Abstract: Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive leukemia for which we developed a nationwide network to collect data from new cases diagnosed in France. In a retrospective, observational study of 86 patients (2000-2013), we described clinical and biological data focusing on morphologies and immunophenotype. We found expression of markers associated with plasmacytoid dendritic cell origin (HLA-DRhigh, CD303+, CD304+, and cTCL1+) plus CD4 and CD56 and frequent expression of isolated markers from the myeloid, B-, and T-lymphoid lineages, whereas specific markers (myeloperoxidase, CD14, cCD3, CD19, and cCD22) were not expressed. Fifty-one percent of cytogenetic abnormalities impact chromosomes 13, 12, 9, and 15. Myelemia was associated with an adverse prognosis. We categorized chemotherapeutic regimens into 5 groups: acute myeloid leukemia (AML)–like, acute lymphoid leukemia (ALL)–like, lymphoma (cyclophosphamide, doxorubicin, vincristine, and prednisone [CHOP])–like, high-dose methotrexate with asparaginase (Aspa-MTX) chemotherapies, and not otherwise specified (NOS) treatments. Thirty patients received allogeneic hematopoietic cell transplantation (allo-HCT), and 4 patients received autologous hematopoietic cell transplantation. There was no difference in survival between patients receiving AML-like, ALL-like, or Aspa-MTX regimens; survival was longer in patients who received AML-like, ALL-like, or Aspa-MTX regimens than in those who received CHOP-like regimens or NOS. Eleven patients are in persistent complete remission after allo-HCT with a median survival of 49 months vs 8 for other patients. Our series confirms a high response rate with a lower toxicity profile with the Aspa-MTX regimen, offering the best chance of access to hematopoietic cell transplantation and a possible cure.

Abstract: Blastic plasmacytoid dendritic cell neoplasm is a clonal disease derived from precursors of plasmacytoid dendritic cells (pDC). It is a rare neoplasm involving the skin which may or may not be associated from the outset with a leukemic component. The disease invariably progresses to aggressive leukemic dissemination, leading to a differential diagnosis with acute leukemia. In 2004, we set up a French network to recruit biological data at diagnosis. Diagnosis was according to recommendations (Swerdlow et al, 2008), with, in addition, a mandatory panel of pDC markers (Garnache-Ottou et al, 2009) detected by flow cytometry or by immunohistochemistry on infiltrated blood, bone marrow or cutaneous lesions. In total, 109 cases of BPDCN were included in 35 hospitals (2000-2013). BPDCN is more prevalent in men (sex ratio 4.4/1) and in elderly subjects (median age: 63 years; 7 patients were 〈 20 yo).S kin lesions are very prevalent (85%) with variable lesion types. Blood cell counts show variable leukocytosis (figure 1A) with presence of blasts in 65% of cases. Anemia and thrombopenia were present in 59% and 76% of cases respectively. Bone marrow aspiration showed blastic infiltration in 94% of cases. Indeed, in 7 cases, there was isolated cutaneous involvement at diagnosis, with neither blood nor bone marrow infiltration. Morphologies of blast cells were heterogeneous. Typical morphologies were the most frequent, including medium-sized cells with a blastic round or irregular nucleus, cytoplasm displayed faint and irregular basophilia and no granulation. In a contingent of the blastic populations, we observed small vacuoles in a peculiar arrangement under the cytoplasmic membrane (42%) or the presence of large pseudopodia (28%) or both (17%) (Figure 1B, C, D). Some cases showed a more immature morphology with larger cells, higher nucleo-cytoplasmic ratio, very visible nucleoli and reinforced basophilia (28%) or a pseudomonoblastic morphology (5%) (Figure 1E). Rare cases presented a pseudolymphocytic form (7%, figure 1F) or large granulations in the cytoplasm (2%). Peroxidase and esterase were negative in all cases. Dysplasia of hematopoietic lineages was observed in 29% (figure 1G). For 8% of patients, myelodysplastic syndrome was diagnosed before the diagnosis of BPDCN. Immunophenotype showed that HLA-DR and CD4 were expressed in all cases, but 4 cases did not express CD56 (confirmed using 3 different antibodies). Expression of markers of others hematopoietic lineages was frequent. Among myeloid markers, the most frequent was CD33 (46%), followed by CD117 (23%), whereas CD13, CD11c, CD15 and CD65 were rarely expressed. Monocyte markers (CD14, CD64, CD11b) and myeloperoxidase were never expressed. For the T lineage, CD2 and CD7 were the most frequent (62% and 58% respectively) whereas CD5 was rare (7%). No cytoplasmic or surface CD3 were detected. For the B lineage, CD22 was expressed in 16%, and low levels of cCD79a in 5%. Both were never expressed together, and no CD19, CD20 and immunoglobulins were found. Generally, we observed one of these antigens (Ags) per case, but in 44% of cases, there was a combination of 2 or 3 Ags from 2 or 3 different lineages. Immature Ags such as CD34 and CD133 were never found, and Tdt was found in 14% of cases. Cytogenetic analysis revealed abnormal caryotype in 65% of the 78 caryotypes evaluated, with 20 cases having a complex caryotype. The frequency of the chromosomal abnormalities involved are shown in Figure 1H. In conclusion, we describe the largest series of BPDCN to date in the literature. Detailed clinical and biological data at presentation allow improved recognition of this rare form of acute and aggressive leukemia, enabling early initiation of appropriate management. Figure 1. A: Blood cell count in 109 BPDCN patients at diagnosis. Bars represent the median. B: Typical BPDCN morphology. C: In this case, the nuclei were peripheral, cytoplasm presented heterogenous basophilia, vacuoles were rare but large pseudopodia are frequent. D: Typical morphology with frequent microvacuoles under the cytoplasmic membrane. E: Immature morphology. F: Pseudolymphocytic morphology. G: Presence of dysplasia in myeloid cells with Auer Rods in the granulocytes. The morphology of the Blastic cells is typical. H. Chromosomal abnormalities in 78 caryotypes evaluated: The histogram represents the number of cases in which each chromosome was involved (deletion, gain, translocations). Figure 1. A: Blood cell count in 109 BPDCN patients at diagnosis. Bars represent the median. B: Typical BPDCN morphology. C: In this case, the nuclei were peripheral, cytoplasm presented heterogenous basophilia, vacuoles were rare but large pseudopodia are frequent. D: Typical morphology with frequent microvacuoles under the cytoplasmic membrane. E: Immature morphology. F: Pseudolymphocytic morphology. G: Presence of dysplasia in myeloid cells with Auer Rods in the granulocytes. The morphology of the Blastic cells is typical. H. Chromosomal abnormalities in 78 caryotypes evaluated: The histogram represents the number of cases in which each chromosome was involved (deletion, gain, translocations). Disclosures Bardet: Celgene: Research Funding. Deconinck:CHUGAI: Other: Travel for international congress; PFIZER: Research Funding; ROCHE: Research Funding; NOVARTIS: Other: Travel for international congress; ALEXION: Other: Travel for international congress; JANSSEN: Other: Travel for international congress; LFB loboratory: Consultancy.

Abstract: Rd continuous significantly extended OS compared with MPT and resulted in comparable OS to that with Rd18 in patients with multiple myeloma. Patients achieving complete or very good partial response with Rd benefited greatly from continuous vs fixed treatment in terms of PFS.

Abstract: Background: In the pivotal FIRST trial, at the pre-specified planned analysis for progression-free survival (PFS), treatment (Tx) with lenalidomide plus low-dose dexamethasone until disease progression (Rd continuous) improved outcomes for transplant-ineligible patients (pts) with newly diagnosed multiple myeloma (NDMM) compared with melphalan, prednisone, and thalidomide (MPT), as well as Rd for 18 cycles (Rd18; Benboubker, NEJM 2014). Rd18 was added as a third arm to investigate whether Rd continuous Tx would control progression of NDMM longer than Rd18. Here, we present the final analysis of the overall survival (OS) data from the trial. Methods: Transplant-ineligible pts with NDMM were randomized 1:1:1 to Rd continuous (with lenalidomide given on days 1-21 of 28-day cycles until disease progression), Rd18 (with lenalidomide given on days 1-21 of eighteen 28-day cycles), or MPT (twelve 42-day cycles); both Rd18 and MPT were 72 weeks in duration. The primary endpoint was PFS and the key secondary endpoint was OS; the primary comparison was Rd continuous vs MPT. Other secondary endpoints included time to second therapy (TTST) and safety. Time from randomization to second progression or death (PFS2) was an exploratory analysis. Response assessment used for PFS and PFS2 analysis was determined by investigators based on International Myeloma Working Group criteria. Results: At the time of cutoff for the final OS analysis (January 21, 2016), 52 of the 535 pts in the Rd continuous arm and none of the pts in the Rd18 (n = 541) and MPT (n = 547) arms continued to receive Tx. The median follow-up for surviving pts was 67.0 months (range, 0-86.8 months). In the pre-specified final OS analysis for the primary comparison, a statistically significant advantage in OS was shown with Rd continuous over MPT (hazard ratio [HR], 0.78; 95% confidence interval [CI] , 0.67-0.92; P = .00234; Table). OS for Rd continuous vs Rd18 was evaluated (HR, 1.02; 95% CI, 0.86-1.20). In this updated analysis, a PFS advantage continued to be seen for Rd continuous vs MPT (HR, 0.69; 95% CI, 0.59-0.79; P 〈 .00001) and vs Rd18 (HR, 0.70; 95% CI, 0.60-0.81). Median TTST was longer for Rd continuous vs MPT (HR, 0.63; 95% CI, 0.54-0.73; Table). More pts in the Rd18 and MPT arms started second-line therapy (n = 377 and 381, respectively) compared with the Rd continuous arm (n = 299). Pts received a variety of Tx at progression, with bortezomib-based regimens the most common in the Rd continuous (n = 179; 59.9%), Rd18 (n = 208; 55.2%), and MPT (n = 170; 44.6%) arms. Pts who received bortezomib after Rd continuous or Rd18 had better outcomes than those who received it after MPT. PFS2 for Rd continuous was improved vs MPT (HR, 0.74; 95% CI, 0.64-0.85). Grade 3/4 adverse events (AEs) occurred in 86.3%, 80.2%, and 88.7% of the 532, 540, and 541 pts in the safety populations of the Rd continuous, Rd18, and MPT arms, respectively; the most common grade 3/4 AEs were neutropenia (29.5%, 26.5%, and 44.9%) and infections (31.6%, 21.9%, and 17.2%), and no new safety signals were seen compared with earlier analyses. Study discontinuation was most commonly due to disease progression and was less common in the Rd continuous vs Rd18 and MPT arms (50.7% vs 66.9% and 61.6%, respectively). Discontinuation due to AEs was similar across the Rd continuous, Rd18, and MPT arms (12.0%, 13.1%, and 13.9%). Solid tumor second primary malignancies (SPMs) occurred in 6.0, 6.9%, and 5.9% of pts, and hematologic malignancies occurred in 0.8%, 0.4%, and 2.6% of pts in the Rd continuous, Rd18, and MPT arms, respectively. Conclusions: Rd continuous significantly prolonged PFS and OS, and improved other secondary endpoints compared with MPT in transplant-ineligible pts with NDMM. Rd continuous also showed a PFS benefit compared with Rd18, delaying the time to next Tx. PFS2 outcomes suggest that Rd does not induce resistant relapses. Few hematologic malignancies occurred in the Rd arms, and the incidence of SPMs was similar between Rd continuous and Rd18. Rd continuous remains a standard of care for transplant-ineligible pts with NDMM. Disclosures Facon: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: travel and expense, Speakers Bureau. Dimopoulos:Genesis: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: 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. Dispenzieri:Celgene: Research Funding. Belch:Takeda: Honoraria; Janssen: Honoraria; Amgen: Honoraria; Celgene: Honoraria. Cavo:Bristol-Myers Squibb: Consultancy, Honoraria; Janssen-Cilag: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Millennium: Consultancy, Honoraria. Weisel:BMS: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Onyx: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Novartis: Consultancy, Research Funding. Ludwig:Janssen: Speakers Bureau; BMS: Speakers Bureau; Takeda: Research Funding, Speakers Bureau; Amgen: Research Funding, Speakers Bureau. Bahlis:BMS: Honoraria; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Other: Travel Expenses, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Other: Travel Expenses, Research Funding, Speakers Bureau; Onyx: Consultancy, Honoraria. Delforge:Janssen: Honoraria; Celgene: Honoraria; Amgen: Honoraria. Cavenagh:Amgen: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau. Geraldes:Celgene: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. Oriol:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. De La Rubia:Amgen, Bristol, Celgene, Janssen: Consultancy, Speakers Bureau. White:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Moreau:Celgene: Honoraria; Amgen: Honoraria; Takeda: Honoraria; Novartis: Honoraria; Janssen: Honoraria, Speakers Bureau; Bristol-Myers Squibb: Honoraria. Attal:janssen: Consultancy, Research Funding; amgen: Consultancy, Research Funding; celgene: Consultancy, Research Funding; sanofi: Consultancy. Ervin-Haynes:Celgene: Employment, Equity Ownership. Chen:Celgene: Employment, Equity Ownership. Houck:Celgene: Employment. Hulin:celgene: Honoraria; Bristol: Honoraria; Janssen: Honoraria; Amgen: Honoraria; takeda: Honoraria. Benboubker:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Abstract: Numerous cytogenetic and Fluorescence In Situ Hybridization (F) data have been previously published with the aim of defining prognosis subgroups of B-CLL patients. These studies included heterogeneous series of patients (treated or not, and at various stages of the disease). We have studied with conventional cytogenetic and F analyses an homogeneous cohort of 125 untreated Binet stages B or C B-CLL patients enrolled in a prospective trial on the basis of biological and morphological criteria, with a Matutes score 4/5. Karyotype (K) was systematically performed and F analysis carried out using four probes CEP12, 13q14, 11q22 (ATM), 17p13 (TP53) on metaphases and interphase nuclei. Out of 104 successful K, 65 (63%) showed abnormalities. Among them, 32% exhibited complex K, 25% balanced translocations and 35% unbalanced translocations. The most frequent abnormalities were 11q– (13%), +12 (13%), 13q– (10%), 6q– (8%), 17p– (5%), 14q32 rearrangement (5%), X or Y loss (4%), +19 (4%). Two translocations not previously reported involving the 14q32 locus were observed. F analyses were performed on 116 patients, 108 with the four probes, 8 with only 1–3 probes. 82 out of the 108 patients (76%) analyzed with 4 probes showed one or more abnormalities. Deletions of 13q were observed in 52%, ATM in 26%, TP53 in 10%, and trisomy 12 was present in 13%. Abnormal F patterns were observed in 51% of patients with normal K with at least one of the 4 probes, versus 92% of patients with abnormal K. Among abnormal K, F analyses detected additional cryptic deletions in 6/19 cases for ATM (31%), 29/39 for 13q14 (74%), and 4/9 for TP53 (45%). TP53 deletion was never detected among normal K, but in 15% of abnormal K. Among them, there were more TP53 deletion in complex K (24% vs 2%, p=0.005). Additional karyotypic abnormalities were found with a single F anomaly in 6/7 (86%) cases with del ATM, 12/17 (71%) with del13q, 4/6 (67%) with +12, 1/2 with del TP53. In the group of patients with normal F pattern, 81% had a normal K whereas 19% had an abnormal one (p & lt;0.0001). A preliminary correlation with the immunoglobulin heavy chain variable regions (IgVH) mutational status was performed for 54 patients. The unmutated status (41/54, 76%) was more frequently associated with abnormal K (deletions 11q, ATM, and TP53, unbalanced translocations, and complex K), than mutated status. There were more del13q alone (25% vs 3%, p=0.01) and trisomy 12 in mutated patients when compared with unmutated ones. This preliminary study underscores the interest of performing both conventional cytogenetic (classically stimulated) and systematic F analysis in advanced stage CLL. Results are complementary and, as previously reported, display a better prognostic significance than F alone. Furthermore, the systematic use of the 6q21, 14q32 and CEP19 probes in F analyses should be recommended when the K is normal. Comparison with other relevant biological parameters (ZAP70, sCD23, CD38) is ongoing.

Abstract: Abstract 698 Introduction: Between 11/2007 and 01/2009, the FCGCLL/MW and the GOELAMS conducted a multicenter phase III trial, CLL2007FMP, to evaluate the efficacy of FCCam versus FCR in previously untreated medically fit patients. PFS was the primary-end-point of this trial. The trial was discontinued after randomisation of 165 patients for unacceptable toxicity in the FCCam arm. PFS and OS are not yet evaluable but as a sensitive 6 color flow cytometry technique was used to assess MRD in blood and bone marrow at month 9, we were able to evaluate the quality of the response in both arms. Methods and patients: A cohort of 178 medically fit patients (cumulative illness rating scale (CIRS) score 〈 or = 6 and creatinine clearance ≥ 60 ml/min), younger than 65 years old, were enrolled. 165 patients were randomized to receive six oral courses of FC (F 40mg/m2 d1-3 and C 250 mg/m2 d1–3; q 28 days) in combination with either R (n=83; 375 mg/m2 i.v. d 0 at first cycle and 500 mg/m2 d1 all subsequent cycles; q 28 days) or Cam (n=82; 30 mg s/c d1-3; q 28 days). Patients were stratified according to IGHV mutational status and presence of 11q deletion. Cases with 17p deletion were excluded. The trial recruitment was discontinued because of an excess of mortality in the FCCam arm (6 deaths versus 0 in FCR arm), and the last 13 patients enrolled were not randomized. Clinical response was evaluated based on IWCLL criteria. We established a sensitive and specific approach for the evaluation of minimal residual disease (MRD) at month 9, using a 6-color flow cytometry technique with 3 combinations including characteristic markers and light chain expression. We determined the limit of detection (LOD) of the assay by studying normal blood samples, LOD varied from 0.5 to 0.7×10-5 depending on the combination considered. Result: The Overall Response Rate (ORR) was 91% in the FCR arm and 85% in the FCCam arm (ns). Clinical responses were as follows: CR (FCR: 56/80=70%, FCCam: 45/79 =59%, ns), CR I (FCR:13/FCCam: 11), PR (FCR:5/FCCam:15), and stable and progressive cases (FCR: 6/FCCam:8). When considering together CR and CR I, response rate appeared significantly higher in the FCR arm (86%) than in FCCam arm (70%) (p=0.03). MRD was assessed both in blood and bone marrow at month 9, and was undetectable in 58% patients in blood and only in 36 % in bone marrow. No patient had an undetectable MRD in marrow when detectable in blood. Similarly, MRD was detectable in bone marrow in 15 cases with histologically normal bone marrow biopsy, whereas no nodal PR had undetectable MRD. Therefore, flow cytometry MRD in bone marrow appears as the most sensitive technique for the evaluation of response. Of note, 9 patients had a very good PR with presence of a residual lymphnode, and had undetectable blood and bone marrow MRD (4 in FCCAm arm and 5 in FCR arm). When considering MRD independently from clinical response, the number of MRD negative cases was not significantly different between the two arms (FCR: 45%/FCCam: 26 %) arm. But when combining MRD negativity with clinical complete response, the number of MRD negative CR was significantly higher with FCR (40%) than with FCCam (15%)(p= 0.029). The number of courses of chemotherapy received was slightly but significantly lower in the FCCam arm. Nonetheless, this difference was not accountable for the difference in the quality of response as the number of MRD negative CR remained significantly higher with FCR than with FCCam when considering only the patients having received at least 4 courses of either chemotherapy. The quality of response was not influenced by either presence of deletion11q or mutational status as well. In conclusion, detection of MRD in bone marrow by flow cytometry is a sensitive technique for the evaluation of minimal residual disease. Combining clinical CR with flow cytometry bone marrow MRD allows detecting the best responders. In this randomized phase III trial, besides leading to a lower rate of toxicity, the FCR regimen yielded a significantly higher rate of MRD negative CR than FCCam, and therefore had a positive impact on the quality of the response. Disclosures: Veronique: roche: Consultancy, Membership on an entity's Board of Directors or advisory committees; mundipharma: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; genzyme: Membership on an entity's Board of Directors or advisory committees; celgene: Membership on an entity's Board of Directors or advisory committees; jansen: Membership on an entity's Board of Directors or advisory committees.

Abstract: Abstract 762 Pediatric AML is a heterogeneous disease. We showed that differential outcomes of 11q23/MLL-rearranged AML depend on the fusion partner involved in the translocation in a large international retrospective study from 11 collaborative groups comprising 756 children (Balgobind et al, Blood 2009). In the current analysis we focused on the clinical characteristics and prognostic impact of additional cytogenetic aberrations (ACA). All patients with complete karyotypes (n=733) were centrally reviewed and classified for type and number of aberrations. Cases with 2 or more aberrations (including 11q23/MLL-rearrangement), were included in the ACA group (n=344/733, 47%). Numerical and structural ACA were divided into gains and losses of full or partial chromosomes, and balanced translocations were defined by the breakpoints. A complex karyotype was defined as 3 or more aberrations. ACA occurring in at least 10 patients were considered for statistical analysis, including differences in presenting characteristics (chi-square or Fisher's exact tests) and survival estimates (Kaplan-Meier method and Cox proportional hazards model for Event free survival (EFS), 5 year estimates and 95% confidence intervals (CI) are given). Multivariate analysis included the fusion partners with independent prognostic significance, as identified by Balgobind et al. Patients with ACA were found to be older (median age, 3.0 y vs 1.8 y, p=.001) and had a higher frequency of FAB M7 phenotype (4.5 % vs 1.1 %, p=.007) than those without ACA. For the complete cohort (n=733) estimates of EFS and overall survival (OS) were .44 and .56, and cumulative incidence of relapse (CIR) was .35 (standard errors .03). Patients with ACA showed significantly poorer clinical outcome than cases without ACA (EFS .38 vs .48, p=.002; OS .47 vs .62, p 〈 .001; CIR .52 vs .38, p 〈 .001). The most frequent specific ACA that was identified was trisomy 8 (130/344 cases, 38%). Patients with trisomy 8 were older (median age, 4.4 y vs 1.9 y, p 〈 .001), presented with lower WBC counts (median 2.3 vs 27.1*109/l, p 〈 .001), were found more frequently in association with t(9;11)(p22;q23) (58% vs 42%, p=.01) and had a higher frequency of FAB M5 (78% vs 61%, p=.01) compared to patients without trisomy 8 cases. Trisomy 8 appeared to independently predict better clinical outcome within the ACA group (EFS .53 vs .29, p 〈 .001; OS .61 vs .39, p=.003; CIR .35 vs .62, p 〈 .001. and Hazard Ratio (HR) .57, CI .36-.92, p=.02). Trisomy 19 was found in 37/344 cases (11%). Trisomy 19 independently predicted poor clinical outcome in ACA cases. This effect appears to be mainly determined by refractory disease rather than relapse (probability of complete remission 62% vs 87%, EFS .17 vs .40, p=.003; OS .24 vs .50, p 〈 .001; CIR .54 vs .51, p=.88; HR 1.77, CI 1.13–2.78, p=.01). Structural ACA were identified in 204 cases. Analyses in which all structural ACA were grouped together showed that they are of independent prognostic significance compared to only numerical aberrations (EFS .32 vs .47, p=.02; OS .42 vs .56, p=.10; CIR .59 vs .41, p=.003; HR 1.36, CI 1.07–1.80, p=.01). However, no specific structural ACA was present in more than 10 patients, precluding a more detailed analysis. Complex karyotype was found in 192/733 (26%) patients. Outcome was worse in these patients than those without complex karyotype (EFS .37 vs .46, p=.02; OS .45 vs .59, p=.003; and CIR .53 vs .42, p 〈 .001), however, no independent prognostic significance was shown. In the context of the newly identified prognostic factors, the translocation partners 10p12, 6q27, 1q21 and 10p11.2 still showed independent prognostic value (HR 1.36, 2.29, .12 and 2.12 respectively). In conclusion, here we show that in addition to fusion partners, ACA have independent prognostic significance in pediatric 11q23/MLL-rearranged AML. Trisomy 8 was identified as an independent indicator of better prognosis in pediatric 11q23/MLL-rearranged AML. The presence of any ACA other than trisomy 8 predicts for worse clinical outcome. More specifically, trisomy 19 and structural aberrations were independent negative prognostic factors. Complex karyotype was a frequent finding and was a negative prognostic factor in univariate analysis only. This study shows that MLL-translocation partner and additional cytogenetic aberrations are important for patient stratification. Future studies should aim to understand the biology underlying these prognostic differences. Disclosures: Smith: Pfizer, Inc:.

Abstract: Introduction In immune thrombocytopenia (ITP), isotopic assessment of the site of platelet destruction using autologous111Indium-oxinate-labelled platelet sequestration study could be an helpful parameter to determine whether or not to perform splenectomy. Two independent studies have suggested that a purely splenic sequestration could be a significant predictive factor of long-term complete response after splenectomy. An increasing number of patients receives thrombopoietic receptor-agonists (TPO-RAs) but such treatments are not curative and therefore do not necessarily prevent from considering splenectomy in the course of ITP. TPO-RAs increase platelet production by inducing proliferation and differentiation of the megakaryocyte lineage. We have only very few data evaluating the impact of TPO-RAs, on mean platelet life span (MPLS), platelet production and platelet site of destruction. The aim of this study was to assess these parameters and clinical outcome of patients treated with TPO-RAs who underwent kinetic study of autologous111Indium-oxinate-labelled platelet. Patients and Methods We carried out a retrospective study in the Ile de France region, between 2008 and 2016. Patients were retrospectively selected from a prospective clinical database at the Cellular Biology Department of Saint Louis Hospital. We selected adult patients with definite ITP according to the international criteria. The isotopic method used to study platelet lifespan was previously described. Analyses were based on the radioactivity accumulation slopes in the hepatic or splenic area. We excluded patients who had received less than 3Mbeq of 111In. Data from patients' medical charts were collected using the standardized form of the Referral Center for Adult ITP. Complete response (CR) and Response (R) were defined according to standardized international criteria: platelet count 〉 30x 109/L with at least a doubling of the baseline value or 〉 100 x 109/L. Results of platelet kinetic study from patients treated with TPO-RAs were compared with those from patients receiving no treatments. Results Two hundred and fifty three adults ITP patients were included. At the time of platelet kinetic study, 24 patients (10 men/14 women) with a median age of 63 years [range: 22-83] were treated with TPO-RAs (romiplostim n= 10, eltrombopag n = 14) and 229 (81 men/148 women) had no treatment. Among the TPO-RAs treated patients, some also received low dose steroids (n=6), dapsone (n=1) or intravenous immunoglobulins (n=2) at least two weeks before the kinetic study. Three were newly diagnosed, 9 had persistent ITP and 12 chronic ITP. The median platelet count was 62 x109/L [range: 22-175] , and 7 patients had a platelet count 〉 100 x109/L. The median Mean Platelet Life Span (MPLS) was reduced in both groups (1.44 day [range: 0.4-7.5] (normal: 7-10) in patients treated with TPO-RAs), but was significantly higher in untreated patients (2.3 day [0.4-11] , p = 0.004). The median turnover platelets ratio was increased in both groups (48% per day [range: 11-173] in patients treated with TPO-RAs), but was significantly lower in untreated patients (30% per day [range: 0.8-247] ). Ratio of platelet production was significantly increased in patients treated with TPO-RAs (median: 2, [range: 0.1-5.0]) compared with untreated patients (median: 0.84, [range: 0.1-85.0] ). Repartition of the site of platelet sequestration was similar in the two groups, 12 (50%) patients treated with TPO-RAs had a splenic uptake, versus 112 (49.1%) in untreated patients, and 2 (20%) patients treated with TPO-RAs had an hepatic uptake versus 9 (3.9%) in untreated patients. A splenectomy was performed in 9 out of the 12 patients with a purely splenic sequestration. After a median follow-up of 26 months [range 0-53], 8 (88%) had achieved CR and 1 had relapsed 5 months after splenectomy. Conclusion Our study shows that despite an increase production and turnover of platelets due to the stimulation of the megakaryopoiesis by TPO-RAs, the MPLS was clearly reduced and the repartition of platelet sequestration was not modified in patients receiving these drugs. Moreover, it would seem that a purely splenic sequestration is also predictive of CR after splenectomy in this group of patients. More importantly platelet kinetic study can be used in patients treated with TPO-RAs to position the splenectomy in the therapeutic management. Disclosures No relevant conflicts of interest to declare.

Abstract: Translocations involving chromosome 11q23 frequently occur in pediatric acute myeloid leukemia (AML) and are associated with poor prognosis. In most cases, the MLL gene is involved, and more than 50 translocation partners have been described. Clinical outcome data of the 11q23-rearranged subgroups are scarce because most 11q23 series are too small for meaningful analysis of subgroups, although some studies suggest that patients with t(9;11)(p22;q23) have a more favorable prognosis. We retrospectively collected outcome data of 756 children with 11q23- or MLL-rearranged AML from 11 collaborative groups to identify differences in outcome based on translocation partners. All karyotypes were centrally reviewed before assigning patients to subgroups. The event-free survival of 11q23/MLL-rearranged pediatric AML at 5 years from diagnosis was 44% (± 5%), with large differences across subgroups (11% ± 5% to 92% ± 5%). Multivariate analysis identified the following subgroups as independent prognostic predictors: t(1;11)(q21;q23) (hazard ratio [HR] = 0.1, P = .004); t(6;11)(q27;q23) (HR = 2.2, P 〈 .001); t(10;11)(p12;q23) (HR = 1.5, P = .005); and t(10;11)(p11.2;q23) (HR = 2.5, P = .005). We could not confirm the favorable prognosis of the t(9;11)(p22;q23) subgroup. We identified large differences in outcome within 11q23/MLL-rearranged pediatric AML and novel subgroups based on translocation partners that independently predict clinical outcome. Screening for these translocation partners is needed for accurate treatment stratification at diagnosis.

Abstract: Background Melphalan, prednisone and thalidomide (MPT) is a standard therapy for NDMM recognized worldwide based on a statistically significant advantage in overall survival (OS) and progression-free survival (PFS) vs. MP (Facon Lancet 2007; Fayers Blood 2011; NCCN 2013). The combination of lenalidomide and low-dose dexamethasone (Rd) increased OS with fewer adverse events (AEs) than treatment with lenalidomide and high-dose dexamethasone in NDMM pts (ECOG E4A03) (Rajkumar Lancet Oncol 2010). The FIRST trial is a multicenter, open-label, phase III trial comparing the efficacy and safety of Rd versus MPT in transplant-ineligible NDMM pts. Methods NDMM pts either ≥ 65 years of age, or not candidates for SCT were randomized to one of three arms: Rd in 28-day cycles until disease progression (Arm A), Rd in 28-day cycles for 72 weeks (18 cycles, Arm B), or MPT in 42-day cycles for 72 weeks (12 cycles, Arm C). Assessments by International Myeloma Working Group criteria were done after each cycle. Pts with renal impairment were enrolled; however, pts on dialysis were excluded. Starting doses of lenalidomide and dexamethasone were adjusted based on renal function and age, respectively. Melphalan starting dose was adjusted based on age, absolute neutrophil count, platelet count, and renal function; and thalidomide was adjusted for age. Dose adjustments were permitted for AEs. All pts were required to receive anti-thrombotic prophylaxis. Stratification factors included age, International Stage System, and country. The primary endpoint was a comparison of PFS in Arm A vs. Arm C. Secondary endpoints included OS, overall response rate (ORR), time to response, duration of response (DOR), safety, and quality of life (QOL). A preplanned additional analysis included time from randomization to second progression event or death (PFS2). The final preplanned analysis of independently adjudicated progressive disease (PD) events in Arm A vs. Arm C conducted after 960 events of death or PD, and an interim of OS in 64% of survival events (574/896 events) are presented in this abstract. Comparisons of PFS and all secondary endpoints, including OS for all three arms, will be presented at the meeting. Results A total of 1,623 pts were randomized 1:1:1 in three arms. As of today, 121 pts continue to receive lenalidomide on study (Arm A). The median age was 73 (40.0–92.0) years; 35% pts were aged ≥ 75 years; and 41% of pts had ISS stage 3 disease. After a median follow-up of 37 months, the trial met its primary endpoint (PFS), demonstrating a 28% reduction in risk of progression or death (HR=0.72; p= 0.00006). The preplanned interim analysis of OS demonstrated a 22% reduction in risk of death in favor of Arm A vs. Arm C (HR=0.78, p=0.01685); however, the pre-specified boundary (p 〈 0.0096) was not crossed. All other secondary endpoints consistently showed improvement in favor of Arm A vs. Arm C; ORR (PR or better) 75% vs. 62% (p 〈 0.00001), DOR (HR=0.63; p 〈 0.00001), and PFS2 (HR=0.78, p=0.0051). Relevant Grade 3/4 adverse events in Arm A vs. Arm C were neutropenia (28% vs. 45%), thrombocytopenia (8% vs. 11%), febrile neutropenia (1% vs. 3%), infection (29% vs. 17%), neuropathy (5% vs. 15%), and deep-vein thrombosis (5% vs. 3%). The incidence of secondary primary malignancies (SPM) was evaluated. Hematologic malignancies were 0.4% in Arm A vs. 2.2% in Arm C; the overall incidence of solid tumors was identical (2.8%). Conclusion Continuous treatment with the all oral doublet Rd significantly improved the primary endpoint of PFS compared with the standard triplet, MPT. All secondary endpoints support the clinical benefit of continuous Rd treatment. The safety profile of Rd was manageable, with reduced hematologic SPM compared to MPT. Disclosures: Facon: Celgene: Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau. Off Label Use: Lenalidomide as treatment for NDMM. Dimopoulos:Celgene, Orthobiotech: Honoraria. Dispenzieri:Celgene, Millenium, Jansenn, Pfizer: Research Funding. Catalano:Celgene, Roche: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding. Hulin:Janssen: Honoraria; Celgene: Honoraria. Cavo:Celgene, Janssen, Millennium, Onyx, Brystol Myers Squibb: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees. Pinto:Mundipharma: Consultancy, Honoraria; Roche: Honoraria; Celgene: Consultancy, Honoraria. Weisel:Janssen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding. Ludwig:Celgene: Honoraria, Research Funding, Speakers Bureau. Bahlis:Celgene: Consultancy, Honoraria. Delforge:Celgene: Honoraria. Chen:Celgene: Consultancy, Research Funding; Lundbeck: Consultancy; Johnson & Johnson: Consultancy, Research Funding; Roche: Honoraria; GlaxoSmithKline: Research Funding. Oriol:Celgen: Consultancy. White:Celgene: Honoraria, Research Funding. Binder:Celgene: Research Funding. Anderson:Acetylon, OncoPep: Equity Ownership; Celgene, Onyx, Sanofi Aventis, Gileod: Consultancy. Moreau:Celgene Corporation: Honoraria, Speakers Bureau. Attal:Janssen: Lectures, Lectures Other, Membership on an entity’s Board of Directors or advisory committees; Celgene Corporation: Lectures Other, Membership on an entity’s Board of Directors or advisory committees. Knight:Celgene: Employment, Equity Ownership. Chen:Celgene: Employment. Van Oostendorp:Celgene: Employment. Jacques:Celgene: Employment. Ervin-Haynes:Celgene: Employment, Patents & Royalties. Benboubker:Celgene: Consultancy.