Early transfusion patterns improve the Molecular International Prognostic Scoring System (IPSS-M) prediction in myelodysplastic syndromes

BACKGROUND

The Molecular International Prognostic Scoring System (IPSS-M) is the new gold standard for diagnostic outcome prediction in patients with myelodysplastic syndromes (MDS). This study was designed to assess the additive prognostic impact of dynamic transfusion parameters during early follow-up.

METHODS

We retrieved complete transfusion data from 677 adult Swedish MDS patients included in the IPSS-M cohort. Time-dependent erythrocyte transfusion dependency (E-TD) was added to IPSS-M features and analyzed regarding overall survival and leukemic transformation (acute myeloid leukemia). A multistate Markov model was applied to assess the prognostic value of early changes in transfusion patterns.

RESULTS

Specific clinical and genetic features were predicted for diagnostic and time-dependent transfusion patterns. Importantly, transfusion state both at diagnosis and within the first year strongly predicts outcomes in both lower (LR) and higher-risk (HR) MDSs. In multivariable analysis, 8-month landmark E-TD predicted shorter survival independently of IPSS-M (p < 0.001). A predictive model based on IPSS-M and 8-month landmark E-TD performed significantly better than a model including only IPSS-M. Similar trends were observed in an independent validation cohort (n = 218). Early transfusion patterns impacted both future transfusion requirements and outcomes in a multistate Markov model.

CONCLUSION

The transfusion requirement is a robust and available clinical parameter incorporating the effects of first-line management. In MDS, it provides dynamic risk information independently of diagnostic IPSS-M and, in particular, clinical guidance to LR MDS patients eligible for potentially curative therapeutic intervention.

Patient-Specific Measurable Residual Disease Markers Predict Outcome in Patients With Myelodysplastic Syndrome and Related Diseases After Hematopoietic Stem-Cell Transplantation

PURPOSE

Clinical relapse is the major threat for patients with myelodysplastic syndrome (MDS) undergoing hematopoietic stem-cell transplantation (HSCT). Early detection of measurable residual disease (MRD) would enable preemptive treatment and potentially reduced relapse risk.

METHODS

Patients with MDS planned for HSCT were enrolled in a prospective, observational study evaluating the association between MRD and clinical outcome. We collected bone marrow (BM) and peripheral blood samples until relapse, death, or end of study 24 months after HSCT. Patient-specific mutations were identified with targeted next-generation sequencing (NGS) panel and traced using droplet digital polymerase chain reaction (ddPCR).

RESULTS

Of 266 included patients, estimated relapse-free survival (RFS) and overall survival (OS) rates 3 years after HSCT were 59% and 64%, respectively. MRD results were available for 221 patients. Relapse was preceded by positive BM MRD in 42/44 relapses with complete MRD data, by a median of 71 (23-283) days. Of 137 patients in continuous complete remission, 93 were consistently MRD-negative, 39 reverted from MRD+ to MRD-, and five were MRD+ at last sampling. Estimated 1 year-RFS after first positive MRD was 49%, 39%, and 30%, using cutoff levels of 0.1%, 0.3%, and 0.5%, respectively. In a multivariate Cox model, MRD (hazard ratio [HR], 7.99), WHO subgroup AML (HR, 4.87), TP53 multi-hit (HR, 2.38), NRAS (HR, 3.55), and acute GVHD grade III-IV (HR, 4.13) were associated with shorter RFS. MRD+ was also independently associated with shorter OS (HR, 2.65). In a subgroup analysis of 100 MRD+ patients, presence of chronic GVHD was associated with longer RFS (HR, 0.32).

CONCLUSION

Assessment of individualized MRD using NGS + ddPCR is feasible and can be used for early detection of relapse. Positive MRD is associated with shorter RFS and OS (ClinicalTrials.gov identifier: NCT02872662).

Identification and surveillance of rare relapse-initiating stem cells during complete remission after transplantation

ABSTRACT

Relapse after complete remission (CR) remains the main cause of mortality after allogeneic stem cell transplantation for hematological malignancies and, therefore, improved biomarkers for early prediction of relapse remains a critical goal toward development and assessment of preemptive relapse treatment. Because the significance of cancer stem cells as a source of relapses remains unclear, we investigated whether mutational screening for persistence of rare cancer stem cells would enhance measurable residual disease (MRD) and early relapse prediction after transplantation. In a retrospective study of patients who relapsed and patients who achieved continuous-CR with myelodysplastic syndromes and related myeloid malignancies, combined flow cytometric cell sorting and mutational screening for persistence of rare relapse-initiating stem cells was performed in the bone marrow at multiple CR time points after transplantation. In 25 CR samples from 15 patients that later relapsed, only 9 samples were MRD-positive in mononuclear cells (MNCs) whereas flowcytometric-sorted hematopoietic stem and progenitor cells (HSPCs) were MRD-positive in all samples, and always with a higher variant allele frequency than in MNCs (mean, 97-fold). MRD-positivity in HSPCs preceded MNCs in multiple sequential samples, in some cases preceding relapse by >2 years. In contrast, in 13 patients in long-term continuous-CR, HSPCs remained MRD-negative. Enhanced MRD sensitivity was also observed in total CD34+ cells, but HSPCs were always more clonally involved (mean, 8-fold). In conclusion, identification of relapse-initiating cancer stem cells and mutational MRD screening for their persistence consistently enhances MRD sensitivity and earlier prediction of relapse after allogeneic stem cell transplantation.

Single-cell Multiomics Analysis of Myelodysplastic Syndromes and Clinical Response to Hypomethylating Therapy

Alterations in epigenetic marks, such as DNA methylation, represent a hallmark of cancer that has been successfully exploited for therapy in myeloid malignancies. Hypomethylating agents (HMA), such as azacitidine, have become standard-of-care therapy to treat myelodysplastic syndromes (MDS), myeloid neoplasms that can evolve into acute myeloid leukemia. However, our capacity to identify who will respond to HMAs, and the duration of response, remains limited. To shed light on this question, we have leveraged the unprecedented analytic power of single-cell technologies to simultaneously map the genome and immunoproteome of MDS samples throughout clinical evolution. We were able to chart the architecture and evolution of molecular clones in precious paired bone marrow MDS samples at diagnosis and posttreatment to show that a combined imbalance of specific cell lineages with diverse mutational profiles is associated with the clinical response of patients with MDS to hypomethylating therapy.

SIGNIFICANCE

MDS are myeloid clonal hemopathies with a low 5-year survival rate, and approximately half of the cases do not respond to standard HMA therapy. Our innovative single-cell multiomics approach offers valuable biological insights and potential biomarkers associated with the demethylating agent efficacy. It also identifies vulnerabilities that can be targeted using personalized combinations of small drugs and antibodies.

Integrated Genomic and Transcriptomic Analysis Improves Disease Classification and Risk Stratification of MDS with Ring Sideroblasts

PURPOSE

Ring sideroblasts (RS) define the low-risk myelodysplastic neoplasm (MDS) subgroup with RS but may also reflect erythroid dysplasia in higher risk myeloid neoplasm. The benign behavior of MDS with RS (MDSRS+) is limited to SF3B1-mutated cases without additional high-risk genetic events, but one third of MDSRS+ carry no SF3B1 mutation, suggesting that different molecular mechanisms may underlie RS formation. We integrated genomic and transcriptomic analyses to evaluate whether transcriptome profiles may improve current risk stratification.

EXPERIMENTAL DESIGN

We studied a prospective cohort of MDSRS+ patients irrespective of World Health Organization (WHO) class with regard to somatic mutations, copy-number alterations, and bone marrow CD34+ cell transcriptomes to assess whether transcriptome profiles add to prognostication and provide input on disease classification.

RESULTS

SF3B1, SRSF2, or TP53 multihit mutations were found in 89% of MDSRS+ cases, and each mutation category was associated with distinct clinical outcome, gene expression, and alternative splicing profiles. Unsupervised clustering analysis identified three clusters with distinct hemopoietic stem and progenitor (HSPC) composition, which only partially overlapped with mutation groups. IPSS-M and the transcriptome-defined proportion of megakaryocyte/erythroid progenitors (MEP) independently predicted survival in multivariable analysis.

CONCLUSIONS

These results provide essential input on the molecular basis of SF3B1-unmutated MDSRS+ and propose HSPC quantification as a prognostic marker in myeloid neoplasms with RS.

Postazacitidine clone size predicts long-term outcome of patients with myelodysplastic syndromes and related myeloid neoplasms

Azacitidine is a mainstay of therapy for myelodysplastic syndrome (MDS)-related diseases. The purpose of our study is to elucidate the effect of gene mutations on hematological response and overall survival (OS), particularly focusing on their posttreatment clone size. We enrolled a total of 449 patients with MDS or related myeloid neoplasms. They were analyzed for gene mutations in pretreatment (n = 449) and posttreatment (n = 289) bone marrow samples using targeted-capture sequencing to assess the impact of gene mutations and their posttreatment clone size on treatment outcomes. In Cox proportional hazard modeling, multihit TP53 mutation (hazard ratio [HR], 2.03; 95% confidence interval [CI], 1.42-2.91; P < .001), EZH2 mutation (HR, 1.71; 95% CI, 1.14-2.54; P = .009), and DDX41 mutation (HR, 0.33; 95% CI, 0.17-0.62; P < .001), together with age, high-risk karyotypes, low platelets, and high blast counts, independently predicted OS. Posttreatment clone size accounting for all drivers significantly correlated with International Working Group (IWG) response (P < .001, using trend test), except for that of DDX41-mutated clones, which did not predict IWG response. Combined, IWG response and posttreatment clone size further improved the prediction of the original model and even that of a recently proposed molecular prediction model, the molecular International Prognostic Scoring System (IPSS-M; c-index, 0.653 vs 0.688; P < .001, using likelihood ratio test). In conclusion, evaluation of posttreatment clone size, together with the pretreatment mutational profile as well as the IWG response play a role in better prognostication of azacitidine-treated patients with myelodysplasia.

Characterization of the bone marrow niche in patients with chronic myeloid leukemia identifies CXCL14 as a new therapeutic option

Although tyrosine kinase inhibitors (TKIs) are effective in treating chronic myeloid leukemia (CML), they often fail to eradicate the leukemia-initiating stem cells (LSCs), causing disease persistence and relapse. Evidence indicates that LSC persistence may be because of bone marrow (BM) niche protection; however, little is known about the underlying mechanisms. Herein, we molecularly and functionally characterize BM niches in patients with CML at diagnosis and reveal the altered niche composition and function in these patients. Long-term culture initiating cell assay showed that the mesenchymal stem cells from patients with CML displayed an enhanced supporting capacity for normal and CML BM CD34+CD38- cells. Molecularly, RNA sequencing detected dysregulated cytokine and growth factor expression in the BM cellular niches of patients with CML. Among them, CXCL14 was lost in the BM cellular niches in contrast to its expression in healthy BM. Restoring CXCL14 significantly inhibited CML LSC maintenance and enhanced their response to imatinib in vitro, and CML engraftment in vivo in NSG-SGM3 mice. Importantly, CXCL14 treatment dramatically inhibited CML engraftment in patient-derived xenografted NSG-SGM3 mice, even to a greater degree than imatinib, and this inhibition persisted in patients with suboptimal TKI response. Mechanistically, CXCL14 upregulated inflammatory cytokine signaling but downregulated mTOR signaling and oxidative phosphorylation in CML LSCs. Together, we have discovered a suppressive role of CXCL14 in CML LSC growth. CXCL14 might offer a treatment option targeting CML LSCs.

Omalizumab alleviates pruritus in myeloproliferative neoplasms

Not available.

[Two cases of VEXAS syndrome]

VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) is a newly discovered syndrome caused by a somatic mutation in the UBA1 gene, located in the X chromosome. The syndrome mainly affects older men, and presents with persistent inflammation and rheumatological symptoms like polychondritis, lung infiltrates and dermatitis. Related hematological disturbances are thromboembolic events, macrocytic anemia, myelodysplastic syndrome, and vacuoles found in bone marrow hematopoietic cells. A genetic test of the UBA1 gene confirms the diagnosis when a clinical suspicion of VEXAS is raised. Patients usually respond to prednisolone at a dose of 15-20 mg/day but an effective and well tolerated long-term treatment strategy is still to be defined. The only potentially curative treatment is allogeneic stem cell transplantation. In this case report we present two cases of VEXAS, one of which has undergone an allogeneic stem cell transplantation.

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.

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.

Myelodysplastic syndromes: moving towards personalized management

The myelodysplastic syndromes (MDS) share their origin in the hematopoietic stem cell but have otherwise very heterogeneous biological and genetic characteristics. Clinical features are dominated by cytopenia and a substantial risk for progression to acute myeloid leukemia. According to the World Health Organization, MDS is defined by cytopenia, bone marrow dysplasia and certain karyotypic abnormalities. The understanding of disease pathogenesis has undergone major development with the implementation of next-generation sequencing and a closer integration of morphology, cytogenetics and molecular genetics is currently paving the way for improved classification and prognostication. True precision medicine is still in the future for MDS and the development of novel therapeutic compounds with a propensity to markedly change patients' outcome lags behind that for many other blood cancers. Treatment of higher-risk MDS is dominated by monotherapy with hypomethylating agents but novel combinations are currently being evaluated in clinical trials. Agents that stimulate erythropoiesis continue to be first-line treatment for the anemia of lower-risk MDS but luspatercept has shown promise as second-line therapy for sideroblastic MDS and lenalidomide is an established second-line treatment for del(5q) lower-risk MDS. The only potentially curative option for MDS is hematopoietic stem cell transplantation, until recently associated with a relatively high risk of transplant-related mortality and relapse. However, recent studies show increased cure rates due to better tools to target the malignant clone with less toxicity. This review provides a comprehensive overview of the current status of the clinical evaluation, biology and therapeutic interventions for this spectrum of disorders.

Treatment of myelodysplastic syndrome in the era of next-generation sequencing

Next-generation sequencing (NGS) is rapidly changing the clinical care of patients with myelodysplastic syndrome (MDS). NGS can be used for various applications: (i) in the diagnostic process to discriminate between MDS and other diseases such as aplastic anaemia, myeloproliferative disorders and idiopathic cytopenias; (ii) for classification, for example, where the presence of SF3B1 mutation is one criterion for the ring sideroblast anaemia subgroups in the World Health Organization 2016 classification; (iii) for identification of patients suitable for targeted therapy (e.g. IDH1/2 inhibitors); (iv) for prognostication, for example, where specific mutations (e.g. TP53 and RUNX1) are associated with inferior prognosis, whereas others (e.g. SF3B1) are associated with superior prognosis; and (v) to monitor patients for progression or treatment failure. Most commonly, targeted sequencing for genes (normally 50-100 genes) reported to be recurrently mutated in myeloid disease is used. At present, NGS is rarely incorporated into clinical guidelines although an increasing number of studies have demonstrated the benefit of using NGS in the clinical management of MDS patients.

Comprehensive mapping of the effects of azacitidine on DNA methylation, repressive/permissive histone marks and gene expression in primary cells from patients with MDS and MDS-related disease

Azacitidine (Aza) is first-line treatment for patients with high-risk myelodysplastic syndromes (MDS), although its precise mechanism of action is unknown. We performed the first study to globally evaluate the epigenetic effects of Aza on MDS bone marrow progenitor cells assessing gene expression (RNA seq), DNA methylation (Illumina 450k) and the histone modifications H3K18ac and H3K9me3 (ChIP seq). Aza induced a general increase in gene expression with 924 significantly upregulated genes but this increase showed no correlation with changes in DNA methylation or H3K18ac, and only a weak association with changes in H3K9me3. Interestingly, we observed activation of transcripts containing 15 endogenous retroviruses (ERVs) confirming previous cell line studies. DNA methylation decreased moderately in 99% of all genes, with a median β-value reduction of 0.018; the most pronounced effects seen in heterochromatin. Aza-induced hypomethylation correlated significantly with change in H3K9me3. The pattern of H3K18ac and H3K9me3 displayed large differences between patients and healthy controls without any consistent pattern induced by Aza. We conclude that the marked induction of gene expression only partly could be explained by epigenetic changes, and propose that activation of ERVs may contribute to the clinical effects of Aza in MDS.

Azacitidine in Lower-Risk Myelodysplastic Syndromes: A Meta-Analysis of Data from Prospective Studies

BACKGROUND

After erythropoiesis-stimulating agent (ESA) failure, lenalidomide and hypomethylating agents are the only remaining treatment options for most patients with lower-risk myelodysplastic syndromes (LR-MDS). Optimal choice of these agents as front-line therapy in non-del(5q) LR-MDS is unclear. Because azacitidine clinical data mainly describe experience in higher-risk MDS, we performed a meta-analysis of patient-level data to evaluate azacitidine in patients with red blood cell (RBC) transfusion-dependent LR-MDS.

MATERIALS AND METHODS

We searched English-language articles for prospective phase II and III azacitidine clinical trials and patient registries published between 2000 and 2015, and Embase abstracts from 2015 conferences. Patient-level data from identified relevant studies were provided by investigators. Meta-analyses followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Efficacy endpoints were RBC transfusion independence (TI) and Clinical Benefit (RBC-TI, erythroid response, and complete or partial remission, per International Working Group 2006 criteria for MDS).

RESULTS

Data for 233 patients from 6 clinical studies and 1 registry study met criteria for inclusion in analyses. Overall, 90.3% of patients had non-del(5q) LR-MDS. Pooled estimates from random-effects models of RBC-TI and Clinical Benefit were 38.9% and 81.1%, respectively; for the ESA-refractory subgroup, they were 40.5% and 77.3%; and for patients with isolated anemia, they were 41.9% and 82.5%. In multivariate analyses, planned use of ≥6 azacitidine treatment cycles was significantly predictive of response.

CONCLUSION

Azacitidine effects in these patients, most with non-del(5q) LR-MDS, were promising and generally similar to those reported for lenalidomide in similar patients. The choice of initial therapy is important because most patients eventually stop responding to front-line therapy and alternatives are limited.

IMPLICATIONS FOR PRACTICE

Lower-risk myelodysplastic syndromes (LR-MDS) are primarily characterized by anemia. After erythropoiesis-stimulating agent (ESA) failure, lenalidomide and hypomethylating agents are the only remaining treatment options for most patients. This meta-analysis of 233 azacitidine-treated red blood cell (RBC) transfusion-dependent patients with LR-MDS (92.3% non-del[5q]) from 7 studies showed 38.9% became RBC transfusion-independent. There is no clear guidance regarding the optimal choice of lenalidomide or hypomethylating agents for patients with non-del(5q) LR-MDS following ESA failure. Clinical presentation (e.g., number of cytopenias) and potential outcomes after hypomethylating agent failure are factors to consider when making initial treatment decisions for LR-MDS patients.

Mutations in histone modulators are associated with prolonged survival during azacitidine therapy

Early therapeutic decision-making is crucial in patients with higher-risk MDS. We evaluated the impact of clinical parameters and mutational profiles in 134 consecutive patients treated with azacitidine using a combined cohort from Karolinska University Hospital (n=89) and from King's College Hospital, London (n=45). While neither clinical parameters nor mutations had a significant impact on response rate, both karyotype and mutational profile were strongly associated with survival from the start of treatment. IPSS high-risk cytogenetics negatively impacted overall survival (median 20 vs 10 months; p<0.001), whereas mutations in histone modulators (ASXL1, EZH2) were associated with prolonged survival (22 vs 12 months, p=0.01). This positive association was present in both cohorts and remained highly significant in the multivariate cox model. Importantly, patients with mutations in histone modulators lacking high-risk cytogenetics showed a survival of 29 months compared to only 10 months in patients with the opposite pattern. While TP53 was negatively associated with survival, neither RUNX1-mutations nor the number of mutations appeared to influence survival in this cohort. We propose a model combining histone modulator mutational screening with cytogenetics in the clinical decision-making process for higher-risk MDS patients eligible for treatment with azacitidine.

SF3B1-initiating mutations in MDS-RSs target lymphomyeloid hematopoietic stem cells

Mutations in the RNA splicing gene SF3B1 are found in >80% of patients with myelodysplastic syndrome with ring sideroblasts (MDS-RS). We investigated the origin of SF3B1 mutations within the bone marrow hematopoietic stem and progenitor cell compartments in patients with MDS-RS. Screening for recurrently mutated genes in the mononuclear cell fraction revealed mutations in SF3B1 in 39 of 40 cases (97.5%), combined with TET2 and DNMT3A in 11 (28%) and 6 (15%) patients, respectively. All recurrent mutations identified in mononuclear cells could be tracked back to the phenotypically defined hematopoietic stem cell (HSC) compartment in all investigated patients and were also present in downstream myeloid and erythroid progenitor cells. While in agreement with previous studies, little or no evidence for clonal (SF3B1 mutation) involvement could be found in mature B cells, consistent involvement at the pro-B-cell progenitor stage was established, providing definitive evidence for SF3B1 mutations targeting lymphomyeloid HSCs and compatible with mutated SF3B1 negatively affecting lymphoid development. Assessment of stem cell function in vitro as well as in vivo established that only HSCs and not investigated progenitor populations could propagate the SF3B1 mutated clone. Upon transplantation into immune-deficient mice, SF3B1 mutated MDS-RS HSCs differentiated into characteristic ring sideroblasts, the hallmark of MDS-RS. Our findings provide evidence of a multipotent lymphomyeloid HSC origin of SF3B1 mutations in MDS-RS patients and provide a novel in vivo platform for mechanistically and therapeutically exploring SF3B1 mutated MDS-RS.

Integrative Genomics Identifies the Molecular Basis of Resistance to Azacitidine Therapy in Myelodysplastic Syndromes

Myelodysplastic syndromes and chronic myelomonocytic leukemia are blood disorders characterized by ineffective hematopoiesis and progressive marrow failure that can transform into acute leukemia. The DNA methyltransferase inhibitor 5-azacytidine (AZA) is the most effective pharmacological option, but only ∼50% of patients respond. A response only manifests after many months of treatment and is transient. The reasons underlying AZA resistance are unknown, and few alternatives exist for non-responders. Here, we show that AZA responders have more hematopoietic progenitor cells (HPCs) in the cell cycle. Non-responder HPC quiescence is mediated by integrin α5 (ITGA5) signaling and their hematopoietic potential improved by combining AZA with an ITGA5 inhibitor. AZA response is associated with the induction of an inflammatory response in HPCs in vivo. By molecular bar coding and tracking individual clones, we found that, although AZA alters the sub-clonal contribution to different lineages, founder clones are not eliminated and continue to drive hematopoiesis even in complete responders.

Myelodysplastic syndromes are propagated by rare and distinct human cancer stem cells in vivo

Evidence for distinct human cancer stem cells (CSCs) remains contentious and the degree to which different cancer cells contribute to propagating malignancies in patients remains unexplored. In low- to intermediate-risk myelodysplastic syndromes (MDS), we establish the existence of rare multipotent MDS stem cells (MDS-SCs), and their hierarchical relationship to lineage-restricted MDS progenitors. All identified somatically acquired genetic lesions were backtracked to distinct MDS-SCs, establishing their distinct MDS-propagating function in vivo. In isolated del(5q)-MDS, acquisition of del(5q) preceded diverse recurrent driver mutations. Sequential analysis in del(5q)-MDS revealed genetic evolution in MDS-SCs and MDS-progenitors prior to leukemic transformation. These findings provide definitive evidence for rare human MDS-SCs in vivo, with extensive implications for the targeting of the cells required and sufficient for MDS-propagation.

Limited clinical efficacy of azacitidine in transfusion-dependent, growth factor-resistant, low- and Int-1-risk MDS: Results from the nordic NMDSG08A phase II trial

This prospective phase II study evaluated the efficacy of azacitidine (Aza)+erythropoietin (Epo) in transfusion-dependent patients with lower-risk myelodysplastic syndrome (MDS). Patients ineligible for or refractory to full-dose Epo+granulocyte colony stimulation factors for >8 weeks and a transfusion need of 4 units over 8 weeks were included. Aza 75 mg m(-2) d(-1), 5/28 days, was given for six cycles; non-responding patients received another three cycles combined with Epo 60 000 units per week. Primary end point was transfusion independence (TI). All patients underwent targeted mutational screen for 42 candidate genes. Thirty enrolled patients received one cycle of Aza. Ten patients discontinued the study early, 7 due to adverse events including 2 deaths. Thirty-eight serious adverse events were reported, the most common being infection. Five patients achieved TI after six cycles and one after Aza+Epo, giving a total response rate of 20%. Mutational screening revealed a high frequency of recurrent mutations. Although no single mutation predicted for response, SF3A1 (n=3) and DNMT3A (n=4) were only observed in non-responders. We conclude that Aza can induce TI in severely anemic MDS patients, but efficacy is limited, toxicity substantial and most responses of short duration. This treatment cannot be generally recommended in lower-risk MDS. Mutational screening revealed a high frequency of mutations.

High prevalence of restless legs syndrome among patients with polycytemia vera treated with venesectio

In order to examine whether symptoms of iron deficiency anemia are due to the iron deficiency itself or the associated anemia, 34 patients with polycytemia vera (PV) treated with venesectio, who had iron deficiency but normal hemoglobin (Hb) levels, were given a questionnaire covering symptoms of iron deficiency including the international RLS-scale and the Fact-fatigue quality of life scale (QoL). We found a prevalence of pica of 11.7%, mouth paresthesias of 5.8% and rest-less legs 29.6% (RLS "normal" prevalence 10%). Thus, the prevalence of RLS is significantly higher in our population. We also saw a significant difference in QoL between patients with and without RLS (P = 0.015) and QoL correlated with the severity of RLS (R = 0.85). In conclusion, RLS seems to be a frequent and serious problem for PV patients treated with venesectio according to standard guidelines.