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To evaluate the clinical response rate and cosmetic outcome after full-dose intraoperative electron radiotherapy (IOERT) in early breast cancer (BC) treated with conserving surgery. Inclusion criteria were: >60 years old, clinical tumor size ≤2 cm, luminal A carcinoma, patological negative lymph nodes, excluded lobular carcinoma histology. IOERT was delivered with a dose of 21 Gy at 90% isodose. Clinical, cosmetic and/or instrumental follow-up were performed 45 days after IOERT, 6 months after the first check, and every 12 months thereafter. Acute and late toxicities were assessed with the CTCAE v.4.03 and EORTC-RTOG scales, respectively. Cosmetic outcome was evaluated using the Harvard/NSABO/RTOG Breast Cosmesis Grading Scale. Overall, 162 consecutive patients were included in this analysis (median follow-up: 54 months, range: 1–98 months). The overall response rate was 97.5% (CI 95%: 0.93–0.99%). Locoragional relapse occurred in 2.5% of patients. No patient showed distant metastases. No patient showed radiation-related acute complications, with 3.7% showing late G2–3 toxicity. Only 3.7% of patients showed poor cosmetic results. Our data confirmed that IOERT is a feasible and valid therapeutic option in low-risk BC patients treated with lumpectomy. A low local recurrence rate combined with good cosmetic results validates the settings of our operative method in routinely clinical practice.

Breast cancer (BC) is a heterogeneous malignancy that still represents the second cause of cancer-related death among women worldwide. Due to the heterogeneity of BC, the correct identification of valuable biomarkers able to predict tumor biology and the best treatment approaches are still far from clear. Although molecular imaging with positron emission tomography/computed tomography (PET/CT) has improved the characterization of BC, these methods are not free from drawbacks. In recent years, radiomics and artificial intelligence (AI) have been playing an important role in the detection of several features normally unseen by the human eye in medical images. The present review provides a summary of the current status of radiomics and AI in different clinical settings of BC. A systematic search of PubMed, Web of Science and Scopus was conducted, including all articles published in English that explored radiomics and AI analyses of PET/CT images in BC. Several studies have demonstrated the potential role of such new features for the staging and prognosis as well as the assessment of biological characteristics. Radiomics and AI features appear to be promising in different clinical settings of BC, although larger prospective trials are needed to confirm and to standardize this evidence.

The development of chimeric antigen receptor (CAR)-T cell therapy has revolutionized the treatment of hematological diseases. However, approximately 60% of patients relapse after CAR-T cell therapy, and no clear cause for this failure has been identified. The objective of the Bio-CAR-T BS study (ClinicalTrials.gov: NCT05366569) is to improve our understanding of the lymphocyte harvest to maximize the quality of the CAR-T cell product. Of the 14 patients enrolled, 11 were diagnosed with DLBCL, 2 with PMBCL, and 1 with ALL. Five of 11 DLBCL patients met the criteria for “pre-emptive” Lymphocytes-apheresis (being at high risk of second relapse), and 6 were included in the standard-of-care Lymphocytes-apheresis group. Previous autologous stem cell transplantation (ASCT) and age were significantly different between the two groups. At the time of Lymphocyte-apheresis, patients in the “pre-emptive” group had more “fit” lymphocytes (higher CD4+/CD8+ ratio; higher naïve T cells levels) compared with standard group, probably due to the impact of ASCT. At the same time, also being older than 60 years results in a more “exhausted” lymphocyte profile. Overall, “pre-emptive” Ly-apheresis in DLBCL patients at high risk of relapse appears to be feasible and may allow the timely collection of “fit” lymphocytes for CAR-T cell manufacturing.

This Technical Note validates previously published data about the dosimetry of the electron beams produced by a mobile accelerator dedicated for intraoperative radiation therapy (IORT). The evaluation of the directional response of a PTW microDiamond detector is presented together with a detailed analysis of the output factors (OFs) for bevelled applicators.The OFs of the 6, 8, 10 and 12 MeV electron beams produced by a light intraoperative accelerator (LIAC, SIT, Italy) were measured in a commercial water phantom using the microDiamond. A set of flat and bevelled applicators with sizes ranging from 4 to 10 cm was characterized. For bevelled applicators, a correction for the angular dependence of the microDiamond was calculated using a home-made spherical phantom. Correction factors were obtained through measurements performed rotating the accelerator treatment head at 0°, 15°, 30° and 45°.For flat applicators, the average deviation between measured and simulated OFs was (-1.1 ± 0.7)%. The microDiamond showed a higher angular dependence for the 6 MeV beam (∼8% for angles up to 45°, range 92 % ÷ 100 %), while the variations for 8, 10 and 12 MeV beams were ∼ 4 % (range 97 % ÷ 101 %). Correcting for this dependence, the average deviation of the OFs for bevelled applicators was (-0.9 ± 1.6)%.The presented results were in very good agreement with those reported in literature. Very similar deviations were found between flat and bevelled applicators confirming the suitability of our method to determine the angular dependence correction factors of the microDiamond detector.

Purpose : Monte Carlo (MC) simulation in Nuclear Medicine is a powerful tool for modelling many physical phenomena which are difficult to track or to measure directly. MC simulation in SPECT/CT imaging is particularly suitable for optimizing the quantification of activity in a patient, and, consequently, the absorbed dose to each organ. To do so, it is mandatory validate MC results with real data acquired with gamma camera. The aim of this study was the validation of SIMIND Monte Carlo code for modelling a Siemens Symbia Intevo Excel SPECT-CT gamma camera both for 99m Tc and 177 Lu. Methods : Phantom experiments using 99m Tc and 177 Lu have been performed with the purpose to measure spatial resolution, sensitivity and evaluate the calibration factor (CF) and recovery coefficients (RC) from acquired data. The geometries used for 2D planar imaging were (1) Petri dish and (2) capillary source while for 3D volumetric imaging were (3) a uniform filled cylinder phantom and (4) a Jaszczack phantom with spheres with different volumes. The experimental results have been compared with the results obtained from Monte Carlo simulations performed in the same geometries. Results : Comparison shows good accordance between simulated and experimental data. The measured planar spatial resolution was 8.3±0.8mm for 99m Tc and 12.2±0.7mm for 177 Lu. The corresponding data obtained by SIMIND for 99mTc was 7.4±0.1 mm, while for 177Lu was 11.7±0.1 mm. The CF was 110.1±5.5 cps/MBq for Technetium and 18.3±1.0 cps/MBq for Lutetium. The corresponding CF obtained by SIMIND for 99mTc was 100.1±0.3 cps/MBq, while for 177 Lu 20.4±0.7 cps/MBq. Moreover, a complete curve RCs vs Volume (ml) both for Technetium and Lutetium was determined to correct the PVE for all volumes of clinical interest. In none of the cases a RC factor equal to 100 was found. Conclusions : The results of validation process show that SIMIND can be used for simulating both gamma camera planar and SPECT images of Siemens Symbia Intevo using 99mTc and 177Lu radionuclides for different medical purposes and treatments.

Real-time quantitative PCR (RT-qPCR) is the gold standard to quantify the BCR-ABL1 transcript for molecular response monitoring in chronic myeloid leukemia (CML) patients, and it plays a pivotal role in clinical decision-making process, even if it presents technical limits. Increasing data suggest that digital PCR (dPCR) is more accurate and reliable than RT-qPCR in CML minimal residual disease monitoring and in patients’ selection for treatment discontinuation. But what about the identification of treatment discontinuation failures? We present the case of a CML patient enrolled both in a study aiming to comparatively assess molecular response by RT-qPCR and dPCR and in the progressive arm of the OPTkIMA trial. This is a phase III trial including CML patients randomized to receive a fixed versus a progressive intermittent tyrosine kinase inhibitor regimen. At 24 months, because of two consecutive detections of MR2.0 by RT-qPCR, the patient resumed daily treatment. Conversely, dPCR revealed a stability of molecular response and even a slight decreasing of transcript over time. An additional specimen was sampled one month after the first MR2.0 detection because of clinical decision: RT-qPCR resulted MR3.0 and dPCR confirmed the transcript’s stability. Nowadays, the resumption of therapy is RT-qPCR-driven despite its limits in detection and robustness. In this case, according to dPCR, the patient could have continued intermittent treatment and the stability of response was then confirmed by RT-qPCR. So, dPCR could be able to better identify peculiar clinical response to therapy.

Exosomes are extracellular vesicles playing a pivotal role in the intercellular communication. They shuttle different cargoes, including nucleic acids from their cell of origin. For this reason, they have been studied as carriers of tumor markers in different liquid biopsy approaches, in particular for solid tumors. Few data are available concerning exosomes as markers of myeloid neoplasia. To better understand their real potential and the best approach to investigate leukemic exosomes, we present the results of a pilot feasibility study evaluating the application of next-generation sequencing analysis of dsDNA derived from exosomes isolated in 14 adult patients affected by acute myeloid leukemias. In particular, leukemia-derived exosome fractions have been analyzed. The concentration of dsDNA co-extracted with exosomes and the number and types of mutations detected were considered and compared with ones identified in the Bone Marrow (BM) and Peripheral Blood (PB) cells. Exosomal DNA concentration, both considering the cargo and the DNA surrounding the lipid membrane resulted in a linear correlation with leukemic burden. Moreover, exosomal DNA mutation status presented 86.5% of homology with BM and 75% with PB. The results of this pilot study confirmed the feasibility of a leukemia-derived exosome enrichment approach followed by exosomal dsDNA NGS analysis for AML biomarker detection. These data point to the use of liquid biopsy in myeloid neoplasia for the detection of active leukemic cells resident in the BM via a painless procedure.

Magnetic resonance imaging (MRI) is a non-invasive powerful modern clinical technique that is extensively used for the high-resolution imaging of soft tissues. To obtain high-definition pictures of tissues or of the whole organism this technique is enhanced by the use of contrast agents. Gadolinium-based contrast agents have an excellent safety profile. However, over the last two decades, some specific concerns have surfaced. Mn(II) has different favorable physicochemical characteristics and a good toxicity profile, which makes it a good alternative to the Gd(III)-based MRI contrast agents currently used in clinics. Mn(II)-disubstituted symmetrical complexes containing dithiocarbamates ligands were prepared under a nitrogen atmosphere. The magnetic measurements on Mn complexes were carried out with MRI phantom measurements at 1.5 T with a clinical magnetic resonance. Relaxivity values, contrast, and stability were evaluated by appropriate sequences. Studies conducted to evaluate the properties of paramagnetic imaging in water using a clinical magnetic resonance showed that the contrast, produced by the complex [Mn(II)(L’)2] × 2H2O (L’ = 1.4-dioxa-8-azaspiro[4.5]decane-8-carbodithioate), is comparable to that produced by gadolinium complexes currently used in medicine as a paramagnetic contrast agent.

Context Clinical frailty scale (CFS) is a scale ranging from 1 (very fit) to 9 (terminally ill) for increasing degrees of frailty extensively used in several geriatric contexts. Currently, no study on CFS is available in an allo-HCT setting. Objective To evaluate the prognostic value of CFS on OS and NRM in allo-HCT. Patients and Methods Overall, 234 consecutive patients aged >50 y were transplanted at our center from 2006 to 2020. Median follow-up: 4.03 y (95%CI: 3.54–5.90). CFS was retrospectively calculated by an external physician blind to transplant outcome. Results Cohort characteristics were the following: median age 59 y (range: 50–73), males 147 (63%), AML (44.4%). DRI was high/very-high in 36.8% of cases. Matched related donor was used in 41.5%, unrelated in 46.2%, alternative in 12.3% of cases. Overall, 170 patients (72.6%) received a reduced-intensity conditioning regimen. For the evaluation of patients’ fitness at transplant, the following scores were applied: Karnofsky performance status (≥90 in 91.5%), HCT-CI (≥3 in 43.2%), FIL score (unfit/frail in 6.8%) and CFS (very fit [score 1] in 6.8%, fit [score 2] in 51.3%; managing well [score 3] in 29.9%, and frail [>3] in 12.0%). An increasing CFS score was associated with a higher proportion of FIL frailty and a lower Karnofsky performance status. No significant differences were observed in terms of comorbidities. At last follow-up, 149 (63.7%) patients had died (NRM 41.6%, relapse 58.4%). CFS was strongly associated with OS (2-y-OS of 85.6%, 63.7%, 25.8%, and 7.1% for patients with score 1, 2, 3, and >3, respectively; p Conclusions CFS appears a simple and highly effective tool for transplant outcome prediction among oncohematological patients aged >50 y. These results might suggest the use of this score for improving patient selection.

Malnutrition is a common problem after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and could impair immune function. Immune dysfunction after allo-HSCT may be linked with infections, GVHD, and relapse and negatively affect the outcome. Aim of this review was to identify malnutrition biomarkers, potentially useful for immune-system monitoring, in the setting of allo-HSCT. After a systematic search, no satisfying biomarker was found, except for citrulline. Citrulline could be useful in monitoring gastrointestinal function after allo-HSCT and its role in the complex relationship with immune-system function ought to be better explored. A multi-omics approach, including biomarkers and PRO (patient reported outcomes) is, in our opinion, the optimal way to study the relationship between malnutrition and transplant outcomes.

Background Myelodysplastic syndromes and acute leukemias after allogeneic stem cell transplantation (allo-SCT) are mainly caused by recurrence of the primitive leukemic clones. More rarely, they originate from donor hematopoietic stem cells, developing the so-called donor cell leukemia (DCL) or myelodysplastic syndromes (DC-MDSs). DCL and DC-MDS can be considered as an in vivo model of leukemogenesis, and even if the pathogenetic mechanisms remain speculative, a genetic predisposition of donor progenitor cells, an altered host microenvironment, and the impairment of immune surveillance are considered the main causes. Case presentation We report a case of DC-MDS diagnosed 5 years after an allo-SCT from a matched related donor (patient's sister) in a patient with Philadelphia chromosome-positive B-cell acute lymphoblastic leukemia (Ph+ B-ALL). The sex-mismatch allowed us to identify the donor cell origin. At the onset, the DC-MDS was characterized by chromosome seven monosomy and NRAS, RUNX1, and BCOR mutations. Because of a familiar history of colorectal neoplasia and the variant allele frequency (VAF) of NRAS mutation at the onset, this mutation was searched on germline DNA in both the donor and the recipient, but the result was negative. Moreover, after transplant (+4 months), the patient developed severe and long-lasting chronic graft-versus-host disease (cGVHD), requiring multiple lines of treatments. Because of the severe immunosuppression, recurrent infections occurred and, lately, the patient died due to septic shock. Conclusion This case report highlights the need, whenever possible, to evaluate the donor origin of the posttransplant myelodysplasia and acute leukemias. The potential key role of the impaired immune surveillance and of long-lasting immunosuppression appears to be emerging in the development of this case of DC-MDS. Finally, this case reminds the importance to investigate the familiar genetic predisposition in donors with a familiar history of neoplasia.

Context Evaluation of elderly patients' eligibility for allogeneic stem cell transplantation (allo-SCT) is crucial. A comprehensive geriatric assessment (CGA) has demonstrated important prognostic value in hematology. However, its role in allo-SCT transplant setting has still to be defined. Objective To evaluate the feasibility and efficacy of the Fondazione Italiana Linfomi (FIL)-score, a combined comorbidity (CIRS-G) and functionality (ADL/IADL) score, on allo-SCT outcome. Patients and methods This is a retrospective study involving 228 elderly (>60y) patients consecutively submitted to allo-SCT at our centers from 2008 to 2018. Median follow-up 36 months (range, 1-118). Results The median age was 64 years (range, 60-76), and 155 (68%) were male. AML was the most common indication for transplant (53%), DRI was high/very-high in 42% of cases. A matched unrelated, sibling or alternative donor was utilized in 41%, 30%, and 29% of cases, respectively. Stem cell source was derived from peripheral blood in 82% of patients. Myeloablative conditioning regimen was reserved for only 20% of patients. Based on FIL score, available in 215 patients, 125 (58%) patients were classified as “fit” and 90 as “unfit/frail.” According to FIL score, fit patients were more frequently diagnosed with AML (p Conclusions A comprehensive geriatric assessment with FIL score seems to add significant prognostic information in elderly patients submitted to allo-SCT. The pre-transplant adoption of this easy-to-use tool could help the patients' selection and management.

Nowadays, the evaluation of elderly patients' eligibility for allogeneic stem cell transplantation (allo-SCT) is crucial. We evaluated the feasibility and efficacy of a multidimensional geriatric assessment, the Fondazione Italiana Linfomi (FIL) score, on a cohort of 228 patients older than 60 years submitted to allo-SCT in Italy and France from 2008 to 2018. Based on FIL score, available in 215 patients, 125 (58%) patients were classified as “fit” and 90 as “unfit/frail.” The hematopoietic cell transplantation-specific comorbidity index (HCT-CI) was measured in 222 patients (97%); 71 (32%) patients had HCT-CI 0, 75 (34%) patients scored 1–2, and 76 (34%) ≥3. A total of 121 (53%) patients died after a median follow-up of 36 months. FIL score was found to highly predict survival, due to an excess of NRM in unfit/frail group, and confirmed its independent prognostic role on OS (HR: 0.37; 95% CI: 0.25–0.55; p

Due to the discovery of their role in intra-cellular communications, exosomes, which carry information specific to the cell of origin, have garnered considerable attention in cancer research. Moreover, there is evidence to suggest the possibility of isolating different exosome sub-populations based on target antigens at the cell surface. Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia (CML) is a clonal myeloproliferative neoplasia characterized by the break-point cluster region-proto-oncogene 1 tyrosine-protein kinase (BCR-ABL1) fusion-gene, derived from the t (9;22) translocation. Tyrosine kinase inhibitors (TKIs) target BCR-ABL1 protein and induce major or deep molecular responses in the majority of patients. Despite the fact that several studies have demonstrated the persistence of leukemic cells in the bone marrow niche, even following treatment, TKIs prolong patient survival time and facilitate treatment-free remission. These characteristics render CML a plausible model for investigating the feasibility of tumor-derived exosome fraction enrichment. In the present study, patients in the chronic phase (CP) of CML were treated with TKIs, and the quantification of the BCR-ABL1 exosomal transcript was performed using digital PCR (dPCR). The possibility of tumor-derived exosomes enrichment was confirmed, and for the first time, to the best of our knowledge, the detection of the BCR-ABL1 transcript highlighted the presence of active leukemic cells in patients with CP-CML. According to these findings, tumor-derived exosomes may be considered a novel tool for the identification of active leukemic cells, and for the assessment of innovative monitoring focused on the biological functions of exosomes in CML.

We present a case of a patient with a three-month history of peripheral blood cytopenia without a confirmed diagnosis of myelodysplastic syndrome, who developed a favourable-risk acute myeloid leukemia (AML), according to the European Leukemia Net (ELN) criteria. The patient achieved a complete remission with incomplete platelet recovery (CRi) after induction. The patient achieved the morphological CR after the first consolidation and completed the first-line treatment with a syngeneic stem cell transplantation (SCT). A disease relapse occurred after one year of CR (blast cell count in the bone marrow 15%), and the patient was offered a haplo-SCT, which he refused due to personal reasons. In this paper, we discuss the interplay between clinical and biological risk factors in non-high-risk AML patients and speculate that some old clinical risk factors (e.g., age of the patient, achievement of CR after induction, and previous history of myelodysplastic syndrome) may still impact on the treatment decision algorithm of some of these patients.

Introduction. A multidimensional geriatric assessment has been shown to predict therapy-related toxicities in elderly hematology patients. No data are yet available on the use of combined functional and comorbidity scores in the allogeneic stem cell transplant (alloSCT) setting. The Lymphoma Italian Foundation (FIL) score, a multidimensional approach, combines the geriatric comorbidity score using the cumulative illness rating scale-geriatric (CIRS-G) with the activities of daily living (ADL) score, instrumental activity of daily living (IADL) score, and older age. Aims. The aim of the present study was to evaluate the role of the multidimensional FIL score in predicting alloSCT outcome, in terms of transplant-related mortality (TRM), relapse incidence (RI) and overall survival (OS). Patients and methods. Overall, 228 patients older than 60 years were submitted for alloSCT in Italy and France, during the last 10 years (2009-2018). Patients' characteristics are detailed in Table 1. The median age of the study population was 64 years (range, 60-76), and 155 (68%) were male. Acute myeloid leukemia was the most common indication for transplant (53%) and complete remission status was recorded in 54% of cases at transplantation. A matched unrelated donor, sibling donor or alternative donor was utilized in 41%, 31%, and 28% of cases, respectively. Stem cell source was derived from peripheral blood in 82%, bone marrow in 8%, and cord blood in 10% of cases. Utilization of a myeloablative conditioning regimen was reserved for only 20% of patients. Median number of CD34+ x10^6/Kg infused cells was 5 (range, 0,01-12,9), and of CD3+ x10^7/Kg cells 18 (range, 0,2-47,8). The median follow-up period of the cohort was 36 months (range, 12-138). Overall survival was estimated by the Kaplan-Meier method from the date of transplant to the date of last follow-up or death; the log-rank test was used to detect differences between subgroups. The Fine and Gray competing risk regression model was used for calculation of TRM and RI. Univariate and multivariate analyses were carried out using the Cox proportional-hazards regression model. Results. A total of 121 (53%) patients died at last follow-up. The cause of death was related to TRM in 60 (49%) cases comprising infection (31), toxicity (13), acute GVHD (9), and chronic GVHD (7); disease relapse was the ultimate cause of death in 61 (51%) cases . The 2-year expected TRM, RI and OS were 25%, 36% and 49%, respectively. The FIL score was measured in 215 patients and classified patients as 'fit' in 125 (58%) casesa nd 'unfit/frail' in 90 (42%). According to the FIL score, fit patients were more frequently in complete remission (CR) at alloSCT compared with unfit/frail patients (78% vs 21%, p2 (34%). Interestingly, the HCI-CI (HR 1.06, 95%CI 0.96-1.16, p=0.27) failed to predict alloSCT outcome. In contrast , FIL score, predicted fit patients to have a better 2- and 5-year OS of 66% and 59% compared to 32% and 30% in unfit/frail patients (p 80 (0.53, 95%CI 0.36-0.78, p=0.0013) and FIL frail/unfit status (2.83, 95%CI 1.93-4.17, p80 (HR 0,56, 95%CI 0,37-0,85, p=0.0066) and FIL score (HR 2,20, 95%CI 1,27-3,78, p=0.0046) maintained significant associations with OS (Figure 2). Conclusions. In a fairly large cohort of elderly patients (≥60 years) undergoing alloSCT at two European transplant centers, a multidimensional geriatric approach appears to be more accurate compared to a sole comorbidity assessment, in predicting alloSCT outcome and identifying patients at high risk of TRM. This simple tool could easily be applied before transplant for better patient selection and tailoring of treatment. Disclosures Mohty: Jazz Pharmaceuticals: Honoraria, Research Funding.

CMV represents one of the most serious life-threatening complications of allogeneic stem cell transplantaion (allo-SCT). Pre-emptive treatment with anti-CMV drugs is highly effective, but toxicity and repetitive reactivation of CMV represent a major challenge in the clinical practice. The use of anti-CMV specific immunoglobulins (Megalotect) is controversial. We retrospectively collected data on 539 patients with hematological malignancies submitted to allo-SCT in 6 Italian Bone Marrow Transplant Units between 2016 and 2017. Two hundred and forty two of the 539 patients (45%) developed at least one CMV reactivation. In 94/242 cases (39%) Megalotect was used according to internal guidelines. This report focuses on this group of 94 patient. Megalotect was used as prophylaxis in 15/94 cases (16%) and as pre-emptive therapy together with a specific anti-CMV drug in 79/94 cases (84%). Fifty-six out of 94 cases (60%) received 50 UI/Kg weekly, 33/94 cases (35%) received 50 U/Kg every 2-3 weeks (the remaining patients received different doses and schedule according to the Center policy). Megalotect was used because all the 94 patients were considered at high risk of developing repetitive CMV reactivation. In the prophylaxis setting these risk factors were: haploidentical and cord blood transplantation in 5 cases and unfavorable CMV sireology combiation in 14 cases. In the pre-emptive setting, the risk factors were: haploidentical transplantation in 30 cases, aGVHD requiring high-dose steroids in 37 cases and unfavourable CMV serology combination (D-/R- in 44 cases, D+/R- in 1 case). In the pre-emptive setting the following anti-CMV drugs were used first-line: gancyclovir (31 cases), foscarnet (19 cases), valgancyclovir (14 cases), different combinations (15 cases). Overall, the treatment was well tolerated, with no reported infusion reactions nor other adverse events. Megalotect was administered for a median of 2 doses (range 1-9) and 3 doses (range 1-33) in patients treated prophylactically or pre-emptively. None of the 15 cases treated with Megalotect as prophylaxis developed CMV reactivation. Focusing on the 79 cases treated with Megalotect pre-emptively, 59 patients (75%) achieved at least one CMV viremia negativity during tratment. Median time to first negativity was 19 days (range 3-190). In 30/79 cases (38%) a subsequent CMV reactivation was observed during the follow up, which was treated with a second-line anti-CMV specific drug. Interestingly, only 6/94 cases (6%) developed CMV disease: gut localization in 4 cases and other site in 2 cases.Overall 24/94 patients died (25%) and no death was CMV-related Our preliminary experience with Megalotect suggests that it is safe and well tolerated both in the pre-emptive and prophylaxis setting. We have no conclusive data regarding the efficacy of this treatment in reducing the cumulative dose of anti-CMV specific drugs. Interestingly, when used as prophylaxis, no CMV reactivation was recorded. In the pre-emptive setting, the combination of Megalotect and anti-CMV specific drug was able to induce negativity of CMV viremia in a relatively short time (median 19 days) and 38% of these high-risk patients only developed further CMV reactivation during follow up. Further prospective trials are warrented to address the most appropriate use of Megalotec (preophylaxis vs pre-emptive) and to identify the best setting of patients who can benefit from Megalotect alone or in addition to anti-CMV specific drugs. Disclosures Foà: ABBVIE: Other: ADVISORY BOARD, Speakers Bureau; JANSSEN: Other: ADVISORY BOARD, Speakers Bureau; AMGEN: Other: ADVISORY BOARD; GILEAD: Speakers Bureau; CELGENE: Other: ADVISORY BOARD, Speakers Bureau; INCYTE: Other: ADVISORY BOARD; NOVARTIS: Speakers Bureau; CELTRION: Other: ADVISORY BOARD; ROCHE: Other: ADVISORY BOARD, Speakers Bureau.

Two different rabbit anti-thymocyte globulin (ATG) formulations, thymoglobulin-ATG (tATG) and fresenius-ATG (fATG) are usually employed as prophylaxis for graft-versus-host-disease (GVHD), one of t...

T and B lymphocyte subsets have been not univocally associated to Graft-versus-host disease (GVHD) and relapse of hematological malignancies after stem cell transplantation (SCT). Their sequential assessment together with B and T cell neogenesis indexes has been not thoroughly analysed in relation to these changing and interrelated immunologic/clinic events yet. Lymphocyte subsets in peripheral blood (PB) and B and T cell neogenesis indexes were analysed together at different time points in a prospective study of 50 patients. Principal component analysis (PCA) was used as first step of multivariate analysis to address issues related to a high number of variables versus a relatively low number of patients. Multivariate analysis was completed by Fine-Gray proportional hazard regression model. PCA identified 3 clusters of variables (PC1-3), which correlated with acute GVHD: PC1 (pre-SCT: KRECs≥6608/ml, unswitched memory B 44%, CD8+TCM cells>4%; HR 1.9, p = 0.01), and PC3 (at aGVHD onset: CD4+TEMRA69%, switched memory CD19+ = 0 cells and KRECs

Background Bacterial, fungal, and viral infections often affect non-relapse mortality after allogeneic stem cell transplantation (alloSCT). Recovery from infections depends on a balanced integration between innate and adaptive immune responses. In this complex interplay, a key role is played by Toll-like receptors (TLRs), which are sensors of pathogen-associated molecular patterns. To our knowledge, no previous study deals with both expression and function of all human TLRs together, in relation to infections in the setting of alloSCT. Methods We prospectively evaluated 9 TLRs by flow cytometry on T lymphocytes and monocytes of 35 patients in relation to infectious events from day +30 to day +120. Tumor necrois factor-alpha, interleukin-4, interferon-gamma, and monocyte chemoattractant protein-1 induction upon TLR activation was assessed by enzyme-linked immunosorbent assay on cell supernatants. Results In multivariate Cox regression analysis, levels of TLR-9 expression on T lymphocytes (P = 0.01) and values of natural killer cells (P = 0.01) correlated negatively with bacterial infections, whereas cytomegalovirus (CMV) infection resulted as a positive predictor. We observed a trend for negative correlation between TLR-7 levels on T lymphocytes and fungal infections (P = 0.07). Values of monocytes were negatively associated with CMV infection (P = 0.03), whereas levels of TLR-5 on T lymphocytes were positive predictors (P = 0.01). Age (P = 0.03) and bacterial infections (P = 0.006) negatively influenced overall survival. Monocyte values were positive predictors of survival (P = 0.003). Conclusions Bacterial, fungal, and CMV infections were associated with a different expression of some TLRs on T lymphocytes. The protective role of TLR-7 and TLR-9 seemed dominant over other TLRs involved in recognizing fungi and bacteria. We also observed an atypical involvement of TLR-5 in CMV infection. The dominant and atypical role of some TLRs could depend on their pleiotropic functions and the changing inflammatory environment of transplanted patients. A specific TLR profile and an adequate count of monocytes could improve survival, promoting an effective control of infections, and balanced immune responses. If our findings will be confirmed by further studies, these immunological variables could be useful as parameters to predict susceptibility to infections.

Monitoring of BCR-ABL1 levels by quantitative PCR (qPCR) is essential for the management of CML patients treated with TKIs. Because of intrinsic limits, qPCR does not appear to be an optimal assay to select the best candidates to TKIs discontinuation. Up to 40% of CML patients treated with TKIs can achieve a Deep Molecular Response (DMR), but only 50% maintain a stable Treatment Free Remission (TFR) after therapy discontinuation. Digital PCR (dPCR), giving an absolute quantification of BCR-ABL1, is expected to be more sensitive and accurate than qPCR in the assessment of molecular MRD. dPCR performed on a QuantStudio 3D Digital PCR System (Life Technologies) by using a TaqMan-MGB probes targeting the BCR-ABL1 transcript was used to comparatively analyse 102 CML patients with Major (MR3.0 = 31 cases) or Deep (MR4.0= 33 cases; MR4.5 = 24 cases and MR5.0 = 14 cases) molecular response. Preliminary results showed that: a) ≥77% of deep responders (MR4.0, MR4.5 and MR5.0) fell under the value of 0.468 BCR-ABL1 copies/▢l indicated by the ROC analysis as the value below which the patients with lower levels of MRD might be dissected (spec.=71%, sens.=77%; AUC=0,79); b) BCR-ABL1 transcript levels were detectable by dPCR also in cases resulted undetectable by qPCR. In this study, we analysed the BCR-ABL1 transcript levels by dPCR in 207 samples related to 102 CML patients. Fourteen (14%) out of 102 CML patients discontinued the TKIs therapy. Among them, 3 patients (21%) lost DMR and all of them showed dPCR values > 0.468 BCR-ABL1 copies/▢l (previously described as cut-off for a deep MRD), while 11 (79%) maintained a stable DMR and 9 of them (82%) fell under the value of 0.468 BCR-ABL1 copies/▢l. These latter patients stratified in different DMR classes by qPCR and all had undetectable level of BCR-ABL1 by qPCR. In 149 out of 207, qPCR revealed DMR. They were: MR4.0= 59 samples; MR4.5= 61 cases; MR5.0 = 29 cases. One hundred twenty-five (84%) fell under the value of 0.468 BCR-ABL1 copies/▢l. A linear regression analysis in these samples did not show any correlation between BCR-ABL1 copies/▢l detected by qPCR with the ones detected by dPCR (R2 < 0.01). On the basis of our preliminary results, TFR seems to be correlated to the maintenance of dPCR values < 0.468 BCR-ABL1 copies/▢l. The concordance between qPCR and dPCR quantification in patients with DMR and with BCR-ABL1 copies/▢l value < 0.468 was poor. Patients with dPCR values < 0.468 BCR-ABL1 copies/▢l may have 75% of probability to maintain TFR status. These results suggest that dPCR may be more sensitive to detect the MRD and could be more useful for DMR monitoring and for dissecting the best candidate to discontinuation of therapy with TKIs. Disclosures Tiribelli: Ariad Pharmaceuticals: Consultancy, Speakers Bureau; Bristol-Myers Squibb: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau. Castagnetti:Bristol-Myers Squibb: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; ARIAD Pharmaceuticals: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria. Soverini:Novartis: Consultancy; Ariad: Consultancy; Bristol-Myers Squibb: Consultancy. Rosti:Pfizer: Honoraria, Research Funding, Speakers Bureau; Roche: Honoraria, Research Funding, Speakers Bureau; BMS: Honoraria, Research Funding, Speakers Bureau; Incyte: Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau. Martinelli:Roche: Consultancy; ARIAD: Consultancy; Pfizer: Consultancy, Speakers Bureau; Genentech: Consultancy; Amgen: Consultancy; MSD: Consultancy; Roche: Consultancy; ARIAD: Consultancy; Pfizer: Consultancy, Speakers Bureau; BMS: Speakers Bureau; Genentech: Consultancy; Amgen: Consultancy; Novartis: Speakers Bureau; MSD: Consultancy.

Background : Blood stream infections (BSIs) represent a major complication of allo-SCT and are a major cause of morbidity and mortality during and after bone marrow aplasia. Objectives: The objective of this study was to describe the incidence and outcome of BSIs in a cohort of patients submitted to allo-SCT, in order to track changes of the epidemiology and bacteria resistance. Methods : We retrospectively analyzed the microbiological data of 162 patients allotransplanted in Brescia University Hospital, over a period of 6 years. Results : Eighty patients experienced a BSIs for a total of 119 isolates. In 77 cases (65%) a Gram positive bacteria was isolated, being coagulase negative Staphilococci the most frequent species (77% of the cases). In 42 cases (35%) a Gram negative bacteria was isolated (E. coli 57% and P. aeruginosa 24%). Fluoroquinolones resistance was frequent (90% for S. epidermidis , 92% for E. coli , 90% for P. aeruginosa ). Methycillin resistance of S. epidermidis was 100%, 76% of E. coli were ESBL positive and among P. aeruginosa resistance to carbapenems was 40%. The 2 years overall survival of patients with BSIs vs patients without BSIs was 46% vs 60% (HR1,48, p=0,07). P. areuginosa and E. coli were the species with the highest mortality (50% and 33%, respectively). Conclusions : These data confirms that BSIs, mainly sustained by Gram positive bacteria, are frequent in allotransplanted patients (50% of the cases) and may influence the outcome of allotransplanted patients, being antibiotics resistance highly frequent among these bacteria.

Background Blood stream infections (BSIs) represent a major complication of allo-SCT and are a major cause of morbidity and mortality during and after bone marrow aplasia. Objectives The objective of this study was to describe the incidence and outcome of BSIs in a cohort of patients submitted to allo-SCT, in order to track changes of the epidemiology and bacteria resistance. Methods We retrospectively analyzed the microbiological data of 162 patients allotransplanted in Brescia University Hospital, over a period of 6 years. Results Eighty patients experienced a BSIs for a total of 119 isolates. In 77 cases (65%) a Gram positive bacteria was isolated, being coagulase negative Staphilococci the most frequent species (77% of the cases). In 42 cases (35%) a Gram negative bacteria was isolated (E. coli 57% and P. aeruginosa 24%). Fluoroquinolones resistance was frequent (90% for S. epidermidis, 92% for E. coli, 90% for P. aeruginosa). Methycillin resistance of S. epidermidis was 100%, 76% of E. coli were ESBL positive and among P. aeruginosa resistance to carbapenems was 40%. The 2 years overall survival of patients with BSIs vs patients without BSIs was 46% vs 60% (HR1,48, p=0,07). P. aeruginosa and E. coli were the species with the highest mortality (50% and 33%, respectively). Conclusions These data confirm that BSIs, mainly sustained by Gram positive bacteria, are frequent in allotransplanted patients (50% of the cases) and may influence the outcome of allotransplanted patients, being antibiotics resistance highly frequent among these bacteria.

Introduction In AML and MDS cases, the genetic lesions inherited or acquired by the hematopoietic stem cells are considered as starting events. Familial AML and MDS, recently recognized in the revised WHO classification (2016) provide a useful model for investigation of predisposing genetic mutations. Genetic analysis of several pure familial leukemia pedigrees led to the discovery of well defined syndromes associated with inherited de novo mutations on germline DNA. Growing clinical awareness as well as a widespread use of NGS have led to an enlarged description of familial MDS/AML cases, and the number of mutations involved, suggesting they are more frequent than those previously recognized. Despite the recent discovery of well-established causative gene mutations (RUNX1, GATA2, ETV6, TERT, TERC, SRP72, ANKRD26, DDX41, CEBPA), many cases remain unexplained (about 80%), suggesting that other inherited mutations could predispose to MDS/AML. It is expected that new sequencing approaches will help to the identification of more cases, more genes as well as novel syndromes. In 2017, we started a multicentric prospective study (Clinical trial.gov NCT03058588) aiming to look for predisposing mutations in patients and relatives affected by Familial AML and MDS syndromes (FAMS) by NGS and to screen for old and new mutations potentially associated with the disease. Methods At present, 12 AML/MDS patients have been enrolled. Leukemic (bone marrow) and germline (buccal swab) DNA were analyzed by NGS gene panel approach based on a 28 genes associated to myeloid leukemogenesis, including the 9 above mentioned genes associated to FAMS. NGS libraries were performed by a Nimblegen (Roche) custom panel based on gene capture strategy and the sequencing was performed by MiSeq (Illumina). Results Ten patients did not reveal any germline mutations and the candidates are undergoing to whole exome sequencing. One presented a germline mutation on RUNX1, and the analysis of the affected relatives is on going. One revealed a new mutation. She was a 70 years old woman affected by RARS and her pedigree was characterized by 9 relatives affected by hematologic and solid neoplasia and trombocytopenia (fig 1). The NGS analysis revealed the mutation c.*514C>T in 3'UTR of ETV6 with VAF of 50% on tumor DNA. The variant has never been described before, while ETV6 has been already associated with FAMS. Sanger sequencing confirmed the mutation on the germline DNA in heterozygosis. The screening of 2 affected relatives still alive confirmed the presence of the variant in heterozygosis. In silico analysis performed on PolymiRST Database revealed that c.*514C>T in 3'UTR of ETV6 results in a gain of miRNA binding site: hsa-miR- 4717-3p and hsa-miR- 942-3p. Discussion The variant c.*514C>T in 3'UTR of ETV6 seems to repress ETV6 due to RNA interference. The new binding miRNAs have been already described as over-expressed in solid and hematologic tumors. Moreover, the down-regulation of ETV6 is associated with alteration of cell growth and hematopoiesis. Due to these evidences, c.*514C>T in 3'UTR of ETV6 could be considered as a new mutation involved in FAMS predisposition. Disclosures No relevant conflicts of interest to declare.

Extracorporeal photopheresis (ECP) is considered a valid second-line treatment for acute and chronic graft versus host disease (GVHD).Ninety-four patients with acute GVHD (aGVHD) (n = 45) and chronic GVHD (cGVHD) (n = 49), retrospectively recruited in 6 Italian centers, were submitted to ECP for second-line treatment. At the time of ECP, 22 (49%) and 23 (51%) of 45 patients with aGHVD were nonresponsive and in partial remission (PR) after steroids, respectively, and all the 49 patients with cGVHD were steroid refractory.Forty-one (91%) of 45 patients with aGVHD achieved complete remission (CR) after ECP. Fifteen (33%) of 45 patients developed cGVHD. The CR rate in patients who started ECP being nonresponsive and in PR after steroid was 86% and 96%, respectively. After a median follow-up of 20 months (range, 2-72), 15 (33%) of 45 patients developed cGHVD and 16 (35%) of 45 patients died, in 3 cases for aGVHD. A trend for a better survival was seen among patients who started ECP in PR after steroid (80% vs 50% at 2 years; P = 0.07). Overall, 22 (45%) of 49 patients and 17 (35%) of 49 patients with steroid refractory cGHVD achieved CR and PR after ECP, respectively. After a median follow-up of 27 months, 44 (90%) of 49 patients are alive, 21 of whom (48%) are on steroid.Extracorporeal photopheresis is confirmed as an effective second-line treatment in both aGVHD and cGVHD, because it can induce a response in more than 80% of the patients and a long-term survival in at least 50% of the cases.

Introduction. Blood stream infections (BSIs) represent a common event during allogeneic hematopoietic stem cell transplantation (allo-SCT) and are associated with high rate of mortality. Prophylaxis with fluoroquinolones is commonly adopted to prevent severe infection during the neutropenic phase. The emerging bacterial strains resistant to these antimicrobial agents could lead to change this type of approach. Patients and methods. We retrospectively analyzed positive blood cultures (BCs) from patients allotransplanted from January 2010 to December 2015 within our transplant program. Antimicrobial prophylaxis was conducted with a quinolone during the neutropenic period, acyclovir and fluconazole starting from the day prior to reinfusion until the withdrawn of immunosuppressive therapy and sulfametoxazole/trimethoprim starting from the hematological recovery. GVHD prophylaxis consisted on cyclosporine and methotrexate in all cases, with the addition of ATG in patients transplanted from matched unrelated donor (MUD) or with cord-blood (CB) units. Post-transplant cyclophosphamide was used in the setting of haploidentical donors. At fever onset, BCs were collected from peripheral blood (PB-BCs) and central venous catheter (CVC-BCs). A CVC related infection was defined when a positive CVC-BC proceeded by 2 hours the positivity of PB-BCs. CVC contamination was defined by the presence of positive CVC-BCs and negative PB-BCs. Empirical broad-spectrum antimicrobial therapy was usually conduct with a third or fourth generation cephalosporin with the addiction of a glycopeptide agent, if mucositis occurred. Results. One hundred-sixty-two patients underwent allo-SCT of whom 88 (54%) had acute leukemia (AL); 70 (43%) were transplanted in first CR or up-front; 71 (44%) received a myeloablative conditioning (MAC). The stem cell source was bone marrow (BM) in 33 (20%), peripheral blood stem cells (PBSC) in 122 (75%) and CB in 7 (5%) cases. Donors were matched related donor (MRD) in 58 (36%), MUD in 86 (53%) and alternative (haploidentical or CB) in 18 (11%) cases. The median time to positive BCs since allo-SCT was 13 days (range -4 - +1482). Eighty patients (49%) had a positive BCs, for a total of 119 samples. No difference in the clinical characteristics of patients with or without BSI was detected (Table 1). The median follow up was 399 days (range 21-2039) for the BSI positive group and 437 (range 12-2157) for the BSI negative (p=0.52). In 43 out of 80 patients with BSI (53%) we observed a correlation between the BCs and an organ involvement (mainly the lung in 34% of the cases). Seventy-seven (65%) and 42 (35%) out of 119 BCs were sustained by a Gram positive and a Gram negative agent, respectively. The distribution and the antimicrobial sensitivity of the different species is reported in Table 2. Briefly, S. epidermidis and E. coli were the most frequently isolated Gram positive and Gram negative bacteria, respectively (35% and 20%). 67% of E. coli were ESBL positive and 92% were resistant to fluoroquinolones. Moreover 40% and 90% of P. aeruginosa were resistant to carbapenems and to fluoroquinolones, respectively. Sixty (50%) and 59 (50%) out of 119 BCs were CVC-BCs and PB-BCs, respectively. Regarding positive CVC-BCs, 28 (24%) were CVC related BSIs; CVC contamination was observed in 21 cases (18%). The most common isolate from CVC-BCs was S. epidermidis, with 25 cases (21%). Forty -seven out of 80 patients (59%) in the BSI positive group and 35 out of 82 (43%) in the BSI negative group died (p=0.04). Overall, the infection-related mortality was 19% (15 cases). Species with the higher mortality rate were: P. aeruginosa (50%) and E. faecium (67%). Conclusions: Prophylaxis with fluoroquinolones predominantly selects Gram positive infections the majority of which were CVC related. Infections by Gram negative strains are frequently characterized by multi-antimicrobial agent resistance. These results urge to reconsider the antimicrobial prophylaxis strategy. Prospective surveillance of BSIs is a mainstay in the management of patients addressed to allo-SCT. Disclosures No relevant conflicts of interest to declare.

Introduction . Anti-thymocyte globulin (ATG), has been shown to significantly reduce the incidence and severity of acute and chronic graft versus host disease (GVHD) in pts submitted toallogeneic stem cell transplantation (allo-SCT). Two different ATG formulations, derived from rabbit immunization against T antigens,thymoglobuline-ATG (tATG) andfresenius-ATG (fATG) are usually employed. However, only few retrospective studies are available in order to compare the efficacy and safety of these two drugs. Moreover, the differential impact of the two formulations on immune recovery has been poorly studied. Methods. Clinical and laboratory data of 76 pts receivingfATG (30 mg/kg for 3 days beforeallo-SCT) ortATG (10 mg/Kg for 3 days beforeallo-SCT) as GVHD prophylaxis forallo-SCT from matched unrelated donor (MUD) for hematological malignancies at the Unit of Stem Cells Transplantation ofSpedaliCivili of Brescia between 2009 and 2014, were retrospectively collected. Basic phenotype of circulating lymphocytes was assessed by flow-cytometry at 3-months interval fromallo-SCT. The aims of the study were to compare the two ATG formulations in term of incidence of acute and chronic GVHD, infections, non-relapse mortality, relapse-free survival, overall survival and immune recovery. The study was approved by the local Ethic Committee. Results. Overall, 46 (60%) pts receivedfATG and 30 (40%)tATG as GVHD prophylaxis, in association to cyclosporine andmethotrexate. Baseline characteristics were (median): age, 46 years (range, 17-66); male, 68%; acute leukemia, 53%; complete hematological remission, 51%; HLA full-matched (8/8), 40%; source of stem cells, peripheral blood, 87%;myeloablative conditioning regimen, 49%; median follow-up, 22 months (range, 1-88). No significant differences were observed between the two populations according age, sex, hematological disease, disease status atallo-SCT, HLA match, stem cell source, amount of CD3+ and CD34+ cells infused and conditioning regimen. Overall, 26 (57%)fATGand 19 (61%)tATG-exposed pts developed an acute GVHD (p=0.8); among 18 (24%) pts who developedcGVHD, 2 out of 10 (20%)fATGand 6 out of 8 (75%)tATG-receiving pts evolved towards severecGVHD(p=0.05). In particular, the cumulative incidence of severecGVHD, was 5,2% versus 27,6% at 2 years (p=0.03) infATGandtATGgroup, respectively (Figure 1). Bacterial infections were encountered in 42 (91%) and 25 (81%) (p=0.19), fungal infections in 12 (26%) and 6 (19%) (p=0.58)fATGandtATG-treated pts. CMV reactivation was observed in 28 (61%) and 19 (73%) (p=0.43)fATGandtATG-exposed pts, respectively. However, a trend for a higher incidence of early-CMV reactivation was seen in thetATGgroup, with a cumulative incidence of CMV reactivation at 30 days of 30% versus 52% infATGandtATGcohort, respectively (p=0.09). No differences were observed betweenfATGandtATGpopulations in term of relapse-related mortality (24% versus 40%, p=0.25), non-relapse mortality (28% versus 20%, p=0.48) and overall survival (52% versus 60%, p=0.71). Immunologic reconstitution was evaluated in 48 pts (fATG, 64%). As compared totATG,fATGpts showed a significant lower amount of CD3-/CD16+ NK cells (median, 137/mclvs255/mcl, p=0.05) and a trend for lower CD3+CD4+CD25+CD127- T-regcells (5/mclvs11/mcl, p=0.07) and CD4/CD8 ratio (0.26vs0.57, p=0.08) at 3 months fromallo-SCT. At 6 months CD4/CD8 ratio was significantly lower infATGcompared totATGgroup (0.26vs0.42, p=0.01). At 9 months, lymphoid populations did not differ between the two cohorts. Overall, ATG administration was well-tolerated without grade III-IV adverse events, however an increase in infusion-related events (mainly, fever and chills) was recorded infATGgroup (67%vs32%, p=0.004). Conclusion. This retrospective study, reporting a quite large population ofallo-SCT pts from MUD homogeneously followed in a single Hematology Center, shows thatfATG-treated pts have a lower incidence of severecGVHD compared totATG. On the contrary a slight increase of early CMV reactivation has been observed intATG group. These differences do not result in a higher relapse-related or overall mortality. The distinct immune reconstitution as identified by flow-cytometricanalysis, could justify these observations, that need to be validated by prospective studies. Figure 1 Cumulative incidence of severecGVHD according to type of ATG employed Figure 1. Cumulative incidence of severecGVHD according to type of ATG employed Disclosures No relevant conflicts of interest to declare.

Abstract 4029 Background: Azacitidine (AZA) at a dose of 75 mg/mq/day subcutaneously for 7 days, every 28 days, induces high hematologic response rates and prolongation of survival in high-risk MDS patients (pts) (Fenaux, 2009). However few data are hitherto available concerning the efficacy and safety of Aza in lower risk MDS. A lower dose regimen, AZA 5 (75 mg/mq daily, subcutaneously, for 5 consecutive days every 4 weeks) have shown to induce response rates consistent with the currently approved schedule (Lyons, 2009), however in this study pts were not classified according to IPSS risk. Aim: The use of AZA in the earlier phases of disease could be more effective and useful to control the expansion of MDS clone and disease progression. In our phase II, prospective, multicentric trial, AZA 5 regimen was administered to IPSS low-or-intermediate-1 risk pts, for a total of 8 courses, in order to evaluate its efficacy and safety. Furthermore pharmacogenomic studies (GEP, SNP) cytokine network and PI-PLC-beta1 methylation and gene expression, before and at the end of 4th and 8th course of Aza treatment, were planned to identify new biological markers to predict the response. Methods: From September 2008 to February 2010, 34 patients (24 males, 10 females), with a median age of 71 (56-84) yrs, with symptomatic transfusion-dependent anemia, previously unresponsive to erythropoietin (EPO) or not expected to respond to EPO, or with severe neutropenia or thrombocytopenia, were enrolled into the study. According to WHO classification, 15 pts had RA, 6 RARS, 7 RCMD and 6 RAEB-1. Results: At present time 30/34 pts are evaluable: 23/30 pts (77%) completed the treatment plan (8 courses), 3/30 pts (10%) are ongoing and 4/30 (13%) died during the treatment period. According to the 2006 International Working Group criteria, overall response rate (ORR) was 60,9 % (14/23 pts): 5 pts (21,7%) achieved complete remission (CR), while 9 pts (39,1%) showed an hematologic improvement (HI) (7 erythroid responses, 1 erythroid/platelet response and 1 neutrophil/platelet response). 9/23 pts (39%) maintained a stable disease (SD). Generally the drug was very well tolerated. The most commonly reported hematologic toxicities were neutropenia (55%) and thrombocytopenia (19%). 4 pts (11,7%) died during treatment (2 pts after the 1th cycle and 2 pts after the 4th course) because of septic shock, gastrointestinal hemorrage, pneumonia, and respiratory distress, respectively. The median duration of response was 3,5 months (range 1–14 months). Surprisingly, 3/14 patients (2 CR and 1 HI erythroid) showed a long duration of response (11, 13 and 14 months, respectively), still ongoing, after discontinuation of AZA. Preliminary data on the lipid signalling pathways suggested a direct correlation between the demethylating effect on PI-PLC-beta1 and responsiveness to treatment. Conclusion: Our study shows that AZA low-dose schedule may be a feasible and effective treatment for low-risk MDS pts and may induce durable responses. Despite AZA safety, extreme caution is needed in pts with age-related comorbidities and/or with severe neutropenia or thrombocytopenia, especially in low-risk MDS. Furthermore, PI-PLC–β1 demethylation and gene expression could represent a new biological marker to predict the clinical response to AZA Disclosures: Off Label Use: In Italy the use of Azicitidine for Low-Risk Myelodysplastic patients is off-label. The use of azacitidine in our study is part of a Phase II clinical trial. Finelli:Celgene: Consultancy.

Glioblastoma are the most common and malignant primary brain tumor, and actual treatments consist of surgery (when possible), radiotherapy and chemotherapy. Recent discoveries in biology revealed the important role of radioresistant cancer stem cell in the tumor proliferation and also showed that differentiated tumor cells can revert to a stem-like state because of radiation. These discoveries can be used to create mathematical models to study and plan new optimized radiotherapy schedules. In literature, some models have already been developed on murine population. The aim of this study was to reproduce these models, to perform a sensitivity analysis to find the most sensitive parameters and to adapt them to standard schedules used with human patients. We found that the most sensitive parameters are those involving tumor cell proliferation, radio-sensibility and quiescence times of both stem and tumor cells.