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Komrokji et al examined the proposed international working group proposal to designate SF3B1-mutant myelodysplastic syndrome (MDS) as a unique disease entity, using a single-institution validation cohort of 1779 MDS patients, of whom 320 harbored SF3B1 mutations. They confirmed the demographics of older age, low-risk disease, ring sideroblasts, and low blast percentage. They further confirmed better overall survival that is negatively impacted in those patients with concomitant mutations, high variant allele fraction, and increased blast percentage.

Introduction: Monotherapy with hypomethylating agents (HMA) remains the standard of care for patients (pts) with myelodysplastic syndromes (MDS). Response in MDS is based on the modified International Working Group (IWG) 2006 criteria. Prior studies focusing on unselected MDS pts showed that achieving a complete remission (CR) was associated with favorable overall survival (OS). However, the association of other outcomes with OS was less clear and only 20% of HMA-treated MDS pts achieve a CR. For example, pts who achieved 11 g/dL). To avoid missing clinically meaningful benefits when studying new drugs in clinical trials, a clearly defined response criterion that is less stringent than CR but still captures clinically meaningful hematologic improvement (HI) is needed. Here we sought to evaluate the impact of current IWG 2006 response criteria as well as CRh on OS of pts with HR-MDS treated with frontline HMA monotherapy. Methods: We included all adult (≥18 years) MDS pts treated with frontline HMA (azacitidine [AZA], decitabine [DEC], or ASTX727) monotherapy between 1/1/2012 and 12/31/2020 at Yale University. We decided to use HMA monotherapy as it is the standard care for HR-MDS and to minimize the impact of therapy choice confounding the association of achieved response with OS. Pts were excluded if they received prior treatments for MDS aside from erythropoiesis-stimulating agents and if no baseline with at least one follow-up BM study were available for response assessment. We collected patient and disease characteristics (transfusion burden, IPSS/IPSS-R score, cytogenetics, molecular studies) at baseline. Best responses were assessed based on IWG 2006 criteria for MDS. We defined CRh as We performed Kaplan-Meier analysis to estimate the duration of overall survival and we used log rank test to test the difference in OS between subgroups of pts. Multiple comparisons were adjusted using the Bonferroni method. Results: A total of 100 pts was included in this analysis (Table 1). Median age was 68 years (yrs; range, 23 - 86), 60% were males, and 79% and 18% of pts received AZA and DEC, respectively. Median number of HMA cycles was 6 (interquartile range [IQR]: 4-10), and 33 pts (33%) underwent HCT. During follow-up, 46 pts (48%) progressed to AML. At a median follow-up of 1.5 yrs (IQR: 0.9 - 2.3 yrs), median OS for the entire pt cohort was 1.9 yrs (Figure 1). OS by response category is shown in Table 2. Median OS was not reached for patients who achieved a CR (95% CI: not reached [NR] - NR) as compared to 1.9 yrs (95% CI: 1.5 yrs - NR) and 2.0 yrs (95% CI: 1.2 yrs - NR) among pts with mCR + HI and mCR without HI, respectively. Median OS among patients with stable disease (SD) was similar (2.0 yrs [95% CI: 1.5 yrs - NR]). Finally, we explored the prognostic value of CRh and found a median OS of 1.9 yrs (95% CI: 1.5 yrs - NR), which appeared comparable to mCR +/- HI or SD. Similar results were found with censoring at time of HCT (Figure 2). Discussion: In this retrospective analysis of MDS pts treated with HMA monotherapy in the frontline setting, achieving CR as best response was associated with improved OS compared with mCR +/- HI and SD. However, as the numbers were small these results should be interpreted with caution, and other clinically relevant outcomes such as freedom of transfusion, infectious or bleeding complications, and patient-reported outcomes were not captured in the current analysis. Our results also apply only to MDS pts treated with HMA monotherapy in the frontline setting. The prognostic implications of CRh need to be evaluated in larger patient cohorts. To overcome these limitations, we are currently in the process of expanding the study to a much larger multi-center, international analysis. Figure 1 Figure 1. Disclosures Neparidze: Eidos Therapeutics: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Research Funding; Janssen: Research Funding. Shallis: Curis: Divested equity in a private or publicly-traded company in the past 24 months. Podoltsev: PharmaEssentia: Honoraria; Pfizer: Honoraria; CTI BioPharma: Honoraria; Blueprint Medicines: Honoraria; Incyte: Honoraria; Bristol-Myers Squib: Honoraria; Novartis: Honoraria; Celgene: Honoraria. Brunner: GSK: Research Funding; Aprea: Research Funding; Keros Therapeutics: Consultancy; Agios: Consultancy; AstraZeneca: Research Funding; Novartis: Consultancy, Research Funding; Acceleron: Consultancy; Takeda: Consultancy, Research Funding; BMS/Celgene: Consultancy, Research Funding; Janssen: Research Funding. Zeidan: AbbVie: Consultancy, Other: Clinical Trial Committees, Research Funding; Gilead: Consultancy, Other: Clinical Trial Committees; Epizyme: Consultancy; Amgen: Consultancy, Research Funding; BioCryst: Other: Clinical Trial Committees; Incyte: Consultancy, Research Funding; Boehringer Ingelheim: Consultancy, Research Funding; Cardiff Oncology: Consultancy, Other: Travel support, Research Funding; Acceleron: Consultancy, Research Funding; Agios: Consultancy; Novartis: Consultancy, Other: Clinical Trial Committees, Travel support, Research Funding; Genentech: Consultancy; Jasper: Consultancy; ADC Therapeutics: Research Funding; Jazz: Consultancy; Astex: Research Funding; Daiichi Sankyo: Consultancy; Kura: Consultancy, Other: Clinical Trial Committees; Aprea: Consultancy, Research Funding; BMS: Consultancy, Other: Clinical Trial Committees, Research Funding; Geron: Other: Clinical Trial Committees; AstraZeneca: Consultancy; Pfizer: Other: Travel support, Research Funding; BeyondSpring: Consultancy; Ionis: Consultancy; Loxo Oncology: Consultancy, Other: Clinical Trial Committees; Janssen: Consultancy; Astellas: Consultancy.

In myelodysplastic syndromes (MDSs), the evolution of risk for disease progression or death has not been systematically investigated despite being crucial for correct interpretation of prognostic risk scores. In a multicenter retrospective study, we described changes in risk over time, the consequences for basal prognostic scores, and their potential clinical implications. Major MDS prognostic risk scoring systems and their constituent individual predictors were analyzed in 7212 primary untreated MDS patients from the International Working Group for Prognosis in MDS database. Changes in risk of mortality and of leukemic transformation over time from diagnosis were described. Hazards regarding mortality and acute myeloid leukemia transformation diminished over time from diagnosis in higher-risk MDS patients, whereas they remained stable in lower-risk patients. After approximately 3.5 years, hazards in the separate risk groups became similar and were essentially equivalent after 5 years. This fact led to loss of prognostic power of different scoring systems considered, which was more pronounced for survival. Inclusion of age resulted in increased initial prognostic power for survival and less attenuation in hazards. If needed for practicability in clinical management, the differing development of risks suggested a reasonable division into lower- and higher-risk MDS based on the IPSS-R at a cutoff of 3.5 points. Our data regarding time-dependent performance of prognostic scores reflect the disparate change of risks in MDS subpopulations. Lower-risk patients at diagnosis remain lower risk whereas initially high-risk patients demonstrate decreasing risk over time. This change of risk should be considered in clinical decision making.

Introduction: TP53 mutations have been associated with adverse outcomes in AML and MDS. While these mutations occur in less than 15-20% of pts, they are often associated with complex karyotypes and therapy-related (t)-myeloid neoplasms (MN). Previous studies showed poor outcomes with intensive chemotherapy (IC) and lower-intensity therapies [LIT] (e.g. hypomethylating agents [HMA]), and higher relapse rates after allogeneic hematopoietic stem cell transplant (alloSCT), leaving the question of optimal treatment unanswered. Methods: We conducted a retrospective review of all adult pts with MN and pathogenic TP53 mutations who were treated at Yale University from 9/1/2015 to 5/31/2019. We collected data on age, sex, ethnicity, prior malignancies and their treatments, white blood cell (WBC), hemoglobin, platelet count, disease risk, initial and subsequent lines of therapies, and use of alloSCT. Responses were recorded using modified International Working Group (IWG) criteria 2003 for AML and 2006 for MDS. Overall survival (OS) was measured using Kaplan Meier methods. Results: We identified 83 pts with TP53-mutated MN (45 AML, 31 MDS, 4 chronic myelomonocytic leukemia, and 3 JAK2-positive myeloproliferative neoplasms). Median age was 69 years (range [R], 27-88 years), 52% were male, and 88% were Caucasian [Table 1]. Prior malignancy was noted in 35 pts (42%) and 29 (17 AML, 12 MDS) pts were classified as t-MN. Median WBC on presentation was 3 x 109 /L (R, 0.2 - 74x109) with a median of 0% peripheral blasts (R, 0-43%). Complex (n=75; 90%) and monosomal karyotypes (n=54; 65%) were highly prevalent. We identified 101 unique, pathogenic or likely pathogenic mutations in the TP53 gene with 17 pts harboring more than 1 abnormal variant (16 pts with 2 mutations, 1 pt with 4 mutations). Missense variants were most commonly encountered (n=82 variants, 81%) followed by splicesite (n=9, 9%), frameshift (n=6, 6%), and nonsense variants (n=4, 4.0%). 52 pts had isolated somatic TP53 variants (63%). Among the other 31 pts DNMT3A (n=8 pts), JAK2 (n=6), and TET2 (n=5) variants were the most common somatic mutations. Of note, targetable driver mutations such as FLT3 (n=0), IDH1 (n=3), and IDH2 (n=1) were very rare. Notably, pts with complex karyotype were more likely to have isolated TP53 mutations compared to non-complex karyotype pts (complex karyotype + isolated TP53 mutations: 51 pts [68.0%] vs non-complex karyotype + isolated TP53 mutations: 2 pts [25.0%]; Fisher's exact test: p=0.024) [Table 2]. Median follow up of the cohort was 6.4 months (mos) [R: 0.2-55.3 mos]. Median OS in the entire study cohort was 7.6 mos (95% CI: 5.7-10.0 mos) with a 1-year OS rate of 30.5% (95% CI: 20.0-41.6%). Response rates and outcome for AML and MDS patients by treatment regimen are shown in Table 3. Among AML pts, IC did not appear to improve OS compared to pts receiving LIT (median OS 10.1 mos [95% CI: 6.4-15.5] vs 8.1 mos [95% CI: 1.9-13.6]; p=0.39). AML pts (median OS 6.7 mos [95% CI: 1.9-9.4]; 1-year OS: 23.2% [95% CI: 11%-38%]) had a statistically non-significant trend to poorer outcomes compared to MDS pts (median OS 10 mos [95% CI 5.7-12.9]; 1-year OS: 29.5% [95% CI 13.5-47.4%]; p=0.13). Notably, among the 10 pts who proceeded to alloSCT, only 3 pts relapsed after a median of 2.8 mos post-alloSCT. Relapse-free survival and median OS for pts who underwent alloSCT was not reached at a median follow up of 10.4 mos. Conclusions: In this case series we confirm the poor prognosis for pts with TP53-mutated MN. Median OS was only 7.6 mos, and IC did not appear to improve OS compared to LIT for AML pts. With limited follow-up, pts who underwent alloSCT appeared to benefit. Novel therapies are urgently needed to improve outcomes of this pt population. Disclosures Podoltsev: Kartos Therapeutics: Research Funding; Samus Therapeutics: Research Funding; Alexion: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Agios Pharmaceuticals: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Blueprint Medicines: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Boehringer Ingelheim: Research Funding; Astellas Pharma: Research Funding; Daiichi Sankyo: Research Funding; Sunesis Pharmaceuticals: Research Funding; Jazz Pharmaceuticals: Research Funding; Pfizer: Research Funding; Astex Pharmaceuticals: Research Funding; CTI Biopharma: Research Funding; Celgene: Other: Grant funding, Research Funding; Genentech: Research Funding; AI Therapeutics: Research Funding; Arog Pharmaceuticals: Research Funding. Gore:Celgene Corporation: Consultancy, Research Funding. Prebet:Boehringer Ingelheim: Research Funding; Boehringer Ingelheim: Research Funding; Boehringer Ingelheim: Research Funding; pfizer: Honoraria; pfizer: Honoraria; pfizer: Honoraria; Tetraphase: Consultancy; novartis: Honoraria; novartis: Honoraria; Agios: Consultancy, Research Funding; novartis: Honoraria; Jazz Pharmaceuticals: Consultancy, Honoraria, Research Funding; pfizer: Honoraria; Genentech: Consultancy; pfizer: Honoraria; Bristol-Myers Squibb: Honoraria, Research Funding; novartis: Honoraria; novartis: Honoraria. Isufi:Celgene: Consultancy; Novartis: Consultancy; Astra Zeneca: Consultancy. Foss:Spectrum: Other: fees for non-CME/CE services ; Eisai: Consultancy; Acrotech: Consultancy; miRagen: Consultancy; Mallinckrodt: Consultancy; Seattle Genetics: Consultancy, Other: fees for non-CME/CE services . Huntington:AbbVie: Consultancy; Celgene: Consultancy, Research Funding; DTRM Biopharm: Research Funding; Pharmacyclics: Honoraria; Genentech: Consultancy; Bayer: Consultancy, Honoraria. Neparidze:Janssen Scientific Affairs, LLC: Research Funding; Eidos Therapeutics: Other: Member of Independent Diagnostic Committee; MMRF/Synteract: Membership on an entity's Board of Directors or advisory committees. Zeidan:Celgene Corporation: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; Otsuka: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Medimmune/AstraZeneca: Research Funding; Boehringer-Ingelheim: Consultancy, Honoraria, Research Funding; Trovagene: Consultancy, Honoraria, Research Funding; Incyte: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; ADC Therapeutics: Research Funding; Jazz: Honoraria; Ariad: Honoraria; Agios: Honoraria; Novartis: Honoraria; Astellas: Honoraria; Daiichi Sankyo: Honoraria; Cardinal Health: Honoraria; Seattle Genetics: Honoraria; BeyondSpring: Honoraria; Acceleron Pharma: Consultancy, Honoraria, Research Funding.

Background: Hypomethylating agents (HMA) are the standard of care for higher risk MDS patients (pts). Fewer than one-half will respond to therapy for an average duration of one year, thereby emphasizing the necessity to optimize the use of these disease modifying agents. HMA clinical trials have not addressed the optimal time in the disease course to initiate treatment to maximize disease-modifying potential. The current dogma is to begin HMA therapy in all higher risk MDS pts at the time of initial diagnosis. Nevertheless, a subset of higher risk MDS pts will have adequate hematopoiesis at the time of diagnosis regardless of disease risk, and for these pts therapy may be delayed and reserved for a later time when symptomatic cytopenias develop. We investigated the impact of the timing of HMA initiation on outcomes among higher risk MDS pts presenting with adequate blood counts to discern the possible benefit of early treatment based solely on disease risk. Methods: We identified MDS pts with intermediate-2 and high risk IPSS (higher risk) MDS treated with HMA among the Moffitt Cancer Center database. We included patients with adequate hematopoiesis defined for the purpose of this study as platelets >50 x 109/L, Hgb > 9 g/dl and ANC > 0.5 x 109/L and being transfusion independent to exclude those pts in need of HMA treatment for cytopenias. We divided patients into 4 groups based on the time of HMA initiation (within 30, 31-60 , 61-90 and greater than 90 days from time of diagnosis). We compared baseline characteristics, best response rate to treatment using international working group criteria (IWG 2006), leukemia free survival (LFS) and overall survival (OS) among the 4 groups. Results: We identified 320 higher risk MDS pts with adequate hematopoiesis who were treated with HMA. Baseline characteristics for the 4 groups based upon time of HMA therapy initiation are summarized in Table-1. Pts receiving treatment within 30 days had higher marrow myeloblast percentage at time of diagnosis. There was no difference in mean blood counts at time of diagnosis between the 4 groups; however, mean platelet count was lower at time of initiating HMA therapy in patients treated after 90 days from diagnosis. Table-2 summarizes somatic gene mutation data among 110 patients tested. TET-2 mutations were more common among those treated within 60 days, whereas U2AF1 mutations were more common among those treated after 60 days from diagnosis. The complete response rates were 21%, 26%, 23% and 7%, respectively for pts treated within 30 , 31-60 , 61-90 and greater than 90 days from time of diagnosis (p=0.046). The overall response rates (defined as hematological improvement or better) were 43%, 41%, 43% and 34%, respectively for pts treated within 30, 31-60 , 61-90 and greater than 90 days from date of diagnosis (p .70). There was no difference in mean duration of treatment with HMA among the groups with mean durations of 267, 204, 224 and 215 days, respectively, (p .35). The median OS from the date of diagnosis was 641, 550, 979 and 806 days, respectively for pts treated within 30, 31-60, 61-90 and greater than 90 days from date of diagnosis (p .2). There was no impact of timing for HMA initiation when adjusted for Revised-IPSS risk groups in Cox regression analysis. There was no difference in OS based on HMA initiation time when adjusted for myeloblasts % or karyotype. Further, there was no difference between groups in rate of AML transformation or LFS (p =.7 and .16, respectively). Conclusions A delay in initiating HMA therapy in higher risk MDS pts with adequate blood counts is not associated with worsened overall survival or increased frequency of leukemia transformation. Complete response rates were higher when treatment was started earlier in the disease course, however, there was no difference in overall response rate. Close observation to initiate treatment upon development of clinically significant cytopenias appears to be a safe and equally effective strategy among pts with higher risk MDS. Disclosures Komrokji: Novartis: Honoraria, Speakers Bureau; Celgene: Honoraria, Research Funding; Novartis: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Celgene: Honoraria, Research Funding. Sallman:Celgene: Research Funding, Speakers Bureau. Nazha:MEI: Consultancy. Steensma:Takeda: Consultancy; Syros: Research Funding; Otsuka: Membership on an entity's Board of Directors or advisory committees; Onconova: Consultancy; Novartis: Membership on an entity's Board of Directors or advisory committees; Kura: Research Funding; Janssen: Consultancy, Research Funding; H3 Biosciences: Research Funding; Celgene: Research Funding; Amphivena: Membership on an entity's Board of Directors or advisory committees; Acceleron: Consultancy. Roboz:AbbVie: Consultancy; Daiichi Sankyo: Consultancy; Jazz Pharmaceuticals: Consultancy; Cellectis: Research Funding; Novartis: Consultancy; Celltrion: Consultancy; Astex Pharmaceuticals: Consultancy; Sandoz: Consultancy; Celgene Corporation: Consultancy; Otsuka: Consultancy; Janssen Pharmaceuticals: Consultancy; Aphivena Therapeutics: Consultancy; Daiichi Sankyo: Consultancy; Orsenix: Consultancy; Bayer: Consultancy; Aphivena Therapeutics: Consultancy; Argenx: Consultancy; Orsenix: Consultancy; Novartis: Consultancy; Jazz Pharmaceuticals: Consultancy; Eisai: Consultancy; Celgene Corporation: Consultancy; AbbVie: Consultancy; Roche/Genentech: Consultancy; Cellectis: Research Funding; Otsuka: Consultancy; Bayer: Consultancy; Pfizer: Consultancy; Astex Pharmaceuticals: Consultancy; Argenx: Consultancy; Sandoz: Consultancy; Celltrion: Consultancy; Janssen Pharmaceuticals: Consultancy; Pfizer: Consultancy; Eisai: Consultancy; Roche/Genentech: Consultancy. Sekeres:Celgene: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Opsona: Membership on an entity's Board of Directors or advisory committees; Opsona: Membership on an entity's Board of Directors or advisory committees. List:Celgene: Research Funding.

Introduction: Clinical trial response assessments for follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL) typically mandate bone marrow biopsies (BMBs) at baseline and for confirmation of complete response (CR) as assessed by computed tomography (CT) imaging according to International Working Group (IWG) criteria. BMBs are painful and expensive, and can deter patients (pts) from clinical trial participation. Rutherford et al. (Br J Haematol 2017) suggested that confirmatory BMBs do not impact response assessment in the majority of FL pts treated in clinical trials. We describe the impact of confirmatory BMBs on response in the GALLIUM study (NCT01332968), which randomized previously untreated FL pts to obinutuzumab (G)- or rituximab (R)-chemotherapy (CHOP, CVP, or bendamustine) followed by maintenance with the same antibody in responders, and in the GOYA study (NCT01287741), which randomized previously untreated DLBCL pts to G-CHOP or R-CHOP. Methods: We conducted a retrospective analysis of GALLIUM and GOYA to evaluate the percentage of pts with CR as assessed by CT but with a positive BMB at end of induction (EOI), and the percentage of pts with complete metabolic response (CMR) on positron emission tomography (PET) by Lugano 2014 criteria but with a positive BMB at EOI. Response by PET was an exploratory endpoint and not mandatory. Results: Of 1202 randomized FL pts in GALLIUM, 633 (52.7%) had a positive (613 pts, 51.0%) or indeterminate (20 pts, 1.7%) baseline BMB (data missing for 12 pts, 1.0%). Bone marrow involvement was not prognostic for progression-free survival (PFS; investigator (INV)-assessed PFS: HR 0.99 [95% CI 0.80, 1.23] for pts with positive vs non-positive BMB). At EOI, 209/633 (33%) pts had a CR on CT by IWG criteria, 179 of whom had a follow-up BMB to confirm response; 174/179 (97.2%) had a negative BMB that confirmed CR, 1/179 (0.6%) was positive, and 4/179 (2.2%) were indeterminate. Overall, only 5/179 (2.8%) pts with a positive/indeterminate baseline BMB and EOI CR by CT, or 5/1202 (0.4%) pts enrolled in the trial, had a repeat BMB result that was relevant for response assessment. Lugano 2014 criteria (determined by Independent Review Committee; IRC) were used for response assessment in 282/633 (44.5%) pts with positive/indeterminate baseline BMBs and EOI PET scans available; 251/282 (89.0%) pts had a CMR, and 213/251 (84.9%) underwent confirmatory BMBs at EOI (203 [95.3%] negative, 5 [2.3%] positive, and 5 [2.3%] indeterminate). Thus, BMB results only affected response by Lugano 2014 in 4.7% of pts having a repeat BMB (0.8% of all enrolled pts). Of 1418 randomized DLBCL pts in GOYA, 167 (11.8%) had a positive (154 pts, 10.9%) or indeterminate (13 pts, 0.9%) baseline BMB; information was missing for 14 pts (1.0%). Bone marrow involvement was prognostic for PFS (INV-assessed PFS: HR 0.75 [95% CI: 0.56, 0.99]; 3-year PFS rate 55.3% vs 69.8% for pts with positive vs non-positive BMBs, respectively). At EOI, 69/167 (41.3%) pts had a CR on CT by IWG criteria, 49 of whom had a follow-up BMB to confirm response; 47/49 (95.9%) had a negative BMB and 2/49 (4.0%) were positive. Therefore, only 2/49 (4.0%) pts with a positive/indeterminate baseline BMB and EOI CR by CT, or 2/1418 (0.1%) pts enrolled in the GOYA trial, had a repeat BMB result that was relevant for response assessment. Lugano 2014 criteria (by IRC) were used for response assessment in 121/167 (72.5%) pts with positive/indeterminate baseline BMBs and EOI PET scans available; 96/121 (79.3%) pts had a CMR, and 70/96 (72.9%) underwent confirmatory BMB. Of these, 65/70 (92.9%) were negative. Thus, BMB results only affected response by Lugano 2014 in 7.1% of pts having a repeat BMB (0.4% of all enrolled pts). Conclusions: In previously untreated FL and DLBCL pts in the GALLIUM and GOYA studies, post-induction BMB results impacted the CR rate by IWG criteria in only a minority of pts ( Disclosures Hiddemann: Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; F. Hoffman-La Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Consultancy, Research Funding. Kostakoglu:Roche: Consultancy, Honoraria; Norvatis: Consultancy, Honoraria. Marcus:F. Hoffman-La Roche: Other: Travel support and lecture fees; Roche: Consultancy, Other: Travel support and lecture fees ; Gilead: Consultancy. Martelli:F. Hoffman-La Roche: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Sandoz: Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees; Mundipharma: Membership on an entity's Board of Directors or advisory committees. Sehn:Roche/Genentech: Consultancy, Honoraria; Morphosys: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; TG Therapeutics: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Lundbeck: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Merck: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria. Trněný:Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory board; Sandoz: Honoraria; Incyte: Membership on an entity's Board of Directors or advisory committees, Other: Advisory board; Gilead: Honoraria; Abbvie: Honoraria, Research Funding; Morphosys: Membership on an entity's Board of Directors or advisory committees, Other: Advisory board; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory board; F. Hoffman-La Roche Ltd: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory board, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Advisory board. Trotman:Janssen: Other: Unremunerated member of Ad Board, Research Funding; Beigene: Research Funding; PCYC: Research Funding; F. Hoffman-La Roche: Other: Travel to meeting, Unremunerated member of Ad Board, Research Funding; Celgene: Other: Unremunerated member of Ad Board, Research Funding; Takeda: Other: Unremunerated member of Ad Board. Vitolo:Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda: Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Gilead: Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sandoz: Speakers Bureau. Nielsen:F. Hoffmann-La Roche Ltd: Employment, Other: Ownership interests PLC. Mattiello:Roche: Employment. Sahin:F. Hoffman-La Roche Ltd: Other: Ownership interests PLC. Sellam:Roche: Employment. Martin:Seattle Genetics: Consultancy; Bayer: Consultancy; AstraZeneca: Consultancy; Kite: Consultancy; Janssen: Consultancy; Gilead: Consultancy.

Introduction: The CD19 antigen is broadly and homogeneously expressed across different B-cell malignancies, including diffuse large B-cell lymphoma (DLBCL). MOR208 is an Fc-enhanced, humanized, monoclonal antibody that targets CD19, leading to natural killer (NK) cell-mediated antibody-dependent cytotoxicity, macrophage-mediated antibody-dependent phagocytosis and direct cytotoxicity. The immunomodulatory drug, lenalidomide (LEN), has both antiproliferative and antiangiogenic effects, and can stimulate the activity of immune effectors, such as NK cells. MOR208 and LEN have each shown single agent activity in patients with relapsed or refractory (R-R) DLBCL. In addition, MOR208 and LEN have shown synergy in in vitro and in vivo lymphoma models. We present results of an ongoing, multicenter phase II study designed to assess the safety and efficacy of MOR208 combined with LEN in patients with R-R DLBCL (NCT02399085). Methods:Patients >18 years of age diagnosed with DLBCL, an Eastern Cooperative Oncology Group performance status 0-2, and adequate organ function, who had relapsed after or were refractory to at least one but not more than three prior systemic therapies, including at least one CD20-targeting regimen, and who were not candidates for high-dose chemotherapy (HDC) and autologous stem cell transplantation (ASCT), were eligible. Patients with primary refractory disease (defined as no response to or progression during or within 6 months after completion of frontline therapy for DLBCL) were excluded. Treatment comprises up to twelve 28-day cycles of MOR208, administered intravenously at a dose of 12 mg/kg weekly during cycles 1-3 (plus a loading dose on day 4 of cycle 1), and every second week during cycles 4-12. LEN was administered orally at a daily dose of 25 mg on days 1-21 of each cycle, for up to 12 cycles. Patients who were progression-free after 12 cycles received MOR208 every second week until progression. The primary endpoint is the objective response rate (ORR), centrally assessed, as per the International Working Group criteria 2007, incorporating PET-based imaging. Secondary endpoints include ORR as per investigator assessment, duration of response (DoR), progression-free survival (PFS) and overall survival (OS), safety, and analysis of outcomes by cell of origin and other biomarkers. Results: As of November 2017, 81 patients had been enrolled and recruitment is complete. We report here updated preliminary results with a data cutoff of 5 June 2018. Median age was 72 years (range 41-87); 40 (49%) patients had received ≥2 prior lines of therapy (median 2, range 1-4); 31 (38%) had rituximab refractory disease; 33 (41%) were refractory to the previous line of therapy, 43 (53%) had Ann Arbor stage ≥III disease; and 42 (52%) had an International Prognostic Index of 3-5 at study entry, indicating poor prognosis. The most common treatment-emergent adverse events (any grade/grade ≥3) were neutropenia in 39/35 (48%/43%) patients, thrombocytopenia in 26/14 (32%/17%), anemia in 25/7 (31%/9%), diarrhea in 24/1 (30%/1%), pyrexia in 18/1 (22%/1%) and asthenia in 16/2 (20%/2%) patients. Thirty-four (42%) patients required dose reduction with LEN, 58 (72%) patients overall could stay on a daily LEN dose of 20 mg or higher. Based on investigator assessments, complete and partial responses were observed in 27 (33%) and 20 (25%) patients, respectively, resulting in an ORR of 58%. A further 12 (15%) patients had stable disease. With a median follow-up of 12 months, the median PFS was 16.2 months (95% CI: 6.3-not reached [NR]). Responses were durable with a median DoR not reached (95% CI: NR-NR) and 70% of responding patients were without progression at 12 months (Kaplan-Meier estimate). A significant proportion of patients (37/81; 46%) are still on study treatment, with 19 having been treated for over 12 months. Median OS has not been reached (95% CI: 18.6-NR); the 12-month OS rate was 73% (95% CI: 63-85). Conclusions: MOR208 in combination with LEN has shown highly encouraging activity in patients with R-R DLBCL who were ineligible for HDC and ASCT and who had a poor prognosis. These results indicate a significant improvement in outcome for these patients who have very limited treatment options. MOR208 plus LEN was well tolerated in this population, without evidence of additive toxicity. Treatment and follow-up are currently ongoing, as are cell of origin and other biomarker analyses. Disclosures Salles: Novartis: Consultancy, Honoraria; Epizyme: Honoraria; Gilead: Honoraria; Janssen: Honoraria; Merck: Honoraria; Morphosys: Honoraria; Pfizer: Honoraria; Servier: Honoraria; Takeda: Honoraria; Amgen: Honoraria; Acerta: Honoraria; AbbVie: Honoraria; Celgene: Honoraria, Research Funding; Roche: Honoraria, Research Funding. González-Barca:Roche: Speakers Bureau; Celtrion: Consultancy; Gilead: Consultancy; janssen: Consultancy, Speakers Bureau. Jurczak:Pharmacyclics: Research Funding; MorphoSys: Research Funding; Merck: Research Funding; Nordic Nanovector: Research Funding; Janssen: Research Funding; Epizyme: Research Funding; Celgene: Research Funding; Beigene: Research Funding; Bayer: Research Funding; Afimed: Research Funding; Sandoz-Novartis: Consultancy; Janssen: Consultancy; European Medicines Agency: Consultancy; AstraZeneca: Consultancy; Acerta: Consultancy, Research Funding; Gilead: Consultancy, Research Funding; Servier: Research Funding; Roche: Research Funding; TG Therapeutics: Research Funding. Gaidano:Morphosys: Honoraria; AbbVie: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. Kalakonda:Celgene: Research Funding. Dreyling:Bayer: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Acerta: Consultancy; Roche: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Mundipharma: Consultancy, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Sandoz: Consultancy. Zinzani:Janssen: Honoraria, Speakers Bureau; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Speakers Bureau; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Honoraria, Speakers Bureau; SERVIER: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; PFIZER: Honoraria, Membership on an entity's Board of Directors or advisory committees; TG Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; TG Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celltrion: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bayer: Membership on an entity's Board of Directors or advisory committees; Verastem: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bayer: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; PFIZER: Honoraria, Membership on an entity's Board of Directors or advisory committees. Dirnberger-Hertweck:MorphoSys: Employment. Weirather:MorphoSys: Employment. Ambarkhane:MorphoSys: Employment. Maddocks:Pharmacyclics: Research Funding; Novartis: Research Funding; Pharmacyclics/Janssen: Honoraria; AstraZeneca: Honoraria; Teva: Honoraria; Merck: Research Funding; BMS: Research Funding.

Background Internal tandem duplication (ITD) mutations inFLT3 (fms-like tyrosine kinase III) are detected in approximately 25% of patients (pts) with acute myeloid leukemia (AML) and are associated with an increased risk of relapse and adverse outcome. In the present study we evaluate the potential predictors of induction failure and CR1 duration in pts with FLT3-ITD mutated AML. Methods We retrospectively evaluated adult pts with FLT3-ITDmutated AML treated at our institution from July 2012 to January 2018. Pts with acute promyelocytic leukemia or core-binding factor AML were excluded. Demographic, clinical, laboratory and pathologic data were obtained from clinical records. FLT3-ITD mutational analysis was performed using PCR-based DNA sequencing. FLT3-ITD was quantified by the quantity of mutant allele burden as a percentage of total allele burden, high level was defined as ≥50%. Response to treatment was evaluated according to the 2003 revised International Working Group AML criteria. Patients with available cytogenetic data were classified according to the European Leukemia Net (ELN) guidelines. Statistical analysis included Mann Whitney test for continuous, Fisher's exact test for categorical variables and Kaplan-Meier survival curves for overall survival (OS) and relapse free survival (RFS). Results We identified 235 pts.The median age was 64 years (19-92) with 45% being male. Cytogenetic data at diagnosis was available in 166 pts and risk stratification by the ELN criteria included, 33 (20%) favorable, 117 (70%) intermediate and 16 (10%) adverse risk, respectively. Forty-two (18%) pts had a history of antecedent hematological disease (AHD) and 26 (11%) had therapy related AML (t-AML). Pts were treated with several different therapies as induction treatment for AML, including: high dose cytarabine based (HiDAC) in 84 (36%), conventional dose cytarabine based in 59 (26%), hypomethylating agents (HMA) in 70 (29%) and other in 22 (9%). Approximately half of pts (n=120, 51%) received a FLT3 inhibitor during induction. A total of 166 (71%) pts achieved a complete remission (CR)/CR with incomplete hematologic recovery (CRi) and 69 (29%) failed induction. Baseline characteristic of the pts are shown in Table 1. Compared with responders, pts with primary induction failure were more frequently treated with HMA based induction (p=0.001), were older (p=0.002), male (p=0.01), had an increased incidence of AHD (p=0.04), lower levels of FLT3-ITD allele ratio (p=0.04), and adverse cytogenetic risk (p=0.001). There was no significant difference in analyzed molecular mutations (Table 1). Among the 166 complete responders; 92 (61%) remain in CR1 over a median follow-up of 16 months (range, 2-69). Of the 74 (39%) pts that relapsed, 38 (23%) relapsed within 6 months of CR1, 27 (16%) between 6 to 12 months and 9 (5%) relapsed after 12 months of CR1. Median duration of CR1 was 8 months (range, 0.2-68). We classified pts into 2 categories based on their duration of CR1 including: CR1 duration 65 years (p=0.001), presence of EZH2(p>0.001) or RUNX1(p=0.01) mutations at baseline were associated with early relapse; achievement of a MRDneg by flow cytometry (p=0.0015), CR vs CRi (p Conclusions Achieving a CR and/or MRDneg identified by flow cytometry as well as the intensity of the conditioning regimens demonstrated a significant increase in RFS. The role of EZH2andRUNX1warrants further investigation. Disclosures Kadia: Amgen: Consultancy, Research Funding; Abbvie: Consultancy; Celgene: Research Funding; Pfizer: Consultancy, Research Funding; Jazz: Consultancy, Research Funding; Jazz: Consultancy, Research Funding; Abbvie: Consultancy; BMS: Research Funding; Takeda: Consultancy; Novartis: Consultancy; Amgen: Consultancy, Research Funding; BMS: Research Funding; Celgene: Research Funding; Novartis: Consultancy; Pfizer: Consultancy, Research Funding; Takeda: Consultancy. Daver:Alexion: Consultancy; Incyte: Consultancy; Kiromic: Research Funding; Novartis: Research Funding; BMS: Research Funding; Pfizer: Consultancy; ImmunoGen: Consultancy; Karyopharm: Research Funding; Sunesis: Consultancy; Karyopharm: Consultancy; Pfizer: Research Funding; ARIAD: Research Funding; Sunesis: Research Funding; Daiichi-Sankyo: Research Funding; Otsuka: Consultancy; Incyte: Research Funding; Novartis: Consultancy. Pemmaraju:plexxikon: Research Funding; Affymetrix: Research Funding; abbvie: Research Funding; celgene: Consultancy, Honoraria; samus: Research Funding; novartis: Research Funding; cellectis: Research Funding; stemline: Consultancy, Honoraria, Research Funding; daiichi sankyo: Research Funding; SagerStrong Foundation: Research Funding. Konopleva:Stemline Therapeutics: Research Funding; abbvie: Research Funding; Immunogen: Research Funding; cellectis: Research Funding. DiNardo:Karyopharm: Honoraria; Bayer: Honoraria; Celgene: Honoraria; Agios: Consultancy; Abbvie: Honoraria; Medimmune: Honoraria. Bose:Celgene Corporation: Honoraria, Research Funding; Astellas Pharmaceuticals: Research Funding; Pfizer, Inc.: Research Funding; Incyte Corporation: Honoraria, Research Funding; CTI BioPharma: Research Funding; Constellation Pharmaceuticals: Research Funding; Blueprint Medicines Corporation: Research Funding. Andreeff:Reata: Equity Ownership; United Therapeutics: Patents & Royalties: GD2 inhibition in breast cancer ; Amgen: Consultancy, Research Funding; Oncoceutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Eutropics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Consultancy, Patents & Royalties: MDM2 inhibitor activity patent, Research Funding; SentiBio: Equity Ownership; Jazz Pharma: Consultancy; Aptose: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy; Oncolyze: Equity Ownership; Astra Zeneca: Research Funding. Ravandi:Xencor: Research Funding; Jazz: Honoraria; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Jazz: Honoraria; Sunesis: Honoraria; Seattle Genetics: Research Funding; Seattle Genetics: Research Funding; Orsenix: Honoraria; Sunesis: Honoraria; Abbvie: Research Funding; Xencor: Research Funding; Macrogenix: Honoraria, Research Funding; Orsenix: Honoraria; Amgen: Honoraria, Research Funding, Speakers Bureau; Amgen: Honoraria, Research Funding, Speakers Bureau; Macrogenix: Honoraria, Research Funding; Astellas Pharmaceuticals: Consultancy, Honoraria; Astellas Pharmaceuticals: Consultancy, Honoraria; Abbvie: Research Funding. Cortes:novartis: Research Funding.

In this issue of Blood, Savona and an international consortium of clinical investigators propose uniform response criteria for treatment trials enrolling adult patients with myelodysplastic/myeloproliferative neoplasms (MDS/MPNs). Such a proposal is needed because new drugs are finally being tested in these rare “overlap” syndromes that have both dysplastic and proliferative pathological features, and neither the International Working Group (IWG) response criteria for myelodysplastic syndromes nor the IWG Myeloproliferative Neoplasms Research and Treatment (IWG-MRT) response criteria for myelofibrosis or for other myeloproliferative neoplasms fit such patients well.

In a previous publication on new terminology, definitions, and outcome criteria for immune thrombocytopenia (ITP), the International Working Group (IWG) on ITP acknowledged that response to treatment should consist of clinically meaningful end points such as bleeding manifestations and that platelet count may not be the ideal parameter for capturing the benefits of therapy. The IWG now proposes a consensus-based ITP-specific bleeding assessment tool (ITP-BAT) with definitions and terminology consistent with those adopted for other bleeding disorders. Bleeding manifestations were grouped into three major domains: skin (S), visible mucosae (M), and organs (O), with gradation of severity (SMOG). Each bleeding manifestation is assessed at the time of examination. Severity is graded from 0 to 3 or 4, with grade 5 for any fatal bleeding. Bleeding reported by the patient without medical documentation is graded 1. Within each domain, the same grade is assigned to bleeding manifestations of similar clinical impact. The “worst bleeding manifestation since the last visit” (observation period) is graded (a suitable database collection form is provided), and the highest grade within each domain is recorded. The SMOG system provides a consistent description of the bleeding phenotype in ITP, and the IWG unanimously supports its adoption and validation in future clinical studies.

With the use of the International Working Group for Myelofibrosis Treatment and Research consensus criteria, we re-assessed the efficacy of thalidomide and lenalidomide in 125 patients with myelofibrosis treated in 3 consecutive phase 2 trials: 44 received single-agent thalidomide, 41 single-agent lenalidomide, and 40 a combination of lenalidomide plus prednisone. The thalidomide group included significantly more untreated patients and patients with performance status of 2. The Lenalidomide-based therapy produced higher efficacy (34%-38%) than thalidomide (16%; P = .06). Responses to thalidomide were seen within 3-15 weeks, whereas responses to the lenalidomide-based therapy were also seen after a prolonged course of therapy (range, 2-45 weeks). Lenalidomide plus prednisone therapy resulted in significantly longer response duration (median, 34 months) than single-agent lenalidomide or thalidomide (median, 7 and 13 months, respectively; P = .042). Fewer patients (P = .001) discontinued the lenalidomide plus prednisone therapy (13%) because of side effects then patients on single-agents therapy (32%-39%). In conclusion, the combination of lenalidomide plus prednisone appears to be more ef-fective and safer than single-agent thalidomide or lenalidomide.

Introduction CPX-351 (Vyxeos), a liposomal formulation of cytarabine and daunorubicin encapsulated at a 5:1 molar ratio, has shown enhanced efficacy compared with standard induction in older adults with high-risk AML in phase II clinical trials. Presented here are pre-specified secondary subgroup results from a phase III randomized, open-label study of CPX-351 versus 7+3 (cytarabine plus daunorubicin) in newly diagnosed patients with high-risk features, focusing on efficacy results stratified by age group. Methods Eligible patients were aged 60 to 75 years and had secondary AML, either therapy-related or an antecedent myelodysplastic syndrome (MDS), chronic myelomonocytic leukemia, or AML with World Health Organization-defined MDS-related cytogenetic abnormalities. Patients were randomized 1:1 to receive CPX-351 induction (100 units/m2 [100 mg/m2 cytarabine + 44 mg daunorubicin mg/m2] on days 1, 3, and 5 [first induction only]) or 7+3 induction (cytarabine 100 mg/m2/day x 7 days plus daunorubicin 60 mg/m2 on days 1, 2, and 3 [first induction] or x 5 days [reinduction/consolidation] plus daunorubicin 60 mg/m2 on days 1 and 2). A dynamic allocation procedure was performed to stratify patients by age group (60-69 or 70-75 years) for each arm of the study. The distribution of overall survival (OS) by treatment arm was estimated using the method of Kaplan-Meier. Efficacy for each age group was reported in terms of median OS in months and percentage of patients with a morphologic complete remission (CR) or CR with incomplete platelet or neutrophil recovery (CRi) according to International Working Group criteria. Results Three hundred and nine patients were enrolled from December 2012 to November 2014 at 39 US and Canadian sites, with 153 patients randomized to the CPX-351 arm and 156 to the 7+3 arm. Among patients aged 60-69 years, there were 96 patients in the CPX-351 arm and 102 in the 7+3 arm; for patients aged 70-75 years, there were 57 and 54 patients in each arm, respectively. Demographic data for these age subgroups were similar between the CPX-351 and 7+3 arms of the study. The CR+CRi rates for patients aged 60-69 years were 50.0% for patients in the CPX-351 arm and 36.3% in the 7+3 arm, with an odds ratio (OR) of 1.76 (95% confidence interval [CI], 1.00-3.10); for patients aged 70-75 years, the rates of CR+CRi were 43.9% and 27.8%, respectively, with an OR of 2.03 (95% CI, 0.92-4.49). Kaplan-Meier curves for OS by age group are shown in the Figure. Median OS in months for patients aged 60-69 years was 9.63 in the CPX-351 arm and 6.87 in the 7+3 arm, with a hazard ratio of 0.68 (95% CI, 0.49-0.95); for patients aged 70-75 years these were 8.87 for the CPX-351 arm and 5.62 for the 7+3 arm, with a hazard ratio of 0.55 (95% CI, 0.36-0.84). The allogeneic hematopoietic cell transplant (HCT) rate in patients aged 60-69 years was 37.5% in the CPX-351 arm and 32.4% in the 7+3 arm, with an OR of 1.25 (95% CI, 0.70-2.25). For patients aged 70-75 years, the allogeneic HCT rates were 28.1% and 11.1%, respectively, with an OR of 3.12 (95% CI, 1.12-8.72). Incidence of grade 3-5 adverse events were virtually equal (92% vs 91%) and were similar in frequency and severity in both arms. The most common grade 3-5 nonhematologic adverse events (>10% overall) were febrile neutropenia (CPX-351: 68%; 7+3: 71%), pneumonia (CPX-351: 20%; 7+3: 15%), and hypoxia (CPX-351: 13%; 7+3: 15%). Conclusions This subgroup analysis of patients aged 60-69 and 70-75 years with untreated secondary AML demonstrated that CPX-351 treatment had substantially greater median OS and higher CR+CRi rates than standard 7+3 (cytarabine and daunorubicin) in both age groups. In addition, somewhat more patients in each age group in the CPX-351 arm received allogeneic HCT compared with the 7+3 arm, with the greatest difference in the older age group. Future studies with larger patient groups are warranted. Support: Celator Pharmaceuticals, Inc., a subsidiary of Jazz Pharmaceuticals plc. Disclosures Medeiros: Agios: Consultancy, Research Funding; Amgen: Consultancy; ARIAD: Consultancy; Celgene: Consultancy, Other: Travel, Accomodations, Expenses, Research Funding; Novartis: Consultancy, Research Funding; Pfizer: Consultancy; Roche/Genentech: Consultancy, Research Funding; Celator: Other: Travel, Accomodations, Expenses, Research Funding; MEI Pharma: Research Funding; Merck/Schering Plough: Research Funding. Lancet:Celgene: Consultancy, Research Funding; Quantum First: Consultancy; Kalo Bios: Consultancy; Pfizer: Research Funding; Novartis: Consultancy; Jazz Pharmaceuticals: Consultancy; ERYtech: Consultancy; Biopath Holdings: Consultancy; Karyopharm: Consultancy; Boehringer-Ingelheim: Consultancy; Seattle Genetics: Consultancy; Baxalta: Consultancy; Amgen: Consultancy. Cortes:ARIAD: Consultancy, Research Funding; Bristol-Myers Squib: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Teva: Research Funding. Ritchie:Celgene: Consultancy, Other: Travel, Accomodations, Expenses, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Novartis: Consultancy, Other: Travel, Accommodations, Expenses, Research Funding, Speakers Bureau; Ariad: Speakers Bureau; Pfizer: Consultancy, Research Funding; Astellas Pharma: Research Funding; Bristol-Meyers Squibb: Research Funding; NS Pharma: Research Funding. Stuart:Astellas: Research Funding; Incyte: Research Funding; Agios: Research Funding; Sunesis: Consultancy, Honoraria, Other: Travel, Accomodations, Expenses, Research Funding; Bayer: Research Funding; Celator: Research Funding. Strickland:Sunesis Pharmaceuticals: Consultancy, Research Funding; Boehringer Ingelheim: Consultancy, Research Funding; Celator: Research Funding; Astellas Pharma: Research Funding; Alexion Pharmaceuticals: Consultancy; Sanofi: Research Funding; CTI Biopharma: Consultancy; Karyopharm Therapeutica: Research Funding; Baxalta: Consultancy; Daiichi Sankyo: Consultancy; Ambit: Consultancy; Abbvie: Research Funding; Cyclacel: Research Funding; GlaxoSmithKline: Research Funding. Hogge:Sanofi: Consultancy; Roche: Other: Travel, Accomodations, Expenses. Stone:ONO: Consultancy; Xenetic Biosciences: Consultancy; Seattle Genetics: Consultancy; Amgen: Consultancy; Agios: Consultancy; Karyopharm: Consultancy; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy; Juno Therapeutics: Consultancy; Celator: Consultancy; Roche: Consultancy; Sunesis Pharmaceuticals: Consultancy; Merck: Consultancy; Pfizer: Consultancy; Jansen: Consultancy. Kolitz:Gliead Sciences: Consultancy; Seattle Genetics: Consultancy; Pharmacyclics: Consultancy. Schiller:Celator: Research Funding. Ryan:AbbVie: Equity Ownership; U of Rochester: Patents & Royalties. Chiarella:Celator Pharmaceuticals, Inc., a subsidiary of Jazz Pharmaceuticals plc.: Employment, Equity Ownership. Louie:Celator Pharmaceuticals, Inc., a subsidiary of Jazz Pharmaceuticals plc.: Employment, Equity Ownership. Uy:Glycomimetics: Consultancy; Boehringer Ingelheim: Consultancy.

Introduction. Primary immune thrombocytopenia is a rare disease1. The incidence of ITP is not well estimated in Russia and worldwide. In adults it varies from 1,6 to 3,9/100 000 person-years2-3. The gender and age-associated results are discussed and differ in several investigations4-6. Study objectives: evaluation of the incidence of primary immune thrombocytopenia in adults in one region of Russia Patients and methods. The data source is the Registry of the patients with primary ITP in Russia. 272 adult patients: 77 males (28%) and 195 females (72%), age from 16 to 89 years (median 44 years) with ITP (ICD-10 code D69.3), newly diagnosed cases during the period from 12 Jan 2014 to 24 May 2016. Results. 221 (81%) cases were newly diagnosed in 12 regions of Russia in which registration was performed most actively - more than 5 cases for the duration of the study. But only one region was selected for the first evaluation of epidemiological characteristics because of the number of reasons. There is one hematological central clinic in this region in which diagnosis of ITP can be verified and patients with ITP are treated and monitored most properly. The early started and fully performed registration process can be regarded as covered most part of region population in this target region. 86 cases (27 male, 59 female) were registered in the target region. The gender-age distribution was following: male: age 60 = 10 (37%); female: age 60 = 15 (25%). The estimated incidence rate in the target region is shown in table 1. The estimated incidence rates in gender-age strata in the target region are demonstrated in table 2. Conclusion. Overall ITP incidence in one region of Russia is 3.20/100 000 person-years. It is compatible to the incidence in other European countries. Our data demonstrate the rise of incidence rate in males with age and its decrease with age in female population. Literature. 1) Rodeghiero F., Stasi R., Gernsheimer T., Michel M., Provan D., Arnold D.M., et al. Standardization of terminology, definitions and outcome criteria in immune thrombocytopenic purpura of adults and children: report from international working group. Blood. 2009; 113(11): 2386--93. doi: 10.1182/blood-2008-07-162503. 2) Terrell DR, Beebe LA, Vesely SK, Neas BR, Segal JB, George JN. The incidence of immune thrombocytopenic purpura in children and adults: A critical review of published reports. Am J Hematol. 2010; 85(3): 174-180. 3) Moulis G, Palmaro A, Montastruc J-L, Godeau B, Lapeyre-Mestre M, Sailler L. Epidemiology of incident immune thrombocytopenia: a natiowide population-based study in France. Blood. 2014; 124(22): 3308-3315. 4) Segal JB, Powe NR. Prevalence of immune thrombocytopenia: analyses of administrative data. J Thromb Haemost 2006; 4: 2377-83 5) Schoonen WM, Kucera G, Coelson J, et al. Epidemiology of immune thrombocytopenic purpura in the General Practise Research Database. Br J Haematol 2009; 145(2): 235-244. 6) Lisukov I.A., Maschan A.A., Shamardina A.V., Chagorova T.V., Davydkin I.L., Sycheva T.M., et al. Immune thrombocytopenia: clinical manifestations and response to therapy. Intermediate analysis of data of the Russian register of patients with primary immune thrombocytopenia and review of literature. Oncogematologiya. 2013; 2: 61--9]. Disclosures No relevant conflicts of interest to declare.

Introduction: The 2008 World Health Organization classification recognized a unique overlap category that combines features of myelodysplastic syndromes (MDS) and myeloproliferative neoplasms (MPN). The least well characterized of the 4 overlap diseases is a rare entity known as MDS/MPN Unclassifiable (MDS/MPN-U), comprising Methods: We identified MDS/MPN-U patients within the Moffitt MDS database, baseline characteristics were reviewed, and responses to HMA utilizing IWG 2006 response criteria were assessed. The Kaplan-Meier method was applied to estimate overall survival (OS). Results: Among 127 patients with MDS/MPN-U, 62 patients received HMA treatment. There was no difference in baseline characteristics among those who received HMA or not, except that those treated with HMA were less likely to have low risk disease by IPSS, MD Anderson model or very low risk by revised IPSS (R-IPSS). Among 16 patients who had NextGen sequencing data, the 5 most common mutations were ASXL-1 (56%), TET2 (31%), JAK2 (33%), SRSF2 (25%), as well as SETBP1, DNMT3A, and EZH2(19%). The best overall response to HMA (hematological improvement [HI] or better) according to the International Working Group (IWG) 2006 criteria was 26%. Only 11 patients (low risk) underwent allogeneic stem cell transplant (allo-SCT) with no improvement or decrease in OS. The median OS was 33 months (mo). Among patients with IPSS low/int-1 risk disease, the median OS was 39 and 33 mo respectively for those treated with HMA vs. HMA untreated. (p=0.50). For Int-2/high risk IPSS, the median OS was 11 and 5 mo for those who received HMA and those who did not. (p=0.02). Based on R-IPSS the median OS for very low/low risk was 47 and 39 mo respectively for those treated with HMA and without (p=0.96), for intermediate risk, the median OS was 39 and 25 mo respectively (p 0.75), and for high and very high risk the median OS was 13 and 5 mo respectively for those treated with HMA and those who did not. (p < 0.005). The median OS for patients with HI+, stable disease or progressive disease was 68, 59, and 36 mo respectively (p=0.08). Conclusions: Treatment with HMA is associated with modest improvement in OS among higher risk MDS/MPN-U, reinforcing the unmet need to improve outcomes in this group. Targeted therapy may prove to be of benefit as allo-SCT does not appear to be beneficial for patients even with low risk disease. Furthermore, these data demonstrate the need for prospective analysis of the outcomes of allo-SCT in patients with MDS/MPN-U to determine potential benefit to high risk patients. Disclosures Komrokji: Novartis: Consultancy, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding.

To develop a prognostic scoring system tailored for therapy-related myelodysplastic syndromes (tMDS), we put together a database containing 1933 patients (pts) with tMDS from Spanish, German, Swiss, Austrian, US, Italian, and Dutch centers diagnosed between 1975-2015. Complete data to calculate the IPSS and IPSS-R were available in 1603 pts. Examining different scoring systems, we found that IPSS and IPSS-R do not risk stratify tMDS as well as they do primary MDS (pMDS), thereby supporting the need for a tMDS-specific score (Kuendgen et al., ASH 2015). The current analysis focuses on cytogenetic information as a potential component of a refined tMDS score, based on this large, unique patient cohort. Of the 1933 pts, 477 had normal karyotype (KT), 197 had missing cytogenetics, while 467 had a karyotype not readily interpretable. Incomplete karyotype descriptions will be reedited for the final evaluation. Of the remaining 1269 pts the most frequent cytogenetic abnormalities (abn) were: -7, del(5q), +mar, +8, del(7q), -5, del(20q), -17, -18, -Y, del(12p), -20, and +1 with >30 cases each. Frequencies are shown in Table 1. Some abn were observed mostly or solely within complex KTs, such as monosomies, except -7. Others, like del(20q) or -Y, are mainly seen as single or double abn, while del(5q), -7, or del(7q) are seen in complex as well as non-complex KTs. The cytogenetic profile overlapped with that of pMDS (most frequent abn: del(5q), -7/del(7q), +8, -18/del(18q), del(20q), -5, -Y, -17/del(17p), +21, and inv(3)/t(3q) (Schanz et al, JCO 2011)), with notable differences including overrepresentation of complete monosomies, a higher frequency of -7 or t(11q23), and a more frequent occurrence of cytogenetic subtypes in complex KTs, which was especially evident in del(5q) occurring as a single abn in 16%, compared to 70% within a complex KT. IPSS-R cytogenetic groups were distributed as follows: Very Good (2%), Good (35%), Int (17%), Poor (15%), Very Poor (32%). Regarding the number of abn (including incomplete KT descriptions) roughly 30% had a normal KT, 20% 1, 10% 2, and 40% ≥3 abn, compared to pMDS: 55% normal KT, 29% 1, 10% 2, and 6% ≥3 abn. To be evaluable for prognostic information, abn should occur in a minimum of 10 pts. As a single aberration this was the case for -7, +8, del(5q), del(20q), del(7q), -Y, and t(11;varia) (q23;varia). Of particular interest, there was no apparent prognostic difference between -7 and del(7q); del(5q) as a single abn was associated with a relatively good survival, while the prognosis was poor with the first additional abn; t(11q23) occurred primarily as a single abn and was associated with an extremely poor prognosis, and prognosis of pts with ≥4 abn was dismal independent of composition (Table 1). To develop a more biologically meaningful scoring system containing homogeneous and prognostically stable groups, we will further combine subgroups with different abn leading to the same cytogenetic consequences. For example, deletions, unbalanced translocations, derivative chromosomes, dicentric chromosomes of 17p, and possibly -17 all lead to a loss of genetic material at the short arm of this respective chromosome affecting TP53. Further information might be derived from analyses of the minimal common deleted regions. For some abn, like del(11q), del(3p), and del(9q), this can be refined to one chromosome band only (table 1). Conclusion: Development of a robust scoring system for all subtypes of tMDS is challenging using existing variables. This focused analysis on the cytogenetic score component shows that favorable KTs are evident in a substantial proportion of pts, in contrast to historic data describing unfavorable cytogenetics in the majority of pts. Although complex and monosomal KTs are overrepresented, this suggests the existence of distinct tMDS-subtypes, although some of these cases might not be truly therapy-induced despite a history of cytotoxic treatment. The next steps will be to analyze the prognosis of the different groups, develop a tMDS cytogenetic score, and examine minimal deleted regions to identify candidate genes for development of tMDS, as well as to describe the possible influence of different primary diseases and treatments (radio- vs chemotherapy, different drugs) on induction of cytogenetic subtypes. Our detailed analysis of tMDS cytogenetics should reveal important prognostic information and is likely to help understand mechanisms of MDS development. Disclosures Komrokji: Novartis: Consultancy, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding. Sole:Celgene: Membership on an entity's Board of Directors or advisory committees. Sekeres:Celgene: Membership on an entity's Board of Directors or advisory committees; Millenium/Takeda: Membership on an entity's Board of Directors or advisory committees. Roboz:Cellectis: Research Funding; Agios, Amgen, Amphivena, Astex, AstraZeneca, Boehringer Ingelheim, Celator, Celgene, Genoptix, Janssen, Juno, MEI Pharma, MedImmune, Novartis, Onconova, Pfizer, Roche/Genentech, Sunesis, Teva: Consultancy. Steensma:Amgen: Consultancy; Genoptix: Consultancy; Janssen: Consultancy; Celgene: Consultancy; Millenium/Takeda: Consultancy; Ariad: Equity Ownership. Schlenk:Pfizer: Honoraria, Research Funding; Amgen: Research Funding. Valent:Amgen: Honoraria; Deciphera Pharmaceuticals: Research Funding; Celgene: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Ariad: Honoraria, Research Funding; Deciphera Pharmaceuticals: Research Funding. Giagounidis:Celgene Corporation: Consultancy. Giagounidis:Celgene Corporation: Consultancy. Platzbecker:Celgene Corporation: Honoraria, Research Funding; TEVA Pharmaceutical Industries: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Janssen-Cilag: Honoraria, Research Funding; Amgen: Honoraria, Research Funding. Lübbert:Janssen-Cilag: Other: Travel Funding, Research Funding; Celgene: Other: Travel Funding; Ratiopharm: Other: Study drug valproic acid.

Morel and Duhamel question the statistical methodology used in the validation of the new prognostic scoring system for primary myelofibrosis (PMF) recently proposed by the International Working Group for Myelofibrosis Research and Treatment (IWG-MRT)[1][1] and the need for a new prognostic score.

Background The Immature Platelet Fraction (IPF) is a novel parameter available on the Sysmex XE-Series Hematology analyzers. It can be expressed as both IPF percent (IPF %) and absolute IPF count (AIPF#). It has been shown that IPF% is higher in Immune Thrombocytopenia (ITP) than in the normal population, and correlates with bone marrow platelet production or thrombopoiesis. Objectives To evaluates the utility of the IPF parameters to predict treatment response or recovery in pediatric ITP patients. Method This is a retrospective, single institution study performed at a 165 bed tertiary care pediatric hospital (Children's Hospital of Eastern Ontario, Ottawa, Canada). We reviewed the medical charts and electronic databases of all patients with ITP who had measured IPF parameters between June 2011 and June 2013. The standard definitions and terminology of the International Working Group were used. Patient age, phase of ITP at the time of the study (acute, persistent, and chronic), initial platelet count, IPF%, AIPF#, and type of therapy given (including observation alone) were recorded. For patients who responded to treatment or had spontaneous recovery without treatment, we analyzed the platelet count, IPF% and AIPF# on subsequent CBCs, then looked at the course of IPF% during platelet count recovery. Comparisons between groups were performed using Kruskal-Wallis tests or Mann-Whitney tests, as appropriate. Association between measured blood parameters was measured using the Spearman correlation coefficient. Within-patient Spearman correlations were also used to study the association between IPF% and platelet counts during recovery. The combined significance of these associations was determined using Stouffer’s method. Results Conclusion IPF measurements are easily available parameters that are useful in the management of ITP in pediatric patients. This study suggests the use of AIPF# as a predictive factor for recovery in pediatric ITP patients with and without treatment, and IPF% as a predictive factor for early recovery. Disclosures: No relevant conflicts of interest to declare.

Abstract 1746 Diagnosis of essential thrombocythemia (ET) has been updated in the last World Health Organization (WHO) classification, that provides a guideline to distinguish ET from early/prefibrotic primary myelofibrosis. These two conditions differ in term of disease evolution and survival (Barbui et al, J. Clin. Oncol. 2011). To design a prognostic model for survival in WHO-defined ET (International Prognostic Score for Essential Thrombocythemia, IPSET), we studied 891 patients with strict WHO diagnostic criteria. Demographics have been presented elsewhere (Barbui et al, J. Clin. Oncol. 2011). We tested the prognostic impact on survival of age, prior thrombosis, leukocyte count, platelet count, hemoglobin level, JAK mutational status, splenomegaly. Harrell's C concordance statistics were used to set the best cutoff levels of continuous variables in order to predict survival. Univariate Cox proportional hazard regression showed that age over 60 years (P Disclosures: Vannucchi: Italfarmaco: Consultancy; Novartis: Honoraria. Gisslinger:AOP Orphan Pharmaceuticals AG: Research Funding.

We read with interest Dr Raza's letter[1][1] in response to the International Working Group's (IWG's) proposal to provide standardized response criteria in myelodysplastic syndromes (MDSs).[2][2] Developing consistent guidelines for MDSs presents a challenge since the clinical course of the disease

Abstract 4981 Background. In the two International Prognostic Scoring Systems of Myelodysplastic Syndrom (MDS), the percentage of BLAST cells in the Bone Marrow is the most important parameter implicated in score: either directly in the IPSS (International Prognostic Scoring System) (1) or indirectly in the WPSS (Who classification-based prognostic scoring system) (2). In these two systems, as in the recommendations of the WHO 2001 (3), the morphological criteria defining blasts cells compared to promyelocyte cells are not specified. In 2005, the IWGM-MDS (International Working Group on Morphology of myelodysplastic syndrome) (4-6) has established morphological criteria defining Blasts cells. PURPOSE OF THE WORK. Our objective in this study is to evaluate the reproducibility, among five observers of our laboratory, of the counting of the marrow blasts of 73 myelodysplasia. Materials and Methods. This study was conducted in several stages. 1st step was to test the implementation of the MDS-Foundation (http://www.mds- foundation.org/virtualmicroscopy) by 5 observers. The 2nd step was to perform correlation test of the selected cells from RAEB (selected and stained in our laboratory conditions), for the 5 observers. Finally Step 3 was to assess the correlation of blast percentage of 73 bone marrow smears from MDS patients, selected due to the presence of an excess of blast cells in the first reading on the bone aspiration. Results. Our results show that the correlation on counting blasts is generally satisfactory (percentage agreement: Test 1 = 86% and test 2 = 94%), while the concordance on the counting blasts of bone marow smears of 73 MDS patients and concordance on the WHO classification seems less satisfactory (agreement 3/5 observers. = 95% but agreed to 4–5/5 observers = 64%). These results can be explained partly by the inter-observer variability and by the variability of some parameters specific to smear marrow (poor quality smears, the staining and/or poverty of smears). Conclusion. The evaluation of the blasts in the MDS must be achieved: (i) at least 500 cells counted (ii) by at least two different observers (iii) by a third observer in discordant case. Despite these recommendations, the assessment of the blasts in myelodysplasia is difficult to achieve in many cases. Disclosures: No relevant conflicts of interest to declare.

To the editor: We read with interest the description by Cervantes and the International Working Group for Myelofibrosis Research and Treatment (IWG-MRT) of a new prognostic index for patients with primary myelofibrosis.[1][1] This system, based on 5 adverse characteristics, identified 4 prognostic

Introduction: Several recent publications have advanced our knowledge of the prognostic significance of clonal cytogenetic abnormalities in MDS, yet the genetic risk assessment of the rare karyotypic aberrations in MDS patients (pts) remains unknown. Using the German-Austrian (G-A) Cytogenetics Database, we previously defined 24 cytogenetic prognostic subgroups; however, 12 subgroups characterized by non-complex (isolated or one additional abnormality only) karyotypes with del(9q), del(15q), t(15q), del(12p), −X, t(1q), t(7q), t(17q), −21, t(11q23), +19, t(5q) were observed infrequently ( Patients and Methods: A total of 90 new MDS pts with rare recurring abnormalities was collected from 12 MDS Foundation Centers of Excellence, of which 66 pts fulfilled the non-complex requirement. Survival was estimated by Kaplan-Meier analysis and restricted to pts treated by supportive care only. The final analysis included 108 pts: del(9q)(n=10); del(12p)=17; −X=10; t(1q)=13; t(7q)=14; −21=12; t(11q23)=12; +19=10; t(5q)=10. The frequency of non-complex del(15q), t(15q) and t(17q) remained below ten pts and deemed ineligible for further analysis at this time. Results: The pooled international data showed an excellent correlation with the G-A data set in 6 of 10 cytogenetic subgroups: t(7q): 34.7 months (mo.) median survival (G-A) vs. 34.7 mo. (new data), del(9q): not reached vs. 63.1 mo., t(11q23): 20.0 vs. 28.0 mo, del(12p): 108.0 mo. vs. not reached, +19: 19.8 vs. 21.7 mo., −21: 32.0 vs. 35.0 mo. A moderate correlation was found for t(1q): 34.7 mo. vs. not reached and for del(15q): not reached vs. 26.7 mo. Discordant median survival was observed for t(5q): 4.4 mo. vs. not reached and −X: 56.4 mo. vs. 15.7 mo. Conclusions: Through an international collaboration, we were able to define the prognostic impact of nine distinct yet infrequent, recurring cytogenetic aberrations observed in MDS pts. The discordant median survival differences observed in two subgroups may be attributed to various translocation partners and/or secondary abnormalities. Even though data collection remains ongoing, the current results expand and refine the cytogenetic prognostic classification system for pts suffering from MDS and underscore the need for standardized cytogenetic testing in MDS for further international collaborations.

Background: We sought to retrospectively analyze the clinical differences, at diagnosis and throughout the disease course, between patients with primary myeloifbrosis whom undergo blastic transformation (PMF-BP) and those whom expire from PMF complications without undergoing transformation. Methods: An international collaborative database of patients with PMF which progressed to PMF BP, and a control group of individuals with PMF who expired secondary to PMF was created. Data regarding clinical course, bone marrow, karyotypic, quantitative JAK2V617F analysis (when able), laboratory values, and therapy at the diagnosis of PMF, PMF BP and up to 4 return visits (R1-4) in between these milestones was abstracted. Results: COMPARISON AT DIAGNOSIS OF PMF: 136 cases of PMF who eventually underwent PMF-BP were included, with a control group of 42 PMF patients, were analyzed. Both groups of patients had similar demographic (median age at diagnosis 59 years (range 23–83)/ 59.1 (15–93); and disease parameters (median hemoglobin 10 g/dL (range 2–15.7) /9.8 (4.9–14.6); median platelet count 181 x 109/L (range 7–1400)/168 (16–1916)), and Lille PMF prognostic scores (p = n.s.) for PMF-BP vs. PMF control group respectively. Additionally, blasts (peripheral blood /marrow) were a median of 0% (range 0–18%)/ 2% (range 0–16%) for the study group versus 0.25% (range 0–5%)/ 3% (range 0–4%) (p = n.s. for both) for the control group, respectively. Both groups had similar rates of requiring therapy (86%; 93%) and survival from diagnosis (median 34 months (range 2–441); 29 months (1–236)) (p = n.s.). However, lactate dehydrogenase (LDH) (although high in both groups) was higher at diagnosis (median 802 IU/L (range 83–10353) vs. 416 IU/L (124–2197)) (p=0.04), as well as an abnormal marrow karyotype (85% vs. 25%; p SUBSEQUENT CLINICAL COURSE: Analyzing the clinical evolution between groups demonstrated persistently higher LDH and worsening thrombocytopenia in the PMF-BP cohort (see figure). Decreasing Platelets Approaching PMF BP Decreasing Platelets Approaching PMF BP Peripheral blood blasts increased in both groups, but values above 10% were unique to the PMF BP group. Additionally marrow karyotype displayed clonal evolution developed in 56% of the PMF-BP patients as opposed to 14% of controls (p Conclusions: Increasing LDH, peripheral blood blast percentages >10%, and clonal evolution are features commonly seen in PMF patients whom evolve to blast phase and may be a harbinger of movement towards PMF BP.

Myelodysplastic syndromes (MDS) are hematopoietic disorders characterized by peripheral cytopenias and risk of progression to leukemia. MDS patients (pts) are often anemic, resulting in increased red blood cell transfusions (tfns) and fatigue. Previous studies have shown that 150mcg/week (wk) or 300mcg/wk of the erythropoiesis-stimulating agent (ESA) darbepoetin alfa (DA) can raise hemoglobin (Hb) levels in low-risk MDS pts (Patton et al. J Support Oncol. 2005;3:419–426). We present data from a phase 2, single-arm, open-label study on the efficacy of 500mcg DA administered every three wks (Q3W) for treating anemia in low-risk MDS pts. Eligibility criteria included ≥18 years, anemia (Hb ≤11g/dL), and low- or intermediate-1-risk MDS (IPSS definition). If pts did not respond by wk 7, the dosing frequency was escalated to Q2W. After the last DA dose on wk 52, the end of study (EOS) was wk 53 (Q2W dosing) or wk 55 (Q3W dosing). The primary endpoint was the percentage of pts with an erythroid response (International Working Group criteria) by wk 13. Secondary 53/55-wk endpoints included incidence of erythroid responses, incidence of tfns, and the change in Hb levels and FACT-F score from baseline (BL). Results were stratified by whether pts had prior ESA therapy: ESA-naive (ESA-N) vs prior ESA-treated (ESA-T). A previous interim analysis showed that low-risk MDS pts could achieve an erythroid response after 13 wks of DA 500mcg Q3W (Gabrilove et al. Blood. 2005;106:abstract2541). This is the first reported summary after 53/55 wks (n=148). Of 98 ESA-N pts, 47% were men, 85% were white, and the mean (SD) age was 74 (10) years; the 50 ESA-T pts had similar demographics. Both ESA-N and ESA-T pts had similar BL Hb (Table). By wk 53/55, the percentage (95% CL) of pts with a major erythroid response (≥2g/dL Hb rise from BL or tfn independence) was 56% (46, 66) in ESA-N pts and 30% (17, 43) in ESA-T pts. Both ESA-N and ESA-T pts had a clinically meaningful rise (≥3 points) in FACT-F score from BL. Of the 148 pts, 89% reported adverse events (AEs) with the most common AE being fatigue, 7% had AEs considered related to DA treatment, and 1.4% had thromboembolic events. These results suggested that DA 500mcg Q3W was well tolerated and increased Hb levels in the MDS pts in this study. | | ESA-N, N=98 | ESA-T, N=50 | |:----------------------------------------------------------------- | ------------------- | ------------------- | | KM%= Kaplan-Meier percentage | | Crude % (95% CL) pts with a major erythroid response | 56% (46, 66) | 30% (17, 43) | | Crude % (95% CL) pts with a minor erythroid response | 15% (8, 22) | 20% (9, 31) | | Mean (SD) BL Hb, g/dL | 9.8 (1.0) [n=84] | 10.0 (1.2) [n=41] | | Mean (SD) Hb change (BL to wk 53/55) (last value carried forward) | 1.1 (1.6) [n=84] | 0.2 (1.7) [n=41] | | Crude % (95% CL) pts achieved target Hb (11g/dL) | 68% (58, 78) [n=87] | 46% (31, 60) [n=46] | | Mean (SD) Hb after reached Hb target, g/dL | 11.7 (0.8) [n=68] | 11.6 (0.9) [n=25] | | KM% (95% CL) pts with tfns (wk 1 to EOS) | 29% (19, 39) | 43% (27, 59) | | KM% (95% CL) pts with tfns (wk 5 to EOS) | 28% (19, 38) [n=96] | 43% (26, 60) [n=45] | | Mean (SD) change in FACT-F score (BL to wk 53/55) | 5.8 (8.6) [n=45] | 7.2 (9.3) [n=15]

Background. Clofarabine, an adenosine nucleoside analog, is active in acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL). Its anti-MDS activity is not well defined. Study Aims. To evaluate the safety and efficacy of clofarabine in MDS in two studies, one with intravenous administration and one with oral, using lower doses than those for leukemia (40–52 mg/m2 IV daily x 5). Study Group and Results. The first study randomized patients in a Bayesian design to receive clofarabine 15 or 30 mg/m2 IV daily x 5 every 4–6 weeks. The second study used clofarabine 40 mg/m2 orally daily x 5 every 4–6 weeks (assuming oral bioavailability about 50%). Standard eligibility criteria for MDS were used; only high risk MDS patients (IPSS intermediate or high) were eligible. So far, 16 patients have been treated, 10 on IV clofarabine and 6 on oral clofarabine. Age ≥60 yr in 13 (81%); prior therapy with decitabine/azacitidine 11 (69%); cytogenetic abnormalities 12 (75%). Responses were graded according to International Working Group criteria (IWG). Results are shown in the table below. Myelosuppression was significant resulting in febrile episodes and hospitalization in 4/6 patients on oral clofarabine and in 4/10 patients on IV clofarabine. Rash grade 3 was noted in 1 patient on oral clofarabine. Summary. Clofarabine is active in MDS. The oral dose of 40 mg/m2 daily x 5 may be too high for MDS; lower dose of oral clofarabine 30 mg/m2 orally daily x 5 will be tested with PK studies. The 2 IV schedules (15 vs. 30 mg/m2) are ongoing. Oral Clofarabine IV Clofarabine • Treated/evaluable to date 6/3 10/6 • Response - CR 2 (67%) 3 (50%) - Other IWG response -- 1 (17%)

Background: EPO has been used in the treatment of refractory anemia in MDS patients for many years. Recently, with the identification of definitive patient selection criteria (low serum EPO [sEPO] levels and receipt of minimal transfusions) and standardization of ER rate evaluation methods using the IWGc, response to EPO therapy has been shown to be significantly enhanced in low/int-1 risk MDS patients. The present meta-analysis was conducted to compare ER rates (defined as major + minor response) of the two erythropoiesis-stimulating therapies (ESTs) currently available in the US, EPO and DARB, in MDS patients who were selected and evaluated for ER using the aforementioned uniform criteria. Methods: A systematic review and data extraction of studies from PubMed and ASCO/ASH proceedings from 1990–2006 in MDS patients treated with EPO monotherapy and from 2003–2006 in those treated with DARB monotherapy was performed. Pooled estimates of ER rates were calculated in each group using random-effects meta-analysis methods, which incorporated both between- and within-group variations. Multivariate meta-regression analysis was further conducted to control for differences in baseline characteristics between the two groups. Results: Nine EPO studies (N=619 patients, N evaluable for ER rate =589) and 8 DARB studies (N=442, N evaluable for ER rate =389) were identified. Baseline characteristics were comparable between the two groups with respect to age, gender, mean baseline hemoglobin, transfusion dependency rates, and proportion of patients with refractory anemia/refractory anemia with ringed sideroblasts. The mean baseline sEPO levels were significantly higher in the EPO group, compared to the DARB group (376: range 43–418; vs. 133: range 68–303 mU/mL, p=0.0026). The average initial weekly dose in the EPO studies was 47,851 (range: 30,000–80,000) Units, while that in the DARB studies was 176 (range: 100–315) mcg. There was no significant difference in the pooled estimate of the ER rates for either EST (57.6%: 95% CI; 45–70) for the EPO studies vs. (59.4%: 95% CI; 49–70) for the DARB studies, (p=0.8282). Further, as compared to the studies with standard doses of the two ESTs per week (EPO 30,000–40,000 Units; DARB ≤ 150 mcg), those using higher doses of EPO (60,000–80,000 Units) or DARB (>150 mcg) per week showed significantly higher ER rates (EPO- 47.8% vs. 63.3%, p Conclusions: This current meta-analysis demonstrates that, with the use of standardized patient selection and response evaluation methods, the two clinically available ESTs yield comparable ER rates in MDS patients.

Background: EPO continues to be a primary therapeutic choice for the treatment of anemic patients with low to intermediate-1 risk MDS. Initially, without standardized response criteria, ER rates were modest. Recently, a meta-analysis of EPO monotherapy studies in MDS demonstrated a significant improvement in ER rates with the application of standardized International Working Group criteria (IWGc) for response evaluation (Moyo V et al. 2006 ASCO Annual Meeting Proceedings Part I. Vol 24, No. 18S (June 20 Supplement), 2006: 6572). This meta-analysis was expanded to determine the impact of higher doses of EPO or the addition of granulocyte or granulocyte-macrophage colony stimulating factor (G- or GM-CSF) to EPO on ER rates (defined as major + minor response). Methods: A systematic review and data extraction of studies from PubMed, ASCO and ASH proceedings from 1990–2006 in MDS patients treated with EPO monotherapy or EPO + G-/GM-CSF combination therapy was performed. Pooled estimates of ER rates were calculated in studies defining ER rates without IWGc application (non-IWGc) for EPO monotherapy at Standard (std) dose (30,000–40,000 Units per week) in comparison to studies that defined ER rates using IWGc, where EPO was used at std dose or high dose (60,000–80,000 Units per week) or in combination with G-/GM-CSF. Results: A total of 23 studies were evaluated in this analysis. As shown in the table below the IWGc studies using EPO at std dose or high dose or in combination with G-/GM-CSF demonstrated significantly higher ER rates than the non-IWGc studies (p Conclusions: The findings from this present meta-analysis confirm the impact of IWGc on ER rates for EPO therapy previously observed. Further improvement in ER rates was observed with the use of higher doses of EPO alone or the combination of EPO + G-/GM-CSF. Increasing the EPO dose appeared to have a greater impact on ER than the addition of G-/GM-CSF. Non-IWGc IWGc Study Group EPO Std Dose EPO Std Dose EPO High dose EPO + G-/GM-CSF Starting EPO Dose Units/week 30,000–40,000 30,000–40,000 60,000–80,000 30,000–40,000 No. of Studies 8 5 4 6 No.of Evaluable Patients 262 393 196 152 ER Rates (%)(95% CI) 32.1 (26–38) 47.8 (43–53) 63.3 (57–70) 50.7 (42–59)

All current classifications for myelodysplastic syndromes (MDS) require the identification of the blast population. From the FAB (1976) to the WHO (1999) new criteria such as the results of cytogenetic analysis have been introduced but the percentage of blasts remains a major factor in diagnosis, subclassification and prognosis. The definition of a blast cell is still based on those proposed in 1976 by the FAB group, but it is unclear that it has been applied in the same manner worldwide. Since the WHO has changed the definition for AML (minimum criterion is 20% blasts) and since RAEB has been divided into two groups (5 to 9 and 10 to 19% blasts respectively) it has become clear that the definition of blasts of granulocyte lineage should be more precise. Definition: Experts in morphology from the IWG on MDS have proposed that all cells from undifferentiated blast (without granules) to but not including the promyelocyte would qualify as “blasts”. A promyelocyte starts with the appearance of a “clearly visible Golgi zone” independently of the number of granules. Mature granulocyte starts with disappearance of cytoplasmic basophilia and more mature nucleus. Methodology: To verify agreement between experts on this new definition, a unique digital picture was produced from the bone marrow smear of an AML patient with FAB M2 by the association of 150 consecutive native pictures (600x800 pixels). The mosaic picture is 8340x2386 pixels (about 30 M in jpeg format or 16 M in pdf). All the 265 nucleated cells have been numbered and a drop down menu for choices was included. The picture was placed on the server of the MDS Foundation (http://www.mds-foundation.org/goasguenfollowup) and after evaluation the results were automatically sent to the MDS foundation center and registered. The five experts evaluated exactly the same cells (numbered from 1 to 265) and results were submitted for statistical analysis. Results: for 176 cells (66.6%) there was complete concordance (5/5) and for 60 others (22.7%) concordance was 4/5. If we consider that concordance of at least 4/5 is acceptable, we obtained 89.4% good concordance. Moreover, 23 cells (8.7%) had a concordance of 3/5 while only 5 (1.89%) had a concordance of 2/5. We conclude that these definitions of blasts and promyelocytes are reproducible and may help to standardize the classification of AML and MDS. All experts would have produced the same diagnosis since standard deviations of the percentages of various cell types were very low. Conclusion: the production of large field digital pictures may be very useful for education and quality control in morphology. In addition, use of such images may help to provide a new approach to difficult cells and may be useful in proposing new criteria for classification. Table: Minimum, maximum and mean percentage of cells for 5 experts % of cells Minimum Maximum Mean Standard deviation Blasts 58.1 61.7 59.9 1.54 Promyelocytes 12.2 22.3 17.7 4.82 Matures cells 14.4 21.6 18.8 3.12

The CALGB conducted a series of clinical trials with azacitidine (Vidaza®) administered subcutaneously or intravenously in patients with MDS using the FAB classification (JCO2002;20:2429). Since completion of these CALGB studies (8421, 8921, 9221), a new classification system was developed by the WHO that distinguishes MDS from AML (blasts > 20%). Although studies with azacitidine in patients with AML had previously shown activity, the 75 mg/m2/day dose in the CALGB studies was lower than previously studied. Using the WHO system, the diagnosis for CALGB study patients was redefined and patients with AML were analyzed separately. Most of the 105 patients were previously considered refractory anemia with excess blasts in transformation (RAEB-T). Also, new treatment response criteria for MDS were published by the IWG (Blood2000; 96:3671). Using IWG response criteria, azacitidine patients with WHO AML in studies 8421, 8921, or 9221 had an overall response rate (CR+PR+HI) of 48% (12/25), 32% (9/28), and 37% (10/27), respectively. Best Response using IWG Response Criteria for WHO AML Patients in Studies 8421, 8921, and 9221 Median duration of any response (CR, PR or HI) in the 33 azacitidine-treated responders was 279 days (range: 61 to 724 days). The median duration of CR in the 8 azacitidine-treated responders was not achieved; however, the 25th percentile was 115 days (range: 92 to 274+ days). In Study 9221, the median duration of transfusion independence (defined as ≥56 days) in patients independent at baseline was significantly longer in the azacitidine group compared with supportive care for red blood cells (azacitidine [n=8]: 411 days vs. supportive care [n=9]: 133 days, p=0.02) and platelets (azacitidine [n=13]: 363 days vs. supportive care [n=18]: 125 days, p=0.004). In the azacitidine group, 22% (6/27) of patients had a hemoglobin improvement to >11 g/dL that was maintained for ≥56 days compared with 8% (2/25) in the supportive care group (p=0.2). The proportions of patients with ANC >1500/m3 and platelets >100,000/mm3 lasting for ≥56 days were similar between the treatment arms. Azacitidine patients with WHO AML had a longer median survival (19.3 months) compared with the supportive care group (12.9 months) (p=0.2). Further studies investigating azacitidine in patients with AML with dysplasia are warranted.

The CALGB conducted a series of clinical trials with azacitidine (Vidaza®) administered subcutaneously or intravenously in patients with MDS using the FAB classification (JCO2002;20:2429). Since the publication of these CALGB studies (8421, 8921, 9221), new response criteria for evaluating new treatments for MDS have been published by the IWG (Blood2000;96:3671). Two general differences between the CALGB and IWG response criteria are the required duration of improvement (CALGB: ≥4 weeks; IWG: ≥8 weeks) and peripheral blood values (CALGB: different criteria for hemoglobin targets for males and females; IWG: same criteria for males and females). The results reported here are based on re-collected data from patients described in the published report. After applying the IWG response criteria, the overall response rate (CR+PR+HI) in the azacitidine groups were similar across studies 8421, 8921, and 9221: 44% (21/48), 40% (28/70), and 48% (47/99), respectively. Best Response using IWG Response Criteria for MDS in Studies 8421, 8921, and 9221 Median duration of any response (CR, PR or HI) in the 114 azacitidine-treated responders was 366 days (range: 56 to 4641+ days). The median duration of CR in the 32 azacitidine-treated responders was 379 days (range: 92 to 4412+ days). The median number of cycles from first treatment with azacitidine to any response (CR, PR or HI) was 3 cycles (range: 1 to 17 cycles). Although 75% of the responders achieved a response by cycle 4, the other 25% achieved a response as late as cycle 17. The majority (90%) of responders achieved a response by cycle 6. Best response was observed, on average, 2 cycles after the initial response. In summary, reanalysis of the response rates using IWG criteria demonstrate consistent results across three sequential studies and further validate the superiority of azacitidine over supportive care alone.

Standardizing any aspect of a disease as clinically and biologically heterogeneous as the myelodysplastic syndromes (MDSs), whose natural history is not infrequently confounded by wide fluctuations in the peripheral blood (PB) indexes and where therapeutic options range from a simple watch-and-wait