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.

Molecular International Prognostic Scoring System for Myelodysplastic Syndromes

MDS Molecular International Prognostic Scoring SystemSamples from over 2500 patients with MDS were profiled for gene mutations and used to develop the International Prognostic Scoring System-Molecular (IPSS-M). TP53multihit, FLT3 mutations, and MLLPTD were identified as top genetic predictors of adverse outcomes. IPSS-M improves prognostic discrimination across all clinical end points versus prior versions.

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.

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.

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.

Pre-analytical parameters associated with unsuccessful karyotyping in myeloid neoplasm: a study of 421 samples

Cytogenetics is essential in myeloid neoplasms (MN) and pre-analytical variables are important for karyotyping. We assessed the relationship between pre-analytical variables (time from collection to sample processing, material type, sample cellularity, and diagnosis) and failures of karyotyping. Bone marrow (BM, n=352) and peripheral blood (PB, n=69) samples were analyzed from acute myeloid leukemia (n=113), myelodysplastic syndromes (n=73), myelodysplastic syndromes/myeloproliferative neoplasms (n=17), myeloproliferative neoplasms (n=137), and other with conclusive diagnosis (n=6), and reactive disorders/no conclusive diagnosis (n=75). The rate of unsuccessful karyotyping was 18.5% and was associated with the use of PB and a low number of nucleated cells (≤7×10³/µL) in the sample. High and low cellularity in BM and high and low cellularity in PB samples showed no metaphases in 3.9, 39.7, 41.9, and 84.6% of cases, respectively. Collecting a good BM sample is the key for the success of karyotyping in MN and avoids the use of expensive molecular techniques.

Hepatic and cardiac and iron overload detected by T2* magnetic resonance (MRI) in patients with myelodisplastic syndrome: A cross-sectional study

INTRODUCTION

Transfusion-dependent anemia and iron overload are associatedwith reduced survival in myelodysplastic syndrome (MDS). This cross-sectional study aimed to evaluate the prevalence of hepatic and cardiac overload in patients with MDS as measured by T2* magnetic resonance imaging (MRI), and its correlation with survival.

METHODS

MDS or chronic myelomonocytic leukemia patients had iron overload evaluated by T2* MRI. HIO was considered when hepatic iron concentration ≥ 2 g/mg. Cardiac iron overload was considered with a T2*-value < 20 ms.

RESULTS

Among 71 patients analyzed, median hepatic iron concentration was 3.9 g/mg (range 0.9-16 g/mg), and 68%of patients had hepatic iron overload. Patients with hepatic iron overload had higher mean ferritin levels (1182 ng/mL versus 185 ng/mL, p < 0.0001), transferrin saturation (76% versus 34%, p < 0.0001) and lower survival rates. Median cardiac T2*value was 42 ms (range 19.7-70.1 ms), and only one patienthad a T2* value indicative of cardiac iron overload.

CONCLUSIONS

Hepatic iron overload is found in two thirds of patients, even in cases without laboratory signs of iron overload. Hepatic iron overload by T2* MRI is associated with a decreased risk of survival in patients with MDS.

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.

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-β 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.

JAK2 inhibitors for myelofibrosis: why are they effective in patients with and without JAK2V617F mutation?

An activating mutation (V617F) in the pseudokinase domain of the Janus kinase (JAK)-2 tyrosine kinase has been described in 90% of patients with polycythemia vera (PV) and 50% of patients with essential thrombocythemia (ET) and primary myelofibrosis (MF). The discovery of JAK2V617F stirred the development of JAK2 inhibitors for treatment of patients with MF, ET and PV. Similar to other tyrosine kinase (TK) inhibitors in current use, JAK2 inhibitors target the adenosine triphosphate (ATP) binding site at the TK domain and not the pseudokinase domain, thus affecting both mutated and wild-type kinases. In fact, clinical trials of these compounds have demonstrated improvements in constitutional symptoms and splenomegaly in patients with both mutated and wild-type JAK2 MF. It is believed that these drugs may act not only through inhibition of neoplastic cell proliferation, but also by downregulating signaling through proinflammatory cytokine receptors. In this article, we review the current state of JAK2 inhibitors and discuss why these drugs could be a valuable addition to the treatment armamentarium for patients with and without the JAK2V617F mutation.

Dasatinib for the treatment of Philadelphia chromosome-positive leukemias

INTRODUCTION

Dasatinib is a dual Abl/Src tyrosine kinase inhibitor (TKI), which was developed to treat patients with chronic myelogenous leukemia (CML), who had failed or were intolerant to therapy with imatinib.

AREAS COVERED

In this article, we review preclinical and clinical studies with dasatinib for the therapy of Philadelphia (Ph)-positive leukemias.

EXPERT OPINION

Dasatinib is very effective in the setting of CML resistance or intolerance to imatinib, particularly in patients in chronic phase (CP). Dasatinib is also effective against most BCR-ABL1 mutations that arise during therapy with imatinib. Further studies have confirmed activity of dasatinib as a single-agent, and combined with chemotherapy, for the treatment of patients with Philadelphia-positive acute lymphoblastic leukemia (Ph+-ALL). More recently, randomized trials have demonstrated that dasatinib is superior to imatinib in the initial therapy of patients with CML, and the drug was approved by the FDA for this indication in 2011.

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.

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.

Evolution of therapies for chronic myelogenous leukemia

The clinical outcome for patients with chronic myelogenous leukemia (CML) has changed dramatically in the past 15 years. This has been due to the development of tyrosine kinase inhibitors (TKIs), compounds that inhibit the activity of the oncogenic BCR-ABL1 protein. Imatinib was the first TKI developed for CML, and it led to high rates of complete cytogenetic responses and improved survival for patients with this disease. However, approximately 35% of patients in chronic phase treated with imatinib will develop resistance or intolerance to this drug. The recognition of the problem of imatinib failure led to the design of second-generation TKI (dasatinib, nilotinib, and bosutinib). These drugs are highly active in the scenario of imatinib resistance or intolerance. More recently, both nilotinib and dasatinib were approved for frontline use in patients with chronic phase CML. Ponatinib represents the last generation of TKI, and this drug has been developed with the aim of targeting a specific BCR-ABL1 mutation (T315I), which arises in the setting of prolonged TKI therapy and leads to resistance to all commercially available TKI. Parallel to the development of specific drugs for treating CML, major advances were made in the field of disease monitoring and standardization of response criteria. In this review, we summarize how therapy with TKI for CML has evolved during the last decade.

Pilot study of bortezomib for patients with imatinib-refractory chronic myeloid leukemia in chronic or accelerated phase

BACKGROUND

Proteasome inhibitors are anticancer compounds that disrupt the proteolytic activity of the proteasome and lead to tumor cell growth arrest and apoptosis. Bortezomib is a proteasome inhibitor that is currently approved for use in multiple myeloma (MM) and mantle-cell lymphoma. It induces apoptosis of chronic myeloid leukemia (CML) cells in vitro, but the activity of bortezomib in patients with imatinib-resistant CML is unknown.

METHODS

We conducted a pilot trial to evaluate the activity of single-agent bortezomib in CML. Seven patients with imatinib-refractory CML were treated with bortezomib at a dose of 1.5 mg/m2 on days 1, 4, 8, and 11 every 3 weeks.

RESULTS

The median number of cycles received was 2. No patient had a hematologic or cytogenetic response. Three patients had a temporary decrease in basophil counts associated with therapy with bortezomib. Six patients experienced grade 3/4 nonhematologic toxicities.

CONCLUSION

Bortezomib had minimal efficacy and considerable toxicity in patients with imatinib-refractory CML. Further studies should focus on alternative approaches to using proteasome inhibitors in the treatment of CML, such as in combination with tyrosine kinase inhibitors (TKIs) or as a strategy to eradicate leukemic stem cells.

New drugs for chronic myelogenous leukemia

The introduction of tyrosine kinase inhibitors (TKIs) has changed the landscape of therapy for chronic myelogenous leukemia (CML). Once considered an incurable malignancy, CML now has become a manageable chronic condition. Despite the great advances that imatinib has brought to the treatment of CML, some patients still develop resistance to imatinib and other TKIs, such as dasatinib and nilotinib. Furthermore, none of the clinically available TKIs is capable of eradicating leukemia stem cells and therefore curing CML. Several new compounds have been developed in recent years in an attempt to manage TKI-resistant CML. These include third-generation TKIs (ponatinib, danusertib) and even old compounds such as omacetaxine, which were developed before imatinib and now find a possible niche in the treatment of imatinib-resistant CML. We review the current preclinical and clinical data on the most promising new compounds for the treatment of CML.

JAK2 inhibitors: are they the solution?

The discovery of the JAK2V617F mutation in patients with Philadelphia-negative myeloproliferative neoplasms (Ph-negative MPN) started the era of targeted therapy for these diseases. Until now, patients had few treatment options available, which usually were restricted to hydroxyurea, interferon preparations, and chemotherapy in more aggressive cases. JAK2 inhibitors have been developed over the past 5 years, and the results of the first clinical trials with JAK2 inhibitors for patients with myelofibrosis were recently published. Current research results suggest that JAK2 inhibitors have a potential to decrease disease burden and its activity, as manifested by a decrease in splenomegaly and improvement in systemic disease-related symptoms, but they do not seem to be able to eradicate the malignant clone. However, JAK2 inhibitors help patients regardless of their mutation status, because patients without JAK2V617F mutation benefit to the same extent as patients with JAK2V617F mutation. A greater understanding of the pathophysiology of MPNs is needed before we can cure myelofibrosis with drug therapy. Currently, several new JAK2 inhibitors are in clinical trials for patients with myelofibrosis, and clinical trials for patients with polycythemia vera and essential thrombocythemia have also started. We review recent data on JAK2 inhibitors for the management of patients with Ph-negative MPNs.

The search for better prognostic models in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a group of heterogeneous bone marrow disorders characterized by a failure of hematopoiesis and an increased propensity for transformation to acute myeloid leukemia. Determining the prognosis of patients with MDS is essential for discerning the best therapy, which can vary from supportive care to allogeneic stem cell transplantation. The most widely used prognostic model in MDS is the International Prognostic Scoring System (IPSS), which estimates survival and risk of transformation to acute myeloid leukemia based on the percentage of blasts, karyotype, and number of cytopenias, but the IPSS has several limitations that preclude more widespread application. Over the past decade, several studies have reported on new prognostic factors for MDS, including transfusion dependency and DNA methylation abnormalities. More recently, two prognostic models for MDS that aim to overcome the limitations of the IPSS have been published. This review focuses on the most recent advances in this field, detailing current prognostic models and the more important risk factors in MDS.

Histone deacetylase inhibitors for the treatment of myelodysplastic syndrome and acute myeloid leukemia

Epigenetic changes have been identified in recent years as important factors in the pathogenesis of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Histone deacetylase inhibitors (HDACIs) regulate the acetylation of histones as well as other non-histone protein targets. Treatment with HDACIs results in chromatin remodeling that permits re-expression of silenced tumor suppressor genes in cancer cells, which, in turn, can potentially result in cellular differentiation, inhibition of proliferation and/or apoptosis. Several classes of HDACIs are currently under development for the treatment of patients with MDS and AML. Although modest clinical activity has been reported with the use of HDACIs as single-agent therapy, marked responses have been observed in selected subsets of patients. More importantly, HDACIs appear to be synergistic in vitro and improve response rates in vivo when combined with other agents, such as hypomethylating agents. Furthermore, HDACIs are also being investigated in combination with non-epigenetic therapies. This article synthesizes the most recent results reported with HDACIs in clinical trials conducted in patients with MDS and other myeloid malignancies.

Bafetinib, a dual Bcr-Abl/Lyn tyrosine kinase inhibitor for the potential treatment of leukemia

Bafetinib (NS-187, INNO-406) is a second-generation tyrosine kinase inhibitor in development by CytRx under license from Nippon Shinyaku for treating Bcr-Abl+ leukemia's, including chronic myelogenous leukemia (CML) and Philadelphia+ acute lymphoblastic leukemia. It is a rationally developed tyrosine kinase inhibitor based on the chemical structure of imatinib, with modifications added to improve binding and potency against Bcr-Abl kinase. Besides Abl, bafetinib targets the Src family kinase Lyn, which has been associated with resistance to imatinib in CML. In preclinical studies, bafetinib was 25- to 55-fold more potent than imatinib in vitro and ≥ 10-fold more potent in vivo. Bafetinib inhibits 12 of the 13 most frequent imatinib-resistant Bcr-Abl point mutations, but not a Thr315Ile mutation. A small fraction of bafetinib crosses the blood-brain barrier, reaching brain concentrations adequate for suppression of Bcr-Abl+ cells. Data from a phase I clinical trial conducted in patients with imatinib-resistant or -intolerant CML have confirmed that bafetinib has clinical activity in this setting, inducing a major cytogenetic response in 19% of those patients in chronic phase. Currently, bafetinib is being developed in two phase II clinical trials for patients with B-cell chronic lymphocytic leukemia and prostate cancer, and a trial is in progress for patients with brain tumors.

Acute erythroleukemia: diagnosis and management

Acute erythroleukemia is a rare subtype of acute myeloid leukemia that has undergone several changes in classification over the past 30 years. There are two subtypes of acute erythroleukemia: the more common erythroid/myeloid subtype, defined by the presence of increased erythroid cells and myeloid blasts; and the rarer, pure erythroid subtype, characterized by expansion of immature erythroid cells only. The erythroid/myeloid subtype of acute erythroleukemia is closely related to acute myeloid leukemia with myelodysplasia-related changes, and is frequently characterized by morphological dysplasia and complex karyotype. Pure erythroleukemia is a very uncommon subtype of leukemia associated with a very poor response and survival to current available therapeutic agents. Treatment results for this disease are suboptimal and new drugs are needed. This article summarizes current knowledge in the field of acute erythroleukemia.

Prognostic value of FLT3 mutations among different cytogenetic subgroups in acute myeloid leukemia

BACKGROUND

The impact of FMS-like tyrosine kinase 3 (FLT3) mutations and mutation burden among cytogenetic subgroups of patients with acute myeloid leukemia (AML) other than normal karyotype (NK) AML is unclear.

METHODS

Patients with newly diagnosed AML were divided among 3 cytogenetic subgroups: core binding factor (CBF) AML, NK-AML, and poor-risk AML.

RESULTS

In total, 481 patients were included: 13% had, CBF-AML, 57% had NK-AML, and 30% had poor risk AML, and the frequency of any FLT3 mutations was 20%, 32%, and 7.6% in the respective cytogenetic subgroups. FLT3 mutation did not have an impact on event-free survival (EFS) in patients with CBF-AML (P = .84) and poor-risk AML (P = .37). In patients with NK-AML, EFS was worse in the FLT3-internal tandem duplication (ITD) group (20 weeks vs 41 weeks; P < .00,001) but not in the FLT3-tyrosine kinase domain (TKD) point mutation group (61 weeks vs 41 weeks; P = .15). Worse EFS and overall survival (OS) were observed among patients with NK-AML and higher FLT3-ITD burden but not among patients with FLT3-TKD mutation. In multivariate analysis, FLT3-ITD mutation was prognostic of EFS in patients with NK-AML (hazard ratio, 3.1; P = .03).

CONCLUSIONS

FLT3 mutations did not have a prognostic impact in patients with AML who had good-risk and poor-risk karyotypes. In patients with NK-AML, FLT3-ITD mutations led to worse survival, which was even worse among patients who had high mutation burden.

Long-term prognostic impact of the use of erythropoietic-stimulating agents in patients with chronic myeloid leukemia in chronic phase treated with imatinib

BACKGROUND

Anemia is a frequent side effect of imatinib in patients with chronic myeloid leukemia (CML). Erythropoietic-stimulating agents have been used for treatment of imatinib-induced anemia. There are no data on long-term safety of erythropoietic-stimulating agents in CML patients.

METHODS

The records of chronic phase CML patients who received treatment with imatinib were reviewed for use of erythropoietic-stimulating agents and occurrence of thrombotic events. Data on cytogenetic response and survival were analyzed by use of erythropoietic-stimulating agent.

RESULTS

A total of 608 patients were included, and 217 patients received erythropoietic-stimulating agents. There were 30 thrombotic episodes. Patients who received erythropoietic-stimulating agents had a higher rate of thrombosis (8.5% vs 2.6%, P = .0025). There was no difference in cytogenetic response rate and survival by use of erythropoietic-stimulating agent. Development of grade 3-4 anemia occurred in 62 (10%) patients and was associated with significantly worse response and survival in patients in late chronic phase. By multivariate analysis, use of erythropoietic-stimulating agents was not a risk factor for event-free survival.

CONCLUSIONS

In our cohort of chronic phase CML patients, use of erythropoietic-stimulating agents did not impact survival or cytogenetic response rate, but was associated with a higher thrombosis rate. Severe anemia is associated with worse survival and response.

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.

Feasibility of therapy with hypomethylating agents in patients with renal insufficiency

BACKGROUND

To our knowledge, the feasibility of therapy with hypomethylating agents (HAs) in patients with renal insufficiency (RI) has not been examined.

PATIENTS AND METHODS

We reviewed 41 patients with a diagnosis of acute myeloid leukemia (n = 17), myelodysplastic syndromes (n = 15), and chronic myelomonocytic leukemia (n = 9) who had RI and were receiving therapy with azacitidine or decitabine. The median number of administered cycles was 3. Most patients (39; 95%) received a standard dose of the drugs at the initiation of therapy. Nine patients (22%) required treatment interruptions or discontinuation, and 10 patients (24%) required dose reductions.

RESULTS

The overall response rate was 63%, and 4 patients (10%) achieved a complete response. Twenty patients (51%) experienced grade 3 or 4 myelosuppression-related toxicities. Hospitalization was required in 68% of the patients. Among 12 patients with an estimated glomerular filtration rate of 29 mL per minute or less, 6 required dose reductions attributable to myelosuppression (n = 3) or to worsening renal function (n = 3). The overall survival (OS) at 18 months was 12%, and the median OS was 8.6 months.

CONCLUSION

The use of HA in patients with RI is feasible, but is associated with a higher incidence of toxicity. Dose adjustments and the use of growth factor may be necessary for some patients.

Decitabine in the treatment of myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a group of heterogeneous clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis, peripheral blood cytopenias and a propensity to transform into acute myeloid leukemia. There are few treatment options available for patients with MDS. Studies into the molecular biology of MDS have demonstrated abnormal patterns of DNA methylation that lead to silencing of tumor-suppressor genes. Hypomethylating agents are compounds that have the potential to reverse the aberrant DNA methylation and increase the expression of silenced genes, leading to cellular differentiation and/or apoptosis. Decitabine is a cytidine analogue that has activity as a hypomethylating agent and has been evaluated in the therapy of patients with high-risk MDS. Several studies have confirmed the clinical activity of low-dose decitabine in patients with high-risk MDS, leading to responses in approximately 50% of patients, with low treatment-related mortality. Responses have even been seen in patients with high-risk cytogenetic abnormalities, and some studies have demonstrated increased re-expression of genes that were previously silenced by hypermethylation, such as CDKN2B/p15INK4B. There are still some issues concerning the ideal dose and schedule of decitabine for treating patients with MDS. This article focuses on the most recent clinical studies of decitabine for therapy of MDS.

Advances in treatment of chronic myelogenous leukemia--new treatment options with tyrosine kinase inhibitors

Imatinib is considered standard therapy for patients with chronic myelogenous leukemia (CML), inducing a high rate of hematologic and cytogenetic responses. Despite these excellent results, several patients develop resistance to imatinib. Mechanisms of resistance are varied and include BCR-ABL1 kinase domain mutations, decreased entry of imatinib into cells, acquisition of secondary genetic changes and activation of alternate signaling pathways. Second-generation tyrosine kinase inhibitors (TKI) (dasatinib, nilotinib) were developed as an alternative for patients that develop resistance or are intolerant to imatinib. Dasatinib is a dual Abl/Src kinase TKI that is structurally unrelated to imatinib and is approved for therapy of all phases of CML in patients who are resistant or intolerant to imatinib. Nilotinib is a compound related to imatinib that has greater specificity and improved binding characteristics, and has clinical activity in the setting of imatinib failure. Resistance to multiple TKIs does occur, particularly in patients with the T315I mutation. Several new agents are in development including new TKIs, aurora kinase inhibitors and homoharringtonine.

Adult acute erythroleukemia: an analysis of 91 patients treated at a single institution

Acute erythroleukemia (AML-M6) is an uncommon subtype of acute myeloid leukemia (AML); it is considered to have a poor prognosis. From 1 January 1980 to 21 May 2008, 91 patients with newly diagnosed AML-M6 were seen at the University of Texas-M.D. Anderson Cancer Center (UT-MDACC). Forty-five patients (50%) had a history of myelodysplatic syndrome (MDS), compared with 41% in our control group (patients with other AML subtypes) (P=0.08). Poor-risk cytogenetics were more common in patients with AML-M6 (61% versus 38%, P=0.001). Complete remission rates were 62% for patients with AML-M6, comparing with 58% for the control group (P=0.35). Median disease free survival (DFS) for patients with AML-M6 was 32 weeks, versus 49 weeks for the control group (P=0.05). Median overall survival (OS) of patients with AML-M6 was 36 weeks, compared with 43 weeks for the control group (P=0.60). On multivariate analysis for DFS and OS, AML-M6 was not an independent risk factor. AML-M6 is commonly associated with a previous diagnosis of MDS and poor-risk karyotype. The diagnosis of AML-M6 does not impart by itself a worse prognosis, and treatment decisions on this disease should be guided by well known AML prognostic factors.