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There are different BCR-ABL1 fusion genes that are translated into proteins that are different from each other, yet all leukemogenic, causing chronic myeloid leukemia (CML) or acute lymphoblastic leukemia. Their frequency has never been systematically investigated. In a series of 45503 newly diagnosed CML patients reported from 45 countries, it was found that the proportion of e13a2 (also known as b2a2) and of e14a2 (also known as b3a2), including the cases co-expressing e14a2 and e13a2, was 37.9% and 62.1%, respectively. The proportion of these two transcripts was correlated with gender, e13a2 being more frequent in males (39.2%) than in females (36.2%), was correlated with age, decreasing from 39.6% in children and adolescents down to 31.6% in patients ≥ 80 years old, and was not constant worldwide. Other, rare transcripts were reported in 666/34561 patients (1.93%). The proportion of rare transcripts was associatedwith gender (2.27% in females and 1.69% in males) and with age (from 1.79% in children and adolescents up to 3.84% in patients ≥ 80 years old). These data show that the differences in proportion are not by chance. This is important, as the transcript type is a variable that is suspected to be of prognostic importance for response to treatment, outcome of treatment, and rate of treatment-free remission.

Background Targeted therapy with Tyrosine-Kinase-Inhibitors (TKIs) totally modified the course of treatment of Chronic Myeloid Leukemia (CML). The objectives and the needs of treatment have been modified during the last years and the discontinuation of therapy is now a feasible aim. However, a lot of biological data acquired in the last twenty years, showed that degree and mechanisms of Leukemic Stem Cells (LSCs) clearance during TKI treatment are not clearly established as well as the predictive criteria for a stable and prolonged Treatment Free Remission (TFR). The multicentre, prospective, single-arm PhilosoPhi34 study (EudraCT: 2012-005062-34) was designed by the Rete Ematologica Lombarda (REL), to verify the in-vivo activity and time-course of first-line Nilotinib (NIL) therapy on Bone Marrow (BM) CD34+/lin-Ph+ cells clearance. An exploratory Gene Expression Profiling (GEP) study of CD34+/lin- cells at diagnosis and at 12 months (mos) of treatment, for the first 30 evaluable pts, was included. Preliminary GEP data suggested a correlation between different NFKBIA expression at diagnosis and at 12 mos and the achievement of a deeper Molecular Response (MR) (Pungolino et al, AJH 2018). We report here some results of GEP analysis on all enrolled evaluable pts and their possible correlation with clinical data. Methods BM cells were collected and stored at diagnosis and at 12 mos of treatment. CD34+/lin- cells were purified with a Diamond CD34 Isolation Kit Miltenyi (97% of purity). For GEP analysis we used Affymetrix HG-U133 Plus 2.0 microarray and Genechip platform (Affymetrix) and the Affymetrix GeneChip Scanner 3000. Data was pre-processed and normalized using the Robust Multi-array Average (RMA) algorithm. The Significant Analysis of Microarrays (SAM) was used to identify genes with statistically significant changes in expression. P-values were corrected for multiple testing using false discovery rate, for differentially expressed genes confirmation. We chose to analyse different expression of NFKBIA (the inhibitor of NF-kB onco-gene) in order to confirm the preliminary data reported on the first 30 analysed pts. Pts were monitored according to ELN-recommendation. Biological data were correlated with MR at 3, 12 and 36 mos of therapy. We use Fishers test to compare unbalanced group. Results Out of the 87 enrolled pts, 80 completed the first 12 mos of treatment and 78 (1 failure and 77 CCyR) were evaluable for GEP analysis. We observed 2726 genes symbol differentially expressed of which 1868 are coding genes. Among these, JAK-2 showed a down regulation at 12 mos (p: .024). JAK-2 expression ranged from 2.62 to 4.95 at diagnosis and from 1.48 to 5.58 at 12 mos. Only 26/78 pts increased JAK-2 expression that was > 4 in 1/26 pts, at diagnosis; 2/26 (7.69%) pts showed a H Sokal. Other 52/78 pts decreased JAK-2 expression that was ≥ 4 in 21/52 pts, at diagnosis; 10/52 (19.23%) pts and 6/21 (28,57%) pts showed a H Sokal. Similarly, when we compared low JAK-2 expression (< 3.5) vs vary high expression (≥ 4) 2/21 vs 6/22 pts had H Sokal (9.52% vs 27.27%; p: .0057). Considering the role of JAK-2 and NFKBIA in cell regulation and survival, we evaluated how the combination of their different expression impact on MR (i.e. NFKBIA increased expression/JAK-2 decreased expression vs NFKBIA decreased expression/JAK-2 increased expression). Data are reported in Table 1 and 2. Conclusion GEP analysis showed a down regulation of JAK-2 expression after 12 mos of first line NIL treatment, in 78 early chronic phase CML pts. Data suggest that high expression of JAK-2, at diagnosis, correlate with H Sokal score. However, H Sokal pts with a JAK-2 down regulation, obtain during treatment similar MR compared to L Sokal pts. Additionally, the study confirms our preliminary observation on 30 pts , concerning the role of NKBIA up - regulation in increasing percentage of earlier and deeper MR . The better condition of NFKBIA and JAK-2 expression (up regulation of NFKBIA and down regulation of JAK-2) is associated with a higher percentage of early MR3 and optimal responses over time, despite the higher number of H Sokal pts in this group. A study with NIL as first line treatment combined with low dose of JAK-2 inhibitor and a natural inhibitor of NF-kB (such as curcuma), during the first year of treatment, to increase the deeper MR rate and the probability of TFR is warrented. Disclosures Rossi: Sandoz: Honoraria; Jazz: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria; Teva: Membership on an entity's Board of Directors or advisory committees; Mundipharma: Honoraria; Novartis: Honoraria; Pfizer: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees.

The prospective 1-year Evaluation of Patients' Iron Chelation with Exjade (EPIC) study enrolled a large cohort of 116 patients with aplastic anemia; the present analyses evaluated the efficacy and safety of deferasirox in this patient population. After 1 year, median serum ferritin decreased significantly from 3254 ng/mL at baseline to 1854 ng/mL (P < .001). Decreases occurred in chelation-naive (3229-1520 ng/mL; P < .001, last-observation-carried-forward analysis), and previously chelated (3263-2585 ng/mL; P = .21, last-observation-carried-forward analysis) patients and were reflective of dose adjustments and ongoing iron intake. Baseline labile plasma iron levels were within normal range despite high serum ferritin levels. The most common drug-related adverse events were nausea (22%) and diarrhea (16%). Serum creatinine increases more than 33% above baseline and the upper limit of normal occurred in 29 patients (25%), but there were no progressive increases; concomitant use of cyclosporine had a significant impact on serum creatinine levels. The decrease in mean alanine aminotransferase levels at 1 year correlated significantly with reduction in serum ferritin (r = 0.40, P < .001). Mean absolute neutrophil and platelet counts remained stable during treatment, and there were no drug-related cytopenias. This prospective dataset confirms the efficacy and well characterizes the tolerability profile of deferasirox in a large population of patients with aplastic anemia. This study was registered at www.clinicaltrials.gov as #NCT00171821.

PubMedID: 20451251 The prospective 1-year EPIC study enrolled 341 patients with myelodysplastic syndromes (MDS); although baseline iron burden was >2500. ng/mL, ~50% were chelation-naïve. Overall median serum ferritin decreased significantly at 1 year (p=0.002). Decreases occurred irrespective of whether patients were chelation-naïve or previously chelated; changes were dependent on dose adjustments and ongoing iron intake. Sustained reductions in labile plasma iron were observed. Discontinuation rate (48.7%) and adverse event profile were consistent with previously reported deferasirox data in MDS. Alanine aminotransferase levels decreased significantly; change correlated significantly with reduction in serum ferritin (p

Background Following a clinical evaluation of deferasirox (Exjade) it was concluded that, in addition to baseline body iron burden, ongoing transfusional iron intake should be considered when selecting doses. The 1-year EPIC study, the largest ever investigation conducted for an iron chelator, is the first to evaluate whether fixed starting doses of deferasirox, based on transfusional iron intake, with dose titration guided by serum ferritin trends and safety markers, provides clinically acceptable chelation in patients (agedor=2 years) with transfusional hemosiderosis from various types of anemia.The recommended initial dose was 20 mg/kg/day for patients receiving 2-4 packed red blood cell units/month and 10 or 30 mg/kg/day was recommended for patients receiving less or more frequent transfusions, respectively. Dose adjustments were based on 3-month serum ferritin trends and continuous assessment of safety markers. The primary efficacy end-point was change in serum ferritin after 52 weeks compared with baseline.The 1744 patients enrolled had the following conditions; thalassemia (n=1115), myelodysplastic syndromes (n=341), aplastic anemia (n=116), sickle cell disease (n=80), rare anemias (n=43) and other transfused anemias (n=49). Overall, there was a significant reduction in serum ferritin from baseline (-264 ng/mL; P0.0001), reflecting dosage adjustments and ongoing iron intake. The most common (5%) adverse events were gastrointestinal disturbances (28%) and skin rash (10%). Conclusions Analysis of this large, prospectively collected data set confirms the response to chelation therapy across various anemias, supporting initial deferasirox doses based on transfusional iron intake, with subsequent dose titration guided by trends in serum ferritin and safety markers (clinicaltrials.gov identifier: NCT00171821).

Background and Objectives While tyrosine kinase inhibitors (TKIs) have transformed CP-CML management, limited data exist on their use in clinical practice. Methods SIMPLICITY (NCT01244750) is an observational study in CP-CML patients, exploring first‑line (1L) TKI use and management patterns in the US and Europe. Over half of the patients recruited in Europe are from Italy (n=266). This is an analysis of the Italian cohort and a comparison with the rest of the European SIMPLICITY population. Baseline demographic, factors influencing choice of first-line TKI, response monitoring patterns and predictors of monitoring, and treatment interruptions, discontinuations and switching by index TKIs are presented for the Italian cohort in the first year of treatment and compared with that for the overall European SIMPLICITY cohort. Results Italian patients received 1L imatinib (IM; retrospective [(n=31]; prospective [n=106]), dasatinib (DAS; n=56) or nilotinib (NIL; n=73). Documented cytogenetic response monitoring by 12 months was lower than expected, but almost all patients had documented molecular response monitoring. Fewer patients discontinued first-line TKI by 12 months in Italy compared with the rest of the European SIMPLICITY population (p=0.003). Of those with ≥12 months follow-up since start of 1L TKI, only 7.1% (n=19) of Italian patients switched to a second-line TKI, a third less than in the rest of the European SIMPLICITY population. Of interest, intolerance as opposed to resistance, was the main reason for switching. Conclusion This analysis provides valuable insights into management and treatment patterns in Italian patients with CML within routine clinical practice.

BACKGROUND: The incidence of chronic myeloid leukemia (CML) increases with age, but it is unclear how the characteristics of the disease vary with age. In children, where CML is very rare, it presents with more aggressive features, including huge splenomegaly, higher cell count and higher blast cell percentage. PATIENTS AND METHODS: To investigate if after childhood the disease maintains or loses these characteristics of aggressiveness, we analyzed 2784 adult patients, at least 18 years old, registered by GIMEMA CML WP over a 40-year period. RESULTS: Young adults (YAs: 18-29 years old) significantly differed from adults (30-59 years old) and elderly patients (at least 60 years old) particularly for the frequency of splenomegaly (71%, 63% and 55%, P < 0.001), and the greater spleen size (median value: 4.5, 3.0 and 1.0 cm, P < 0.001). According to the EUTOS score, that is age-independent, high-risk patients were more frequent among YAs, than among adult and elderly patients (18%, 9% and 6%, P < 0.001). In tyrosine kinase inhibitors-treated patients, the rates of complete cytogenetic and major molecular response were lower in YAs, and the probability of transformation was higher (16%, 5% and 7%, P = 0.011). CONCLUSIONS: The characteristics of CML or the host response to leukemia differ with age. The knowledge of these differences and of their causes may help to refine the treatment and to improve the outcome. CLINICAL TRIAL NUMBERS: NCT00510926, NCT00514488, NCT00769327, NCT00481052. © The Author 2014. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Chronic Myeloid Leukemia is a clonal disorder characterized by the presence of the Ph-chromosome and the BCR-ABL tyrosine-kinase (TK). Target-therapy with Imatinib has greatly improved its outcome. Deeper and faster responses are reported with the second-generation TKI Nilotinib. Sustained responses may enable TKI discontinuation. However, even in a complete molecular response, some patients experience disease recurrence possibly due to persistence of quiescent leukemic CD34+/lin−Ph+ stem cells (LSCs). Degree and mechanisms of LSCs clearance during TKI treatment are not clearly established. The PhilosoPhi34 study was designed to verify the in-vivo activity and timecourse of first-line Nilotinib therapy on BM CD34+/lin−Ph+ cells clearance. Eighty-seven CP-CML patients were enrolled. BM cells were collected and tested for Ph+ residual cells, at diagnosis, 3, 6 and 12 months of treatment. FISH analysis of unstimulated CD34+/lin− cells in CCyR patients were positive in 8/65 (12.3%), 5/71 (7%), 0/69 (0%) evaluable tests, respectively. Per-Protocol analysis response rates were as follows: CCyR 95% at 12 months, MR4.5 31% and 46% at 12 and 36 months, respectively. An exploratory Gene Expression Profiling (GEP) study of CD34+/lin− cells was performed on 30 patients at diagnosis and after, on 79 patients at diagnosis vs 12 months of nilotinib treatment vs 10 healthy subjects. Data demonstrated some genes significantly different expressed: NFKBIA, many cell cycle genes, ABC transporters, JAK-STAT signaling pathway (JAK2). In addition, a correlation between different expression of some genes (JAK2, OLFM4, ICAM1, NFKBIA) among patients at diagnosis and their achievement of an early and deeper MR was observed.

Background Generic formulations of imatinib mesylate have been introduced in Western Europe since 2017 to treat patients with chronic myeloid leukemia (CML). However, results on the safety and efficacy of generic formulations are contrasting. The aim of this study was to investigate the safety and efficacy of generic imatinib in CML patients treated in 12 Italian institutes. Methods This is an observational, retro-prospective analysis of patients with CML for whom the treatment was switched from brand to generic imatinib. We analyzed and compared the variation in quantitative PCR values before and after the switch, and the proportion of patients who maintained molecular response after changing from brand to generic imatinib. Adverse events (AEs) were also evaluated. Results Two hundred patients were enrolled. The median PCR value after the switch was reduced by 0.25 compared to the values before the switch. A significant difference was found between median PCR values before and after the switch in favor of generic imatinib (P = 0.003). Molecular responses remained stable in 69.0%, improved in 25.5%, and worsened in 5.5% of patients. AEs were similar in the pre- and post-switch periods; however, a significant difference was found in favor of generic imatinib for muscular cramps (P < 0.0001), periorbital edema (P=0.0028), edema of the limbs (P

TO THE EDITOR: The Imatinib Suspension and Validation (ISAV) study1 is a multicenter trial of imatinib discontinuation (ID) among patients with chronic myeloid leukemia (CML) in undetectable deep molecular remission (U-DMR). After 12 months of follow-up, 48% of patients relapsed (total n = 107), with the majority of relapses occurring within the first 9 months. An inverse relationship between patient age and risk of relapse was also observed at this timepoint. Here we report the final results of ISAV after a median follow-up of 49 months, as well as the dynamics of leukemic tumor load as determined by digital polymerase chain reaction (dPCR) in nonrelapsed patients. This trial is registered at www.clinicaltrials.gov (NCT01578213). Eligible patients were 18 years and older and had CML, either in chronic or accelerated phase, with U-DMR of at least 18 months’ duration and at least...

In the PhilosoPhi34 study (EudraCT: 2012-005062-34) on 87 CP-CML patients, we analyzed the gene expression profiling (GEP) of bone marrow (BM) CD34+/lin- cells of 79 patients with chronic-phase chronic myeloid leukemia (CP-CML) patients at diagnosis and after 12 months of nilotinib treatment (Pungolino et al. AM J Hematol. 2018). FISH analyses identified CD34+/lin- Ph+ cells in all 79 CML-CP patients at diagnosis. 78/79 patients achieved at least a complete cytogenetic response after 12 months of nilotinib whereas 1/79 patients relapsed at 12 months. No Ph+ nuclei were detected in 78/79 patients at 12 months. We have demonstrated that genes involved in the JAK-STAT signaling pathway, the cell cycle, and the ATP-binding cassette (ABC) transporters were significantly over expressed in patients at diagnosis compared to 12 months of nilotinib treatment (Trojani et al, PLoS One. 2019). In this preliminary study, we isolated BM CD34+/lin- cells from 9 healthy donors (CTRLs). We investigated the gene expression profiling of 79 CP-CML patients at diagnosis vs. the same patients after 12 months of nilotinib treatment (12 months) vs. 9 CTRLs using Affymetrix HTA 2.0. Data was preprocessed and normalized using RMA and ComBat. Selection of differentially expressed genes (DEg) was performed at diagnosis vs. 12 months of nilotinib vs. CTRLs, using Statistical Analysis for Microarrays (SAM) on 3 groups and a Benjamini Hochberg false discovey rate threshold of 5%, followed, for significance comparisons, by a pair-wise SAM test. We focused on 34 genes of the cell cycle and mitosis, 6 genes belonging to the JAK-STAT signaling pathway, and the ABC transporter gene ABCD3 which were significantly under expressed at diagnosis vs. 12 months of nilotinib vs. CRTLs (Tab.1). In the cell cycle, we found that ORC2, ORC4, ORC5, MCM6, and HDAC2 (G1 phase) were progressively significantly down regulated at diagnosis vs. 12 months vs. CTRLs. We noticed HDAC2 which showed the high fold changes of 2.89 and 4.29 in the comparison between 12 months vs. CTRLs and between diagnosis vs. CTRLs, respectively. This gene plays a crucial role in CML, as HDAC inhibitors treatment represent an effective strategy to target leukemic stem cells in CP-CML patients receiving tyrosine kinase inhibitors. CCNA2, CDK7, CDC6, DBF4 (S phase), WEE1, PRKDC, ATM, MDM2, CCNB1 (G2 phase), and TTK, MAD2L1, BUB1, BUB3, ANAPC4, CDC27, SMC3, YWHAE, and YWHAZ (M phase) were progressively down regulated at diagnosis vs. 12 months vs. CTRLs. Among them, SMC3, YWHAE and YWHAZ showed the following high fold changes in the comparison between 12 months vs. CTRLs and between diagnosis vs. CTRLs: 2.31 and 3.15, 2.59 and 3.94, 2.75 and 4.15, respectively. Notably, the proto-oncogene MDM2 which promotes the development of tumors by targeting p53, was progressively up regulated in CTRLs vs. 12 months vs. diagnosis. In the mitosis, we detected that 10 genes playing a crucial role in mitotic chromosome organization, were progressively under expressed at diagnosis vs. 12 months vs. CTRLs (Tab.1). Notably, CLAPS2, ZW10 and ANLN (hematopoietic cell differentiation) regulate the exit from mitosis. NDC80, SMC4, ZNF207, and NEK2 take part in the mitotic sister chromatid segregation whereas CENPE and SMC2 are mitotic cell cycle check points. In the JAK-STAT signaling pathway, SOS1, PIK3CA, IL7, JAK2, STAM, and PTPN11 were progressively up regulated in CTRLs vs. 12 months vs. diagnosis (Tab.1). ABCD3, encoding a protein which pumped drugs out of the cells, was progressively under expressed at diagnosis vs. 12 months vs. CRTLs as shown in Tab.1. In conclusion, we found progressive gene expression changes in BM CD34+/lin- cells of 79 CP-CML patients at diagnosis vs. 12 months of nilotinib vs. the normal cell counterparts of 9 CTRLs in the cell cycle, JAK-STAT, and the ABC transporter ABCD3. FISH analyses demonstrated that the BM CD34+/lin- cells of 78/79 patients after 12 months of nilotinib were Ph-negative. Despite, our GEP results suggested that BM CD34+/lin- cells after 12 months of nilotinib treatment and the normal cell counterparts differed mostly in the expression of genes regulating the cell cycle and the JAK-STAT signaling pathway. Disclosures Rossi: Daiichi-Sankyo: Consultancy; Roche: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Jazz: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria; Mundipharma: Honoraria; BMS: Honoraria; Sandoz: Honoraria. Elena:Novartis: Consultancy; Pfizer: Consultancy. Iurlo:Pfizer: Other: Speaker Honoraria; Incyte: Other: Speaker Honoraria; Novartis: Other: Speaker Honoraria.

Introduction Chronic myeloid leukemia (CML) is a stem cell disease characterized by the constitutive activity of the oncoprotein BCR-ABL that activates multiple signal transduction pathways. Tyrosine-kinase inhibitor (TKI) nilotinib successfully inhibits the activation and the proliferative function of BCR-ABL in patients with CP-CML. Despite the success of nilotinib, some patients become refractory suggesting the presence of a population of Philadelphia positive (Ph+) quiescent stem cells escaping the drug activity. Thus, the molecular mechanisms underlying CML remain poorly understood. In this study, we enrolled 87 CP-CML patients (Pungolino et. al. Am J Hematol. 2018). Samples were collected on the behalf of the Rete Ematologica Lombarda (REL) the PhilosoPhi34 study (EudraCT: 2012-005062-34), which included 15 centers from Italy. We undertook gene expression profiling (GEP) of selected bone marrow (BM) CD34+/lin- cells of 80 patients at diagnosis vs. the same patients after 12 months of nilotinib to investigate gene expression changes induced by the treatment. Methods We isolated CD34+/lin- cells from BM samples in 87 patients at diagnosis whereas the same cells were also selected from 80/87 patients after 3, 6 and 12 months of nilotinib (Trojani et. al. Cancer Biomark. 2017). BM mononuclear cells (MNCs) as well as BM CD34+/lin- cells of all 80 CML patients were counted at diagnosis and during the treatment with nilotinib (at 3, 6, and 12 months, respectively). Standard FISH tested isolated BM CD34/lin- cells for the 87 patients at diagnosis, and for 80/87 patients after 3, 6 and 12 months of nilotinib treatment, respectively. Therefore, we performed GEP analyses of selected BM CD34+/lin- cells of 80/87 patients at diagnosis vs. the same patients after 12 months of nilotinib treatment. Then, we executed bioinformatic preprocessing and correction for batch effects on raw microarray data. Finally, we conducted differential expression analysis and significantly perturbed genes were subjected to functional clustering. Results We observed a wide variability of the number of BM MNCs as well as the number of the BM CD34+/lin- cells among the 80 CP-CML patients at diagnosis and after 3, 6 and 12 months of nilotinib for each patient (Table 1). Figure 1 showed that the number of the BM CD34+/lin- cells dramatically decreased between the diagnosis and after 3 as well as 6 months of nilotinib. We noticed that the BM CD34+/lin- cells slightly increased between 6 and 12 months of nilotinib which might be caused by the gradual repopulation of the normal CD34+/lin- cells in the bone marrow as FISH results suggested. FISH analysis detected CD34+/lin- Ph+ cells in 87 CP-CML patients at diagnosis. No positive Ph+ nuclei were detected on CD34+/lin- cells of 79/80 patients after 12 months of treatment (to categorize a sample as negative, at least 200 nuclei were examined). All of these 79 patients achieved at least complete cytogenetic response. 1/80 patient relapsed at 12 months. We conducted GEP analyses on 78 subjects because, due to experimental issues, two patients were not considered for differential expression analyses, as the microarray CEL files of the 12 months' samples were corrupted and missed probe intensities for most of the probes. GEP analyses determined 2,959 significantly differently expressed probes between diagnosis and after 12 months of nilotinib treatment. Functional clustering identified some pathways significantly enriched between diagnosis and 12 months of nilotinib. Among these pathways, we found that ABCC4, ABCC5, and ABCD3 genes associated with ATP-binding cassette (ABC) transporters were up regulated at diagnosis. GEP results highlighted that 26 genes belonging to cell cycle, mitosis, DNA damage and repair were over expressed at diagnosis. Moreover, GEP data demonstrated that JAK-STAT signaling pathway was deregulated: JAK2, IL7, STAM, PIK3CA, PTPN11, RAF1, SOS1 were over expressed whereas IL22RA1 was under expressed at diagnosis vs. 12 months of nilotinib, respectively. Conclusions In summary, we reported that BM CD34+/lin- cells from CP-CML patients after 12 months of nilotinib were characterized by changes of expression of genes involved in cell cycle checkpoints and mitosis, ABC transporters genes that pump drugs outside form the cells, and JAK-STAT signaling pathway genes responsible for the proliferation, differentiation and cell survival in CML. Disclosures Rossi: Teva: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Jazz: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria; Mundipharma: Honoraria; BMS: Honoraria; Sandoz: Honoraria; Gilead: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees.

Background Chronic Myeloid Leukemia (CML) is a clonal myeloproliferative disorder which molecular base is represented by the bcr-abl fusion gene, encoding for the constitutionally activated BCR-ABL tirosine-kinase. Three Tirosin-Kinase Inhibitors (TKI) are approved for first line treatment: Imatinib (IM) and the second generation (2G) TKI Nilotinib (NIL) and Dasatinib. 2G TKI are known to provide faster and deeper molecular responses (MR) compared to Imatinib, but serious toxicities may hamper long term treatment with these molecules. Furthermore, 2G TKI were usually employed as second line after IM failure, while the inverse sequence from second to first generation TKI (like an induction-maintenance model) has not been explored yet. We used this schedule in a small group of patients in the PhilosoPhi34 study (EudraCT: 2012-005062-34), a clinical trial designed by the REL (Rete Ematologica Lombarda) cooperative group. This study was composed by three consecutive phases: a Recruitment Phase, a Core Phase (CP) in which patients received NIL 300 mg BID for 12 month (mos), and an Observational Phase (OP), restricted for patients who obtained at least complete cytogenetic response at the end of the CP. During OP, treatment choice was up to the physician and any TKI approved for first line treatment could be used, including IM. In 2017 we presented preliminary data showing that a 12-mos-NIL treatment followed by IM appears as a safe and effective choice for first line therapy in chronic phase CML. Fluctuations in BCR/ABL ratio were similar between IM and NIL treated pts, and the probability of loss of MR4 or MR3 was the same in the two groups; furthermore, despite fluctuations, MR was maintained or improved over time in IM subgroup. Our purpose is to verify these data after 24 mos follow up (FU) at the end of OP. Methods We analyze PhilosoPhi34 database; MR is reported at 3, 6 and 12 mos during the CP and every 6 mos during the OP. The last pt completed the 24 mos of OP in June 2018. Database is still open, evaluations ongoing, and some data can be missing yet: our preliminary observations concern pts with available data of 24 mos OP. Results Seventy-nine pts started the OP. Fourteen pts switched to IM during the OP (Table 1) due to high cardiovascular risk or grade 1-2 chronic AEs . Only 11 pts started IM since the beginning of OP, and we consider these pts in our analysis. Sokal score was high in 2 pts (18%), intermediate in 5 (45.5%), low in 4 (36.5%). At the beginning of OP, 6 pts had a MR ≥ 4 (54.5%), 5 had MR3 (45.5%). At 12 mos of the OP, 7 had MR ≥ 4, 3 had MR3 and 1 had lost MR3 with PCR 0.192%IS (1/5, 20%). At 24 mos of the OP, 9 had MR ≥ 4 (81,8%), and 2 had MR3. Notably, none of pts lost MMR; 2/3 pts(66%) improved response from MR 3 to MR 4 and the pt who transiently lost MMR at 12 mos, recovered it at 24. Sixty-four pts maintained 2G TKI: 62 NIL, 2 other TKI (not considered for analysis). Of them, 4 were lost during this phase: 2 within the first year of OP, other 2 within 12 and 24 mos of OP. In the NIL group, Sokal score was high in 10 pts (16.6%), intermediate in 19 (31.6%) and low in 31 (51.6%). At the beginning of OP, 32 pts had MR ≥ 4 (51.6%), 21 had MR3 (33.8%) and 9 less than MR 3 (14.5%). Responses were improved over time: at 12 mos, 36 pts had MR ≥ 4 (60%), 20 had MR3 (33%) and 4 less than MR3 (6%). At 24 mos 46 pts had MR ≥ 4 (78%), 8 MR3 (13.5%) and 4 less than MR3 (8,5%), Among them, 1 pt experienced disease progression due to a mutation. In particular, during the second year of OP, 11 pts improved response from MR3 to MR ≥ 4(11/20, 55%). Discussion Our data show progressive MR improvement in both IM and NIL group. In particular, risk of loss of MMR is not increased in IM group. More data, more balanced groups and a longer FU are necessary to further confirmations, but after three years of FU, we consider this combination of NIL-followed-by-IM a possible strategy for first line treatment in chronic phase CML, in particular for pts with cardiovascular risk factors. Disclosures Rossi: Janssen: Membership on an entity's Board of Directors or advisory committees; Jazz: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria; Gilead: Membership on an entity's Board of Directors or advisory committees; Teva: Membership on an entity's Board of Directors or advisory committees; Mundipharma: Honoraria; BMS: Honoraria; Sandoz: Honoraria; Pfizer: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees.

Imatinib is effective for the treatment of chronic myeloid leukemia (CML). However even undetectable BCR-ABL1 by Q-RT-PCR does not equate to eradication of the disease. Digital-PCR (dPCR), able to detect 1 BCR-ABL1 positive cell out of 10(7) , has been recently developed. The ISAV study is a multicentre trial aimed at validating dPCR to predict relapses after imatinib discontinuation in CML patients with undetectable Q-RT-PCR. CML patients under imatinib therapy since more than 2 years and with undetectable PCR for at least 18 months were eligible. Patients were monitored by standard Q-RT-PCR for 36 months. Patients losing molecular remission (two consecutive positive Q-RT-PCR with at least 1 BCR-ABL1/ABL1 value above 0.1%) resumed imatinib. The study enrolled 112 patients, with a median follow-up of 21.6 months. Fifty-two of the 108 evaluable patients (48.1%), relapsed; 73.1% relapsed in the first 9 months but 14 late relapses were observed between 10 and 22 months. Among the 56 not-relapsed patients, 40 (37.0% of total) regained Q-RT-PCR positivity but never lost MMR. dPCR results showed a significant negative predictive value ratio of 1.115 [95% CI: 1.013-1.227]. An inverse relationship between patients age and risk of relapse was evident: 95% of patients45 years relapsed versus 42% in the class ≥45 to65 years and 33% of patients ≥65 years [P(χ(2) ) 0.0001]. Relapse rates ranged between 100% (45 years, dPCR+) and 36% (45 years, dPCR-). Imatinib can be safely discontinued in the setting of continued PCR negativity; age and dPCR results can predict relapse.

The study analyzed 30 chronic phase CML patients at diagnosis and at 3, 6 and 12 months of first-line nilotinib treatment. As optimal molecular response was achieved at 3, 6 and 12 months after nilotinib in all the 30 patients (figure 1), we established cut off values of molecular response (MR) to define groups of CML patients (n =30), and to investigate differences of gene expression profiles between patients at diagnosis based on the MR achieved after 3, 6 and 12 months of nilotinib, respectively. We used the following cut off values: 1% IS at 3 months of nilotinib, 0.1% IS at 6 months of nilotinib, and 0.01% IS at 12 months of nilotinib. Patients were divided into 2 groups based on MR values of each patient at 3 months of nilotinib: group A (n =24) with MR ≤1.0% IS and group B (n =6) with MR >1% IS. Based on the values of MR at 6 months of nilotinib, patients were divided into 2 groups: group C (n =22) with MR ≤0.1% IS and group D (n =8) with MR >0.1% IS. At 12 months of nilotinib, patients were divided into the following groups: group E (n =18) with MR ≤0.01% IS and group F (n =12) with MR >0.01% IS. Gene expression profiling (GEP) on the selected bone marrow (BM) CD34+/lin- cells of 30 CML patients at diagnosis was performed using Affymetrix GeneChip HTA 2.0. GEP data was preprocesses using RMA. SAMR and GSEA were used to detect differentially expressed genes and pathways (i.e. MSigDB Canonical pathways and GOBP gene sets) associated with the different groups, respectively. In both cases, correction for multiple testing was performed using the false discovery rate procedure with a threshold 0.05 for SAMR and 0.25 for GSEA as suggested by the software developers. GSEA detected significant differences in the transcriptional signature between group A and group B associated with the MR at 3 months as well as between group C and group D in respect to the MR at 6 months of nilotinib, whereas no genes were identified as significantly differentially expressed. Based on the MR at 3 months, we identified Reactome pathways "P130 cascade" and "GRB2 SOS linkage to MAPK signaling for integrins" significantly upregulated in group A compared to group B. FGA, FGB, FGG, APBB1IP, ITGA2B and CRK genes contributed to call the pathways upregulated. In vitro studies (Ding J et al. PloS One, 2013) demonstrated that nilotinib induced dephosphorilation of the BCR-ABL1 target CRK oncogene which acts in the CML hematopoietic stem cells like an adaptor in diverse signaling pathways and cellular processes playing an apoptotic role in CML. Our GEP results highlighted that the Reactome pathway involved in MAPK signaling (CRK gene) wasover expressed in CML patients with a better MR ≤1% IS at 3 months of nilotinib. Pathway "aminoacid and amine transport across the plasma membrane" was also significantly over expressed, whereas "lipid metabolism" was significantly down regulated (genes AKR1C1 and ANGPTL3) in group A compared to group B, respectively. Based on the MR at 6 months, GEP results showed that "positive regulation of cytokine secretion" and "interleukin 1 secretion" were significantly upregulated in group C compared to group D, involving PYCARD8, NLRP2, NLRC4, NLRP3 and CARD8 genes. Of note, PYCARD and CARD8 represent key mediators, which promote caspase-mediated apoptosis processes involving the recruitment of certain recognition receptors, such as NLRP2, NLRP3 and NLRC4. In addition, CARD8 and PYCARD promote apoptosis inhibiting NFKB activation. In conclusion, the study showed that MAPK signaling for integrins and amine transport across the plasma membrane were significantly over expressed in CML patients with a MR ≤1.0% IS while lipid metabolism was significantly over expressed in CML patients with a MR >1% IS after 3 months of nilotinib. After 6 months of nilotinib, positive regulation of cytokine secretion and interleukin 1 secretion were significantly over expressed in CML patients with a MR ≤0.1 IS compared to patients with a MR >0.1% IS. We identified distinct sets of genes involved in apoptotic processes differentially expressed in 30 CML patients based on the MR at 3 months as well as 6 months of first-line nilotinib treatment. Studies in a larger cohort of CML patients are ongoing to define the expression, role and functions of the genes regulating apoptosis CRK, PYCARD and CARD8 as candidate prognostic factors for molecular response to first-line nilotinib treatment. Disclosures No relevant conflicts of interest to declare.

The aim of this study was to investigate the effects of a non-standard, intermittent imatinib treatment in elderly patients with Philadelphia-positive chronic myeloid leukaemia and to answer the question on which dose should be used once a stable optimal response has been achieved. Seventy-six patients aged ⩾65 years in optimal and stable response with ⩾2 years of standard imatinib treatment were enrolled in a study testing a regimen of intermittent imatinib (INTERIM; 1-month on and 1-month off). With a minimum follow-up of 6 years, 16/76 patients (21%) have lost complete cytogenetic response (CCyR) and major molecular response (MMR), and 16 patients (21%) have lost MMR only. All these patients were given imatinib again, the same dose, on the standard schedule and achieved again CCyR and MMR or an even deeper molecular response. The probability of remaining on INTERIM at 6 years was 48% (95% confidence interval 35–59%). Nine patients died in remission. No progressions were recorded. Side effects of continuous treatment were reduced by 50%. In optimal and stable responders, a policy of intermittent imatinib treatment is feasible, is successful in about 50% of patients and is safe, as all the patients who relapsed could be brought back to optimal response.

Therapeutic approach for chronic myeloid leukemia (CML) patients has undergone a revolutionary change with the introduction of tyrosine kinase inhibitors, which improved overall survival and quality of life. Optimal therapy adherence has become of paramount importance to maximize the benefits in the long-term outcome. Several evidences have been reported that personal factors, such as social support, psychological and subjective perceptions about the drug used and the future, could influence adherence. We here report the results of a questionnaire specifically designed to evaluate factors influencing adherence and perceptions about the future, distributed to patients during regional Italian meetings. Overall, 1133 patients compiled the questionnaire: median age was 57 years. High rate of adherence was reported, but 42% of interviewed patients admitted that they had occasionally postponed a dose and 58% had discontinued therapy mainly for forgetfulness. The majority of patients discussed with personal physician about the importance of adherence and received sufficient information about illness and treatment, but would like to have discussed more about discomfort, anxiety and fear of the future. Summarizing personal drug compliance and estimating how many days a month, on average, the patients did not take the drug, the majority answered that it was less than 3 days (55%) and only a minority (4%) admitted that it was more than 7 days. Interviewed about discontinuation, 49% of patients answered that wouldn't interrupt because of fear of losing all the results achieved so far. This study suggests a higher level of satisfaction with more information received but the need of improving communication about possible future treatment free remission.

Background. Chronic Myeloid Leukaemia (CML) can be effectively treated with the first generation Tyrosine Kinase Inhibitor (TKI) Imatinib, and more effectively with the second generation TKI, like Nilotinib. However, despite the deeper and faster responses induced by nilotinib in a large proportion of patients, the possible eradication of the pathological stem cells is not yet clearly elucidated. In fact, in vitro data suggest that quiescent stem cells are not sensitive to Bcr/Abl inhibition (Corbin AS, et al 2011; Hamilton A, et al 2012). A preliminary in-vivo study (Defina M, et al 2012) shows that in patients in CCyR even after short-term of nilotinib therapy, residual leukemic progenitors are rarely detected. Methods. On behalf of Rete Ematologica Lombarda (REL), Italy, we designed a single arm prospectic study, PhilosoPhi34 (EudraCT: 2012-005062-34), with the aim to investigate the efficacy of nilotinib 300 mg BID in obtaining the disappearance of Bone Marrow (BM) leukemic stem cells (CD34+/lin-Ph+) in newly diagnosed CP-CML. Primary objective of the study: to enumerate the BM CD34+/lin-Ph+ cells at the end of 6 months of treatment. Secondary objectives: to enumerate the BM CD34+/lin-Ph+ cells at 3 and 12 months; to assess the percentage of patients showing MR ≤10% IS at 3 months and MR ≤1% IS at 6 months and the MMR IS and MR4.5 IS by 3, 6 and 12 months of treatment. BM blood samples (range of 5-20 ml) were collected at diagnosis and after 3, 6 and 12 months of nilotinib treatment. BM mononuclear cells were purified by density gradient centrifugation and then CD34+/lin- cells were isolated using Diamond CD34 Isolation Kit (Miltenyi Biotec). The purity of CD34+/lin- cells was about 97% as determined by flow cytometry. BM CD34+/lin- cells were counted and a range of 100,000-800,000 has been noted at diagnosis. After the treatment we observed that the number of CD34+/lin- cells dramatically decreased after 3 (1,000-600,000), 6 (1,000-260,000) and 12 months (100-130,000). In particular, CD34+/lin- cells were even less than 1000 at 12 month of treatment. In order to verify the disappearance of leukemic stem cells, isolated CD34+/lin- cells were tested by standard FISH (i.e. to categorize a sample as negative at least 200 nucleus were examined). From April 2013 and June 2015 we enrolled 87 pts, as for protocol. We report here the preliminary results. Results. Of 56 patients in CCyR after 6 months of treatment, FISH performed on BM CD34+/lin- cells nuclei was evaluable in 51 cases (5 negative cases were excluded because of less than 200 nucleus were analysed). In 4 out of 51 patients (7.8%), Ph+ nuclei were detected. The Sokal score of these 4 patients was 1 low, 2 intermediate and 1 high risk with a ratio (positive nuclei/total nuclei) of 295/300, 1/200, 2/92, 3/300, respectively. Among 58 patients tested at 3 months and 44 tested at 12 months of treatment, the number of evaluable patients was 48 and 37, respectively; 8/48 (16.6%) and 0/37 (0%) patients showed Ph+ nuclei. Only 2 out of 8 positive patients had a high Sokal score. Regarding efficacy of treatment, Table 1 summarizes the MRs IS observed after 3, 6 and 12 months of treatment in 71, 57 and 41 patients, respectively. Conclusion. Data of this prospective study confirms that nilotinib 300 mg BID, rapidly and progressively induces the clearance of BM CD34+/lin-Ph+ cells in CP-CML patients. In particular, on CD34+/lin- cells, after 6 months of treatment, only 7.8% of patients showed positive nuclei. On 37 patients after 12 months of treatment, no positive nuclei were detected. So far, the kinetic of reduction of such cells seems not influenced by Sokal score. According to international studies, PhilosoPhi34 shows a very high efficacy of Nilotinib to induce MRs in CP-CML patients, at the standard time points. Table 1. Molecular Response (MR) in CP-CML patients treated with Nilotinib 300mg BID from diagnosis. MR IS 3 months 6 months 12 months ≤10% 67/71 94% 57/57 100% 40/41 97.50% ≤1% 57/71 80% 55/57 96.50% 40/41 97.50% ≤0.1% 17/71 24% 41/57 72% 35/41 85% ≤0.01% 3/71 4% 19/57 33% 20/41 48.70% MR4.5(UD) 2/71 2.80% 10 (6)/57 17.5% (10.5%) 15 (9)/41 36.5% (22%) UD: undetectable We acknowledge all REL Colleagues for their collaboration and Novartis SpA for the partial financial support to the study. Disclosures No relevant conflicts of interest to declare.

This study aimed to determine the gene expression profiling (GEP) of bone marrow (BM) CD34+/lin- cells of CML patients at diagnosis and after nilotinib treatment.Microarray was performed on 30 CML patients at diagnosis as well as 8 patients after 12 months of nilotinib treatment using the latest generation Affymetrix GeneChip HTA 2.0 to further investigate genomic complexity. Bone marrow blood (in a range of 5-20 ml) samples were collected from patients at diagnosis and after 3, 6 and 12 months of nilotinib treatment. BM mononuclear cells were purified by density gradient centrifugation at 800 rpm for 20 min and soon after CD34+/lin- cells were isolated using Diamond CD34 Isolation Kit (Miltenyi Biotec). The purity of CD34+/lin-cells was about 97% as determined by flow citometry and the cells were counted at diagnosis and after the treatment with nilotinib (at 3, 6, and 12 months). BM CD34+/lin- cells of 30 patients at diagnosis and after 3 and 6 months of nilotinib were resuspended in RNAlater (Ambion, Life Technologies) and stored at -20°C until RNA extraction was performed. Total RNA was extracted from BM CD34+/lin- cells using MagMAX 96 Total RNA Isolation Kit (Ambion). BM CD34+/lin- cells were counted and a range of 100,000-800,000 has been noted at diagnosis. cRNA was prepared according to OvationPico WTA System V2 kit followed by Encore Biotin Module Kit (NuGEN). Ultimately, cRNA was hybridized to HTA 2.0 and signals were scanned by Affymetrix GeneChip Scanner 3000 following the manufacturer’s instructions. We observed that the number of CD34+/lin- cells dramatically decreased at 3 months (1,000-600,000), after 6 months (1,000-260,000) and after 12 months (100-130,000). In particular, CD34+/lin- cells were even less than 1000 after 12 months of nilotinib. If the number of CD34+/lin- cells after 12 months of nilotinib was less than 1000, we directly resuspended the cells in Prelude direct Lysis module (NuGEN) and microarray experiments were performed without RNA extraction. In this case, cRNA was prepared using Ovation One Direct System kit followed by Encore Biotin Module Kit (Nugen) and finally hybridized to the HTA 2.0. Microarray experiments were performed on CD34+/lin- cells of 30 CML patients at diagnosis with HTA 2.0. Moreover, we performed microarray experiments on CD34+/lin- cells of 8 CML patients at diagnosis vs. 8 CML patients after 12 months of nilotinib using HTA 2.0. Data was preprocessed and normalized using Robust Multi-array Average (RMA) algorithm. The Significant Analysis of Microarrays (SAM) was used to identify genes with statistically significant changes in expression in CML patients at diagnosis and at 12 months of treatment. P-values were corrected for multiple testing using false discovery rate. In conclusion, as far as we know, this is the first study which has isolated BM CD34+/lin-cells from CML patients at diagnosis and after nilotinib treatment. We observed a wide variety of the number of CD34+/lin- cells in 30 CML patients at diagnosis as well as after 3, 6 and 12 months of nilotinib. In particular, CD34+/lin- cells of CML patients at diagnosis were over 100.000. RNA was extracted and cRNA was prepared with OvationPico WTA System V2 kit followed by Encore Biotin Module Kit (NuGEN) and finally hybridized to HTA 2.0. On the other hand, the number of CD34+/lin- cells of CML patients after 12 months of nilotinib markedly decreased as low as 100 cells. In this case, we decided to avoid RNA extraction from the cells and we directly prepared cRNA using Ovation One Direct System kit and Encore Biotin Module Kit (Nugen) followed by the hybridization to the HTA 2.0 Array. To increase the statistical power in biomarker identification, we combined samples pre-processed with different experimental protocols (NuGEN) using ComBat, an empirical Bayes framework that adjusts data for batch effects and is robust to outliers in small datasets. Principal component analysis applied to the expression data before and after ComBat adjustment shows that the adopted normalization procedure effectively removes the systematic bias introduced by different protocols. Disclosures No relevant conflicts of interest to declare.

We report a study of an alternative treatment schedule of imatinib (IM) in chronic myeloid leukemia (CML). Seventy-six Philadelphia-positive (Ph+), BCR-ABL-positive patients aged 65 years or older who had been treated with IM for more than 2 years and who were in stable complete cytogenetic response (CCgR) and major molecular response (MMR) were enrolled in a single-arm study to test the effects of a policy of intermittent IM (INTERIM) therapy for 1 month on and 1 month off. With a minimum follow-up of 4 years, 13 patients (17%) lost CCgR and MMR and 14 (18%) lost MMR only. All these patients resumed continuous IM and all but one (lost to follow-up) regained CCgR and MMR. No patients progressed to accelerated or blastic phase or developed clonal chromosomal abnormalities in Ph+ cells or BCR-ABL mutations. In elderly Ph+ CML patients carefully selected for a stable CCgR (lasting >2 years), the policy of INTERIM treatment affected the markers of residual disease, but not the clinical outcomes (overall and progression-free survival). This trial was registered at www.clinicaltrials.gov as NCT 00858806.

Background Imatinib mesylate is the first line treatment for chronic myeloid leukemia. In patients with advanced phase of the disease, the advent of imatinib significantly increased survival. However, few long-term data, based on large, prospective and controlled trials are available on the outcome of these patients. Design and Methods We conducted a phase II trial of imatinib 600 mg daily in patients with chronic myeloid leukemia in blast crisis. The return to chronic phase was defined as

Chronic lymphocytic leukemia (CLL) cells could be undetectable by flow cytometry or polymerase chain reaction after sequential treatment with fludarabine and Campath-1H. Concern has been raised regarding the ability to mobilize sufficient peripheral blood progenitor cells (PBPCs) for autografting after purine analogues, and there are few data about PBPC collection after Campath-1H. In all, 16 CLL patients responding to sequential chemo-immunotherapy entered the study. In 10, mobilization regimen consisted of granulocyte colony-stimulating factor (G-CSF) 5-10 microg/kg/die. Patients failing mobilization or not achieving the target of 2.5 x 10(6) CD34+ cells/kg underwent a second attempt using intermediate-dose (ID) Ara-C, 800 mg/m(2) every 12 h for six doses+G-CSF. PBPC collection after G-CSF alone was successful in two out of 10 patients. An adequate number of CD34+ cells were collected after ID Ara-C+G-CSF in eight patients failing the mobilization with G-CSF alone and in five out of six who did not receive G-CSF before. Greater yields of PBPCs were collected with Ara-C+G-CSF compared with G-CSF alone (13.8 vs 3.3). The extrahematologic toxicity was manageable. In conclusion, PBPC collection is feasible in CLL patients treated with sequential therapy including fludarabine and Campath-1H. Excellent yields were obtained in 92.8% of patients primed with ID Ara-C+G-CSF.

Introduction. Chronic myeloid leukemia (CML) patients (pts) treated with imatinib first line achieve complete cytogenetic response (CCyR) in > 70% of cases and major molecular response (MMR) in 18-58%. These pts have a life expectancy similar to the general population. However even undetectable BCR-ABL may not equate to eradication of the disease because of the sensitivity of Q-RT-PCR. A new diagnostic method, the digital-PCR (dPCR), able to detect 1 BCR-ABL+ cell out of 107 cells, has been recently developed (Goh HG et al., 2011). dPCR corresponds to a 100 fold increase in sensitivity as compared to Q-RT-PCR. Therefore, dPCR by assessing the presence of minimal residual disease with higher sensitivity, could potentially identify pts in whom CML has been eradicated. Aims. The Imatinib Suspension And Validation (ISAV) study is aimed at validating the capability of dPCR to predict relapses after imatinib discontinuation in CML pts with negative Q-RT-PCR results. 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) under imatinib therapy since more than 2 years and in complete molecular remission (CMR) were eligible for this study. Patients had to be in CMR for at least 18 months (mts), with a minimum of 3 Q-RT-PCR performed at their own sites. After signing the informed consent, blood samples are obtained for dPCR and the pts discontinue imatinib therapy. Standard Q-RT-PCR is performed monthly (mts 1-6) and then bimonthly for 36 mts to assess the maintenance of the molecular remission. The loss of molecular remission is defined as two consecutive positive Q-RT-PCR tests with at least one BCR-ABL/ABL value above 0.1%. Patients losing molecular remission resume imatinib treatment at the same dosage used before interruption. Patients’ quality of life during imatinib discontinuation/resumption is evaluated through the EORTC – C30 Quality of Life questionnaire. Results. The enrolment in ISAV began in November 2011 and ended in July 2013. The study enrolled 112 pts: Italy 69.6%, Germany 21.4%, Canada 5.3%, Spain 2.6% and Israel 0.9%. Among the 112 pts, 59.3% were male and 37.0% were aged 65 or older; median duration of imatinib treatment was 103.1 mts with median duration of CMR of 25.8 mts before imatinib discontinuation. To date, the median follow-up (FUP) time is 16.6 mts [95% CI: 14.9-18.2]. Forty-seven pts (43.5%, 95% CI: 34.0-53.4) of the 108 eligible pts relapsed and resumed imatinib; 38/47 (80.9%) of them relapsed in the first 9 mts and the last relapse occurred 19.6 mts after imatinib discontinuation. A loss of CCyR occurred in 11 pts (23.4%): 10/11 CCyR losses were recovered; 1 patient withdrew the consent shortly after obtaining a partial cytogenetic response. No case of CML progression was observed. After the resumption of imatinib the median time to either MMR or CMR was 1.9 [95% CI: 1.2-2.4] mts. Of the 61 not-relapsed pts, 43 (39.8% of the total) regained Q-RT-PCR positivity but never lost MMR. The median time to Q-RT-PCR positivity was 3.6 mts [95% CI: 3.0-4.8] and the range of duration of Q-RT-PCR positivity (below 0.1%) was between 5.7 and 29.2 mts. No significant correlation between relapse and previous duration of imatinib treatment, use of interferon, time to CCyR or duration of CMR was identified. An inverse relationship between pts age and risk of relapse is evident: 90% of pts < 45 years relapsed vs 37.5% in the class ≥ 45 - < 65 years and 27.5% of pts ≥ 65 years, p(χ2) Conclusions. After 32 mts from the beginning of the study, with a median FUP of 16.6 mts, 43.5% of pts relapsed; the majority of relapses developed in the first 9 months after imatinib discontinuation. Age < 45 years and dPCR positivity are significantly associated with relapses. Funded by Regione Lombardia. Figure 1 Figure 1. Figure 2 Figure 2. Disclosures No relevant conflicts of interest to declare.

Chronic myeloid leukemia (CML) is a disease of stemming from genetic damage to a hematopoietic stem cell. Despite nilotinib being a very effective drug for the treatment of CML, drug resistance can emerge. In the contest of the REL-PhilosoPhi34 study on behalf of the Rete Ematologica Lombarda, we performed an exploratory study aimed to identify the gene expression signature of bone marrow (BM) CD34+/lin- cells of CML patients at diagnosis as well as after 12 months of nilotinib to investigate the genes and pathways responsible for the response or resistance to nilotinib. Microarray experiments were performed using the latest generation Affymetrix GeneChip HTA 2.0 to further investigate genomic complexity. The study was developed in two steps as follows: In the first step we analyzed 30 CML patients and from the comparison between the BM CD34+/lin- cell counts from each patient at diagnosis and after 3 and 6 months of nilotinib, patients were divided into 2 classes: class 1 (n=24) showed highly reduced levels of CD34+/lin- cells while class 2 (n=6) demonstrated increasing levels of CD34+/lin- cells after 3 and 6 months of nilotinib, respectively (Fig.1). The 30 patients can be divided into 6 groups showing different patterns of CD34+/lin- cellularity (Figure 1). Data was preprocessed and normalized using Robust Multi-array Average (RMA) algorithm. The Significant Analysis of Microarrays (SAM) was used to identify genes with statistically significant changes in expression in CML patients. P-values were corrected for multiple testing using false discovery rate. No transcripts were selected as differentially expressed using this threshold. However, if a nominal significance level alpha equal to 0.05 is adopted together with a fold-change threshold equal to 2 (absolute value), 56 transcripts were selected in the comparison between the 2 groups of CML patients. Among them, we focused on NFKBIAgene which was over expressed in class 1 compared to class 2.NFKBIA is involved in 68 pathways regulating apoptosis (PI3K,NF-kB) and encodes IkBα protein belonging to the NF-kB pathway which is a potential downstream target of BCR-ABL1 due to its role in regulating cell survival and proliferation. Of note, 31/56 transcripts are located on chromosome 15 suggesting that this region could be crucial for transcriptional regulation of CML correlated to nilotinib response. The second step analyzed the GEP of CD34+/lin- cells of 8 patients at diagnosis (class 1) vs. the same 8 patients after 12 months of nilotinib (class 2) to investigate the gene expression changes and the pathways induced by nilotinib treatment. Data was preprocessed and analyzed as described above. 247 probes (corresponding to 51 genes and 180 non-annotated transcripts) were selected with a p-value lower than 0.05 after multiple testing correction and using a fold-change threshold equal to 3 (absolute value). Functional enrichment analysis was performed using DAVID and highlighted the following pathways and genes: ¯ Defense response and immune system: CAMP, CRISP3, CYBB, RGS1, CEACAM8, LTF (cell growth and differentiation), MNDA and HP (positive regulation of apoptosis) were over expressed in class 2 with high fold changes of 7.65, 9.95, 4.40, 3.47, 4.28, 3.61, 3.60, 3.95, respectively ¯ Transcriptional regulation and cell cycle: MMP8was under expressed in class 1 with the high fold change of 8,94 ¯ S100A12, S100A8, S100A9 (regulation of the cell cycle and differentiation) were over expressed in class 2 with the FC of 8.68, 3.96, 4.49, respectively ¯ RNA5S-ribosomal pseudogenes 310-311-312-313-314-315-316-317-320-363 were downregulated in class 2 ¯ 10 small-nuclear-RNAs and 11 small-nucleolar RNA were differently deregulated between the 2 classes ¯ APOC1, PLBD1 (lipid metabolism) were overexpressed and underexpressed in class 1, respectively In conclusion, this is the first study of GEP of CD34+/lin- cells with HTA 2.0 which demonstrated that 51 genes mostly involved in immune system, transcriptional regulation and cell cycle were significantly differently expressed from the comparison between CML patients at diagnosis and after 12 month of nilotinib. Ongoing studies are focused on examining the genetic and biologic mechanisms underlying nilotinib response or resistance to predict response or failure providing new insights into the molecular mechanisms in CML. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.