Recent Progress in Chronic Neutrophilic Leukemia and Atypical Chronic Myeloid Leukemia

Analysis of CSF3R mutations in atypical chronic myeloid leukemia and other myeloid malignancies

We report a series of patients with CSF3R-mutant (CSF3Rmut) atypical chronic myeloid leukemia (aCML), chronic neutrophilic leukemia (CNL) or other hematologic malignancies. We included 25 patients: 5 aCML and 4 CNL CSF3Rmut patients; 1 aCML, 2 CNL, and 2 myelodysplastic/myeloproliferative neoplasm, not otherwise specified patients without CSF3R mutation; and 11 CSF3Rmut patients with other diseases [8 acute myeloid leukemia (AML), 1 chronic myelomonocytic leukemia (CMML), 1 myelodysplastic syndrome (MDS), and 1 acute lymphoblastic leukemia (ALL)]. Patients with aCML or CNL were tested by Sanger sequencing and pyrosequencing to identify CSF3R T618I. Twenty-two patients underwent gene panel analysis. CSF3R mutations, mostly T618I (8/9), were found at high frequencies in both aCML and CNL patients [5/6 aCML and 4/6 CNL]. Two aCML patients in early adulthood with CSF3R T618I and biallelic or homozygous CEBPA mutations without other mutations presented with increased blasts and exhibited remission for >6 years after transplantation. The other 7 CSF3Rmut aCML or CNL patients were elderly adults who all had ASXL1 mutations and frequently presented with SEBP1 and SRSF2 mutations. Five AML patients had CSF3R exon 14 or 15 point mutations, and 6 other patients (3 AML, 1 CMML, 1 MDS, and 1 ALL) had truncating mutations, demonstrating differences in leukocyte counts and mutation status. In conclusion, CSF3R mutations were found at a higher frequency in aCML patients than in previous studies, which might reflect ethnic differences. Additional studies are needed to confirm these findings and the relationship between CSF3R and CEBPA mutations.

The clinical regimens and cell membrane camouflaged nanodrug delivery systems in hematologic malignancies treatment

Hematologic malignancies (HMs), also referred to as hematological or blood cancers, pose significant threats to patients as they impact the blood, bone marrow, and lymphatic system. Despite significant clinical strategies using chemotherapy, radiotherapy, stem cell transplantation, targeted molecular therapy, or immunotherapy, the five-year overall survival of patients with HMs is still low. Fortunately, recent studies demonstrate that the nanodrug delivery system holds the potential to address these challenges and foster effective anti-HMs with precise treatment. In particular, cell membrane camouflaged nanodrug offers enhanced drug targeting, reduced toxicity and side effects, and/or improved immune response to HMs. This review firstly introduces the merits and demerits of clinical strategies in HMs treatment, and then summarizes the types, advantages, and disadvantages of current nanocarriers helping drug delivery in HMs treatment. Furthermore, the types, functions, and mechanisms of cell membrane fragments that help nanodrugs specifically targeted to and accumulate in HM lesions are introduced in detail. Finally, suggestions are given about their clinical translation and future designs on the surface of nanodrugs with multiple functions to improve therapeutic efficiency for cancers.

Case report: Chronic neutrophilic leukemia associated with monoclonal gammopathies. A case series and review of genetic characteristics and practical management

Chronic neutrophilic leukemia (CNL) is a rare but potentially aggressive BCR::ABL1 negative myeloproliferative neoplasm, characterized by sustained mature, neutrophilic leukocytosis. The discovery of key driver mutations in the colony-stimulating-factor-3 receptor (CSF3R) gene resulted in the updated World Health Organization (WHO) diagnostic criteria in 2016. A significant number of CNL cases have been associated with plasma cell dyscrasias, predominantly multiple myeloma (MM) and monoclonal gammopathy of unknown significance (MGUS). Compared to pure CNL, mutated CSF3R is infrequently reported in CNL cases associated with monoclonal gammopathies (MG). Until now it remains unclear whether CNL and occurring plasma cell neoplasms are clonally related or CNL is developing secondary to the underlying dyscrasia. Owing to its rarity, currently no standard of care management exists for CNL and MG-associated CNL. In this case series we report the multi-center experience of five MG-associated CNL cases with a median age of diagnosis of 69 years. Three patients (66%) showed predominance of lambda light chain expression. Four (80%) eventually evolved to MM, and one CNL-MGUS patient developed secondary acute myeloid leukemia (AML). Mutated CSF3R was present in the patient who developed AML but was absent in other cases. To assess possible associated genetic aberrations we performed recurrent analysis with next-generation sequencing (NGS). Two patients (40%) deceased with a median time of survival of 8 years after CNL diagnosis. Three (60%) are currently in follow-up with no reoccurring leukocytosis. This case series, followed by a short review, provides a long-term clinical and genetic overview of five CNL cases associated with MG.

International Consensus Classification of Myeloid Neoplasms and Acute Leukemias: integrating morphologic, clinical, and genomic data

The classification of myeloid neoplasms and acute leukemias was last updated in 2016 within a collaboration between the World Health Organization (WHO), the Society for Hematopathology, and the European Association for Haematopathology. This collaboration was primarily based on input from a clinical advisory committees (CACs) composed of pathologists, hematologists, oncologists, geneticists, and bioinformaticians from around the world. The recent advances in our understanding of the biology of hematologic malignancies, the experience with the use of the 2016 WHO classification in clinical practice, and the results of clinical trials have indicated the need for further revising and updating the classification. As a continuation of this CAC-based process, the authors, a group with expertise in the clinical, pathologic, and genetic aspects of these disorders, developed the International Consensus Classification (ICC) of myeloid neoplasms and acute leukemias. Using a multiparameter approach, the main objective of the consensus process was the definition of real disease entities, including the introduction of new entities and refined criteria for existing diagnostic categories, based on accumulated data. The ICC is aimed at facilitating diagnosis and prognostication of these neoplasms, improving treatment of affected patients, and allowing the design of innovative clinical trials.

Differential Implications of CSF3R Mutations in t(8;21) and CEBPA Double Mutated Acute Myeloid Leukemia

BACKGROUND

Few data are available exploring mutations of the colony-stimulating factor 3 receptor (CSF3R) in acute myeloid leukemia (AML) in an all-round and systematic manner. The purpose of this study was to analyze the CSF3R mutations (CSF3R_mut) in AML with recurrent genetic abnormalities for potential synergistic pathomechanism.

PATIENTS AND METHODS

We retrospectively screened 1102 adult de novo AML patients with available next-generation sequencing (NGS) information on 132 genes related to hematologic disorders. The χ², Mann-Whitney U tests were used to analyze their associations with clinicopathologic characteristics, and a propensity score matching (PSM) followed by Kaplan-Meier method was applied to measure their prognostic effects.

RESULTS

Overall, CSF3R_mut were detected in 40 (3.6%) of 1102 patients with adult de novo AML. CSF3R_mut were predominantly enriched in AML with the CEBPA double mutations (CEBPA_dm) (16/122, 13.1%), t(8;21) (12/186, 6.5%) and mutated RUNX1 (3/50, 6.0%), respectively. The CSF3R_mut loci and types differed according to AML subtypes, with frameshift-indels and premature stop confined in the t(8;21) AML [10/12 (83.3%)], and missense recurrently aggregated in the CEBPA_dm AML [16/16 (100%)]. Cases with CSF3R_mut had a lower WBC count versus those with CSF3R wild-type (CSF3R_wt) in the t(8;21) AML cohort, with a borderline significance [median 5.45 (range 0.94-20.30) × 10⁹/L) vs. 8.80 (range 0.96-155.00) × 10⁹/L, P = .046]. CSF3R_mut were non-significantly associated with higher WBC counts [median 33.6 (range 6.8-287.6) × 10⁹/L vs. 18.1 (range 1.7-196.0) × 10⁹/L, P = .156] and significantly with lower immunophenotypic CD15 positivity [0/8 (0%) vs. 44/80 (55%), P = .009] as compared to CSF3R_wt in the CEBPA_dm AML cohort. After propensity score matching followed by Kaplan-Meier analysis, CSF3R_mut cases had comparable disease-free survival (DFS) and overall survival (OS) to those with CSF3R_wt (P = .607 and P = .842, respectively) in the t(8;21) AML cohort. By contrast, CSF3R_mut showed an inclination towards inferior DFS compared to CSF3R_wt in the CEBPA_dm AML cohort [median DFS 19.8 (95%CI 3.1-36.5) months vs. not reached (NR), P = .086]. No significant difference was found for OS between CSF3R_mut and CSF3R_wt cases (P = .943).

CONCLUSION

We concluded that CSF3R_mut were frequently enriched in patients with t(8;21) and CEBPA_dm subtypes among AML, but showed divergent clinicopathologic features, mutation loci and types and differing prognostic aspects.

Current Management of Chronic Neutrophilic Leukemia

OPINION STATEMENT

Chronic neutrophilic leukemia (CNL) is a rare myeloproliferative neoplasm (MPN) characterized by oncogenic driver mutations in colony-stimulating factor 3 receptor (CSF3R). Due in large part to the rarity of the disease and dearth of clinical trials, there is currently no standard of care for CNL. Available therapies range from conventional oral chemotherapy to targeted JAK inhibitors to hematopoietic stem cell transplant (HSCT), the latter representing the only potentially curative modality. For this reason, coupled with CNL's typically aggressive clinical course, allogeneic HSCT remains the primary recommended therapy for eligible patients. For ineligible patients, a number of nontransplant therapies have been evaluated in limited trials. These agents may additionally be considered "bridging" therapies pre-transplant in order to control myeloproliferation and alleviate symptoms. Historically, the most commonly utilized first-line agent has been hydroxyurea, though most patients ultimately require second (or subsequent)-line therapy; still hydroxyurea remains the conventional frontline option. Dasatinib has demonstrated efficacy in vitro in cases of CSF3R terminal membrane truncation mutations and may cautiously be considered upfront in such instances, though no substantive studies have validated its efficacy in vivo. Numerous other chemotherapy agents, practically re-appropriated from the pharmaceutical arsenal of MPN, have been utilized in CNL and are typically reserved for second/subsequent-line settings; these include interferon-alpha (IFN-a), hypomethylating agents, thalidomide, cladribine, and imatinib, among others. Most recently, ruxolitinib, a JAK1/2 inhibitor targeting JAK-STAT signaling downstream from CSF3R, has emerged as a potentially promising new candidate for the treatment of CNL. Increasingly robust data support the clinical efficacy, with associated variable reductions in allele burden, and tolerability of ruxolitinib in patients with CNL, particularly those carrying the CSF3RT618I mutation. Similar to conventional nontransplant strategies, however, no disease-modifying or survival benefits have been demonstrated. While responses to JAK-STAT inhibition in CNL have not been uniform, data are sufficient to recommend consideration of ruxolitinib in the therapeutic repertory of CNL. There remains a major unmet need for prospective trials with investigational therapies in CNL.

Germ-Line TP53 Mutation in an Adolescent With CMML/Atypical CML and Familiar Cancer Predisposition

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Efficacy of Ruxolitinib in Patients With Chronic Neutrophilic Leukemia and Atypical Chronic Myeloid Leukemia

PURPOSE

Colony-stimulating factor-3 receptor (CSF3R)-T618I is a recurrent activating mutation in chronic neutrophilic leukemia (CNL) and to a lesser extent in atypical chronic myeloid leukemia (aCML) resulting in constitutive JAK-STAT signaling. We sought to evaluate safety and efficacy of the JAK1/2 inhibitor ruxolitinib in patients with CNL and aCML, irrespective of CSF3R mutation status.

METHODS

We conducted a phase II study of ruxolitinib in 44 patients (21 CNL and 23 aCML). The primary end point was overall hematologic response rate (ORR) by the end of 6 continuous 28-day cycles for the first 25 patients enrolled. We considered a response as either partial (PR) or complete response (CR). We expanded accrual to 44 patients to increase our ability to evaluate secondary end points, including grade ≥ 3 adverse events, spleen volume, symptom assessment, genetic correlates of response, and 2-year survival.

RESULTS

ORR was 32% for the first 25 enrolled patients (8 PR [7 CNL and 1 aCML]). In the larger cohort of 44 patients, 35% had a response (11 PR [9 CNL and 2 aCML] and 4 CR [CNL]), and 50% had oncogenic CSF3R mutations. The mean absolute allele burden reduction of CSF3R-T618I after 6 cycles was greatest in the CR group, compared with the PR and no response groups. The most common cause of death is due to disease progression. Grade ≥ 3 anemia and thrombocytopenia were observed in 34% and 14% of patients, respectively. No serious adverse events attributed to ruxolitinib were observed.

CONCLUSION

Ruxolitinib was well tolerated and demonstrated an estimated response rate of 32%. Patients with a diagnosis of CNL and/or harboring CSF3R-T618I were most likely to respond.

Defining the Boundary Between Myelodysplastic Syndromes and Myeloproliferative Neoplasms

In this article we provide a practical and comprehensive review of myeloid neoplasms with overlapping myelodysplastic (MDS) and myeloproliferative (MPN) features, with emphasis on recent updates in classification, particularly the utility of morphologic, cytogenetic, and molecular findings in better defining and classifying these disease entities. We provide the reader with a summary of the most recent developments and updates that have helped further our understanding of the genomic landscape, clinicopathologic features, and prognostic elements of myeloid neoplasms with MDS/MPN features.

Challenges in Myelodysplastic/Myeloproliferative Neoplasms (MDS/MPN)

Myelodysplastic/myeloproliferative neoplasms (MDS/MPN) are hybrid group of chronic myeloid neoplasms combining features of both MDS and MPN. The World Health Organization classification coined this group designation in 2008 to include chronic myelomonocytic leukemia, atypical chronic myeloid leukemia, juvenile myelomoncoytic leukemia, refractory anemia with ring sideroblasts and thrombocytosis as a provisional entity, and MDS/MPN unclassified. In this review, we highlight the challenges in diagnosing this group of the diseases, summarize the updates in classification, and discuss recent evolving understanding of the genetic landscape. We review risk-stratification models and overview the current management largely adapted from current MDS or MPN therapies. We define clinical benefit of therapy based on new proposed response criteria developed specifically for these groups of neoplasms. Finally, we introduce future opportunities including the planned international ABN MARRO (A Novel therapy combinations in untreated MDS/MPN And Relapsed/Refractory Overlap Syndromes) clinical study led by the MDS/MPN International Working Group.

Chronic neutrophilic leukemia: new science and new diagnostic criteria

Chronic neutrophilic leukemia (CNL) is a distinct myeloproliferative neoplasm defined by persistent, predominantly mature neutrophil proliferation, marrow granulocyte hyperplasia, and frequent splenomegaly. The seminal discovery of oncogenic driver mutations in CSF3R in the majority of patients with CNL in 2013 generated a new scientific framework for this disease as it deepened our understanding of its molecular pathogenesis, provided a biomarker for diagnosis, and rationalized management using novel targeted therapies. Consequently, in 2016, the World Health Organization (WHO) revised the diagnostic criteria for CNL to reflect such changes in its genomic landscape, now including the presence of disease-defining activating CSF3R mutations as a key diagnostic component of CNL. In this communication, we provide a background on the history of CNL, its clinical and hemopathologic features, and its molecular anatomy, including relevant additional genetic lesions and their significance. We also outline the recently updated WHO diagnostic criteria for CNL. Further, the natural history of the disease is reviewed as well as potential prognostic variables. Finally, we summarize and discuss current treatment options as well as prospective novel therapeutic targets in hopes that they will yield meaningful improvements in patient management and outcomes.