Molecular Taxonomy of Myelodysplastic Syndromes and its Clinical Implications.

Myelodysplastic syndromes/neoplasms (MDS) are clonal hematologic disorders characterized by morphologic abnormalities of myeloid cells and peripheral cytopenias. While genetic abnormalities underlie the pathogenesis of these disorders and their heterogeneity, current classifications of MDS rely predominantly on morphology. We performed genomic profiling of 3,233 patients with MDS or related disorders to delineate molecular subtypes and define their clinical implications. Gene mutations, copy-number alterations (CNAs), and copy-neutral loss of heterozygosity (cnLOH) were derived from targeted sequencing of a 152-gene panel, with abnormalities identified in 91, 43, and 11% of patients, respectively. We characterized 16 molecular groups, encompassing 86% of patients, using information from 21 genes, 6 cytogenetic events, and LOH at the TP53 and TET2 loci. Two residual groups defined by negative findings (molecularly not-otherwise specified, absence of recurrent drivers) comprised 14% of patients. The groups varied in size from 0.5% to 14% of patients and were associated with distinct clinical phenotypes and outcomes. The median bone marrow blast percentage across groups ranged from 1.5 to 10%, and the median overall survival from 0.9 to 8.2 years. We validated 5 well-characterized entities, added further evidence to support 3 previously reported subsets, and described 8 novel groups. The prognostic influence of bone marrow blasts depended on the genetic subtypes. Within genetic subgroups, therapy-related MDS and myelodysplastic/myeloproliferative neoplasms (MDS/MPN) had comparable clinical and outcome profiles to primary MDS. In conclusion, genetically-derived subgroups of MDS are clinically relevant and may inform future classification schemas and translational therapeutic research.

Molecular and clinical presentation of UBA1-mutated myelodysplastic syndromes.

Mutations in UBA1, which are disease-defining for VEXAS syndrome, have been reported in patients diagnosed with myelodysplastic syndromes (MDS). Here, we define the prevalence and clinical associations of UBA1 mutations in a representative cohort of patients with MDS. Digital droplet PCR profiling of a selected cohort of 375 male patients lacking MDS disease-defining mutations or established WHO disease classification identified 28 patients (7%) with UBA1 p.M41T/V/L mutations. Using targeted sequencing of UBA1 in a representative MDS cohort (n=2,027), we identified an additional 27 variants in 26 patients (1%), which we classified as likely/pathogenic (n=12) and unknown significance (n=15). Among the total 40 patients with likely/pathogenic variants (2%), all were male and 63% were classified by WHO2016 as MDS-MLD/SLD. Patients had a median of one additional myeloid gene mutation, often in TET2 (n=12), DNMT3A (n=10), ASXL1 (n=3), or SF3B1 (n=3). Retrospective clinical review where possible showed that 83% (28/34) UBA1-mutant cases had VEXAS-associated diagnoses or inflammatory clinical presentation. The prevalence of UBA1-mutations in MDS patients argues for systematic screening for UBA1 in the management of MDS.

What is next beyond janus kinase 2 inhibitors for primary myelofibrosis?

PURPOSE OF REVIEW: Although the approval of the janus kinase (JAK) inhibitor ruxolitinib for therapy of patients with myelofibrosis represents an important step in the development of targeted therapy for these patients, JAK inhibitors do not eradicate the disease, and a review of novel agents with mechanisms of action complementary to JAK2 enzymatic inhibition is timely. RECENT FINDINGS: There are several compounds with different mechanisms of action undergoing preclinical and clinical testing in myelofibrosis. Heat shock protein inhibitors and histone deacetylase inhibitors induce JAK2 degradation and downregulation of intracellular oncogenic signalling, and may overcome resistance to JAK2 inhibitors. Reversal of bone marrow fibrosis is still a therapeutic challenge in this disease, and mAbs targeting transforming growth factor-ß and lysyl oxidase like-2 may prove efficacious. Promising compounds inhibiting signal transducer and activator of transcription 5 activity and inducing megakaryocyte polyploidization are in preclinical testing. SUMMARY: Although none of these new drugs have been approved for therapy of myelofibrosis, their activity is being tested in clinical trials, alone or in combination with JAK2 inhibitors. Patients with myelofibrosis should be encouraged to participate in clinical trials testing novel compounds for this disorder, particularly if they have failed a trial of JAK2 inhibitors.

Results of allogeneic hematopoietic stem cell transplantation for chronic myelogenous leukemia patients who failed tyrosine kinase inhibitors after developing BCR-ABL1 kinase domain mutations.

Hematopoietic stem cell transplantation (HSCT) is effective therapy for patients with chronic myelogenous leukemia (CML) but is now mostly indicated for patients who develop resistance to tyrosine kinase inhibitors (TKIs), which can be associated with point mutations in BCR-ABL1. We reviewed the outcomes of imatinib-resistant CML patients (chronic phase, n = 34; accelerated phase [AP], n = 9; and blast phase [BP], n = 4) who underwent HSCT and had BCR-ABL1 sequencing. Mutations were found in 19 patients (40%); 15 of 19 had advanced CML (AP + BP + second chronic phase). Patients with mutations were more likely to transform to AP/BP at time of imatinib failure (69% vs 35%, P = .03). Forty-two patients (89%) responded to HSCT: 32 (68%) had at least a major molecular response. The 2-year event-free survival was 36% and 58% (P = .05) for the mutant and nonmutant groups, respectively; and the 2-year overall survival was 44% and 76% (P = .02), respectively. HSCT is an important salvage option for TKI-resistant patients with or without BCR-ABL1 mutations. Patients with mutations were more likely to develop advanced disease and had worse outcomes after HSCT. HSCT should be considered early for patients deemed to have a low probability of responding to second-generation TKI.

Characteristics and outcome of patients with acute myeloid leukemia refractory to 1 cycle of high-dose cytarabine-based induction chemotherapy.

Pretreatment characteristics and outcome of patients treated with induction regimens containing high-dose ara-C (HiDAC) at M. D. Anderson Cancer Center refractory to 1 cycle of induction were compared with similar patients achieving a complete response (CR). Among 1597 patients treated with HiDAC-based induction from 1995 to 2009, 285 were refractory to 1 cycle. Median age was 59 years (range, 18-85 years). Induction regimens included HiDAC with anthracyclines (n = 181; 64%) or HiDAC with nonanthracycline chemotherapy (n = 104; 36%). Refractory patients were older (median age, 59 vs 56 years; P < .001), more likely with unfavorable cytogenetics (P < .001) and antecedent hematologic disorder (P < .001), and had a higher presentation white blood cell count (P = .04), but not a higher incidence of FLT3 mutations (P = .85), than those achieving CR. Forty-three patients (22%) responded to salvage (35 CR and 8 CR without platelet recovery). With a median follow-up of 72 months (range, 27-118 months) in responders, 11 are alive. Nineteen patients (7%) were alive and in CR for at least 6 months, including 9 who underwent allogeneic stem cell transplantation. On multivariate analysis, severe thrombocytopenia, leukocytosis, increasing marrow blast percentage, unfavorable cytogenetics, and salvage not including allogeneic stem cell transplantation were associated with a worse survival. Alternative strategies are needed for these patients.

Phase 2 study of CEP-701, an orally available JAK2 inhibitor, in patients with primary or post-polycythemia vera/essential thrombocythemia myelofibrosis.

Few treatment options exist for patients with myelofibrosis (MF), and their survival is significantly shortened. Activating mutation of the JAK2 tyrosine kinase (JAK2(V617F)) is found in approximately 50% of MF patients. CEP-701 is a tyrosine kinase inhibitor that inhibits JAK2 in in vitro and in vivo experiments. We conducted a phase 2 clinical study of CEP-701 in 22 JAK2(V617F)-positive MF patients (80 mg orally twice daily), and 6 (27%) responded by International Working Group criteria (clinical improvement in all cases): reduction in spleen size only (n = 3), transfusion independency (n = 2), and reduction in spleen size with improvement in cytopenias (n = 1). Median time to response was 3 months, and duration of response was more than or equal to 14 months. No improvement was seen in bone marrow fibrosis or JAK2(V617F) allele burden. Phosphorylated STAT3 levels decreased from baseline in responders while on therapy. Eight patients (36%) experienced grade 3 or 4 toxicity, and 6 (27%) required dose reduction. Main side effects were myelosuppression (grade 3 or 4 anemia, 14%; and thrombocytopenia, 23%) and gastrointestinal disturbances (diarrhea, any grade, 72%; grade 3 or 4, 9%; nausea, grade 1 or 2 only, 50%; vomiting, grade 1 or 2 only, 27%). In conclusion, CEP-701 resulted in modest efficacy and mild but frequent gastrointestinal toxicity in MF patients. The study was registered at http://clinicaltrials.gov as NCT00494585.

Molecular Characterization of a First-in-Human Clinical Response to Nimesulide in Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is a hematologic malignancy associated with high morbidity and mortality. Here we describe a case of a patient with AML who presented a partial response after utilization of the non-steroidal anti-inflammatory drug nimesulide. The response was characterized by complete clearance of peripheral blood blasts and an 82% decrease of bone marrow blasts associated with myeloblast differentiation. We have then shown that nimesulide induces in vitro cell death and cell cycle arrest in all AML cell lines (HL-60, THP-1, OCI-AML2, and OCI-AML3). Weighted Correlation Network Analysis (WGCNA) of serial whole-transcriptome data of cell lines treated with nimesulide revealed that the sets of genes upregulated after treatment with nimesulide were enriched for genes associated with autophagy and apoptosis, and on the other hand, the sets of downregulated genes were associated with cell cycle and RNA splicing. Serial transcriptome of bone marrow patient sample confirmed the upregulation of genes associated with autophagy after the response to nimesulide. Lastly, we demonstrated that nimesulide potentiates the cytotoxic in vitro effect of several Food and Drug Administration (FDA)-approved chemotherapy drugs used in AML, including cytarabine.

Molecular International Prognostic Scoring System for Myelodysplastic Syndromes.

BACKGROUND: Risk stratification and therapeutic decision-making for myelodysplastic syndromes (MDS) are based on the International Prognostic Scoring System­Revised (IPSS-R), which considers hematologic parameters and cytogenetic abnormalities. Somatic gene mutations are not yet used in the risk stratification of patients with MDS. METHODS: To develop a clinical-molecular prognostic model (IPSS-Molecular [IPSS-M]), pretreatment diagnostic or peridiagnostic samples from 2957 patients with MDS were profiled for mutations in 152 genes. Clinical and molecular variables were evaluated for associations with leukemia-free survival, leukemic transformation, and overall survival. Feature selection was applied to determine the set of independent IPSS-M prognostic variables. The relative weights of the selected variables were estimated using a robust Cox multivariable model adjusted for confounders. The IPSS-M was validated in an external cohort of 754 Japanese patients with MDS. RESULTS: We mapped at least one oncogenic genomic alteration in 94% of patients with MDS. Multivariable analysis identified TP53multihit, FLT3 mutations, and MLLPTD as top genetic predictors of adverse outcomes. Conversely, SF3B1 mutations were associated with favorable outcomes, but this was modulated by patterns of comutation. Using hematologic parameters, cytogenetic abnormalities, and somatic mutations of 31 genes, the IPSS-M resulted in a unique risk score for individual patients. We further derived six IPSS-M risk categories with prognostic differences. Compared with the IPSS-R, the IPSS-M improved prognostic discrimination across all clinical end points and restratified 46% of patients. The IPSS-M was applicable in primary and secondary/therapy-related MDS. To simplify clinical use of the IPSS-M, we developed an open-access Web calculator that accounts for missing values. CONCLUSIONS: Combining genomic profiling with hematologic and cytogenetic parameters, the IPSS-M improves the risk stratification of patients with MDS and represents a valuable tool for clinical decision-making. (Funded by Celgene Corporation through the MDS Foundation, the Josie Robertson Investigators Program, the Edward P. Evans Foundation, the Projects of National Relevance of the Italian Ministry of University and Research, Associazione Italiana per la Ricerca sul Cancro, the Japan Agency for Medical Research and Development, Cancer Research UK, the Austrian Science Fund, the MEXT [Japanese Ministry of Education, Culture, Sports, Science and Technology] Program for Promoting Research on the Supercomputer Fugaku, the Japan Society for the Promotion of Science, the Taiwan Department of Health, and Celgene Corporation through the MDS Foundation.)

Clinical impact of dose reductions and interruptions of second-generation tyrosine kinase inhibitors in patients with chronic myeloid leukaemia.

Second (2nd)-generation tyrosine kinase inhibitors (TKI) (dasatinib, nilotinib) are effective in patients with all phases of chronic myeloid leukaemia (CML). Dose reductions and treatment interruptions are frequently required due to toxicity, but their significance is unknown. We analysed the impact of dose reductions/interruptions and dose intensity of 2nd-generation TKI on response and survival. A total of 280 patients with CML (all phases) were analysed. Dose reductions were considered when the daily dose was below the standard dose. Dose intensity was determined based on the percentage of the ideal dose intensity. Overall, 176 patients (63%) required treatment interruptions and/or dose reduction at least once during therapy. Dose reductions/interruptions, analysed as a time-dependent covariate, were associated with worse failure-free survival only in patients with untreated CML. Dose intensity analysis did not reveal a worse response or survival in patients who received a lower dose intensity (<100%) during therapy or during the first 6 months. In conclusion, dose reductions and treatment interruptions of 2nd generation TKI in patients with CML have a minimal impact in the response rate and survival of these patients. Further studies are required to determine whether there might be a minimum adequate dose of these agents.

Prognostic impact of RAS-pathway mutations in patients with myelofibrosis.

RAS-pathway mutations are recurrent events in myeloid malignancies. However, there is limited data on the significance of RAS-pathway mutations in patients with myelofibrosis (MF). We analyzed next-generation sequencing data of 16 genes, including RAS-pathway genes, from 723 patients with primary and secondary MF across three international centers and evaluated their significance. N/KRAS variants were present in 6% of patients and were typically sub-clonal (median VAF = 20%) relative to other genes variants. RAS variants were associated with advanced MF features including leukocytosis (p = 0.02), high somatic mutation burden (p < 0.01) and the presence of established "molecular high-risk" (MHR) mutations. MF patients with N/KRAS mutations had shorter 3-year overall survival (OS) (34% vs 58%, p < 0.001) and higher incidence of acute myeloid leukemia at 3 years (18% vs 11%, p = 0.03). In a multivariate Cox model, RAS mutations were associated with decreased OS (HR 1.93, p < 0.001). We created a novel score to predict OS incorporating RAS mutations, and it predicted OS across training and validation cohorts. Patients with intermediate risk/high-risk DIPSS with RAS mutations who received ruxolitinib had a nonsignificant longer 2-year OS relative to those who did not receive ruxolitinib. These data demonstrate the importance of identifying RAS mutations in MF patients.

Implications of TP53 allelic state for genome stability, clinical presentation and outcomes in myelodysplastic syndromes.

Tumor protein p53 (TP53) is the most frequently mutated gene in cancer1,2. In patients with myelodysplastic syndromes (MDS), TP53 mutations are associated with high-risk disease3,4, rapid transformation to acute myeloid leukemia (AML)5, resistance to conventional therapies6-8 and dismal outcomes9. Consistent with the tumor-suppressive role of TP53, patients harbor both mono- and biallelic mutations10. However, the biological and clinical implications of TP53 allelic state have not been fully investigated in MDS or any other cancer type. We analyzed 3,324 patients with MDS for TP53 mutations and allelic imbalances and delineated two subsets of patients with distinct phenotypes and outcomes. One-third of TP53-mutated patients had monoallelic mutations whereas two-thirds had multiple hits (multi-hit) consistent with biallelic targeting. Established associations with complex karyotype, few co-occurring mutations, high-risk presentation and poor outcomes were specific to multi-hit patients only. TP53 multi-hit state predicted risk of death and leukemic transformation independently of the Revised International Prognostic Scoring System (IPSS-R)11. Surprisingly, monoallelic patients did not differ from TP53 wild-type patients in outcomes and response to therapy. This study shows that consideration of TP53 allelic state is critical for diagnostic and prognostic precision in MDS as well as in future correlative studies of treatment response.

Challenges and opportunities in primary CNS lymphoma: A systematic review.

BACKGROUND: Historically, high-dose methotrexate (HD-MTX) plus consolidation chemotherapy and/or whole brain radiotherapy (WBRT) has been the gold standard on Primary Central Nervous System Lymphoma (PCNSL) management. We sought to examine and summarize the data, on clinical trial (CT) setting, investigating multi-modality treatment to PCNSL. METHODS: We performed a systematic review of electronic databases (Medline, EMBASE, Cochrane Database and clinicaltrials.gov) and a manual search to identify original PCNSL phase 2 and phase 3 CT from the last 10years. After a 4stage Prisma based selection process, 32 published (3 Randomized CT and 29 phases 2 CT) studies ultimately were selected for review. Four ongoing clinical trials found on clinicaltrial.gov were reviewed. Two investigators reviewed titles, abstracts, and articles independently. Two investigators abstracted data sequentially and evaluated each study independently. FINDINGS: Treatment of PCNSL requires a multidisciplinary approach. HD-MTX represents the most accepted standard of care induction therapy for newly diagnosed PCNSL. When HD-MTX is given with WBRT for consolidation delayed neurotoxicity can be an important complication, particularly in elderly patients. Studies have suggested that WBRT may be deferred until relapse without compromising survival and deferring WBRT may be the best approach in elderly patients. Results from dose-reduced WBRT and consolidative HD-Ara-C are encouraging. High-dose chemotherapy in combination with autologous stem cell transplantation (HDC-ASCT) as chemotherapy alone has emerged as an important consolidative treatment for selected population. The optimal salvage therapy is still to be defined. CONCLUSION: WBRT for consolidation is a well-studied modality; however emerging options to selected population such as HDC-ASCT, dose-reduced WBRT or chemotherapy alone are associated with similar survival outcome and less neurotoxicity in selected series. Ongoing and future clinical trials will better define the best approach on this rare disease.

Efficacy of ruxolitinib for myelofibrosis.

INTRODUCTION: The discovery of the activating JAK2 V617F mutation in patients with myelofibrosis (MF) led to the development of JAK2 inhibitors. The first such inhibitor to enter clinical trials was ruxolitinib . This review summarizes preclinical and clinical data of ruxolitinib in MF. AREAS COVERED: A literature search through Medline employing the terms 'ruxolitinib,' 'INCB018424' and 'myelofibrosis' was undertaken. The results from Phase I/II studies in patients with MF showed that ruxolitinib led to durable improvements in splenomegaly, and symptoms associated with MF. Two Phase III trials have compared ruxolitinib against placebo and best available therapy, and in both studies ruxolitinib demonstrated superior rates of spleen control and symptom improvement, and additional analysis demonstrated a survival benefit with ruxolitinib treatment. The main toxicities seen with ruxolitinib are cytopenias, which are managed with dose adjustments. Recent reports documented sporadic cases of immunosuppression-related infections. Ruxolitinib is the first drug ever approved for the therapy of patients with MF. EXPERT OPINION: Understanding the factors that predict the rate and duration of response to ruxolitinib would improve our ability to manage patients treated with this medication. Clinical trials combining ruxolitinib with novel compounds that are also active in MF will further improve therapy for this disease.

Splenectomy in patients with myeloproliferative neoplasms: efficacy, complications and impact on survival and transformation.

Splenectomy may be an effective therapeutic option for treating massive splenomegaly in patients with myeloproliferative neoplasms (MPNs). There are still limited data on its short- and long-term benefits and risks. Efficacy and short-term complications were analyzed in 94 patients with different MPNs who underwent splenectomy at M. D. Anderson Cancer Center. The long-term impact of splenectomy on overall survival (OS) and transformation free survival (TFS) was evaluated in 461 patients with myelofibrosis (MF) seen at M. D. Anderson, including 50 who underwent splenectomy during disease evolution. Splenectomy improved anemia and thrombocytopenia in 47% and 66% of patients, respectively. The most common complications were leukocytosis (76%), thrombocytosis (43%) and venous thromboembolism (16%). Post-operative mortality was 5%. Among patients with MF, splenectomy during disease evolution was associated with decreased OS (hazard ratio [HR] = 2.17, p < 0.0001) and TFS (HR = 2.17, p < 0.0001). This effect was independent of the Dynamic International Prognostic Scoring System. Splenectomy is a possible therapeutic option for patients with MF and other MPNs, and its greatest benefits are related to improvement in spleen pain and discomfort, anemia and thrombocytopenia. However, in patients with MF it appears to be associated with increased mortality.

Breakthroughs in myeloproliferative neoplasms.

The discovery of the JAK2V617F mutation ushered the field of Philadelphia-negative myeloproliferative neoplasms (MPNs) into the era of targeted therapy. Currently, there are several JAK2 inhibitors in clinical trials for patients with MPNs, particularly for patients with myelofibrosis (MF). These drugs act by blocking the proliferation of neoplastic cells by disrupting the JAK2-STAT signaling and by abrogating inflammatory cytokine signaling which is dependent on JAK kinases. Therapy with JAK2 inhibitors can improve splenomegaly and debilitating constitutional symptoms in great majority of MF patients, improving greatly their quality of life. Long-term follow-up will reveal whether these drugs can also prolong survival by better controlling signs and symptoms of the MF. There are other compounds in clinical trials for MPNs, including the new immunomodulatory drug pomalidomide, and inhibitor of mammalian target of Rapamycin everolimus. In this article, we briefly review the latest therapeutic advances in the field of Philadelphia-negative MPNs.

Therapy with JAK2 inhibitors for myeloproliferative neoplasms.

The development of JAK2 inhibitors followed the discovery of activating mutation of JAK2 (JAK2V617F) in patients with classic Philadelphia-negative myeloproliferative neoplasms (Ph-negative MPN). It is now known that mutations activating the JAK-STAT pathway are ubiquitous in Ph-negative MPN, and that the deregulated JAK-STAT pathway plays a central role in the pathogenesis of these disorders. JAK2 inhibitors thus are effective in patients both with and without the JAK2V617F mutation. This article reviews the rationale for using JAK2 inhibitors in Ph-negative MPN, and the results of more recent clinical trials with these drugs.