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Introduction: Ph-negative myeloproliferative neoplasms (MPNs) are a group of clonal stem-cell disorders with an elevated risk for thrombosis. Leukocytosis is a well-known risk factor for thrombosis. Neutrophils from MPN patients display features of activation. On stimulation, neutrophils produce neutrophil extracellular traps (NETs), which have been implicated in the pathogenesis of thrombosis. Myeloperoxidase-conjugated DNA levels (a specific NET marker) have been found increased in plasma of thrombotic MPN patients (Guy, A, ISTH 2019 OC 77.3). Ex vivo, activated neutrophils from JAK2V617F patients are primed to form NETs, diminishing under ruxolitinib treatment. Mice with conditional knock-in of JAK2V617F have increased NETs formation and thrombotic events. Inhibition of JAK/STAT signaling by ruxolitinib abrogated NETs formation and reduced thrombosis in this murine model (Wolach, O,Sci. Transl. Med. 2018). Thus, a link between JAK2V617F expression, NETs formation and thrombosis has been suggested (Wolach, O, 2018). It remains unclear whether, in MPN patients, JAK/STAT independent pathways are implicated in the NETs formation. With this aim, we explored the effects of different cytoreductors in NETs formation. Patients and Methods: In a multicentric study conducted at Hospital General Universitario Morales Meseguer (Murcia, Spain) and Hospital del Mar (Barcelona, Spain), EDTA plasma samples were collected from MPN patients (n=104). Patients include polycythemia vera (PV, n=35, all of them JAK2V617F), essential thrombocythemia [ET, n=47; 38 JAK2V617F, 4 CALRmut, 5 triple negative (TN)], myelofibrosis (MF, n=9; 4 JAK2V617F, 2 CALRmut, 3 TN), and unclassifiable MPN by WHO-2016 (MPN-u, n=13; 12 JAK2V617F, 1 CALRmut). Samples were collected at different time points following up the disease: at diagnosis or before any cytoreductive treatment, time 0, (n=100), less than 6 months of treatment (time 6; n=60), from 6 to 12 months of treatment (time 12; n=60), and from 12 to 24 months of treatment (time 24; n=49). Among the 104 patients, we had clinical information about treatment on 99 cases, included hydroxyurea (HU, n=69), ruxolitinib (n=15), IFN-α (n=2), and non-treated (n=13, all basal samples). We measured citH3-DNA complexes, as specific marker of NETs, by ELISA using rabbit anti-citH3 (Abcam) and peroxidase-conjugated anti-DNA antibody (Cell Death Detection ELISA). The absorbance at 405 nm (A405) was measured in a plate reader (Biotek®). Thus, we followed up the NETosis marker evolution with treatment over time. One-tailed and paired Wilcoxon test was applied and p Results: Overall, regardless of the treatment, we observed a reduction of citH3-DNA levels over time (Fig. 1A), being these significant between time 0 and times 6 and 12 (p=0.02 for both time-points), Importantly, patients treated with HU showed a substantial reduction of NETs in all time-points (Fig. 1B, left), which was statistically significant between times 0 and 6 (p=0.03) and between times 0 and 24 (p=0.02). Although in patients treated with ruxolitinib, the citH3-DNA levels seem to be reduced at time 12, the difference was not significant (Fig. 1B, right), probably because of the small sample size. Regarding the MPN phenotype, decrease of citH3-DNA levels over time was only observed in PV patients (Fig. 1C, left), specially at time 12 (p=0.03). In contrast, under cytoreductive treatment, ET patients did not show significant differences in NETs levels over time (Fig. 1C, middle). In MF, there were not enough samples to obtain a clear conclusion (Fig. 1C, right). Regarding the driver gene mutations, we detected a significant decrease in the citH3-DNA levels in JAK2V617F patients (Fig. 1D, left), specifically between basal time and times 6 and 12 (p Conclusions: Our results showed that hydroxyurea reduces NETosis levels in plasma from MPN patients, suggesting that JAK-STAT independent pathways could be implicated in the NET formation. Hydroxyurea could decrease thrombosis in MPN patients, not just reducing the number of functionally abnormal cells in peripheral blood, but also by abrogating NET formation. Acknowledgements: This study was supported in part by ISCIII (PI18/00316 & PI16/0153) & Fundación Séneca (20644/JLI/18). Disclosures Bellosillo: Qiagen: Consultancy, Speakers Bureau; Roche: Consultancy, Research Funding, Speakers Bureau.

Eltrombopag is effective and safe in immune thrombocytopenia (ITP). Some patients may sustain their platelet response when treatment is withdrawn but the frequency of this phenomenon is unknown. We retrospectively evaluated 260 adult primary ITP patients (165 women and 95 men; median age, 62 years) treated with eltrombopag after a median time from diagnosis of 24 months. Among the 201 patients who achieved a complete remission (platelet count >100 × 109/l), eltrombopag was discontinued in 80 patients. Reasons for eltrombopag discontinuation were: persistent response despite a reduction in dose over time (n = 33), platelet count >400 × 109/l (n = 29), patient's request (n = 5), elevated aspartate aminotransferase (n = 3), diarrhea (n = 3), thrombosis (n = 3), and other reasons (n = 4). Of the 49 evaluable patients, 26 patients showed sustained response after discontinuing eltrombopag without additional ITP therapy, with a median follow-up of 9 (range, 6–25) months. These patients were characterized by a median time since ITP diagnosis of 46.5 months, with 4/26 having ITP

INTRODUCTION The 2017 WHO classification requires the presence of ≥1x109/L and ≥10% of monocytes in peripheral blood (PB) for the diagnosis of CMML. Recently, Geyer et al. defines oligomonocytic CMML (O-CMML) as those MDS cases with relative monocytosis (≥10% monocytes) and monocyte count 0.594% is a highly sensitive and specific diagnostic marker for CMML. In the extent of our knowledge, there are no data about PB monocyte subset distribution by FC in O-CMML. Moreover, CD2 and CD56 expression is common in CMML and rarely observed in MDS, the group where O-CMML are currently included. Furthermore, we compared: the molecular profile; cytogenetic abnormalities; cytopenias; BM dysplasia; BM blast and monocyte percentage; PB monocyte percentage, and monocyte and leukocyte counts. METHODS 50 CMML and 33 O-CMML from a single institution were prospectively studied from 02/2016 to date. Table 1 summarizes morphologic, cytogenetic, molecular and clinical findings. We studied PB monocyte subsets by FC: Mo1 (CD14bright/CD16-), Mo2 (CD14bright/CD16+) and Mo3 (CD14dim or -/CD16bright). In addition, we assessed the expression of CD56 and CD2 in monocytes (positivity ≥ 20%). Finally, targeted NGS of the entire exonic sequence of 25 genes recurrently mutated in myeloid malignancies was performed (VAF sensitivity: 2%). Chi-Square, Fisher exact or Man-Whitney U tests were used as appropriate. RESULTS AND DISCUSSION The Mo1 percentage (%) was significantly inferior in O-CMML (P=0.007), but it is noteworthy that median and mean of Mo1% in O-CMML were upper the cutoff of 94% (median: 96.1 vs 98.1; mean: 94.7 vs 96.9). Moreover, the % of patients with >94% Mo1 was no significantly different when comparing O-CMML and CMML although a clear trend was observed (72% vs 90%; P=0.082). This result is impressive since, as previously reported, the specificity of the Mo1 >94% test is around 90-95% and only 5-10% of false positive rate (FP) should be expected. However, in O-CMML a 72% of FP was observed since following 2017 WHO recommendation these patients should be considered as MDS. No differences were observed neither in the % of patients showing CD56+ monocytes (65.6% vs 66.7%; P=0.923) nor in the % of them showing CD2+ (28.1% vs 37.5%; P=0.53) when comparing O-CMML and CMML. We observed no significant differences in platelet count, hemoglobin, BM dyserythropoiesis, BM dysgranulopoiesis, BM dysmegacaryopoiesis, BM blast %, percentage of abnormal karyotypes, and Spanish cytogenetic risk stratification. The main differences were observed in leukocyte count, monocyte count, PB monocyte %, BM monocyte %, and BM promonocyte percentage. Table 1. There were no differences in the number of mutated genes or in the number of mutations between CMML and O-CMML (Table 1). As expected, TET2 and SRSF2 were the most frequently mutated genes in both groups. Moreover, no significant difference was observed in the presence of TET2/SRSF2 co-mutation, the gene signature of CMML (32% vs 26% in CMML). The genes mutated at a frequency >10% in O-CMML were: TET2 (79%), SRSF2 (36%), SF3B1 (29%), ZRSR2 (25%), DNMT3A (15%), and ASXL1 (14%). The genes mutated at a frequency >10% in CMML were: TET2 (81%), SRSF2 (28%), ASXL1 (23%), CBL (23%), SF3B1 (16%), and NRAS (14%). Only two genes were mutated at a significant different frequency: CBL (4% vs 23% in CMML, P=0.041) and ZRSR2 (25% vs 7% in CMML, P=0.043). As expected, CMML showed a higher % of RAS pathway mutations (CBL, NRAS or KRAS) since these have been associated with proliferative features (4% vs 40%, P=0.001). This is especially evident in proliferative CMML in which genes associated with proliferation are present at higher frequencies: CBL (4% vs 39% in CMML, P=0.01), NRAS (0 vs 23% in CMML, P=0.029) and ASXL1 (14% vs 62% in CMML, P=0.004). A significant lower percentage of O-CMML with ZRSR2mut presented Mo1 >94% (33% vs 86%, P=0.024). As shown, O-CMML without ZRSR2mut showed this feature in a similar percentage than CMML (86% vs 90%). At a median follow-up of 31.2 months, 19% of O-CMML evolved to CMML showing a median time to evolution of 34 months. CONCLUSION Our data support the diagnosis of O-CMML as a distinctive subtype of CMML. Table 1 Disclosures Bellosillo: Qiagen: Consultancy, Speakers Bureau; TermoFisher Scientific: Consultancy, Speakers Bureau.

Introduction. Genetic studies in patients with Ph-negative myeloproliferative neoplasms (MPNs) are essential to establish a correct diagnosis and to optimize their management. Recently, it has been demonstrated that it is possible to detect molecular alterations present in solid tumors and hematologic neoplasms by the analysis of circulating tumor DNA in plasma samples, which is known as liquid biopsy. It has been reported that most of the circulating cell-free DNA (cfDNA) has its origin in immature hematopoietic and bone marrow cells; however, there is limited information about liquid biopsy applications in MPNs. Objective. To analyze the molecular profile of circulating tumor DNA in patients with MPNs. Patients and methods. Peripheral blood samples from 75 patients with MPNs were collected at the time of diagnosis: 21 polycythemia vera (PV), 42 essential thrombocythemia (ET), 10 primary myelofibrosis (PMF) and two non-classifiable MPNs. Cellular DNA was extracted from the granulocytic fraction isolated by density gradient centrifugation and cfDNA was obtained from 1-3ml of plasma (MagMAX Cell-Free DNA Isolation Kit, Thermo Fisher Scientific). cfDNA purity was ascertained by capillary electrophoresis (4200 TapeStation system, Agilent). Molecular characterization was performed in paired samples of granulocytes DNA and cfDNA by next generation sequencing (NGS). Libraries were prepared using a custom panel that covered the whole codifying region of 25 myeloid-associated genes (QIAseq Custom DNA Panels, Qiagen) and sequenced using Illumina technology (Miseq, Nextseq) with a 3000x minimum coverage. Results. The amount of total cfDNA/mL in plasma was significantly higher in PMF (mean 97 ng/ml) than in PV and ET (mean 18 and 23g/ml, respectively) (p = 0.003, Kruskal-Wallis). Overall, 144 mutations in driver (JAK2, CALR, MPL) and non-driver genes were detected in the granulocytic fraction with similar frequencies to what has been described for PV, ET and PMF. The most frequently mutated non-driver genes where ASXL1 (18.7%), TET2 (17.3%), DNMT3A (6.7%), SRSF2 (6.7%) and IDH2 (5.3%). Sequencing of cfDNA showed a total of 146 mutations. All mutations detected in the granulocytic fraction were also detected in the paired cfDNA sample (100% concordance); two additional mutations in MPL and ASXL1 were detected in plasma in one case. The median variant allele frequency (VAF) present in cfDNA was 29% (range 0.86 - 91.73%), which is far superior to what has been described in solid neoplasms or lymphomas (median 0.41%, range 0.03% - 97.6%). A strong correlation was observed between the VAFs of granulocytic DNA and cfDNA (r = 0.875, p < 0.001, Spearman) (Figure 1). The mutation VAFs detected in cfDNA were significantly higher than VAFs detected in granulocytes (p < 0.001, Wilcoxon). In particular, MPL mutations presented 2.5 higher VAF in cfDNA than in granulocytes (p = 0.018, Wilcoxon). This finding was confirmed and quantified by digital PCR. Interestingly, in one PMF patient the p.W515L MPL driver mutation was originally only detectable by NGS in cfDNA, but not in granulocytes. This mutation was identified by ultra-sensitive digital PCR in both cfDNA (VAF 2.30%) and granulocytes (VAF 0.16%). Conclusions. The analysis of circulating tumor DNA allows the characterization of the molecular abnormalities of patients with Ph negative myeloproliferative neoplasms. The sensitivity for mutation detection in driver and non-driver genes was equal or even superior to that obtained when studying the isolated granulocytic population. Disclosures Salar: Roche: Research Funding, Speakers Bureau; Janssen Pharmaceuticals: Consultancy, Speakers Bureau; Gilead: Consultancy, Speakers Bureau; Celgene: Consultancy. Besses:Gilead: Research Funding. Bellosillo:TermoFisher Scientific: Consultancy, Speakers Bureau; Qiagen: Consultancy, Speakers Bureau.

Introduction. It is known that imatinib can be safely discontinued in patients (pts) with Chronic Myeloid Leukemia (CML) with minimal residual disease. Here we report an update of the Imatinib Suspension And Validation (ISAV) study at 79 months (mts) from study initiation to provide long term follow up data. Aims. The ISAV study aims to validate the capability of digital PCR (dPCR) to predict relapses after imatinib discontinuation in CML pts with negative Q-RT-PCR and to evaluate relapse rate, time to recurrence, survival and the impact of imatinib treatment on Quality of Life (QoL). Methods. This study involves 15 sites, 10 in Italy and 1 in each of the following countries: Germany, Spain, The Netherlands, Canada and Israel. CML pts (chronic or accelerated phase) treated with imatinib for more than 2 years and in complete molecular remission (CMR) were eligible. Patients had to be in CMR for at least 18 mts, with a minimum of 3 Q-RT-PCR performed at their own sites. After discontinuation of imatinib therapy, Q-RT-PCR was performed monthly (mts 1-6), bimonthly for 36 mts and then every 6 mts for additional 2 years, to assess the maintenance of the molecular remission. The loss of molecular remission was defined as two consecutive positive Q-RT-PCR tests with at least one BCR-ABL/ABL value above 0.1%. Patients losing molecular remission resumed imatinib treatment at the same dosage used before interruption. dPCR was performed at screening and at 36 mts for those pts who were still in remission. Patients' QoL during imatinib discontinuation/resumption was evaluated through the EORTC QLQ-C30 questionnaire. Results. The ISAV study enrolled 112 pts with a median follow-up time of 60.0 mts [95% CI: 59.6-60.6] for pts who do not relapsed; 66.1% of them completed the study as per protocol. The 58.9% of pts were male and 37.4% were aged 65 or older; median duration of imatinib treatment was 103.2 mts with median duration of CMR of 25.6 mts before imatinib discontinuation. At 79 mts from imatinib discontinuation, 56 pts of the 107 eligible ones relapsed and resumed imatinib with a relapse rate of 52.3% [95%CI: 20.4-32.6]; 69.6% of them relapsed in the first 9 mts. Of the 52 not-relapsed pts, 40 (76.9%) regained Q-RT-PCR positivity without losing MMR. In this latter group 2 pts experienced late relapses, at 30.6 and 45.5 mts respectively. A loss of CCyR occurred in 13 pts (23.6%): 10/13 CCyR losses were recovered, the remaining 3 were not assessed for response. No case of CML progression or resistance to imatinib was observed. After the resumption of imatinib the median time to MMR/CMR was 1.8 [95% CI: 1.0-2.0] mts. No significant correlation between relapse and previous duration of imatinib treatment, use of interferon, time to CCyR, Sokal score or duration of CMR was identified, while an inverse relationship between pts age and risk of relapse was evident. dPCR results before imatinib discontinuation showed that 23.4% of pts were positive and 76.6% negative at the time of discontinuation, with a Negative Predictive Value ratio (dPCR/Q-RT-PCR) of 1.1 [95%CI: 0.99-1.22]. At 36 mts from imatinib discontinuation 80.4% [95%CI: 30.6-50.4] of the pts tested were positive in dPCR. Moreover, the results of dPCR performed at imatinib discontinuation and age together can predict the risk of relapse: pts with less than 45 years and with a positive dPCR had the highest risk of relapse (100%) as opposed to pts ≥45 years and with negative dPCR (36.1%). The analysis of QoL evidenced a statistically significant improvement in the general well-being and symptoms scales at 1 month after imatinib discontinuation, particularly with regard to nausea, diarrhea, fatigue and insomnia (p Conclusions. At 79 mts from the beginning of the study, 52.3% of pts relapsed, with 24% loosing CCyR. The majority of relapses occurred in the first 9 mts after discontinuation however late relapses were also observed, up to the 4th year. Therefore, pts who discontinue imatinib should be monitored for a long period of time, especially if they show positive PCR values after discontinuation. All relapsed pts including those who lost CCyR regained their original response after restarting TKI. Age Disclosures le Coutre: Pfizer: Honoraria; Incyte: Honoraria; BMS: Honoraria; Novartis: Honoraria. Abruzzese:BMS: Consultancy; Novartis: Consultancy; Pfizer: Consultancy; Ariad: Consultancy. Assouline:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Honoraria, Research Funding, Speakers Bureau; Pfizer: Honoraria, Research Funding, Speakers Bureau; BMS: Honoraria, Research Funding, Speakers Bureau; Novartis: Research Funding. Kim:Pfizer: Research Funding; BMS: Research Funding; Ilyang: Research Funding; Novartis: Research Funding. Gambacorti-Passerini:Pfizer: Consultancy, Honoraria, Research Funding; BMS: Consultancy.

Summary The thrombopoietin receptor agonists (THPO-RAs), romiplostim and eltrombopag, are effective and safe in immune thrombocytopenia (ITP). However, the value of their sequential use when no response is achieved or when adverse events occur with one THPO-RA has not been clearly established. Here we retrospectively evaluated 51 primary ITP adult patients treated with romiplostim followed by eltrombopag. The median age of our cohort was 49 (range, 18–83) years. There were 32 women and 19 men. The median duration of romiplostim use before switching to eltrombopag was 12 (interquartile range 5–21) months. The reasons for switching were: lack of efficacy (n = 25), patient preference (n = 16), platelet-count fluctuation (n = 6) and side-effects (n = 4). The response rate to eltrombopag was 80% (41/51), including 67% (n = 35) complete responses. After a median follow-up of 14 months, 31 patients maintained their response. Efficacy was maintained after switching in all patients in the patient preference, platelet-count fluctuation and side-effect groups. 33% of patients experienced one or more adverse events during treatment with eltrombopag. We consider the use of eltrombopag after romiplostim for treating ITP to be effective and safe. Response to eltrombopag was related to the cause of romiplostim discontinuation.

Pediatric deep vein thrombosis (DVT) is an emerging problem in tertiary care hospitals, recent reviews shows a rate of 40.2/10,000 admissions. Experts affirm that enoxaparin has become in the drug of choice for DVT therapy. Despite this, there is a little information regarding the optimal dose schedule for enoxaparin therapy in children and the therapeutic guidelines for enoxaparin use in children are extrapolated from adult guidelines. Monitoring by antifactor Xa (anti-Xa) measurement and target concentrations between 0.5-1 U/ml at 4-6 h postdose are recommended. This study was designed to analyse our experience in paediatric-specific dosage requirements for enoxaparin therapy. A retrospective study was performed with patients less than 16 years old, who were treated with enoxaparin for DVT and monitored by anti-Xa concentration, between January 2005 and March 2012. Demographic and clinical characteristics and outcomes were obtained. Fourteen patients were analyzed: boy/girl ratio, 8/4; median age, 3.5 months. Cerebral venous sinus thrombosis was the most common indication for therapy. All patients presented thrombosis risks factors. Dose increases were necessary only in patients less than 6 years old. Target anti-Xa concentrations were achieved in 12 (85%) patients. Children younger than 1 year required a higher dose of enoxaparin/kg (1.5-2.7 mg/kg per 12 h). Complete resolutions of DVT were registered in all cases. The mean number of dose increases was three and a median of 11 days to achieve target anti-Xa concentration. This study indicates that an initial higher enoxaparin dose may be necessary in neonates and infants, but other factors must be considered to improve management.

Background: Eltrombopag is a thrombopoietin receptor agonist approved for primary chronic ITP patients. Due to the non-existence of clinical trials using eltrombopag in persistent and newly diagnosed ITP, there are no clear data about its usefulness in this setting. Aims: To evaluate efficacy and safety of eltrombopag in persistent, newly diagnosed and chronic ITP in routine clinical practice in Spain. Methods: Two hundred and twenty adult ITP patients from thirty Spanish centers who had been treated with eltrombopag and included in the Spanish Eltrombopag Registry were retrospectively evaluated. This study was performed in accordance with the standards of the Helsinki declaration and approved by the Hospital Universitario de Burgos Ethics Committee. Results: Here we report efficacy and safety results of primary ITP Spanish Eltrombopag Registry cohort. According to the standard definition, patients were allocated to newly diagnosed (n=30), persistent (n=30) and chronic (n=160) ITP groups. Each group is described separately in Table I. There are no statistical significant differences regarding response and duration of response among ITP groups. There is a trend towards a greater efficacy in newly diagnosed ITP with 93.3% of responses (platelet count ≥30 x109/L and at least two-fold increase the baseline count and absence of bleeding) and 86.7% of complete responses (CR; platelet count >100 x 109/L). Persistent ITP achieved 83.3% of responses and 80.0% of CR. Similarly 79.4% of responses with 73.1 of CR were observed in chronic ITP. Response rates were similar in all groups regardless all other studied parameters. Another trend towards a longer response duration in persistent ITP was found, with a median of 424 (IQR, 288-664) days. Response durations were similar in chronic ITP (median, 370 days; IQR, 174-624) and in newly diagnosed ITP (median, 378 days; IQR, 154-485). In newly diagnosed ITP, eight adverse events (AEs) with only three grade 3-4 AEs were observed. We reported three deaths; Two of them were due to upper respiratory tract infections in previously diagnosed pulmonary patients. A cerebral hemorrhage was the only death directly related to thrombocytopenia. In persistent ITP, four grade 1-2 AEs and two grade 3-4 AEs (one stroke, one cerebral bleeding) were reported. The only observed death was secondary to the mentioned cerebral hemorrhage. Twenty-one grade 1-2 AEs, ten grade 3-4 AEs and eight deaths (only two caused by bleeding) occurred in chronic ITP. Conclusion: Use of eltrombopag for treating persistent and newly diagnosed ITP is effective and safe. However, more studies are needed to confirm usefulness of TPO-RAs in this setting. | Variable | Newly-Diagnosed ITP (n = 30) | Persistent ITP (n=30) | Chronic ITP (n=160) | | | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------- | --------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------ | | | Age, years, median [Q1;Q3] | 66[46;79] | 66[47;76] | 61[47;75] | | | Men/Women n | 12/18 | 15/15 | 47/113 | | | Charlson comorbidity Index > 1, n (%) | 7(25.9) | 5(17.2) | 25(16.7) | | | Months with ITP, median [Q1;Q3] | 1[1;2] | 6[4;10] | 79[30;193] | | | Past ITP treatments, median [Q1;Q3] Rituximab, n (%) Splenectomy, n (%) Romiplostim, n (%) | 2[1;3] 3(10.7) 2(7.1) 3(10.7) | 2[1;3] 5(17.2) 4(13.8) 4(13.8) | 3[2;4] 43(28.3) 47(30.7) 37(24.3) | | | Platelet count at start of eltrombopag treatment, (x109/L), median [Q1;Q3] Bleeding at start of eltrombopag treatment , n (%) Concomitant treatment, n (%) Corticoids Immunoglobulins Corticoids and Immunoglobulins | 15[7;29] 13(43.3) 10(33.3) 6(60) 0 2(20) | 14[6;26] 10(33.3) 9(30) 7(77.8) 0 2(22.2) | 22 [9;38] 50 (31.3) 46 (28.8) 27 (57.4) 10 (21.3) 8 (17) | | Table 1. Patient characteristics Disclosures Off Label Use: We describe the possibility of using eltrombopag, an oral thrombopoietin receptor analog, for persistent and newly diagnosed ITP patients..

Background: For molecular assessment in CML, NCCN and European LeukemiaNet had defined the cut-off values. Until now the gold standard for BCR-ABL quantification is the real time quantitative polymerase chain reaction (RQ-PCR), and this technique has a limited sensibility to MR4.0 or MR4.5 in the majority of laboratories worldwide. There are several discontinuation studies for CP-CML patients under imatinib therapy who achieved and sustained at least MR4.0 during 2 years or more, and the fact of achieve a deeper response and the time during this response had been the major factors for good outcomes in these studies, now situated in around 40% of success. The droplet digital PCR (ddPCR), and other kind of digital PCR as the nanofluidic ddPCR, had showed more sensitivity for detect minimal amounts of BCR-ABL transcripts in patients with undetectable BCR-ABL transcripts by RQ-PCR, leading a window for investigation in this field. Aims: to evaluate the usefulness of the ddPCR in detect the presence of transcripts of BCR-ABL in patients with CP-CML under TKI therapy compared with RQ-PCR. Material & methods: A total of 54 samples from 32 patients with CP-CML under TKI therapy were analyzed. Sampling was performing obtaining one sample in EDTA for RQ-PCR and other in a TempusTM tube for ddPCR. The RNA was obtained from peripheral blood using TempusTM Spin RNA isolation kit according manufacturer recommendations. The analysis by ddPCR for each sample was done using 5 μg of the obtained RNA and processed in Qx100 Droplet Digital PCR, Biorad; using primers and probes described by Gabert et al., 2003 using ABL1 for control; the results was analyzed using QuantaLife Biorad software and expressed in absolute copies of BCR-ABL and in ratio BCR-ABL/ABL1. Only experiments with >32,000 copies of ABL1 were considered as valid for ddPCR to consider at least MR4.5. The use of a dual-determination in the same experiment with the ddPCR; one for BCR-ABL and other for ABL1 permit us to relativize the experiment and create results expressed in ratios easy to compare with the results obtained during the analysis by RQ-PCR for the same samples. Period of Study: August-2013 to Jun 2014. Results: The final analysis shows that 26 of the 54 analyzed samples presents values of BCR-ABL/ABL1 ratio within MR4.0 or more in the RQ-PCR test, of them 15 with MR4.5 values and 11 with MR4.0. However only 13 (50%) shows ratio values according to MR4.5/4.0 in the ddPCR analysis. The other 13 samples were compatible to MR3.0 or inferior. The samples that for RQ-PCR obtained values of MR4.5 or more (15), in only 6 (40%) a MR3.0 or inferior value of ratio were obtained by ddPCR, however in samples with values of MR4.0 by RQ-PCR (11), the proportion of samples with MR3.0 or inferior was higher, 63.6% (7 samples). See Table 1. The rest of the samples (28) the molecular results were within MR3.0 or inferior response values by RQ-PCR and for ddPCR this was confirmed, except in 3 samples in with ddPCR show a MR4.0 or superior response value. This led us to hypothesize that the use of ddPCR for confirms the response of the patients with MR4.0 or superior would improve the follow-up of the patients, and the success ratio for discontinuation. Comments: The ddPCR offers a new way to assess CP-CML patients, in especially in patients with >MR4.0 molecular response, and would offer a more accurately tool to select patient for discontinuation trials. Actually around 60% of patients who discontinues therapy lost MR4.0 or MR4.5 at 6 months, in our cohort, 50% of samples classified as MR4.0 for RQ-PCR had MR3.0 or less by ddPCR and would not be suitable for discontinuation trials; maybe if we use ddPCR as the standard for select patient to discontinuation less patients will lost the response. Table 1. Molecular response correlation between RQ-PCR and ddPCR ddPCR(RM4.0) Total RQ-PCR (RM4.0) 7 (63.6%) 4 (36.4%) 11 RQ-PCR (RM4.5) 6 (40.0%) 9 (60.0%) 15 Total 13 13 26 Disclosures No relevant conflicts of interest to declare.

Gaucher disease (GD) is characterized by a latent chronic inflammatory macrophage activation expressed by an imbalance of pro-inflammatory cytokines, hyperferritinemia, hypergammaglobulinemia, altered calcium homeostasis and metabolic syndrome. The incidence of Monoclonal Gammopathy of Uncertain Significance (MGUS) and multiple myeloma (MM) is increased in GD1 patients (3.5-12.5). The hypothesis is that deregulation of immune system resulting from glucocerebroside accumulation may influence the development of hematological malignancies. However, the pathological mechanisms that influence in MM development in GD1 patients are unknown. Cytokines produced secondary to glucocerebroside accumulation, may be a critical factor to explain the pathogenesis of MM in GD. This cytokine environment could trigger lymphocyte expansion and ultimately transformation. Objective: To analyze and compare the proinflammatory cytokines profile among MGUS, MM and GD1patients. Methods: Between February-May 2014 we have analyzed a panel of eight cytokines (IL4, IL6, IL7, IL10, IL13, MIP1α, MIP1β and TNF) by Luminex®100 platform and Millipore cytokine kits. The analysis was performed in plasma samples stored at diagnosis in Aragon Biobank. We have studied four cohorts: 71 healthy controls, 38 GD1 patients (36.8% women, mean age 39.2 years, range: 17-79), 36 MGUS (58.3% women, mean age: 75 years, range 53-89), 11 IgGk; 6 IgGL; 5 IgAk; 8 IgAL; 3 IgMk; 3 doble IgG+IgA and 49 MM (42% women, mean age 68 years, range 39-89), 20 IgGk; 5 IgGL; 8 IgAk; 5 IgAL, 8 ligth chain disease and 3 doble IgG+IgA. Concerning ISS classification 44.0% MM patients had a score 1, 24.3% score 2 and 31.7% score 3. All patients with MGUS or MM had been diagnosed consecutively during 2009 and followed until now. Clinical and analytical data of MGUS and MM were obtained from the records of the Hematology Department; and the data of GD1 patients from the Spanish Registry (FEETEG). Data were analyzed using non-parametric tests (Mann-Whitney-U and Kruskall-Wallis). Results: After 5 years in follow-up 21 MM patients had died (42.8%) and 8 in the MGUS group (22.2%), 4 MGUS developed a MM (11.1%); and 8 another neoplasia (22.2%); in MM patients 7 developed a second tumor (14.2%). Between GD1 patients one developed a MM and two a solid tumor (7.9%). Concerning the cytokine analysis, a significant difference (p Conclusions: These results support that GD1 and MM patients share similar proinflammatory profiles. The chronic cytokines increase in GD patients would contribute to the development of malignancies in these patients. GD1 and MM share skeletal complications, MIP-1α as osteoclast-activating factor could be a good biomarker during follow-up of GD1 or MGUS to detect patients in risk to develop bone complications. MIP-1α is described as significantly elevated in osteopenic MGUS patients(1). Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Background: The trombopoietin receptor agonists (TRAs) romiplostim and eltrombopag are effective and safe in the treatment of chronic immune thrombocytopenia (ITP). However, when no response is achieved or when adverse events occur with one TRA the value of the sequential use of romiplostim and eltrombopag has not been clearly established. Here we have evaluated the efficacy and tolerance of using eltrombopag after romiplostim in ITP. Methods: Fifty-one primary ITP patients (aged 18 years or more) who had been sequentially treated first with romiplostim and then with eltrombopag in the Spanish Eltrombopag Registry were retrospectively evaluated. In accordance with the usual standards, complete response was defined as a platelet count of 100x109/L and a response as a platelet count of 30x109/L or a count of at least twice the initial (pre-treatment) value. This study was performed in accordance with the standards of the Helsinki declaration and approved by the Hospital Universitario de Burgos Ethics Committee. Results: The median age of our cohort was 49 [range, 18–83] years. There were 32 women and 19 men. According to the standard definition, patients were allocated to newly diagnosed (n=2), persistent (n=5) and chronic (n=44) ITP groups. The median number of therapies prior to administration of eltrombopag was 4 [range, 2–9], including splenectomy (39%), rituximab (33%) and romiplostim (100%). The median duration of romiplostim use before switching to eltrombopag was 12 (IQR 5–21) months. The reasons for switching from the romiplostim to eltrombopag were: lack of efficacy of romiplostim (n=25), patient's preference (n=16), platelet-count fluctuation (n=6), and side-effects (n=4). The initial response rate to eltrombopag was 41/51 (80.5%), including 67% (n=34) of cases with complete remission. After a median follow-up of 13 months with eltrombopag, 39 patients maintained their response. When eltrombopag was used for patients who were refractory to the maximum romiplostim dose the initial response rate of eltrombopag was 25%. However, 83% of patients who relapsed after their initial response to romiplostim responded to eltrombopag. Sixteen romiplostim responders requested their physicians to switch them to eltrombopag because they preferred an oral drug. The efficacy was maintained after switching in all 16 patients. In the platelet-count fluctuation group, the initial response rate was also 100%. All 4 patients who were switched to eltrombopag because they experienced side-effects of romiplostim achieved complete remission with eltrombopag and their adverse events were resolved. 16 / 51 (33%) patients experienced one or more adverse event during treatment with eltrombopag. The frequency of grade 3–4 adverse events during treatment with eltrombopag was 9.8%. Conclusion: The use of eltrombopag after romiplostim for treating ITP is effective and safe. The reason for discontinuing romiplostim was associated with the response to eltrombopag. Disclosures No relevant conflicts of interest to declare.

Background. Enzymatic replacement therapy (ERT) had modified the natural history of Gaucher disease (GD). Historically the GD patients had growth retardation; frequently spleen removal, and multiple bone complications. It is known that more than 70% of GD patients diagnosed in adulthood have bone complications. Nowadays we have learnt through clinical trials that patients treated regularly with ERT during childhood achieve a normal percentile of growing and avoid complications. In this report we are summarizing the Spanish experience in the last two decades treating children with GD in every day clinical practice. Patients & Methods: From 376 patients included in the Spanish Registry of Gaucher Disease working since 1993, a total of 79 patients were diagnosed under18 years old, 26 of them were classified as GD type 2; 13 developed a GD3 during follow-up and 40 were classified as GD1. For the analysis we have only included GD1 and GD3 patients, 53 patients. Statistical analysis: Descriptive and frequency analysis were performed in a SSPS data base. Results: Baseline characteristics: Gender: 18 females and 35 males. Mean age at diagnosis 5.8 y.o. (range 0.5-17), 78.4% (62) of cases were the initial case for familiar studies, mean age at start ERT 8.5 years (0.5-18), Mutational analysis: L444P/L444P was the most frequent genotype in GD3 and N370S heterozygosis in GD1, there was only one case with N370S homozygosis, Three patients were splenectomised before diagnosis and 60% underwent a bone marrow aspiration or biopsy and 3 liver biopsy during the initial workout. The paediatric Gaucher Score Index (PGSI) (Kallish S, Kaplan P 2012) shows: mild-disease: 62.5%, moderate: 31.25% and severe: 6.25%, missing data 5 patients. Mean chitotriosidase: 12,535 nmol.ml/h (871-49,031), hemoglobine: 11.4g/dL (6.9-17), 43% of patients presented anemia at diagnosis. Mean platelet count: 121 x109 (12,363), 53% of patients presents with < 100 x109 platelets. Bone assessment: 49% (26) of patients shows bone manifestations: Erlenmeyer flask deformity, 24.5%; Bone crisis, 13.2%; avascular necrosis, 5.6%; bone infiltration, 7.5%, Bone infarction: 3.7%; isolated bone pain, 13.2%. The mean follow-up was 13 y (2-21), 45 received ERT following diagnosis, mean years on therapy 13.2 (2-21). In first line: Alglucerase, 8.9% (4); Imiglucerase, 75.5% (34); Velaglucerase, 6.7% (3) and Taliglucerase 8.9% (4). Actual therapies: Imiglucerase: 47.1% (25); Velaglucerase: 17% (9); Taliglucerase: 3.7% (2); Miglustat: 7.5% (4), Eliglustat: 1.8% (1), no ERT/ loss of contact: 7.5%. Mean time on ERT: 13,2 years, twenty-one patients had received ERT during 15 or more years (15-21); 12 for > 10 years (12-14) and 11< 10 years (2-9). Actual status: mean haemoglobin levels: 13, 3g/dL, mean platelets count: 162 x109, Chitotriosidase: 497 mg.prot.h, there are no patients with hepatomegaly and only 3 patients have splenomegaly. Events related to therapy: infusion reactions G3/4: 4, all patients had IgG specific antibodies, and all reactions occurs between 1 and 7 months after start therapy; abandonment 2; changes of ERT, 7 (excluding alglucerase to imiglucerase); related to disease: growth retardation 9 (bellow 25 percentile for age/high); bone crisis 3; joint replacement 1, osteopenia 2 cases (after 2 years on ERT), normalization of coagulation factors (VW,FV,FIX,FXI), others: early diabetes 1, early menarche 1, thyroiditis 1, sacroileitis 1, pregnancies 3, lost follow-up 4. Conclusions: The incidence of GD related complications, especially bone complications, in paediatric patients on ERT is lower than in adults, probably related to early ERT onset. Endocrine complications are rare, difficult to correlate to ERT. Growth retardation was resolved with ERT in the majority of cases. The early onset of therapy in symptomatic child is highly recommended. Table 1. Immune reactions and endocrine complications Patient Age at Dx Gender Genotype Time on ERT Type of reaction 1 4 F N370S/84GG 6 m (Imiglucerase) Infusion reaction 2 3 F N370S/IVS4-2ª>G;c.(-203)A>G 7 m (Imiglucerase) Infusion reaction 3 3 F N370S/L444P 1 m (Velaglucerase*) Infusion reaction 4 9 F N370S/ G4384delC 3 m(Imiglucerase) Infusion reaction 5 4 M N370S/L444P 72 m (Imiglucerase) Diabetes 6 0,5 F N370S/L444P 12 m (Imiglucerase) Thyroiditis 7 4 F N370S/R47X 48 m (Imiglucerase) Early manarche Disclosures No relevant conflicts of interest to declare.

Substrate reduction therapy (SRT) has showed as an useful therapy in type 1 GD patients with mild or moderate disease. The main limitation to use miglustat has been the gastrointestinal adverse events. Since 2004 we have conducted the ZAGAL (Zavesca en Gaucher Leve) study for monitoring the real-life use of miglustat in Spanish adult patients with mild-to moderate disease. The study included GD1 patient’s naïve to therapy as well as patients who have previously been treated with ERT. For follow-up, the therapeutic goals for GD therapy by Pastores GM et al were applied. To date a total of 351 GD1 patients have been diagnosed in Spain (FEETEG unpublished. 2013); from 2004 until 2013, 53 of them have been exposed of miglustat (15.1%). In 16 patients (30.2%) miglustat was the first line of therapy and the remaining 38 switched from ERT. Currently 37 patients (mean age 43.6 y, range 22-83) 50.9% females, are on miglustat therapy (20 at least for 5 years and 13 during more than 8 years). Related to efficacy, the therapy permit to achieve a stable hemoglobin concentration level and spleen reduced volume, but we recorded a decrease of absolute platelet count in 15 patients (28.3%) (mean: 35x109/L, range: 10-86x109/L). Related to biomarkers changes an increase in CT activity was observed in 56.6% of patients (mean: 2,448 nmol/mL.h, range 135-13,687) and 43.4 % for CCL18/PARC (mean: 250 ng/mL, range: 19-1016). Seventeen patients (32.1%) had transitory gastrointestinal disturbances. Sixteen patients (30.2%) discontinued therapy: one of them for pregnancy, two by bone crisis, two by weight loss, one for bad compliance and ten by gastrointestinal discomfort or intolerance (18.8%). 60% of patients has a fine tremor in first months on therapy. 4 died by non-related causes (2 cancer, 1 hearth attack, 1 liver failure), Conclusion The long term follow-up of GD patients treated with Miglustat shows that more than 69% had achieved and maintains the therapeutic goals. A high individual variability had been observed related to miglustat gastrointestinal intolerance apparently no related with GBA genotype, gender and age, but possibly associated with disacaridases inhibition and food habits. Disclosures: No relevant conflicts of interest to declare.

Background Proteasoma inhibitors have proven to be one of the major advances on multiple myeloma (MM) therapy. Their principal effect in growth inhibition of MM cells is achieved not only through the inhibition of proteasomes but also by preventing the adhesion of myeloma cells to stromal cells, induction of cytokines by the microenvironment, decrease angiogenic activity and a direct apoptotic effect on MM cells. Actually it is part of the first-line standard of care therapy for patients with MM. On the other hand, multiple strategies have been developed for trying to predict response or improve the assessment of response and follow-up of MM patients. Currently, the International Myeloma Working Group (IMWG) criteria of response include immunophenotype and immunoparesis analysis. The HevyLiteTM and FreeLiteTM assays (The Binding Site Ltd. Birminghan. UK) permit a separate quantification of the amount of kappa- and lambda-bound to a given immunoglobulin (HLC) and the free light chains kappa or lambda amount quantification (FLC), both being excellent tools for immunoparesis assessment. Aims To analyze the usefulness of immunoparesis analysis by HevyLiteTM and FreeliteTM in patients who receive bortezomib-based therapy in our institution. Patients and Methods A retrospective chart review was performed including the patients diagnosed with secretor IgA or IgG MM who received therapy with bortezomib either at relapse or as first-line therapy. General clinical characteristics, therapy schedules, number of cycles, response to therapy according IMWG criteria and relapse were recorded. For the analysis, only patients with at least 4 cycles of bortezomib based regimen and HLC and/or FLC analysis performed between 4-12 weeks after complete therapy were included. Period of study: June 2004 to April 2013. Results At the end of study a total of 67 MM patients had received bortezomib-based therapy, 63 of them completed 4 or more cycles and were included in the analysis. Male/Female ratio: 31/32, mean age: 66.9 years old (46-81), therapeutic schedules were: bortezomib-prednisone: 3 (4.7%), bortezomib-dexametasone: 33 (51.6%), bortezomib-melfalan-prednisone: 18 (28.1%), bortezomib-dexametasone-lenalidomide: 8 (12.5%) and bortezomib-talidomide-dexametasone: 1 (1.6%). 55% of patients received at least 6 cycles of therapy. Immunoglobulin Myeloma subtype: IgAL: 13 (20.4%) patients, IgAK: 10 (15.6%) patients, IgGK: 32 (50.8%) patients and IgGL: 8 (14.1%) patients. A total of 46 (73%) patients showed an abnormal HLC ratio at diagnosis and 48 (76,2%) had immunoparesis before therapy; a total of 47 (74.6%) registered an abnormal FLC ratio at diagnosis. The response to therapy was: 15 (23.8%) of cases achieved a stringent complete response (SR), 3 (4.8%) a very good partial response (VGPR), 36 (57.1%) obtained a partial response (PR) and 9 (14.3%) patients had not-response/progressive-disease. At the time of post-therapy evaluation, 26 (37%) of patients had normalized FLC-ratio, 15 (23.8%) maintain the SR, 1 (1,6%) patient in VGPR and 5 (11.1%) in PR and 1 (1.6%) of non-responder patients. Normalization of HLC-ratio was only observed in patients with SR and VGPR: 13 (20.6%). Regarding the immunoparesis analysis, only 15 (23.8%) of patients with immunoparesis recovered the immune restitution (IR) at the end of therapy, of which 8 (11.7%) were SR patients, 2 VGPR and 5 PR patients. At the end of the study 47(71.4%) patients relapsed, 5 (11.11%) are on maintenance therapy and 11(17.4%) after a median follow-up of 29 months (9-94) without therapy not-relapsed; the association of SR with IR was related to a less tendency to relapse and need of therapy, 7/8 patients who achieved this status are not-relapsed. Conclusion In our cohort, patients who achieved a SR with a normalization of immunoparesis shows a clear tendency to less incidence of relapse; probably reflecting a better response with not only an undetectable monoclonal protein but also the recovery of the immune function. Even in small cohorts, the immunoparesis recovery analysis through HLC quantifications seems to be an useful tool to determine a new level of response. More investigations on this field are warranted. This work has been partially supported by a grant from Fundación para el Estudio de la Hematología y hemoterapia en Aragón (FEHHA) Disclosures: No relevant conflicts of interest to declare.

Abstract 5097 Background: Monoclonal IgM is the biomarker that characterize to Waldenstrom's macroglobulinemia (WM), a rare low grade B-cell lymphoma derived of the lymphoplasmacytic cell, even serum IgM component also is presented in MGUS. Recently new determinations of heavy chain/light chain immunoglobulins pairs (HLC) have been developed as biomarkers to apply to every day clinical practice. The diagnostic and prognostic potential of these biomarkers is under investigation. The aim of this study is to present our experience in the use of free light chain assay (sFLC) and HLC as biomarkers at diagnostic in order to discriminate between MGUS and WM, and to evaluate their potential prognostic value during disease course. Patients and Methods: A total of 43 patients (pts) were detected as having a serum monoclonal IgM in the Hematology Department of MSUH. Pts were classified as MGUS or WM according to the morphological, immunophenotype characteristics of lymphoplasmacitic bone marrow cells and CT-scan data. Pts were examined every 3–6 months following our clinical protocol in order to detect progression or transformation. Serum samples were collected prior and during treatment and were kept frozen at −70°C since collection and incorporate to our regional Biobank. Analysis of IgM were performed with the sFLC, (Freelite® test, the Binding Site, Birmingham, UK) and the HLC (Hevylite® immunoassay the Binding Site). Freelite® test is a nephelometric measurement of kappa and lambda light chains that circulate not bound to immunoglobulin heavy chain. Hevylite® immunoassay is based on specific polyclonal antibodies that recognize epitopes spanning the junction of the heavy and light chains of the individual immunoglobulin isotypes, it measures specifically IgMkappa and IgMlambda, separately. A normal range of IgM Hevylite assay was produced from normal (blood donor) sera, median (CI 95%) were: IgMkappa, 0. 634 g/L (0. 29–1. 82); IgMlambda, 0. 42g/L (0. 17–0. 94); HLC ratio (HLCR), 1. 6 (0. 95–2. 3). For ease of comparison IgM HLCR was expressed as the involved monoclonal immunoglobulin (iHLC)/uninvolved polyclonal immunoglobulin (uHLC). Results: The study included a series of 25 WM, 18 IgM-MGUS (included 2 IgM-cryoglobulinemia), 36 at diagnosis and 7 at relapse/refractory. The median age was 67. 1 years (13–85); IgM HLCR was 114. 68 (1. 02 – 353) in WM symptomatic, 71. 55 (1. 02 – 286. 43) in WM asymptomatic and 9. 5 (0. 45 – 50. 74) in IgM MGUS (p=0. 003). HLCR was higher in WM patients requiring treatment (n=13) at diagnosis than in pts (n=30) not requiring treatment (113 v 15. 77 p=0. 019) and also HLCR was significantly higher at relapse/refractory (n=9) than in pts (n=34) not relapse (113 v 17. 17 p=0. 012) uHLC was significantly higher in IgM-MGUS than WM to IgMkappa (n=28) and IgMlambda (n=15) iHLC: 0. 37 g/L (0. 11–1. 25) v 0. 1 g/L (0. 02–4. 03), p=0. 022; and 0. 69 g/L (0. 08–4. 09) v 0. 32 g/L (0. 22–0. 63), p=0. 05 respectively. sFLC level was 64 mg/L (10. 88–993) in WM and 31. 7 mg/L (6. 08–141) in IgM MGUS (p=0. 05). sFLC level was higher in WM requiring treatment at diagnosis than in pts not requiring treatment (73. 7 v 36. 85 p=0. 039). sFLC level was not significative in relapse/refractory (p=0. 168), it was not separate between WM asymptomatic and WM symptomatic (p=0. 092). There was a good correlation between HLCR and sFLC ratio (r=0. 3, p=0. 044) but not with sFLC level, HLCR, sFLC level and sFLC ratio did not predict for overall survival (OS) and progression free survival (PFS) in our study. Mean estimated OS was 78. 3 months (95% CI: 53. 67–102. 94) and PFS 69. 7 months (95% CI: 47. 28–92. 13). Conclusion: It seems that HLCR and sFLC could be good biomarkers to differentiate between IgM-MGUS and WM at diagnostic. High levels of HLC and sFLC were also seen in pts requiring treatment. HLCR discriminates WM symptomatic/asymptomatic and progressing pts uHLC levels were significantly higher in IgM-MGUS than WM pts showing that IgM-MGUS have a more robust immune system. Further studies are needed to evaluate their prognostic value. This work has been partially sponsored by a grant from FEHHA Disclosures: No relevant conflicts of interest to declare.

Abstract 2742 Introduction: 90Y Ibritumomab tiuxetan (90Y-IT) has become an efficient alternative to therapy in non-Hodgkin Lymphoma, mainly in elderly patients. The aim of this study is to analyse our updated information of patients treated with 90YIbritumomab/tiuxetan in a prospective study according clinical practice setting and to analyse treatment outcome. Subjects and Methods: 39 non Hodgkin lymphoma patients were included in a clinical protocol conducted by a multidisciplinary team and treated in the same centre. According the inclusion criteria: patients over 65 years old diagnosed as CD20+ NHL with neutrophils ≥ 1,5 × 109/L, platelets ≥ 100 × 109/L, bone marrow lymphocytes CD20+ ≤ 25%. All patients received 0,3 or 0,4 mCi /kg IV (88%) of 90YIbritumomab/tiuxetan and response evaluation was performed 12 weeks after. Period of study: September 2005/July 2012. The 90Y-IT was administered as consolidation of first line therapy (Rituximab alone, R-COP, R-CHOP21) or in relapsed/refractory status. Endpoints: Objective response rate (ORR), time to relapse (PFS) overall survival (OS) and safety. Other clinical prognostic factors were observed to assess their possible influence upon treatment value. Results: Until May 2012, 39 patients had received treatment with 90YIbritumomab/tiuxetan and completed the evaluation protocol and were considered to analysis; M/F 18/21 mean age 72.8 years (65–87); ECOG 0–1 92.3%. According OMS classification: NHL-follicular 27 (69.2%), mantle cell Lymphoma 7 (17.9%), DLBCL 4 (10.3%) and 1MALT (2.6%). Score distribution: low risk 19 (48.7%), intermediate 12 (30.8.2%) and advanced 8 (20.5%). Previous therapy schedules ≤2 (66.7%), >2 (33.3%). The median follow-up time: 42.0 months (95% CI: 4.0; 62.0), mean PFS: 38.1 months (95% CI: 30.8; 45.4) median NR. 13 patients received 90Y-IT as consolidation of first line therapy (33.3%) and 26 relapsed/refractory (66.6%). ORR was 84.6 % CR: 29 (74.3%); PR 4 (10.2%) and 6 failures (15.4%) in relapsed/refractory disease. Mean estimated OS since 90Y-IT: 54.4 months (95% CI: 49.4; 59.3) and mean estimated OS since diagnosis 159 months. Median PFS was NR. The mean PFS for patients in consolidation therapy was 54.2 months (95% CI: 47.4; 61.1). Safety: thrombocytopenia being the most frequent, G3–4 (35.9%), median time to developed haematological toxicity: fourth week, and neutropenia G3–4 (41.0%), the median time to recover normal values was 4.2 and 2.6 weeks respectively. In 5 (12.9%) of patients red blood cell transfusion was required, and 10 platelet transfusions (25.6%). The most frequent non haematological toxicity was asthenia. One patient developed a severe mucositis. Four patients have concomitant associated tumours (colon, breast, lung and prostate) and two patients over 77 years developed a rectum carcinoma after 18 months of 90Y-IT and another prostate and renal tumour after 8 years. Comments: In our experience 90Y Ibritumomab tiuxetan is a safety and effective therapy in patients with NHL over 65 years. According to obtained PFS results, it seems like the use of this kind of therapy as used in early part of therapy offers good and maintained response rate with lower toxicity in this fragile population. The OS in this population was not inferior to observed in younger NHL patients. Disclosures: No relevant conflicts of interest to declare.

Abstract 3762 Introduction: In late 2009 it was published the second version of the international recommendations for CML monitoring and treatment with Imatinib and other tyrosine kinase inhibitors(TKI) (Bacarrani M et al JCO 2009). Although widely distributed and discussed, there has not been any report describing the adherence of hematologists to those guidelines, or analyzing the differential outcomes in the setting outside clinical trials. Objectives: To study the association between the compliance to ELN 09 recommendations in every timepoint, and the response to TKI treatment. Methods and patients: CML patients in first chronic phase, treated upfront with imatinib, outside clinical trials. The adherence to ELN 09 in the given timepoint was classified, as orthodox if, monitoring and treatment were done accordingly, and heterodox, if monitoring or treatment were done disaccordingly. Study variables: Best complete cytogenetic response (CCyR) and major molecular response (MMR) with Imatinib and second line TKI, and progression rates. Besides, we analyzed the association between response grades considering the value obtained in the precedent timepoint. Results: 374 patients (229 men, 145 women) were included. The Sokal risk distribution was: low (L): 138(39%), intermediate (I): 172 (48%), and high (H): 44(12%). Correspondent values for Euro score were 170(48%), 165(47%) y 19(5%). EUTOS score: L: 294(91%), H: 30(9%). Median age: 52 years (15–88). Median follow-up 59.3 months (0,6–131,9). A summary of the results is shown in Table 1. Most of the patients were evaluated on time (73–90%), and 2/3 of the patients were monitored and managed in an orthodox way in the specific timepoints. The rate of CCyR and MMR were significantly higher in patients managed in an orthodox way. In contrast, progression rates were significantly higher only in those patients whose management was heterodox at 3 months. Besides, a better response at any given timepoint was associated with better ulterior responses. Conclusions: Our results reinforce the use of ELN 09 recommendations, showing that those patients whose monitoring and treatment is done according to these recommendations have a higher probability of response. An orthodox management in the first trimester of treatment is specially important, because it is associated with a lower progression rate. Disclosures: Casado: Novartis: Consultancy, Speakers Bureau; BMS: Consultancy, Speakers Bureau; Pfizer: Consultancy, Speakers Bureau. Martínez-López:Celgene: Honoraria. Steegmann:Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Consultancy, Speakers Bureau.