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The EUROPE phase 2 trial investigated the predictive value of biomarkers on the clinical efficacy of single agent romiplostim (ROM) treatment in patients with lower-risk myelodysplastic neoplasms (LR-MDS) and thrombocytopenia within the ‘European Myelodysplastic Neoplasms Cooperative Group‘ (EMSCO) network. A total of 77 patients with LR-MDS and a median platelet count of 25/nl were included, all patients received ROM at a starting dose of 750 μg by SC injection weekly. Thirty-two patients (42%) achieved a hematologic improvement of platelets (HI-P) with a median duration of 340 days. Neutrophil (HI-N) and erythroid (HI-E) responses were observed in three (4%) and seven (9%) patients, respectively. We could not confirm previous reports that HI-P correlated with baseline endogenous thrombopoietin levels and platelet transfusion history, but SRSF2 mutation status and hemoglobin levels at baseline were significantly linked to HI-P. Sequential analysis of variant allelic frequency of mutations like SRSF2 did not reveal an impact of ROM on clonal evolution in both responders and non-responders. In summary, our study confirms the safety and efficacy of ROM in LR-MDS patients and may allow to better define subgroups of patients with a high likelihood of response.

Introduction Our objective was to evaluate characteristics, treatment and outcome of vasculitis associated with myelodysplastic syndrome (MDS) and chronic myelomonicytic leukemia (CMML) Patients and Methods Retrospective descriptive analysis of MDS/CMML-related vasculitis and comparison with MDS/CMML patients without dysimmune features. Results Seventy patients with vasculitis and MDS/CMML were included, with median age of 71.5 [21–90] years and male/female ratio of 2.3. Vasculitis was diagnosed prior to MDS/CMML in 31 patients (44%), and after in 20 patients. In comparison with MDS/CMML without autoimmune/inflammatory features, vasculitis with MDS/MPN showed no difference in MDS/CMML subtypes distribution nor International Prognostic Scoring System and CMML-specific prognostic (IPSS/CPSS) scores. Vasculitis subtypes included Giant cell arteritis in 24 patients (34%), Behcet's-like syndrome in 11 patients (20%) and polyarteritis nodosa in 6 patients (9%). Glucocorticoids (GCs) were used as first-line therapy for MDS/CMML vasculitis in 64/70 patients (91%) and 41 (59%) received combined immunosuppressive therapies during the follow-up. After a median follow-up of 33.2 months [1–162], 31 patients (44%) achieved sustained remission. At least one relapse occurred in 43 patients (61%). Relapse rates were higher in patients treated with conventional Disease Modifying Anti-Rheumatic Drug (DMARDs) (odds ratio 4.86 [95% CI 1.38 - 17.10]), but did not differ for biologics (odds ratio 0.59 [95% CI 0.11–3.20]) and azacytidine (odds ratio 1.44 [95% CI 0.21–9.76]) than under glucocorticoids. Overall survival in MDS/CMML vasculitis was not significantly different from MDS/CMML patients without autoimmune/inflammatory features (p = 0.5), but acute leukemia progression rates were decreased (log rank Conclusion This study shows no correlation of vasculitis diagnoses with subtypes and severity of MDS/CMML, and no significant impact of vasculitis on overall survival. Whereas conventional DMARDs seem to be less effective, biologics or azacytidine therapy could be considered for even low-risk MDS/CMML vasculitis.

International audience; No abstract available

Background: Systemic autoimmune and inflammatory diseases (SAIDs) occur in 10-15% of MDS or CMML patients. They are often severe, difficult to treat and steroid resistant/dependent disorders. In a retrospective report of 22 patients with steroid-dependent MDS/CMML associated SAID, we observed promising results with azacytidine (AZA) on the SAID component (Fraison et al, Leuk Res, 2016). In this prospective French nationwide trial, we aimed at confirming this effect prospectively. Patients and Methods: This open-label, single-arm multicenter, phase II study included MDS/CMML patients with IPSS/CPSS int 2 or high, or lower IPSS/CPSS but with significant cytopenias, especially ESA resistant anemia (or, for CMML, proliferative features) and SAID with steroid dependence and/or resistance. The primary endpoint was response rate (RR, including CR and PR) of SAID after 6 cycles of AZA. Secondary endpoints included RRof SAID after 3 cycles of AZA, response of MDS, time to MDS progression (including to AML), overall survival (OS) and safety. AZA was used at 75 mg/m²/d x 7 days, every 4 weeks for a minimum of 6 cycles (unless overt disease progression occurred before). At the onset of AZA, prednisone (PRED) was administered at 1 mg/kg during 1 month and then decreased progressively over 6 months. Results: 30 patients were included between July 2017 and June 2020 , 29 of whom received AZA and were considered evaluable: median age 72 [range 68-78], 69% males; WHO: MDS ML (n=11; 41%), CMML (n=11, 41%), MDS-RS (n=2, 7%), EB-1 (n=1) and EB-2 (n=1), unclassified (n=3); IPSS-R : good (n=15, 54%), very good (n=3; 11%, each), intermediate (n=7; 25%) and very poor profile (n=3; 11%) (all CMML had WBC 19 patients (65.5%, IC95% [45.7.82.1]) obtained a SAID response after 6 cycles (including 8 CR and 11 PR), while 17 (58.6% (IC95% [38.9; 76.5]) patients achieved an IWG 2006 hematological response (7 CR, 9 SD with HI and 1 marrow CR). All the 13 patients who received 12 cycles of AZA achieved SAID CR or PR at 12 months, and 10 of them had a hematological response (6 CR, 1PR, 2 HI, 1 marrow CR). The SAID response rate at 12 month was at 72.4% (IC95% : [51.3;85.6]). SAIDs complete/partial response occurred in 3/9 (33%) UBAI-positive versus 8/19 (42%) non-mutated cases. No significant prognostic factor of SAID response after 6 cycles, including sex, age, WHO classification, IPSS-R, UBA1 and TET-2 mutation status was found. With a median follow-up of 18.5 months [11.8; 24.3], 9 (31%) patients had died, with a 1-year OS of 82.3% (IC95% [69.4; 97.7]. At least one SAE occurred in 23 patients, with a median of 2 events/patient [1.5; 5.5]. Death was due to infection (n=5, two of them in patients with good IPSS-R, but severe steroid dependent SAID), MDS progression (n=2), or unrelated causes (n=2). Conclusion We confirmed prospectively an effect of AZA on the autoimmune/inflammatory component in two thirds of MDS/CMML patients with steroid dependent / refractory concomitant systemic autoimmune/inflammatory disease. No significant difference in AZA response was noted between UBA1 mutated and unmutated MDS patients. The adverse events and mortality rates, often from infectious origin, appear to be those expected in such an MDS population, potentially worsened by the associated SAID and background of immunosuppressive treatment (especially steroids) Disclosures Terriou: Alexion, AstraZeneca Rare Disease: Consultancy, Membership on an entity's Board of Directors or advisory committees. Vey: Amgen: Honoraria; BMS: Honoraria; BIOKINESIS: Consultancy, Research Funding; NOVARTIS: Consultancy, Honoraria, Research Funding; SERVIER: Consultancy; JAZZ PHARMACEUTICALS: Honoraria; JANSSEN: Consultancy. Ades: ABBVIE: Honoraria; TAKEDA: Honoraria; CELGENE/BMS: Honoraria; NOVARTIS: Honoraria; JAZZ: Honoraria, Research Funding; CELGENE: Research Funding. Fenaux: Abbvie: Honoraria, Research Funding; JAZZ: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Celgene/BMS: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Syros Pharmaceuticals: Honoraria.

*UP, LA contributed equally Introduction A significant proportion of lower risk (LR)-MDS patients present with thrombocytopenia, being associated with shortened survival and higher risk of progression to acute myeloid leukemia (AML). Treatment options for patients with LR-MDS and severe thrombocytopenia remain limited apart from transfusion support. Romiplostim (ROM), a thrombopoietin receptor agonist (TPO-RA) has shown safety and efficacy dependent on endogenous TPO levels as well as platelet transfusion history in a poorly defined subset of LR-MDS patients (Giagounidis et al. Cancer 2014, Sekeres et al. BJH 2014). Methods The multicenter phase 2 EUROPE trial investigated potential biomarkers of response (e.g. TPO levels, molecular markers) to single agent ROM in LR-MDS patients with severe thrombocytopenia. Patients were eligible if platelet counts were ≤30 G/L or ≤50 G/L in case of bleeding history. The primary efficacy endpoint was the rate of hematologic improvement of platelets (HI-P, according to IWG 2006 criteria) lasting for at least 8 weeks after 16 weeks of ROM (750µg SC qw) treatment. At the time of screening, patients were assigned into 3 different cohorts based on their previous platelet transfusion events (PTE) as well as centrally assessed TPO serum levels (A: TPO Results From 2015 to 2019, a total of 79 patients were included at 29 trial sites in Germany, France and the Czech Republic. Patients' median age was 74 years (range 42-93), median baseline platelet count was 25.5 G/L (range 3-50 G/L) and they were stratified into cohort A (n=51) or B+C (n=28), respectively. The primary endpoint was met with 34 out of 79 (43%) patients responding (HI-P), with response being markedly higher in cohort A (49%, n=25) vs. cohort B and C (32%, n=9) (p=0.145). Ten (13%) and eight (10%) patients had additional neutrophil (HI-N) and erythroid (HI-E) responses, respectively. During treatment, six patients had transient increases in peripheral blasts to more than 10% and one patient progressed to AML after one month of ROM. Although a higher number of responders was observed in group A, neither TPO level at screening (p=0.21), nor number of pretreatment PTE (p=0.12) were significantly associated with response to ROM treatment. Thus, our findings do not confirm that baseline TPO levels and number of pretreatment PTE alone allow reliable prediction of response to ROM. With the aim to identify new molecular patterns correlating with response, we performed a targeted NGS analysis for somatic variants in 54 candidate genes in 75 patients at baseline and in 44 patients after 16 weeks of ROM. Responders (R) more frequently exhibited mutations like SRSF2 (R=39%, NR=17%), RUNX1 (R=24%, NR=14%) and TET2 (R=30%, NR=29%), whereas non-responders (NR) exhibited mutations like DNMT3A (R=12%, NR=21%), U2AF1(R=9%, NR=14%) or ASXL1 (R=6%, NR 17%) more frequent. The percentages of patients with a response to ROM were similar regardless of total number of baseline somatic mutations. Comparing responders vs. non-responders, we found no significant changes of variant allelic burden of variants detected pre- and post-ROM (Fig. 1). We identified the presence of a SRSF2 mutation as a significant predictor of response to ROM treatment (p=0.031, logistic regression). Mutated SRSF2 was significantly more frequent in responders (39%) compared to non-responders (17%) (p=0.036, Fisher's exact test) (Fig. 2A,B). We used logistic regression with stepwise backward selection to assess the influence of the presence of ASXL1, DNMT3A, RUNX1, TET2 and SRSF2 mutations on response. Our final regression model excludes the non-significant ASXL1, DNMT3A, RUNX1 and TET2 mutations and includes the significant SRSF2 mutation, resulting in an overall accuracy of 64.0% for a correct ROM response prediction in this patient cohort. Conclusion: This prospective study did not confirm a significant association between response to ROM, pretreatment PTE burden and endogenous TPO levels. Instead, patients with a mutated SRSF2 displayed a significantly higher response to ROM treatment. This may allow personalized treatment approaches in patients with LR-MDS and severe thrombocytopenia. In this study, extended treatment with ROM did not lead to a significant increase in AML cases. Disclosures Kubasch: Shire: Research Funding; Celgene: Research Funding; Novartis: Research Funding. Giagounidis:AMGEN: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Götze:Celgene: Research Funding. Cony-Makhoul:Novartis: Consultancy; Pfizer: Consultancy; Incyte Biosciences: Speakers Bureau; BMS: Consultancy; BMS: Speakers Bureau. Laribi:takeda: Research Funding; novartis: Honoraria, Research Funding; amgen: Research Funding; abbvie: Honoraria, Research Funding. Park:Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Other: Travel expenses. Metzeler:Astellas: Honoraria; Otsuka Pharma: Consultancy; Pfizer: Consultancy; Jazz Pharmaceuticals: Consultancy; Novartis: Consultancy; Celgene: Consultancy, Honoraria, Research Funding; Daiichi Sankyo: Honoraria. Thiede:AgenDix GmbH: Other: Co-owner and CEO. Schlenk:PharmaMar: Research Funding; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accomodations, Expenses, Research Funding, Speakers Bureau; Novartis: Speakers Bureau; Roche: Research Funding; AstraZeneca: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Fenaux:Novartis: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; Jazz: Honoraria, Research Funding; BMS: Honoraria, Research Funding. Platzbecker:Novartis: Consultancy, Honoraria, Research Funding; Amgen: Honoraria, Research Funding; BMS: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Geron: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding. Ades:Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding; takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; novartis: Research Funding; Celgene/BMS: Research Funding; jazz: Membership on an entity's Board of Directors or advisory committees, Research Funding. OffLabel Disclosure: Romiplostim is a thrombopoietin receptor agonist indicated for the treatment of thrombocytopenia in patients with chronic immune thrombocytopenia (ITP). Limitations of Use: Romiplostim is not indicated for the treatment of thrombocytopenia due to myelodysplastic syndrome (MDS) or any cause of thrombocytopenia other than chronic ITP.

We have previously described the safety and efficacy of pegylated interferon-α2a therapy in a cohort of 62 patients with myeloproliferative neoplasm-associated myelofibrosis followed in centers affiliated to the French Intergroup of Myeloproliferative neoplasms. In this study, we report their long-term outcomes and correlations with mutational patterns of driver and non-driver mutations analyzed by targeted next generation sequencing. The median age at diagnosis was 66 years old, the median follow-up since starting pegylated interferon was 58 months. At the time of analysis, 30 (48.4%) patients were alive including 16 still being treated with pegylated interferon. The median survival of patients with intermediate and high-risk prognostic Lille and dynamic International Prognostic Scoring System scores treated with pegylated interferon was increased in comparison to that of historical cohorts. In addition, overall survival was significantly correlated with the duration of pegylated interferon therapy (70 versus 30 months after 2 years of treatment, P

Introduction: Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis and peripheral cytopenia. In about half of patients with lower-risk (LR) MDS, thrombocytopenia is present at the time of diagnosis and associated with shortened survival and an increased risk of progression to acute myeloid leukemia (AML). The thrombopoietin receptor agonist (TPO-RA) romiplostim has shown safety and marked efficacy in a still poorly-defined subset of LR-MDS patients with thrombocytopenia. Methods: The EUROPE multicenter phase 2 trial within the EMSCO network investigated the impact of biomarkers like endogenous thrombopoietin (TPO) level and platelet transfusion events (PTE) on the efficacy of romiplostim (750µg SC qw) treatment in patients with LR-MDS (IPSS low/int-1). Patients were eligible if baseline bone marrow blast count was Results: From 2015 to 2018, a total of 68 patients were included in 20 trial sites in Germany, France and Czech Republic. Patients displayed a median age of 74 years and a median platelet count of 25 G/L (range 1-50 G/L) and were stratified into cohort A (n=47), B (n=17) or C (n=4), respectively. All patients received at least one cycle of romiplostim with a median weekly dose of 750μg and a median of 15 cycles of romiplostim until week 16. Reasons for premature study discontinuation before week 16 were investigator/patient decision (n=8), adverse events (n=5), disease progression (n=4) or death (n=1). There were 9 reported severe treatment-related adverse events in seven patients including pulmonary embolism (n=1), subacute stroke (n=1), mucocutaneous hemorrhage (n=1), asthenia (n=1), suspicion of anti-romiplostim antibodies (n=1), progression to AML (n=1) and varicella zoster infection (n=1). Two patients had transient increases in peripheral blasts to more than 10% and 1 patient progressed to AML after 1 month of treatment. HI-P was observed in 26 of 68 (38%) patients, while response was ongoing in 24 of them beyond week 16. Moreover, rate of HI-P lasting for at least 8 weeks was notably higher in cohort A (45%, n=21/47) compared to patients in cohort B and C (24%, n=5/21) (p=0.11). Median peak increase of PLT count in responding patients was 199 G/L in cohort A and 83 G/L in cohort B (p=0.25) and was observed in median after 7 weeks (range 3-16). In addition, responses occurred also in 2 patients in the neutrophil (HI-N) and in 7 patients in the erythroid (HI-E) lineage according to IWG 2006 criteria (Table 1). Explorative analysis showed a correlation between pretreatment platelet transfusion requirement and endogenous TPO-levels (spearman-test, p=0.034). Median pretreatment endogenous TPO-level was lower in responders compared to non-responders (82 vs. 103 pg/ml, p=0.15). Higher response rates occurred in patients with lower TPO-levels ( Conclusion: This prospective study confirms that romiplostim treatment is highly effective in a subgroup of LR-MDS patients, but neither baseline platelet transfusion requirements nor baseline TPO levels were significantly associated with clinical response to romiplostim. Further translational analyses are ongoing to elucidate potential biomarkers of response. Disclosures Platzbecker: Celgene: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria. Götze:AbbVie: Membership on an entity's Board of Directors or advisory committees. Cony-Makhoul:Pfizer: Consultancy; Novartis: Consultancy; Incyte Biosciences: Honoraria, Speakers Bureau; BMS: Consultancy, Honoraria, Speakers Bureau. Park:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding. Thiede:Daiichi Sankyo: Honoraria; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; AgenDix GmbH: Employment, Equity Ownership; Diaceutics: Membership on an entity's Board of Directors or advisory committees. Ades:Helsinn Healthcare: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Silence Therapeutics: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Jazz: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding. OffLabel Disclosure: Romiplostim is formally not licensed for the treatment of thrombocytopenia due to myelodysplastic syndrome (MDS).

International audience; Myeloproliferative neoplasm-related myelofibrosis is associated with cytopenic or proliferative phases, splenomegaly and constitutional symptoms. Few effective treatments are available and small series suggested that interferon could be an option for myelofibrosis therapy. We performed a retrospective study of pegylated-interferon α-2a (Peg-IFNα-2a) therapy in myelofibrosis. Sixty-two patients treated with Peg-IFNα-2a at 17 French and Belgian centres were included. Responses were determined based on the criteria established by the International Working Group for Myelofibrosis Research and Treatment. Mean follow-up was 26 months. Sixteen of 25 anaemic patients (64%) (eight concomitantly receiving recombinant erythropoietin) achieved a complete response and transfusion-independence was obtained in 5/13 patients (38*5%). Constitutional symptoms resolved in 82% of patients. All five leucopenic patients normalized their leucocyte counts, whereas a normal platelet count was obtained in 5/8 thrombocytopenic patients. Splenomegaly was reduced in 46*5% of patients, and complete resolution of thrombocytosis and leucocytosis were observed in 82*8% and 68*8% of patients, respectively. Side effects (mostly haematological) were mainly of grade 1-2. The only factor independently associated with treatment failure was a spleen enlargement of more than 6 cm below the costal margin. In conclusion, Peg-IFNα-2a induced high response rates with acceptable toxicity in a large proportion of patients with primary and secondary myelofibrosis, especially in early phases.

Hydroxyurea is the standard therapy of chronic myelomonocytic leukemia (CMML) presenting with advanced myeloproliferative and/or myelodysplastic features. Response to hypomethylating agents has been reported in heterogeneous series of CMML. We conducted a phase 2 trial of decitabine (DAC) in 39 patients with advanced CMML defined according to a previous trial. Median number of DAC cycles was 10 (range, 1-24). Overall response rate was 38% with 4 complete responses (10%), 8 marrow responses (21%), and 3 stable diseases with hematologic improvement (8%). Eighteen patients (46%) demonstrated stable disease without hematologic improvement, and 6 (15%) progressed to acute leukemia. With a median follow-up of 23 months, overall survival was 48% at 2 years. Mutations in ASXL1, TET2, AML1, NRAS, KRAS, CBL, FLT3, and janus kinase 2 (JAK2) genes, and hypermethylation of the promoter of the tumor suppressor gene TIF1γ, did not predict response or survival on DAC therapy. Lower CJUN and CMYB gene expression levels independently predicted improved overall survival. This trial confirmed DAC efficacy in approximately 40% of CMML patients with advanced myeloproliferative or myelodysplastic features and suggested that CJUN and CMYB expression could be potential biomarkers in this setting. This trial is registered at EudraCT (eudract.ema.europa.eu) as #2008-000470-21 and www.clinicaltrials.gov as #NCT01098084.

Background: Hypomethylating agents, especially AZA, have become the reference treatment of higher risk MDS, but the median survival of about 2 years obtained with AZA remains modest, and must be further improved. In addition, AZA yields only about 30% of marrow responses (including CR+PR+marrow CR). Intensive chemotherapy combining Idarubicin (IDA) and AraC yields 30 to 50 % CR in higher risk MDS (Beran and all, cancer 2001) and IDA, as single agent, induces about 30% CR in elderly AML patients (Carella, haematologica 1990). We designed a phase I/II study evaluating the safety and efficacy of the combination of AZA and IDA (1 day during each AZA cycle) in higher risk MDS patients (NCT01305135). Methods: Main Inclusion criteria were: (1) IPSS int-2 or high MDS, or CMML with WBC < 13 G/l and marrow blasts > 10%, or AML with 20-30% marrow blasts (2) Age ≥ 18 years (3) Performance Status (PS) Results: Between Dec 2010 and Jan 2014, 41 patients (from 13 centers) were enrolled, including 13 women and 28 men with a median age of 74 years [IQR 70; 76]. At inclusion, WHO classification was RCMD in 1 pt, CMML in 2 pts, RAEB-1 in 10 pts, RAEB-2 in 13 pts, AML in 12 pts and unclassified MDS in 3 pts. Median marrow blast % was 9.5 [IQR: 6-19.9] and karyotype according to IPSS was favorable in 12 (29%), intermediate in 9 (22%) and unfavorable in 18 pts (44%) (2 cytogenetic failures). IPSS was int-2 and high in 56% and 44%, respectively. PS was 0 in 39%, 1 in 55% and 2 in 6% pts. 10 patients received 5 mg/m2 of idarubicin (cohort 1) and 31 received 10 mg/m2 (cohort 2). 375 cycles of AZA were administered (219 of them with AZA+IDA, as IDA was used only for the first 9 cycles), with a median number of 6 cycles/patient (median 6 in the IDA 5 mg/m2 cohort and 4 in the 10 mg/m2 cohort (p=0.9). Of the 41 patients enrolled, 20(48.8%, 95%CI: 32.9-64.9) achieved response (6 CR, 7 PR, 4 mCR and 3 stable disease with HI) with no difference between the two cohorts (50% vs 48%) and a marrow response rate (CR + PR + mCR) of 41,5%. Thirteen of the 22 patients with abnormal karyotype were evaluable for cytogenetic response: 5 achieved cytogenetic response (4 complete, 1 partial), 1 in cohort 1 and 4 in cohort 2. With a median follow up of 14 months, 9 of the 20 responders had relapsed. Median response duration was 11 months [3.2-42.7], with no difference between the two cohorts. Median OS was 14.3 months [IC95%: 12.5; NA] and 2y OS was 24.8%, with no significant difference between the 2 cohorts (p=0.43). By univariate analysis no baseline parameter including gender, karyotype, marrow blast %, IPSS and IDA dosage (5 or 10 mg/m2), had any significant impact on response or survival. 45 SAEs were reported in 26 patients, including febrile neutropenia (n=25), bleeding (n=7) and 2 non-clinically significant reductions in left ventricular ejection fraction (1 transient, and 1 persisting without symptoms). The number of infections per cycle [9/85 (10%) in the IDA 5 mg/m2 arm and 38/281 (14%) in the IDA 10 mg/m2 arm] and the number of bleeding events (9% vs 17%) did not significantly differ between the two cohorts. Conclusion: In our experience, Idarubicin (on day 8 of each cycle) can be combined to Azacitidine without any additional toxicity. The marrow response rate obtained with the combination (41.5%) may be higher than with AZA alone. We are currently comparing in higher risk MDS patients this AZA-IDA combination versus AZA alone (and other combinations of AZA with other drugs) in a prospective randomized GFM trial. Disclosures Sebert: Celgene: Research Funding. Fenaux:Celgene: Research Funding.

Background: Therapeutic guidelines in essential thrombocytemia (ET) are based on established criteria, ie. age more than 60 years, history of thrombosis, platelets more than 1000-1500 ×109/L and to lesser degree cardio-vascular risk factors. Hydroxyurea and anagrelide are the most commonly used cytoreductive therapy for high risk ET. Despite a proven activity in Ph negative myeloproliferative disorders, generalized use and efficacy of Interferon-alpha (IFN-α) have been hampered by frequent side effects. Nonetheless it is a non leukemogenic therapeutic option for younger patients (pts) and during pregnancy. Two phase II trials using Pegylated (Peg) forms of IFN-α in pts with polycythemia vera (PV) or high risk ET have provided interesting results: i) an improved toxicity profile generally associated with a rapid hematolologic response, ii) a molecular response described in a subset of JAK2V617F positive PV or ET pts treated with PegIFN-α. Aim: To estimate the rationale of PegIFN-α therapy selection in high risk ET patients, efficacy and tolerance. Methods:Cases of high risk ET patients, who started PegIFN-α therapy between 2006 and 2011, were reported by centres of the French Intergroup of Myeloproliferative disorders and included in an observational study. We collected information regarding history of MPN, treatment, hematologic response at different timepoints, toxicities related to PegIFN-α, thrombo-hemorrhagic events and hematologic progression. The current analysis was performed on 103 consecutive pts. Results: Median follow-up from ET diagnosis was 9 years (3-27). 74% of pts were female, median age was 37 years (range 16-67). Previous vascular event was observed in 36% of cases and JAK2V617F mutation was detected in 52% of pts. . Median time from diagnosis to PegIFN-α was 40 months (1-255). PegIFN-α was administered after hydroxyurea and anagrelide in second or third line (56% and 27% respectively). No prior therapy has been used for 16% of pts. Reasons for starting PegIFN-α were lack of hematologic response (21%), toxicity to prior therapies (17%), pregnancy (15%), or medical decision for younger pts (47%). Pts received either PegIFNα-2a (n=91) or PegIFNα-2b (n=12), based on physician decision. According to the 2009 European LeukemiaNet criteria and with a median exposure to PegIFN-α of 29 months (1-92), 81% of pts achieved a complete hematologic response (CHR). Cumulative incidence of CHR were 58 % (95% CI: 49-68), 73% (95% CI: 65-81) and 80% (95% CI: 71-87) at 6, 12 and 24 months respectively. By analysing the response according to JAK2 status, cumulative incidence of CHR was better for the JAK2V617F positive subgroup (p=0.0183, overall). At 36 months estimated CHR rates were 89% (95% CI: 79-95) and 70% (95% CI: 57-82) for JAK2VF positive vs negative subgroup respectively. Median exposure to PegIFN-α was 29 months in both groups. At last follow-up, with a median of 42 months since PegIFN-α initiation, 53% of the pts were still treated with PegIFN-α. Among them, 76% have maintained a CHR. Reasons for discontinuation of PegIFN-α (47% of pts) were consecutive to PegIFN-α toxicity (59%), -mainly chronic moderate non hematologic toxicity-, or hematologic responses were considered insufficient in16%. In addition, PegIFN-α has been stopped in a subset of pts who achieved a durable stable CHR. In Conclusion, This study provides results of PegIFN-α therapy in a cohort of high risk ET pts not included in clinical trials. In this selected population of young pts, a durable efficacy of therapy was observed in half of patients. Characteristics of hematologic response according to molecular status will be presented. These results support the PegIFN-α as an alternative therapy to hydroxyurea and anagrelide in high risk ET, and warrant its investigation in further prospective randomized studies. Disclosures Roy: Merck: Peg-Interferon provided for academic clinical trial in CML Other. Off Label Use: Peg-Interferon in essential thrombocythemia. Gyan:Roche: Research Funding. Nicolini:BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Ariad: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Kiladjian:Roche: Peg-Interferon provided for academic clinical trial in PV Other.

Background Higher risk MDS and AML with del(5q) carry very poor prognosis, but show some response to AZA and LEN as single agents (Adès et al. Blood 2009, Itzykson, Blood, 2010). The combination of LEN and AZA has been tested in non-del 5q MDS patients with encouraging results and limited toxicity (Sekeres, Blood 2012). Sequential combination of AZA and LEN has also shown to be feasible and potentially effective in higher-risk MDS with del(5q) in a phase I study (Platzbecker et al, Leukemia 2013 ). In this phase I-II trial, we combined escalating doses of LEN to AZA in higher risk MDS and AML with del(5q). Methods Patients aged 18 or more, with IPSS int-2 or high MDS, CMML with WBC < 13,000/mm3 and marrow blasts > 10% and AML (20-30% marrow blasts) with 5q deletion with or without additional cytogenetic abnormalities could be included provided they had not previously received LEN or AZA. Patients should also have contra indication to intensive chemotherapy (IC), precluding inclusion in a GFM competing trial combining IC and LEN in higher risk MDS and AML with del 5q (results of that trial are also submitted to ASH 2013). In the present trial, patients received AZA (75 mg/m2 x5days, every 28 days) combined to escalating doses of LEN (5 mg/d x14 days in cohort 1, 5 mg/d x21 days in cohort 2 and 10 mg/d x21 days in cohort 3). For patients in hematological CR, PR , HI or marrow CR (MDS) and CR or PR (AML) after cycle 2 or 4, treatment was to be continued at the same schedule unless unacceptable toxicity or overt progression occurred. The main endpoint was response assessed after 2-4 cycles (IWG 2006 criteria). Median [IQR] are reported unless specified. Results 35 patients were enrolled in the study, including 15, 10 and 10 patients in cohort 1 (LEN 5mg/d x14d), 2 (LEN 5mg/d x21d) and 3 (LEN 10mg/d x21d) respectively. 18 were males and the median age was 68.9 (62.7-73). According to WHO classification, 1 patient had CMML, 7 RAEB1, 15 RAEB2 and 11 AML (with 20 to 30% marrow blasts). PS was 0, 1, 2 in 31%, 40%, 29% patients respectively. However, as said above, patients included in this trial were considered unfit for IC due to their age and/or comorbidities including cardiovascular events in 23 patients (still active in 19 at inclusion), pulmonary events in 7 (still active in 5), and neurological events in 6 pts. Del(5q) was isolated in only 2 pts, and 33 pts (94%) had del (5q) and at least 2 additional abnormalities. Baseline platelet count was 50 G/L (25-74), baseline Hb level was 9.15 (8.60-9.80), and baseline ANC was 1 G/l (0.545-1.66), including 38% patients with less than 0.8 G/L. IPSS was int-2 in 27% patients and high in 73% patients. With a median follow-up of 3.5 months, 98 cycles were administered (median 2 /patient, including 4 patients who received 6 or more cycles). In the three cohorts, the median number of cycles received was 2, 2 and 2 respectively. 15 (43%) patients discontinued treatment before the second cycle, due to early death (n=10), adverse events (n=2), progression (n=2), or CNS hemorrhage (n=1). They were all considered as non responders (primary endpoint). Of the 35 pts, 4 (11%) achieved CR and 2 (5.5 %) marrow CR after 2 cycles. After 4 cycles, The 2 marrow CR converted into CR and one additional patient achieved stable disease with HI leading to an overall response rate (ORR) of 7 (20%). The ORR was 13% in cohort 1, 10% in cohort 2, and 30% in cohort 3 (p=0.53). 4/6 complete responders achieved cytogenetic response, including 1 complete (CCyR) and 3 partial. The 6 CR included one of the 2 patients with isolated del(5q), who also obtained CCyR, and 5 of the 33 (15%) patients with complex karyotype. One year OS was 39%. Regarding toxicity, 31 SAEs (grade 3-4) were reported in 19 patients, including 1 cardiovascular event, 6 pulmonary infection, 5 gut events, 3 neurological events. No difference in grade >2 toxicity was seen in the 3 cohorts (10, 10, and 11 events, respectively). Conclusion In this elderly population of higher risk MDS or AML considered unfit for intensive chemotherapy , and with del 5q that was part of a complex karyotype in almost all cases , the combination of AZA with escalated doses of LEN was associated with early discontinuation ( Disclosures: Off Label Use: LEN in higher risk MDS. Fenaux:CELGENE: Research Funding.

Abstract 1720 Background: hypomethylating agents, especially AZA, have become the reference treatment of higher risk MDS, but the median survival of about 2 years obtained with AZA remains modest, and must be further improved. In addition, if it is able to increase overall survival in MDS, AZA yields only about 30% of marrow response (including CR+PR+ mCR), Idarubicin given at conventional dose (12 mg/m2/d during 3 days) is the anthracycline of choice in the intensive chemotherapy given with cytarabine in patients with high risk MDS and, given as a single agent, induces up to 30% of complete remission (CR) in elderly AML patients. Thus, we designed a phase I/II study evaluating the safety and efficacy of 2 doses of Idarubicin combined with Azacitidine in high risk MDS patients (clinical trial NCT01305135). Methods: For this trial Azacitidine was combined with increasing doses of Idarubicin. Main Inclusion criteria were: (1) IPSS int 2 or high MDS, or CMML with WBC < 13,000/mm3 and marrow blasts > 10% or AML with 20–30% marrow blasts (corresponding to EU label for AZA) (2) Age 3 18 years (3) Performance Status (PS) Results: The 20 study patients (from 8 centers) were enrolled between Dec 2010 and Feb 2012, including 7 women and 13 men with a median age of 75 years. At inclusion, WHO classification was RCMD in 1 pt, CMML in 1 pt, RAEB-1 in 6 pts, RAEB-2 in 7 pts, AML in 3 pts and unclassified in 2 pt. Median marrow blasts were 6.5% (0–26) Karyotype (IPSS) was favorable in 7 pts, int in 3 pts and unfav in 8 pts (2 pts had cytogenetic failure). IPSS was high in all patients. PS was 0 in 28% pts, 1 in 50% and 2 in 22%. A total of 92 cycles of treatment had been administrated with a median number of 5 cycles/patient and 10 pts had received 6 or more cycles. 14 patients had terminated the study due to side effects (severe febrile pancytopenia, n=2), disease progression (n=5, after 2–10 cycles), death (disease progression, severe septic shock after Cycle 2, and unrelated coma), stable disease after 6 cycles (n=3), and patient decision (n=1). Overall 7 pt had died. 18 SAEs were reported observed in 9 patients, including 10 episodes of febrile neutropenia, 3 episodes of bleeding and 5 unrelated SAE. Of the 20 patients enrolled in the study, 19 were evaluable for response after 3 cycles, including 10/10 in the First cohort and 9/10 in the second cohort. One patient achieved CR, 2 PR, 1 mCR and 2 additional patients achieved stable disease with HI, leading to an Overall response rate of 6/19 (32%). Two patients were still on study but did not reached cycle 6. Thus, after 6 cycles, 17 patients, only could be evaluated. Among them 9/17 (53%) patients were still on study, 2 pts had died, 3 progressed, 2 had experienced sides effects and had terminated the study and 1 pt had withdrawn consent. Two patients achieved CR (including 1 already in CR at cycle 3), 2 PR and 2 additional patients achieved stable disease with HI leading to an Overall response rate of 6/17 (35%). At the time of the present analysis, none of the responder had relapsed. Conclusion: The phase I/II results presented here show that Idarubicin can be combined to Azacitidine with acceptable toxicity. Whether the azacitidine- Idarubicin combination can improve the outcome of higher risk MDS patients will be evaluated in a phase II randomized trial comparing this combination (and other combinations of azacitidine with other drugs) to azacitdine alone alone. Data of the present phase I/II trial will be updated at the meeting. Disclosures: No relevant conflicts of interest to declare.

Abstract 2786 Background: LEN is currently the reference treatment of low/int 1 (lower) risk MDS with del 5q, yielding RBC transfusion independence (TI) in two thirds of the cases, with a median RBC-TI duration of 2.2 years. (MDS 003 trial, List, NEJM, 2006). In case of primary or secondary failure of LEN, however combined analysis of MDS 003 and MDS 004 trial showed prognosis to be unfavorable and treatment approaches uncertain. We report results of treatment with AZA in 13 lower risk MDS with del 5q with primary or secondary failure of LEN. Methods: The 13 cases were treated between November 2005 and June 2011 in 10 centers of the Groupe Francophone des Myelodysplasies (GFM). At onset of LEN, median age was 71 years, M/F 0.43, 7 patients (pts) had RAEB 1 and 6 RA, 11 had isolated del 5q and 2 had 1 additional chromosomal abnormality. IPSS was low in 6 and int 1 in 7 patients. The LEN dose was 5mg/d, 10mg/d 3 weeks/4weeks, 10mg/d in 8, 3 and 2 patients, respectively. 11 (85%) patients had achieved RBC-TI, for a median duration of 26.3m (range 5.8–57.3)(secondary failures), while 2 patients had not achieved RBC-TI (primary failures). At onset of AZA, 11 patients had progressed with a change in WHO category (RA to RAEB1, or RAEB 1 to RAEB2) in 8 patients, and/or acquisition of additional chromosomal abnormalities in 9 patients, 5 eventually having complex karyotype, of whom 2 had chromosome 17 abnormality leading to TP53 gene deletion (TP53 mutation analysis is in progress); IPSS was low (n=0), int 1 (n= 3), int 2 (n=2), high (n=8). Prior to onset of AZA, attempts had been made to increase the LEN dose from 5 to 10 mg/d in 2 patients, without success. Results: AZA was administered at the FDA/EMEA approved schedule (75mg/m2/dx7) in 12 pts, and reduced (5 day schedule) in 1 pt. The median number of cycles administered was 6 (range 1–23). Five patients (46%) achieved a response according to IWG 2006 criteria, including CR, PR, HI in 1, 0 and 4 pts respectively. All 5 responders achieved RBC –TI. 4 patients received less than 4 cycles of AZA: 2 stopped AZA after 1 cycle for hematological toxicity, 1 stopped after 3 cycles for progression, 1 pt died from septic shock after 3 cycles. Response duration was 2.9+, 4.4+, 6.2+, 13.8, and 24.6 months, respectively. No responder was allografted, but the age of responders was 68, 70, 78, 78 and 86 years, respectively. Median survival from onset of AZA was 8.8 m (range 0.8–24.9). The 5 responders were still alive 3+, 4.4+, 6.2+, 13.9+ and 24.8+ m after onset of AZA, while median survival in non-responders was 8.7 months. Among the 5 patients who responded to AZA, 4 had at onset of AZA a high IPSS, 3 had complex karyotype and 2 one additional chromosomal abn, while 4/5 had previously achieved RBC-TI with LEN (with a median duration of 26.1 months). Neither of the 2 patients with TP53 deletion responded to AZA. Finally, among the 2 primary failures to Lenalidomide, one achieved HI with AZA (of 4.4+ months duration) and the other died within 2 months. Conclusion: In this relatively small series almost 40% of the patients with lower risk MDS and del 5q who progressed under LEN could be salvaged by AZA, and might expect survival prolongation. The appearance of novel chromosomal abnormalities or complex karyotype at progression did not predict poor response to AZA, while we are currently analyzing the prognostic value of TP 53 mutations, which occur frequently at th at disease stage (Jadersten, JCO 2011), on response to AZA. Disclosures: Fenaux: Celgene: Honoraria, Research Funding.

Abstract 2911 Background: AZA gives 50–60% responses and improves OS in higher-risk MDS but its role in t MDS/AML, characterized by a high frequency of unfavorable karyotypes and poor response to available treatments, remains unknown. Methods: An AZA compassionate program (ATU) was opened in France between Dec 2004 and Jan 2009 for higher risk MDS, and for AML not candidates to or refractory to intensive chemotherapy (IC). We analyzed t MDS/AML included in this program and having received at least 1 cycle of AZA, excluding patients (pts) previously treated with chemotherapy (CT) for their tMDS/AML. Results: 60 tMDS/AML were included: M/F:24/36, median age 69 (range 20–87). Primary disease was Breast Carcinoma (n=17), CLL (n=6), Hodgkin's disease (n=4), NHL (n=7), ALL (n=2), ovarian (n=2), liver(n=2), prostate carcinoma (n=2), other cancers (n=16), immunosuppressive therapy for lupus or Lung transplant in the last 2 pts. Treatment of primary neoplasm consisted in C×T in 86% and R×T in 61%. Diagnosis (WHO) was RCMD+/− RS in 4 pts, RAEB-1 in 10 pts, RAEB-2 in 28 pts MDS with myelofibrosis in 1 pt, and AML in 17 pts (including 12 FAB RAEBt). IPSS cytogenetics were fav in 4 (6.7%), int in 11 (18.3%), and unfav in 45 (75%, including 71% Complex karyotypes). Patients received a median of 4 cycles (range 1–24) of AZA, at FDA/EMEA-approved schedule (75 mg/m2/d ×7d/4 week) in 73% patients and a less intensive schedule (5d/4w, or 4 cycles, ORR was 21/35 (60%). Age, WBC count, baseline platelet count, % marrow blasts, karyotype (whatever the categorization) and ECOG status had no impact on ORR. 1, 2 and 3 year survival was 35%, 15% and 7%. Female gender (p=0.02), achievement of response (p=0.003) and ECOG status (0-1 vs 2–4) (p=0.04) had significant impact on OS while karyotype and % marrow blasts had no impact. However, there was a trend for lower OS in patients with chrom 5 abn (2y 0S 7.7% vs 23 %, p=0.08). 9 (15%) patients, all females, median age 55 (range 35–66) were allografted after a median number of 6 AZA cycles (range 2–17), including 3 pts, 4 pts and 2 pts who had achieved CR, mCR and no response to AZA, respectively. 4 (44%) of them were alive after 5+,17+,32+ and 42+ months. By comparison to the 232 pts with de novo MDS/AML included in the same program, tMDS/AML had a higher frequency of complex karyotype (71 vs 29.5, p Conclusion: In this cohort of tMDS/AML, survival with AZA was shorter than in de novo MDS/AML, probably largely due to their more severe baseline characteristics. Only 15% of tMDS/AML could be allografted, half of them with so far a favorable outcome. Disclosures: Fenaux: CELGENE, JANSSEN CILAG, AMGEN, ROCHE, GSK, NOVARTIS, MERCK, CEPHALON: Honoraria, Research Funding.

Abstract 440 Background: The JAK2V617F mutation is found in a small proportion of MDS, especially in RARS-T and occasionally in other MDS subtypes, but the overall impact of JAK2V617F on MDS characteristics and outcome remains unclear. Method: Diagnostic and follow up data on MDS patients (pts) with known JAK2V617F mutation status were collected from 19 centers of the Groupe Francophone des Myélodysplasies (GFM) and the French Intergroup of MPN (FIM). MDS post MPN and CMML were excluded. Patient characteristics and outcome according to JAK2V617F status were analyzed by univariate analysis. Survival analysis with Cox model matched on age, IPSS score and sex according to JAK2 status was also made. Analysis was performed using STATA 10.0 software. Result: 161 cases were collected, including 65 JAK2V617F mutated (JAK2 pos) and 96 unmutated (JAK2 neg) cases. Median age was 75 years and M/F ratio 1.2 in JAK2 pos vs 71 years (p=NS) and 1 (p=NS) in JAK2 neg pts, respectively (resp). WHO 2008 distribution was RA (8%), RARS (12%), RARS-T (41%), CRDM (15%), RAEB-1 (11%), RAEB-2 (5%), 5q- (3%), unclassified (5%) in JAK2 pos pts and RA (25%), RARS (9%), RARS-T (1%), CRDM (14%), RAEB-1 (28%), RAEB-2 (19%), 5q- (1%), unclassified (3%) in JAK2 neg pts, resp (p Conclusion: We found JAK2V617F mutation in MDS to be associated with higher WBC, ANC and platelet counts, lower % marrow blasts, less progression to AML and better survival than JAK2V617F neg MDS. This positive prognostic impact persisted after exclusion of RARS-T. However, our results will require confirmation in a prospective study. Disclosures: Fenaux: CELGENE, JANSSEN CILAG, AMGEN, ROCHE, GSK, NOVARTIS, MERCK, CEPHALON: Honoraria, Research Funding.

Abstract 1974 Background: Conventional therapeutic guidelines in essential thrombocytemia (ET) are based on established criteria of higher incidence of vascular complications: age more than 60 years, history of thrombosis, platelets more than 1000–1500 ×109/L and cardio-vascular risk factors. Hydroxyurea or anagrelide are the most commonly used cytoreductive therapy for high risk ET. Despite a proven activity of Interferon-alpha (IFN-α) in Ph negative myeloproliferative disorders, generalized use and efficacy have been hampered by frequent side effects. Nonetheless it is still a nonleukemogenic therapeutic option for younger patients and during pregnancy. More recently, phase II trials using Pegylated (Peg-) forms of IFN-α in patients with polycythemia vera (PV) or high risk ET have provided interesting results: first the superior toxicity profile is generally associated with a rapid hematologic response Second the molecular response described for a subset of JAK2 V617F positive PV or ET patients treated with Peg-IFN α-2a have indicated a selective targeting of the malignant clone with that latter agent. Methods: We revised cases of high risk ET having being or currently treated with IFN-α and reported by centres of the French Intergroup of myeloproliferative disorders (FIM). The current retrospective analysis was performed on data collected for the first 67 patients (pts) that have been observed for a median of 72 months (range 11–273). Among them, 59 pts have received Peg-IFNα-2a therapy. Assessment of the hematologic responses was performed at months 1, 2, 3 and then every 6 months. Results: For the entire cohort, median age was 37 years (range 17–64) and sex ratio F/M of 2.33. Previous thrombosis was observed in 19 cases and micro vascular disturbance in 4 pts. At diagnosis, median platelets count was 926.0×109/L (range 428.0; 4000.0), haemoglobin 14g/dl (8.0-14.1), leucocytes count 9.7×109/L (2.7-28.0). Detection of the Jak2V617F mutation was positive in 33 cases and negative for 26 pts. Median time from diagnosis to IFN-α was 50 months (1-256 months). IFN-α was generally administered as second line after Hydroxyurea. No prior therapy has been used for 6 pts. Reasons for IFN-α initiation were absence of hematologic response (31%), toxicity to the prior treatment (14%), pregnancy (16%), or medical decision for younger pts (39%). Of 67 pts of the cohort, 59 pts have been treated with Peg-IFNα-2a with a median duration of Peg-IFNα-2a of 16 months (range 1 day to 45 months). Efficacy and safety of the Peg-IFNα-2a were assessed in that subgroup. Thus 58 pts were evaluable for the hematologic response with at least 1 month exposure to Peg-IFNα2a. Overall, absence of response was observed in 4/58 (7%) pts, partial hematologic responses in 9/58 (16%) and complete hematologic response (CHR) was achieved for 45/58 (76%) of patients according to the European LeukemiaNet criteria. Cumulative incidence of CHR at 1, 3, and 6 months was 29%, 52% and 65% respectively. At 18 months, estimated probability of CHR was 83% (95%CI 71–92). At the last follow up 47/58 (81%) of the pts were still treated with Peg-IFNα-2a and overall 36 pts are in CHR. Median time to achieve CHR was 3 months. Median dose of Peg-IFNα-2a was 88μg weekly (range 28–180μg weekly). Reasons for discontinuation of Peg-IFNα2a (11pts) were related non hematologic toxicity in 7/59 pts (12%), 1 failure, and 3 pregnancies. By analysing the response according to the Jak2 status (58 pts), the overall CHR rates were 31 and 14 for the 37 JAK2 V617F mutated and the 21 JAK2 negative pts respectively. The median time to achieve CHR was 6 and 3 months. At 18 months the estimated CHR rates were 87% (73-95) and 66% (45-86). The difference is not statistically significant. Median doses of Peg-IFNα2a were 90μg (12-180) and 75μg (45-144) weekly. Duration of exposure to Peg-IFNα2a was 16 months (1-36) and 15 months (1-45). Conclusion: This retrospective analysis is the first attempt to present results on efficacy and tolerance of Peg-IFN on a large cohort of high risk ET not included in clinical trials. These results support the use of Peg-IFN in HR ET pts. Increase patients number, molecular analysis and update of these preliminary data will be presented. Disclosures: Off Label Use: Interferon alpha and Pegylated-Interferon alpha for myeloproliferative disorders.

Abstract 3812 Poster Board III-748 Background. DAR is a hyperglycosylated erythroblastic stimulating agent (ESA) with prolonged half life. Previous studies have shown high erythroid response rates with DAR +/− G-CSF in anemia of lower risk MDS (Mannone et al, Br J Haem 2006) with improvement in quality of life (QoL) (Greenberg et al, Blood 2009). In addition, treatment with ESAs in lower risk MDS does not increase progression to AML and may improve survival (Park, Grabar, Kelaidi et al, Blood 2008; Jadersten et al, JCO 2008). To better document the clinical relevance of erythroid response in those pts, we explored whether physical performance was also improved, using a new regimen of DAR+/− G-CSF. Patients and methods. In this phase II study (clinicaltrials.gov n° NCT00443339), low and int-1 MDS pts with anemia and endogenous EPO level Results 99 pts were included by 17 centers. Median age was 72 (41-88), M/F 56/43, WHO distribution: RA 27%, RCMD 17%, RARS 41%, RAEB-1 15%. Karyotype was favorable in 80%, intermediate in 20%. IPSS was low in 60%, int-1 in 40%. Median Hb was 92 g/L and 30% of the pts were RBC transfusion dependent (median 2 RBC units/month). Median endogenous EPO level was 60 IU/L. At the date of analysis, 77 and 65 pts were evaluable at weeks 12 and 24, respectively. Erythroid response rate at 12 weeks (according to IWG 2006 criteria) was 53% and reached 65% (after addition of G-CSF) at 24 weeks. Multivariate analysis for predicting response revealed that endogenous EPO level 100 IU/L, resp, P=0.04). 48 of the pts evaluated for response belonged to the 6 centers that participated in the QoL and exercise capacity part of the trial. All had the 6-min WT and QoL, and VO2peak evaluation could be assessed in 20 of them. Mean VO2peak was 1067 mL/min before treatment and 1157 mL/min at week 24 (p=0.15). Mean 6-min WT was 382 m at onset and 418 m at week 24 (p=0.06). A significant improvement in VO2 and 6-min WT at week 24 (vs baseline) was observed in 60% (p=0.058) and 70% (p=0.052) of responders compared to 0% and 19% of non responders, resp. Significant improvement of exercise capacity was associated with achievement of Hb level >110g/L. QoL tests were also improved in responders at week 24 compared to non responders at week 24 (p=0.04). No severe adverse events of treatment were reported. Conclusion This regimen of DAR every 2 weeks yielded high response rates. An objective improvement in exercise testing with treatment was seen in 60 to 70% of responders, depending on the test used. This finding, and the QoL improvement also observed in responders, confirm the clinical relevance of anemia correction in that elderly population with lower-risk MDS. Disclosures: Off Label Use: Darbepoetin, off-label use in anemia related with lower-risk myelodysplastic syndromes.

While in RARS-T, JAK2V617F mutation is common and associated with good prognosis, the clinical and prognostic impact of this mutation in other MDS is unknown. We collected data from 132 non-RARS-T MDS with known JAK2V617F mutation status. JAK2V617F mutation was significantly correlated with lower progression to AML (p