.8, 95% confidence interval: 1.1-2.8; P=0.01) and also identified age (P<0.01), transfusion need at diagnosis (P<0.01), and abnormal karyotype (P<0.01), as additional risk factors; the impact from SF3B1 or other mutations was not significant. Leukemia-free survival was independently affected by abnormal karyotype (P<0.01), RUNX1 (P=0.02) and IDH1 (P=0.01) mutations, but not by MLD or SF3B1 mutation. Exclusion of patients not meeting ICC-criteria for MDS-SF3B1 did not change the observations on overall survival. MLD-based, as opposed to SF3B1 mutation-based, disease classification for MDS-RS might be prognostically more relevant.

Granularity in disease classification impacts survival prediction in advanced systemic mastocytosis: A single institution study of 329 informative cases.

The World Health Organization (WHO) classification system categorizes advanced systemic mastocytosis (SM-Adv) into aggressive SM (ASM), mast cell leukemia (MCL), and SM with associated hematological neoplasm (SM-AHN). By contrast, the International Consensus Classification (ICC) requires "immature" MC cytomorphology for the diagnosis of MCL and limits SM-AHN to myeloid neoplasms (SM-AMN). The current study includes 329 patients with SM-Adv (median age 65 years, range 18-88; males 58%): WHO subcategories SM-AHN (N = 212; 64%), ASM (N = 99; 30%), and MCL (N = 18; 6%); ICC subcategories SM-AMN (N = 190; 64%), ASM (N = 99; 33%), and MCL (N = 9; 3%); WHO-defined MCL with "mature" MC cytomorphology and SM-AHN associated with lymphoid neoplasms were operationally labeled as "MCL-mature" (N = 9) and SM-ALN (N = 22), respectively, and distinguished from ICC-defined MCL and SM-AMN. Multivariable analysis that included the Mayo alliance risk factors for survival in SM (age >60 years, anemia, thrombocytopenia, increased alkaline phosphatase) revealed more accurate survival prediction with the ICC versus WHO classification order: (i) survival was significantly worse with MCL-immature versus MCL-mature (hazard ratio [HR] 15; p < .01), (ii) prognostic distinction between MCL and SM-AHN/AMN was confirmed in the context of ICC (HR 9.3; p < .01) but not WHO classification order (p = .99), (iii) survival was similar between MCL-mature and SM-AMN (p = .18), and (iv) SM-AMN (HR 1.7; p < .01) but not SM-ALN (p = .37) was prognostically distinct from ASM. The current study provides evidence for the independent prognostic contribution of both the ICC system for SM-Adv and the Mayo alliance risk factors for survival in SM.

Reappraisal of mast cell leukemia based on a single institution review of 16 cases: Mast cell morphology determines clinical outcome.

Cytologic abnormalities of atypical mast cells in mastocytosis. The mature mast cells have oval-shaped nuclei, cytoplasmic hypogranulation and spindle-shaped cytology. or well-differentiated displaying a round nucleus with condensed chromatin, and abundant dense cytoplasmic granulations. Immature mast cells include promastocytes and metachromatic blast-like forms.

PHF6 mutations in chronic myelomonocytic leukemia identify a unique subset of patients with distinct phenotype and superior prognosis.

The current study was inspired by observations from exploratory analyses of an institutional cohort with chronic myelomonocytic leukemia (CMML; N = 398) that revealed no instances of blast transformation in the seven patients with plant homeodomain finger protein 6 (PHF6) mutation (PHF6MUT). A subsequent Mayo Clinic enterprise-wide database search identified 28 more cases with PHF6MUT. Compared with their wild-type PHF6 counterparts (PHF6WT; N = 391), PHF6MUT cases (N = 35) were more likely to co-express TET2 (89% vs. 45%; p < .01), RUNX1 (29% vs. 14%; p = .03), CBL (14% vs. 2%; p < .01), and U2AF1 (17% vs. 6%; p = .04) and less likely SRSF2 (23% vs. 45%; p < .01) mutation. They were also more likely to display loss of Y chromosome (LoY; 21% vs. 2%; p < .01) and platelets <100 × 109/L (83% vs. 51%; p < .01). Multivariable analysis identified PHF6MUT (HR 0.28, 95% CI 0.15-0.50) and DNMT3AMUT (HR 5.8, 95% CI 3.3-10.5) as the strongest molecular predictors of overall survival. The same was true for blast transformation-free survival with corresponding HR (95% CI) of 0.08 (0.01-0.6) and 9.5 (3.8-23.5). At median 20 months follow-up, blast transformation was documented in none of the 33 patients with PHF6MUT/DNMT3AWT but in 6 (32%) of 19 with DNMT3AMUT and 74 (20%) of 374 with PHF6WT/DNMT3AWT (p < .01). The specific molecular signatures sustained their significant predictive performance in the context of the CMML-specific molecular prognostic model (CPSS-mol). PHF6MUT identifies a unique subset of patients with CMML characterized by thrombocytopenia, higher prevalence of LoY, and superior prognosis.

Venetoclax and hypomethylating agent combination therapy in newly diagnosed acute myeloid leukemia: Genotype signatures for response and survival among 301 consecutive patients.

Venetoclax + hypomethylating agent (Ven-HMA) is currently the standard frontline therapy for older/unfit patients with newly diagnosed acute myeloid leukemia (ND-AML). Our objective in the current retrospective study of 301 adult patients (median age 73 years; 62% de novo) with ND-AML was to identify molecular predictors of treatment response to Ven-HMA and survival; European LeukemiaNet (ELN) genetic risk assignment was favorable 15%, intermediate 16%, and adverse 69%. Complete remission, with (CR) or without (CRi), count recovery, was documented in 182 (60%) patients. In multivariable analysis, inclusive of mutations only, "favorable" predictors of CR/CRi were NPM1 (86% vs. 56%), IDH2 (80% vs. 58%), and DDX41 (100% vs. 58%) and "unfavorable" TP53 (40% vs. 67%), FLT3-ITD (36% vs. 63%), and RUNX1 (44% vs. 64%) mutations; significance was sustained for each mutation after adjustment for age, karyotype, and therapy-related qualification. CR/CRi rates ranged from 36%, in the presence of unfavorable and absence of favorable mutation, to 91%, in the presence of favorable and absence of unfavorable mutation. At median follow-up of 8.5 months, 174 deaths and 41 allogeneic stem cell transplants (ASCT) were recorded. In multivariable analysis, risk factors for inferior survival included failure to achieve CR/CRi (HR 3.4, 95% CI 2.5-4.8), adverse karyotype (1.6, 1.1-2.6), TP53 mutation (1.6, 1.0-2.4), and absence of IDH2 mutation (2.2, 1.0-4.7); these risk factors were subsequently applied to construct an HR-weighted risk model that performed better than the ELN genetic risk model (AIC 1661 vs. 1750): low (n = 130; median survival 28.9 months), intermediate (n = 105; median 9.6 months), and high (n = 66; median 3.1 months; p < .001); survival in each risk category was significantly upgraded by ASCT. The current study identifies genotype signatures for predicting response and proposes a 3-tiered, CR/CRi-based, and genetics-enhanced survival model for AML patients receiving upfront therapy with Ven-HMA.

Venetoclax duration (14 vs. 21 vs. 28 days) in combination with hypomethylating agent in newly diagnosed acute myeloid leukemia: Comparative analysis of response, toxicity, and survival.

Overall survival and response rates of 270 patients with newly diagnosed acute myeloid leukemia receiving venetoclax (Ven) plus hypomethylating agent, stratified by Ven dosing schedule (Cycle 1 Ven 14 vs. 21 vs. 28 days).

Phase 1/1b study of azacitidine and hedgehog pathway inhibitor sonidegib in patients with myeloid neoplasms.

BACKGROUND: Myeloid neoplasms (myelodysplastic syndrome [MDS], myelofibrosis, and chronic myelomonocytic [CMML]) are aggressive hematological malignancies for which, despite recent approvals, novel therapies are needed to improve clinical outcomes. The hedgehog (HH) pathway is one of the main pathways for cancer stem cells survival and several HH inhibitors (HHi) are approved in clinical practice. METHODS: Sonidegib (SON), an oral HHi, was tested in this phase 1/1b trial in combination with azacitidine (AZA, 75 mg/m2 days ×7) in patients with newly diagnosed and relapsed/refractory (r/r) chronic MN or acute myeloid leukemia (AML). RESULTS: Sixty-two patients (28 [45%] newly diagnosed) were treated in this study, including 10 patients in the dose-finding component and 52 patients in phase 1b. SON 200 mg oral daily on days 1-28 each cycle was deemed the recommended dose for phase 1b. Out of 21 rrAML patients, two achieved response (one complete response/one morphologic leukemia-free state) with no responses seen in seven r/r MDS/CMML patients. In newly diagnosed AML/MDS, response was seen in six (three had complete remission, two had morphological leukemia-free status) of 27 patients. Median overall survival was 26.4 and 4.7 months for newly diagnosed MDS and AML, respectively. Safety was satisfactory with common (>20%) side effects including fatigue, constipation, nausea, cough, insomnia, and diarrhea. Only 7% of patients died in the study, and none of the deaths were deemed related to treatment. CONCLUSIONS: Our study shows that AZA + SON are a safe combination in a patient with MN. Similar to other hedgehog inhibitors, this combination yielded limited response rate in patients with myeloid neoplasms.

Disparities in receiving disease-directed therapy, allogeneic stem cell transplantation in non-Hispanic Black patients with TP53-mutated acute myeloid leukemia.

BACKGROUND: Although the clinical outcomes of patients with TP53-mutated acute myeloid leukemia (AML) are dismal, subsets of patients eligible for curative-intent therapies may fare better. Because racial disparities are known to affect outcome in hematologic malignancies, the authors sought to explore disparities among patients with TP53-mutated AML. METHODS: A multicenter, retrospective study was conducted in a cohort of 340 patients who had TP53-mutated AML (275 non-Hispanic White [NHW] and 65 non-Hispanic Black [NHB]) to analyze differences in treatment and outcome among NHW and NHB patients. RESULTS: The median patient age was comparable between NHW and NHB patients (p = .76). A higher proportion of NHB patients had therapy-related AML (31% vs. 20%; p = .08) and had co-mutations (74% vs. 61%; p = .06). A higher proportion of NHW patients received intensive chemotherapy compared with NHB patients (47% vs. 31%; p = .02). Conversely, a higher proportion of NHB patients received low-intensity chemotherapy (9% vs. 5.5%; p = .02) or best supportive care (22% vs. 7%; p < .001). The complete response rate (including complete responses with or without complete count recovery) was 31% versus 24.5% (p = .39) in NHW and NHB patients, respectively. Only 5% of NHB patients received allogeneic stem cell transplantation compared with 15.5% of NHW patients (p = .02). The proportion of patients who were event-free (18.5% vs. 8.5%; p = .49) or who remained alive (24.9% vs. 8.3%; p = .13) at 18 months was numerically higher in NHW versus NHB patients, respectively, but was not statistically significant. CONCLUSIONS: The current study highlights disparities between NHW and NHB patients with TP53-mutated AML. Efforts are warranted to eliminate treatment disparities in minority populations.

The clinical and molecular spectrum of ETV6 mutated myeloid neoplasms.

ETV6 mutations are rare but recurrent somatic events in myeloid neoplasms and are negatively prognostic in myelodysplastic syndrome. We set out to examine the clinical and molecular characteristics of patients undergoing investigation for myeloid neoplasms, found to have deleterious ETV6 mutations. ETV6 mutations occurred in 33 of 5793 (0.6%) cases investigated and predominantly in high-risk disease entities including MDS with increased blasts, primary myelofibrosis and AML, myelodysplasia-related. In three cases, isolated iso (17q) karyotype was concurrently detected, an otherwise rare karyotype in myeloid neoplasms. ETV6 mutations were frequently subclonal and never occurred as an isolated abnormality with ASXL1 (n = 22, 75%), SRSF2 (n = 14, 42%) and SETBP1 (n = 11, 33%) the predominant co-mutations. Restricting to patients with MDS, higher rates of ASXL1, SETBP1, RUNX1 and U2AF1 mutations occurred in ETV6 mutated cases, relative to a consecutive control cohort with wild-type ETV6. The median OS of the cohort was 17.5 months. This report highlights the clinical and molecular associations of somatic ETV6 mutations in myeloid neoplasms, suggests their occurrence as a later event, and proposes further translational research questions for their role in myeloid neoplasia.

Clinical and molecular correlates of somatic and germline DDX41 variants in patients and families with myeloid neoplasms.

The diagnosis of germline predisposition to myeloid neoplasms (MN) secondary to DDX41 variants is currently hindered by the long latency period, variable family histories and the frequent occurrence of DDX41 variants of uncertain significance (VUS). We reviewed 4,524 consecutive patients who underwent targeted sequencing for suspected or known MN and analyzed the clinical impact and relevance of DDX41VUS in comparison to DDX41path variants. Among 107 patients (44 [0.9%] DDX41path and 63 DDX41VUS [1.4%; 11 patients with both DDX41path and DDX41VUS]), we identified 17 unique DDX41path and 45 DDX41VUS variants: 24 (23%) and 77 (72%) patients had proven and presumed germline DDX41 variants, respectively. The median age was similar between DDX41path and DDX41VUS (66 vs. 62 years; P=0.41). The median variant allele frequency (VAF) (47% vs. 48%; P=0.62), frequency of somatic myeloid co-mutations (34% vs 25%; P= 0.28), cytogenetic abnormalities (16% vs. 12%; P=>0.99) and family history of hematological malignancies (20% vs. 33%; P=0.59) were comparable between the two groups. Time to treatment in months (1.53 vs. 0.3; P=0.16) and proportion of patients progressing to acute myeloid leukemia (14% vs. 11%; P=0.68), were similar. The median overall survival in patients with high-risk myelodysplastic syndrome/acute myloid leukemia was 63.4 and 55.7 months in the context of DDX41path and DDX41VUS, respectively (P=0.93). Comparable molecular profiles and clinical outcomes among DDX41path and DDX41VUS patients highlights the need for a comprehensive DDX41 variant interrogation/classification system, to improve surveillance and management strategies in patients and families with germline DDX41 predisposition syndromes.

Predictors of anemia response to momelotinib therapy in myelofibrosis and impact on survival.

We retrospectively reviewed 72 anemic patients with myelofibrosis (MF; median age 68 years), who were JAK2 inhibitor-naïve at the time of study entry to a phase-1/2 momelotinib clinical trial. Driver mutation profile included JAK2 69%, CALR 17%, MPL 8%, and triple-negative 6%; other mutations included ASXL1 39% and SRSF2 17%. Momelotinib was administered at a median dose of 300 mg daily. Anemia response was assessed by formal criteria and documented in 44% of all patients with hemoglobin levels below the sex-adjusted reference range (n = 72), 48% of those with hemoglobin <10 g/dl (n = 54), and 46% of those who were transfusion-dependent at the time of study entry (n = 28). Anemia response was more likely with post-essential thrombocythemia MF (83% vs 37%; p = .001), lower serum ferritin (p = .003), and shorter time from diagnosis to momelotinib therapy (p = .001); the first two variables were also predictive in transfusion-dependent patients. Post-momelotinib median survival was 3.2 years; in univariate analysis, survival was superior in anemia responders (median 3.8 vs. 2.8 years; p = .14) and in the presence of type 1/like CALR mutation and inferior in the presence of age > 65 years, ASXL1/SRSF2 mutation, unfavorable karyotype, DIPSS-plus high risk, red cell transfusion need and higher serum ferritin. Multivariable analysis confirmed the favorable impact of anemia response on survival (p = .02; HR 0.5, 3/5/10-year survival; 69%/38%/25%). This survival advantage was also noted in transfusion-dependent patients (3.7 vs. 1.9 years; p = .01; HR 0.3) and appeared to be restricted to patients with an unfavorable genetic profile. The current study suggests a short-term survival benefit associated with anemia response in momelotinib-treated patients with MF.

A phase II study of combination daunorubicin, cytarabine (Ara-c), and nilotinib (TAsigna) (DATA) in patients newly diagnosed with acute myeloid leukemia with KIT expression.

Acute myeloid leukemia (AML) is a challenging cancer in terms of achieving and maintaining long-duration remissions. Many novel therapies have been added to the standard regimen (combining cytarabine and anthracycline "7 + 3") to achieve such goals. Nilotinib is an oral multikinase inhibitor that is active against KIT tyrosine kinase, an important stem cell target. In this trial, we combined nilotinib with 7 + 3 induction (daunorubicin 60 mg/m2), high-dose cytarabine consolidation, and subsequently, if the patient was a candidate, for 2 years' maintenance therapy in patients with AML and KIT (CD117) expression. Patients were allowed to proceed to allogeneic hematopoietic cell transplantation (HCT) if deemed necessary. Our primary goal was increased complete remission rate with this combination. Thirty-four patients (with a median age 58.5 years) were enrolled on a single-arm phase II bi-institutional study; 21 (62%) patients achieved remission. The complete remission rate was 78% in evaluable patients. Thirteen of 34 (38%) patients had allogeneic HCT, all thirteen of which are still alive (100%). Common (>20%) grade 3 non-hematological toxicities included febrile neutropenia, hypophosphatemia, elevated liver enzymes, and hypertension. Only one patient (3%) died in induction due to liver failure, which was thought secondary to daunorubicin. Our current study reveals good outcomes in patients who received HCT and may warrant a larger study to confirm our findings in that specific population.

Cladribine therapy for advanced and indolent systemic mastocytosis: Mayo Clinic experience in 42 consecutive cases.

We describe our single institution experience with cladribine therapy in 42 patients with systemic mastocytosis (SM): 22 advanced (adv-SM; median age 65 years, 68% males) and 20 indolent/smouldering SM (ISM/SSM; median age 56 years, 45% males); subcategories included eight aggressive, 13 associated with another haematological neoplasm, one mast cell leukaemia, 17 ISM and three SSM. Overall/major response rates were 77%/45% for adv-SM and 70%/60% for ISM/SSM, and median (range) duration of response 10 (4-75) and 46 (4-140) months respectively. A >50% reduction in bone marrow mast cell burden and serum tryptase level was documented in 63% and 67% of patients with adv-SM and 50% and 46% with ISM/SSM respectively. The presence of KIT proto-oncogene, receptor tyrosine kinase (KIT)D816V predicted response in adv-SM: 17 (90%) of 19 with and none of three without the mutation responded (P < 0·01). Treatment-emergent adverse events were mostly limited to transient cytopenias: Grade 3/4 neutropenia, thrombocytopenia, or lymphopenia occurred in 27%, 27% and 27% of patients with adv-SM, and 5%, 5% and 30% with ISM/SSM respectively. The present study provides practical information that might be considered when making treatment choices between cladribine and newer KIT-targeted therapies and identifies the absence of KITD816V as a potential marker of cladribine resistance in advanced SM; the latter observation needs confirmation in a larger study.