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Alterations in KRAS have been identified as the most recurring somatic variants in the multiple myeloma (MM) mutational landscape. Combining DNA and RNA sequencing, we studied 756 patients and observed KRAS as the most frequently mutated gene in patients at diagnosis; in addition, we demonstrated the persistence or de novo occurrence of the KRAS aberration at disease relapse. Small-molecule inhibitors targeting KRAS have been developed; however, they are selective for tumors carrying the KRASG12C mutation. Therefore, there is still a need to develop novel therapeutic approaches to target the KRAS mutational events found in other tumor types, including MM. We used AZD4785, a potent and selective antisense oligonucleotide that selectively targets and downregulates all KRAS isoforms, as a tool to dissect the functional sequelae secondary to KRAS silencing in MM within the context of the bone marrow niche and demonstrated its ability to significantly silence KRAS, leading to inhibition of MM tumor growth, both in vitro and in vivo, and confirming KRAS as a driver and therapeutic target in MM.

Background Diffusion‐weighted whole‐body MRI (DW‐MRI) is increasingly used in the management of multiple myeloma (MM) patients, but data regarding the prognostic role of DW‐MRI imaging response after treatment are lacking. The Myeloma Response Assessment and Diagnosis System (MY‐RADS) imaging recommendations recently proposed the criteria for response assessment category (RAC) with a 5‐point scale in order to standardize response assessment after therapy, but this score still needs to be validated. Methods We investigated the prognostic role of RAC criteria in 64 newly diagnosed MM patients after autologous stem cell transplantation (ASCT), and we combined the results of MY‐RADS with those of minimal residual disease (MRD) assessment by multiparametric flow cytometry (MFC). Results Superior post‐ASCT PFS and OS were observed in patients with complete imaging response (RAC1), with respect to patients with imaging residual disease (RAC≥2): median PFS not reached (NR) versus 26.5 months, p = 0.0047, HR 0.28 (95% CI: 0.12–0.68); 3‐year post‐ASCT OS 92% versus 69% for RAC1 versus RAC ≥2, respectively, p = 0.047, HR 0.24 (95% CI: 0.06–0.99). Combining MRD and imaging improved prediction of outcome, with double‐negative and double‐positive features defining groups with excellent and dismal PFS, respectively (PFS NR vs. 10.6 months); p = 0.001, HR 0.07 (95%CI: 0.01–0.36). Conclusion The present study supports the applicability of MY‐RADS recommendations after ASCT; RAC criteria were able to independently stratify patients and to better predict their prognosis and the combined use of DW‐MRI with MFC allowed a more precise evaluation of MRD., The present study supports both the applicability and the clinical usefulness of the proposed Myeloma Response Assessment and Diagnosis System (MY‐RADS) recommendations applied to DW‐MRI imaging obtained after first‐line treatment of MM including ASCT. MY‐RADS RAC criteria were able to independently stratify patients and to better predict their outcome and their prognosis. DW‐MRI proved to be a powerful tool for the assessment of residual bone disease by functional imaging: it complemented bone marrow flow cytometry and may, therefore, represent a step forward in the clinical management of the increasing number of MM patients achieving CR with the novel treatment approaches.

Minimal residual disease (MRD) by multiparameter flow cytometry (MFC) is the most effective tool to define a deep response in multiple myeloma (MM). We conducted an MRD correlative study of the EMN02/HO95 MM phase III trial in newly diagnosed MM patients achieving a suspected complete response before maintenance and every 6 months during maintenance. Patients received high-dose melphalan (HDM) versus bortezomib-melphalan-prednisone (VMP) intensification, followed by bortezomib-lenalidomide-dexamethasone (VRd) versus no consolidation, and lenalidomide maintenance. Bone marrow (BM) samples were processed in three European laboratories, applying EuroFlow-based MFC protocols (eight colors, two tubes) with 10−4−10−5 sensitivity. At enrollment in the MRD correlative study, 76% (244/321) of patients were MRD-negative. In the intention-to-treat analysis, after a median follow-up of 75 months, 5-year progression-free survival was 66% in MRD-negative versus 31% in MRD-positive patients (HR 0.39; p p

Background sustained MRD negativity is emerging as a surrogate biomarker of patients (pts)’ outcome in clinical trials. We implemented this tool in our clinical practice and we analyzed outcome according to sustained MRD negativity in MM pts treated with autologous stem cell transplantation (ASCT) at our Institution. Methods We retrospectively analyzed the outcome of 77 newly diagnosed MM pts (median age 61 years) diagnosed between January 2015 to December 2019 in ≥ VGPR after ASCT. Bone marrow samples were collected for MRD by 8-color FCM (Sn 10-5) at day +100 after ASCT, before maintenance. Sustained 1 year MRD negativity was also evaluated and the prognostic impact of MRD status on PFS and OS was analyzed. Results out of 77 pts, 28 (36%) were ISS stage 3 and 18 (23%) showed high risk cytogenetics. Patients were treated with the following induction regimens: VTD 51, VRD 5, Dara-VRD 5, KRD 14, KCD 2. Single ASCT with MEL200 conditioning was performed in 49 pts (64%), whereas 28 pts (36%) received double ASCT. Subsequent maintenance was performed with lenalidomide (70), daratumumab-lenalidomide (5), carfilzomib-lenalidomide (2). Response rates were VGPR 26%, CR 61% and sCR 13%. MRD before maintenance was positive in 20 pts (26%) and negative in 57 (74%). Sustained MRD negativity lasting ≥ 1 year was documented in 49 pts (64%), whereas early loss of MRD negative status was observed in 8 (10%) of cases. After a median follow up of 40.2 months, PFS was significantly longer in pts with sustained MRD negativity (≥1 year) compared to MRD positive patients before maintenance: median NR vs 41.4 months, p 0.0002, HR 0.17 (0.044-0.65). The worst PFS (24.7 months) was observed in pts with early loss of MRD negativity ( Conclusion we confirm the predictive value of MRD assessment after ASCT and therefore the importance of achieving sustained MRD negativity regardless of different treatment strategies. Moreover, the detection of early loss of MRD negativity can help the physician to identify pts with particularly poor prognosis

Autologous stem cell transplantation (ASCT) is feasible and effective in selected older patients with Multiple Myeloma, but specific criteria for evaluating ASCT eligibility in elderly patients are lacking. We evaluated 131 patients aged 65-75 considered for ASCT at our center: The Charlson Comorbidity Index (CCI), Hematopoietic cell transplantation comorbidity index (HCT-CI) and IMWG frailty score were obtained at diagnosis, but the intensity of treatment was left to physician's choice. The scores and age's impact on outcome was analyzed: 85 patients were judged transplant eligible, whereas 46 patients received a less intensive treatment (median follow up 27 months). No patients classified as frail had been considered eligible to ASCT with a worse outcome compared to fit and unfit patients (median PFS (progression free survival): 7.9 vs 32.9 and 29.6 months; P < .001). PFS was superior in the ASCT group (35.6 vs 19.9 months, P .013). In the ASCT group, PFS was better in patients aged 65-69 years than in patients ≥70 (51.5 vs 27.7 months, P.004). Indeed, in unfit patients aged ≥70 the PFS of the ASCT group was comparable to NO ASCT group (18 vs 27 months, P = .33) whereas in unfit patients aged 65-69 PFS was superior in the ASCT group: 43.3 vs 18.4 months, P .01. ISS III and impaired functional status independently affected PFS in a multivariate analysis (P .011 and P .006). While CCI and HCT-CI did not predict different outcome in ASCT patients, the IMWG frailty score would be of help in identifying unfit patients aged 70-75, whose outcome with ASCT selected by clinical judgment was no better than with less intensive treatments.

Proteasome Inhibitors (PI) have now become the cornerstone of treatment of multiple myeloma (MM). Carfilzomib has been demonstrated to cause more frequent cardiovascular side effects such as dyspnea, hypertension, and heart failure. Recent pre-clinical studies have investigated the effects of proteasome on myocardial and vascular cells, but the pathogenic mechanism underlying the effects of proteasome inhibition on these cells is poorly understood. We reviewed the evidence from clinical trials, post-hoc analysis and small observational studies currently available and summarized the data from experimental, focusing on the pathogenic mechanisms potentially implicated in the cardiovascular toxicity of proteasome inhibitor, particularly of carfilzomib that is most responsible for cardiovascular side effects. Finally, we tried to suggest future perspectives for diagnostic and therapeutic approach to this type of cardiovascular damage.

Introduction: The role of minimal residual disease (MRD) in Multiple Myeloma (MM) as a surrogate biomarker of patients' outcome, as well as the prognostic information of functional imaging response after treatment have been established in recent years. Furthermore, the predictive relevance of sustained MRD negativity assessed by marrow and imaging techniques and its association with an excellent outcome is emerging in clinical trials. Diffusion-weighted whole-body MRI (DW-MRI) is increasingly used in the management of MM patients, but data regarding the predictive role of sustained DW-MRI response after treatment are lacking. The Myeloma Response Assessment and Diagnosis System (MY-RADS) recommendations have established criteria for Response Assessment Category (RAC) (Messiou C et al, Radiology 2019) with a 5 point scale defining the probability of complete imaging response (i.e. RAC 1) or progressive disease after treatment (i.e. RAC 5). We implemented the RAC criteria in our clinical practice and DW-MRI at 1-year in MM patients treated with autologous stem cell transplantation (ASCT) followed by maintenance therapy. Patients and methods: We retrospectively analyzed the outcome of 57 newly diagnosed MM patients (median age 61 years) diagnosed at our institution from January 2015 to December 2019 receiving maintenance therapy after ASCT. Patients underwent DW-MRI evaluation according to MY-RADS criteria at day +100 after ASCT, before maintenance, and after 1 year with the aim of monitoring imaging residual disease. Bone marrow samples were collected for MRD assessment by 8-color FCM (sensitivity 10-5) at day +100 after ASCT, before maintenance, and after 1 year. We focused on sustained 1-year DW-MRI negativity evaluated according to RAC response, and its potential predictive role at that timepoint on progression free survival (PFS) and overall survival (OS). In patients with available 1-year MRD evaluations, concordance between 1-year MRD and DW-MRI results was calculated and the level of agreement was expressed by Cohen's kappa statistics. Results: Out of 57 patients, 23 (40%) were ISS stage 3 and 14 (25%) showed high risk cytogenetics. Patients were treated with the following induction regimens: VTD 42, VRD 5, Dara-VRD 6, KRD 3, KCD 1. Single ASCT with MEL200 conditioning was performed in 33 patients (58%), whereas 24 patients (42%) received double ASCT. Subsequent maintenance was performed with lenalidomide (49 patients, 86%) or daratumumab-lenalidomide (8 patients, 14%). Response rates after ASCT were PR 9%, VGPR 23%, CR 51% and sCR 17%. According to MY-RADS, a complete imaging response (RAC1) at day +100 after ASCT was observed in 34 patients (60%). Sustained 1 year complete imaging response during maintenance therapy was observed in 43 patients (75%). Some residual disease was identified at that timepoint in 14 patients (25%) [RAC 2: 6 (11%), RAC > 2: 8 (14%)]. After a median follow up of 36 months, PFS and OS were significantly longer in patients with sustained 1-year imaging negativity, compared to patients with imaging residual disease (RAC 1 vs RAC ≥2): median PFS 56 vs 24,1 months, p Conclusion: Our real-life data analysis confirms the predictive value of imaging residual disease assessment with DW-MRI after ASCT and highlights the importance of achieving sustained imaging MRD negativity during maintenance therapy regardless of different treatment strategies. Moreover, given the high rates of CR seen in patients with MM with novel effective treatment combinations, the detection of residual disease with the combined evaluation of marrow and functional imaging techniques during maintenance therapy can help the physician to identify patients with increased risk of early relapse and particularly poor prognosis. Our preliminary data regarding the high concordance observed between DW-MRI and MRD results during maintenance therapy suggest that DW-MRI could represent a reliable non-invasive technique to monitor residual disease. Disclosures Belotti: 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; Takeda: Consultancy; GSK: Membership on an entity's Board of Directors or advisory committees. Ribolla: Janssen: Membership on an entity's Board of Directors or advisory committees. Cancelli: Amgen: Membership on an entity's Board of Directors or advisory committees. Roccaro: Amgen, Celgene, Janssen, Takeda: Membership on an entity's Board of Directors or advisory committees; AstraZeneca,: Research Funding; Associazione Italiana per la Ricerca sul Cancro (AIRC): Research Funding; European Hematology Association: Research Funding; Fondazione Regionale per la Ricerca Biomedica (FRRB), Transcan-2 ERA-NET: Research Funding. Rossi: Sanofi: Honoraria; Jazz: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Novartis: 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; Janssen: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Consultancy, Honoraria; Astellas: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Alexion: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees. Tucci: janssen: Membership on an entity's Board of Directors or advisory committees; Gentili: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees.

Background: 18F-FDG-PET/CT is currently the standard technique to define imaging-minimal residual disease (MRD) in multiple myeloma (MM) patients. A joint analysis of 2 prospective randomized trials in newly diagnosed transplant-eligible MM (NDTEMM) patients applied for the first time the Deauville Scores (DS) to focal lesions (FS) and bone marrow uptake (BMS) showing the liver background (DS < 4) as the best cut-off to define PET/CT negativity after therapy and complete metabolic response (CMR) (Zamagni et al, ASH 2018). Validation of this new standardized criteria in an independent prospective series of NDTEMM patients is highly required. Imaging-PET/CT MRD also showed to be complementary to Multiparameter Flow Cytometry (MFC) in predicting patient's outcomes (Moreau P, JCO 2017). In this analysis, we aimed at confirming the applicability and validity of DS criteria to define PET/CT CMR and showing their impact on patient's outcomes in the multicenter phase II randomized FORTE trial for NDTEMM patients. We also looked at the complementarity with BM techniques, especially MFC. Methods: NDTEMM patients ≤ 65 years were randomized to receive carfilzomib, lenalidomide, dexamethasone (KRD) induction - autologous stem cell transplantation (ASCT) intensification-KRd consolidation (arm A); KRd12 (arm B) and carfilzomib, cyclophosphamide, dexamethasone (KCd) induction-ASCT intensification-KCd consolidation (arm C). Thereafter, patients were randomized to maintenance with lenalidomide alone or plus carfilzomib. PET/CT scans were performed locally at baseline (B) and prior to the start of maintenance (PM). DS were applied both in the BM and FLs, as previously described (Zamagni E, EHA 2020). CMR was defined as DS < 4 both in the FLs and BM. MRD evaluation was performed by 8-color second-generation flow cytometry (sensitivity 10-5) in patients who achieved at least VGPR before maintenance (Gay F, ASCO 2019). The impact of each parameter on outcomes was evaluated by landmark analyses at PM. A multivariable Cox regression analysis was adopted to identify independent predictors for PFS and OS. Results: 182 out of the 474 global patients enrolled in the trial had a pre- and post-treatment PET/CT evaluation available and were included in this analysis. Patients' baseline characteristics were: median age 57 years, ISS and R-ISS stage III 18% and 10%, respectively, high-risk cytogenetics (t(4;14) ± del(17p) ± t(14;16), detected by FISH) 26%, reflecting baseline clinical features of the entire FORTE population. At B, 93% of patients had FLs, with a median maximum standardized uptake value (SUVmax) of 5.7 [IQR: 4.1-8.1], 7% presented extra-medullary lesions and nearly all patients had increased BM uptake, with a median SUVmax of 3.4 [IQR: 2.8-4.3]. FS and BMS ≥ 4 were present in 87% and 57% of patients, respectively. At PM, PET/CT negativity according to DS < 4, was present in 80% in the FLs and 85% in the BM, respectively. 63% showed CMR. 92% and 61% of patients achieved ≥ VGPR and CR as best response, respectively, while 73% of them achieved MFC MRD negativity. The achievement of a best CR significantly correlated with BMS < 4 at PM (P= 0.003). In univariate analysis, at Landmark time PM, FS Conclusion: In conclusion, the present analysis confirms the applicability and validity of DS criteria to define PET/CT CMR in an independent prospective series of NDTEMM patients. CMR significantly and independently correlated in uni- and multivariable analysis with patient's outcomes in terms of PFS and OS and was complementary to the MFC MRD negativity. Figure Disclosures Zamagni: Takeda: Honoraria, Other: Travel, Accommodations, Expenses, Speakers Bureau; Celgene Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Speakers Bureau; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Speakers Bureau; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Speakers Bureau. Gay:Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees; Adaptive: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. D'Agostino:GSK: Membership on an entity's Board of Directors or advisory committees. Galli:Takeda: Honoraria; Janssen: Honoraria; Celgene: Honoraria; BMS: Honoraria. Zambello:Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Rivolti:Celgene: Membership on an entity's Board of Directors or advisory committees. Tacchetti:Bristol-Myers Squibb: Honoraria; AbbVie: Honoraria; Takeda: Honoraria; Celgene: Honoraria; Oncopeptides: Honoraria; Janssen: Honoraria; Amgen: Honoraria. Fanti:Bayer, Astellas, GE Healthcare, ANMI, Janssen: Membership on an entity's Board of Directors or advisory committees; Bayer, Astellas, GE Healthcare, Sanofi, AAA: Honoraria. Boccadoro:Bristol-Myers Squibb: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Honoraria; Mundipharma: Research Funding; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Amgen: Honoraria, Research Funding. Cavo:AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel accomodations, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel accomodations, Speakers Bureau; GlaxoSmithKline: Honoraria, Speakers Bureau; Karyopharm: Honoraria. Musto:Amgen: Honoraria; Celgene: Honoraria. Oliva:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria.

Risk stratification in acute myeloid leukemia (AML) patients using prognostic parameters at diagnosis is effective, but may be significantly improved by the use of on treatment parameters which better define the actual sensitivity to therapy in the single patient. Minimal residual disease (MRD) monitoring has been demonstrated crucial for the identification of AML patients at high risk of relapse, but the best method and timing of MRD detection are still discussed. Thus, we retrospectively analyzed 104 newly diagnosed AML patients, consecutively treated and monitored by quantitative polymerase chain reactions (Q-PCR) on WT1 and by multiparametric flow cytometry (MFC) on leukemia-associated immunophenotypes (LAIPs) at baseline, after induction, after 1st consolidation and after 1st intensification. By multivariate analysis, the factors independently associated with adverse relapse-free survival (RFS) were: bone marrow (BM)-WT1 ≥ 121/10(4) ABL copies (P = 0.02) and LAIP ≥ 0.2% (P = 0.0001) (after 1st consolidation) (RFS at the median follow up of 12.5 months: 51% vs. 82% [P

INTRODUCTION. The multiple myeloma (MM) mutational landscape has identified KRAS as the most recurring somatic variant, observed in around 26% of cases, therefore KRAS may represent an important therapeutic target. Despite several attempts to develop a targeted therapeutic for KRAS mutant cancers, either direct KRAS enzymatic inhibition, or inhibition of MAPK- and PI3K- downstream effector cascades have not been successful. Therefore, there is a need to develop novel therapeutic approaches that may target the KRAS mutational event in MM. We have studied AZD4785, a novel, potent and selective high affinity 2'-4' constrained ethyl residues containing therapeutic antisense oligonucleotide (ASO) targeting KRAS, both in vitro and in vivo. METHODS. AZD4785 productive uptake was assessed by measuring KRAS knockdown at both the mRNA and protein level. Molecular mechanisms underlying AZD4785-dependent anti-MM activity were studied, interrogating the transcriptome profiling of AZD4785-treated MM cells. Anti-MM activity of AZD4785 was assessed in vitro in the context of primary MM patients' derived bone marrow stromal cells (BMSCs). Endpoints included evaluation of cell proliferation, cytotoxicity, cell cycle modulation, apoptosis, MM cell migration and adhesion; modulation of MAPK-, PI3K-, apoptotic-signaling. KRAS-mutated (MM1S; KMS20); -wild type (U266; KMS11) MM cell lines; BM MM patients' and peripheral blood healthy donor derived cells were tested. A non-targeting ASO (ASO-ctrl) was used as control. Synergism between AZD4785 and bortezomib, in modulating MM growth was tested. AZD4785-dependent modulation of tumor growth was studied in vivo in a subcutaneous MM.1S.-Luc model and a disseminated GFP/Luc-MM.1S model (BLI); MM cell dissemination to distant BM niches was studied ex vivo, using confocal laser scanning microscopy. RESULTS. AZD4785 led to specific dose-dependent inhibition of KRAS mRNA and protein expression, in KRAS-mutant, -wild-type cell lines and MM patient-derived CD138+ cells; without affecting NRAS and HRAS content. Wide mRNA transcriptome was performed using AZD4785 treated MM.1S cells vs control: GSEA showed down-regulation of MAPK, cell cycle, TP53 signaling pathways (FDR CONCLUSION. Taken together, these data suggest that AZD4785 may represent a novel therapeutic approach for targeting mutant KRAS in MM, either alone or in combination with proteasome inhibitors; and warrant further development. Disclosures Giacomini: Fondazione Cariplo: Research Funding. Belotti:Amgen: 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. Revenko:Ionis Pharmaceuticals: Employment. MacLeod:Ionis Pharmaceuticals: Employment. Willis:AstraZeneca: Employment. Cai:AstraZeneca: Employment. Hauser:AstraZeneca: Employment. Rooney:AstraZeneca: Employment. Ambrose:AstraZeneca: Employment. Staniszewska:AstraZeneca: Employment. Hanson:AstraZeneca: Employment. Rossi: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; Daiichi-Sankyo: Consultancy; Roche: Membership on an entity's Board of Directors or advisory committees. Ronca:Associazione Italiana per la Ricerca sul Canctro (AIRC): Research Funding. Bolli:GILEAD: Other: Travel expenses; JANSSEN: Honoraria; CELGENE: Honoraria. Moschetta:AstraZeneca: Employment. Ross:AstraZeneca: Employment. Roccaro:Celgene: Membership on an entity's Board of Directors or advisory committees; European Hematology Association: Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; Transcan2-ERANET: Research Funding; AstraZeneca: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; Associazione Italiana per al Ricerca sul Cancro (AIRC): Research Funding.

Background: 18F-FDG-PET/CT is currently the standard technique to define minimal residual disease (MRD) status outside the bone marrow (BM) in multiple myeloma (MM) patients. A joined analysis of two prospective randomized trials in newly diagnosed transplant-eligible MM (NDTEMM) patients applied for the first time the Deauville Scores (DS) to focal lesions (FS) and bone marrow uptake (BMS) and showed the liver background (DS < 4) to be the best cut-off to define PET negativity after therapy (Zamagni et al, ASH 2018). Multiparameter Flow cytometry (MFC) at the sensitivity level of 10-5 is one of the standardized methods to assess MRD in the BM (Kumar SK, Lancet Oncol 2016). In this analysis, we aimed at comparing MRD data by PET/TC assessment and MFC in the multicenter phase II randomized FORTE trial for NDTEMM patients. Methods: NDTEMM patients ≤65 years were randomized to receive carfilzomib, lenalidomide, dexamethasone (KRD) induction - autologous stem cell transplantation (ASCT) intensification-KRd consolidation (arm A); KRd12 (arm B) and carfilzomib, cyclophosphamide, dexamethasone (KCd) induction-ASCT intensification-KCd consolidation (arm C). Thereafter, patients were randomized to maintenance with lenalidomide alone or lenalidomide plus carfilzomib. MRD evaluation was performed by 8-color second-generation flow cytometry (sensitivity 10-5) in patients who achieved at least VGPR before maintenance (Gay F, ASCO 2019). PET/CT scans were performed locally at baseline (B) and prior to the start of maintenance (PM) and the DS were applied both in the BM and FLs as previously described. Cramér's V coefficient was used to measure the concordance between PET/TC and MFC; Fisher or X2 tests were adopted, where appropriate, to evaluate the statistical significance, at the level of 0.05. Results: 182 out of the 474 global patients enrolled in the trial had a matched PET/CT and MFC evaluation available and were included in the present analysis. Baseline characteristics of the patients were as follows: median age 57 years, ISS and R-ISS stage III 18% and 10%, respectively, high-risk cytogenetics (t(4;14) ± del(17p) ± t(14;16), detected by FISH) 26%, reflecting baseline clinical features of the entire FORTE population. At B, 92% of the patients had FLs, with a median maximum standardized uptake value (SUVmax) of 5.7 [IQR: 4.1-8.1], 11% presented extra-medullary lesions and nearly all the patients had increased BM uptake, with a median SUVmax of 3.3 [IQR: 2.8-4.3]. FS and BMS ≥4 were present in 87% and 59% of the patients, respectively. A higher FS at B was significantly correlated with ISS stage III (P= 0.04), while higher BMS with lower hemoglobin level (P= 0.002) and higher free light chain ratio (P= 0.004). At PM, PET/TC negativity according to DS < 4, was present in 78% in the FLs and 85% in the BM, respectively. No significant correlations between PET/CT negativity after therapy and baseline prognostic factors or PET/CT characteristics were found. 95% and 67.5% of the patients achieved ≥ VGPR and CR as best response, respectively, while 75% of them achieved MFC MRD negativity. The achievement of a best CR significantly correlated with BMS < 4 at PM (P= 0.013). We analyzed the concordance between MRD results by the two techniques and Cramér's V coefficient measured a strong association, with a value of 0.76 (p Conclusion: In conclusion, the present analysis confirms the applicability and validity of DS criteria for the definition of PET/CT MRD outside the BM in an independent prospective series of NDTEMM patients. PET/CT negativity significantly correlated with the achievement of best CR. PET/CT and MFC at the sensitivity level of 10-5 showed a good concordance in the BM, while were also confirmed to be complementary outside (FLs). Future analyses will show the impact of PET/CT in comparison with BM MRD techniques on patient's outcomes. Disclosures Zamagni: Celgene Corporation: Honoraria, Other: Advisory board, Speakers Bureau; Janssen: Honoraria, Other: Advisory board, Speakers Bureau; Amgen: Honoraria, Other: Advisory board, Speakers Bureau; BMS: Honoraria, Other: Advisory Board, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; Sanofi: Honoraria, Other: Advisory Board, Speakers Bureau. Gay:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees. Omedé:Janssen: Membership on an entity's Board of Directors or advisory committees. Galli:Janssen: Honoraria; Leadiant (Sigma-Tau): Honoraria; Takeda: Honoraria; Bristol-Myers Squibb: Honoraria; Celgene: Honoraria. Zambello:Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Gamberi:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Patriarca:Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees. Tacchetti:Celgene: Honoraria, Speakers Bureau; Amgen: Honoraria, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; Janssen: Honoraria; Oncopeptides: Honoraria, Speakers Bureau; BMS: Honoraria. Boccadoro:Sanofi: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; AbbVie: Honoraria; Mundipharma: Research Funding. Cavo:bms: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau; novartis: Honoraria; takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau. Oliva:Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees.

Background Risk-adapted therapy is a common strategy in curable hematologic malignancies: standard-risk patients receive less intensive treatment, whereas high-risk patients require a more intensive approach. This model cannot be applied in multiple myeloma (MM), which is still incurable. Continuous treatment (CT) is a key strategy for MM treatment, since it improves duration of remission. However, the role of CT according to standard- or high-risk baseline prognosis remains an open question. Patients and methods We performed a pooled analysis of 2 phase III trials (GIMEMA-MM-03-05 and RV-MM-PI-209) that randomized patients to CT vs fixed-duration therapy (FDT). Results In the overall patient population (n = 550), CT improved progression-free survival1 (PFS1) (HR 0.54), PFS2 (HR 0.61) and overall survival (OS) (HR 0.71) vs FDT. CT improved PFS1 both in R-ISS I (HR 0.49) and R-ISS II/III patients (HR 0.55). Four-year PFS1 was 38% in R-ISS II/III patients receiving CT and 25% in R-ISS I patients receiving FDT, with similar trends for PFS2 and OS. High-risk patients benefited more from proteasome-inhibitor plus immunomodulatory-based CT than immunomodulatory alone. Conclusion Good prognosis patients receiving FDT lose their prognostic advantage over high-risk patients receiving CT and high-risk patients may benefit from more intensive maintenance including proteasome inhibitors and immunomodulators.

Herein we dissect mechanisms behind the dissemination of cancer cells from primary tumor site to the bone marrow, which are necessary for metastasis development, with a specific focus on multiple myeloma. The ability of tumor cells to invade vessels and reach the systemic circulation is a fundamental process for metastasis development; however, the interaction between clonal cells and the surrounding microenvironment is equally important for supporting colonization, survival, and growth in the secondary sites of dissemination. The intrinsic propensity of tumor cells to recognize a favorable milieu where to establish secondary growth is the basis of the “seed and soil” theory. This theory assumes that certain tumor cells (the “seeds”) have a specific affinity for the milieu of certain organs (the “soil”). Recent literature has highlighted the important contributions of the vascular niche to the hospitable “soil” within the bone marrow. In this review, we discuss the crucial role of stromal cells and endothelial cells in supporting primary growth, homing, and metastasis to the bone marrow, in the context of multiple myeloma, a plasma cell malignancy with the unique propensity to primarily grow and metastasize to the bone marrow.

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.

Multiple myeloma (MM) is a plasma cell dyscrasia characterized by bone marrow infiltration of clonal plasma cells. The recent literature has clearly demonstrated clonal heterogeneity in terms of both the genomic and transcriptomic signature of the tumor. Of note, novel studies have also highlighted the importance of the functional cross-talk between the tumor clone and the surrounding bone marrow milieu, as a relevant player of MM pathogenesis. These findings have certainly enhanced our understanding of the underlying mechanisms supporting MM pathogenesis and disease progression. Within the specific field of small non-coding RNA-research, recent studies have provided evidence for considering microRNAs as a crucial regulator of MM biology and, in this context, circulating microRNAs have been shown to potentially contribute to prognostic stratification of MM patients. The present review will summarize the most recent studies within the specific topic of microRNAs and circulating microRNAs in MM.

Introduction: Autologous stem cell transplantation (ASCT) has proven effective in Multiple Myeloma (MM) patients (pts) aged 65. With the increase of treatment options, several geriatric assessment tools have been proposed to help physicians in selecting treatment of appropriate intensity. However specific criteria for evaluating ASCT eligibility in elderly MM pts have been seldom investigated.Patients and Methods: From January 2013 to December 2017 131 consecutive newly diagnosed symptomatic MM pts aged 65-75 (M/F: 66/65) were considered for ASCT at our center according to physician's clinical judgement. The variables included in Charlson Comorbidity Index (CCI), Hematopoietic cell transplantation comorbidity index (HCT-CI), and International Myeloma Working Group (IMWG) frailty score were not considered for selection but were retrieved for this study and pts were classified accordingly. Of note, ADL and IADL were referred to pts status prior the occurrence of MM related symptoms. The impact of age and the predictive role of the above mentioned scores on progression-free survival (PFS) of pts selected or not for ASCT was analyzed. Pts characteristics are shown in Table 1. Results: Of 131 pts, 85 (65%) were judged transplant eligible (ASCT ITT arm) by the clinician and received bortezomib-based induction (VTD 94%, VD 5%, VCD 1%); 72 of them (85%) actually underwent ASCT (70% single, 30% double) with melphalan conditioning 200 mg/sqm in 68% of cases. The 46 pts considered ineligible to ASCT received a less intensive first line treatment (89% VMP, 4% Daratumumab-VMP, 2% MP, 5% steroids/palliation). Complete remission (CR) after the first ASCT was higher in the ASCT (ITT) vs the NO ASCT group (43,5% vs 26%, respectively; p 0.048), whereas ORR and ³VGPR rates were comparable (83% vs 74% and 76,4% vs 61%, respectively). Transplant related mortality (TRM) was 0%. 2 year death rate was 13% in the ASCT (ITT) arm and was due to PD in 91% of cases (the latter 9% concerns a cardiac arrest secondary to aspiration pneumonia in a pt in VGPR 3 months after first ASCT). After a median follow-up of 27 months, PFS was 35,6 in the ASCT (ITT) group vs 19,9 months in NO ASCT pts, respectively; p 0,013, HR 0,42 (95% CI: 0,25-0,71). HCT-CI was ≥2 in 87% of pts overall. PFS was better in pts with HCT-CI 0-1 compared to HCT≥2 (NR vs 27,3 months; p 0,025, HR 0,45, 95% CI 0,23-0,91) and also in pts with HCT-CI ³2 undergoing ASCT (ITT) than in NO ASCT pts: median 34 vs 19,9 months, p 0,008 (HR 0,5, 95%CI 0,30-0,84). CCI was 0-3 in 78% of pts. Their outcome according was similar to pts with CCI >3 but ASCT performed better than NO ASCT also in the few (median PFS 51,4 vs 16,9 months; p 0,04, HR 0,37, 95%CI 0,15-0,95). IMWG frailty score was more useful. No pts classified as FRAIL had been considered eligible to ASCT by clinical decision with a significantly worse outcome compared to FIT and UNFIT pts (median PFS: 7,9 months vs 32,9 and 29,6; FIT vs FRAIL: p < 0.0001, HR 0,02, 95%CI 0,004-0,008; UNFIT vs FRAIL: p < 0,001, HR 0,03 95%CI 0,007-0,12). Unlike HCT-CI and CCI, the distribution of patients according to IMWG score was more balanced both overall and between the ASCT (ITT) and NO ASCT groups, particularly for UNFIT pts. However on the whole no outcome differences were observed between FIT and UNFIT pts. PFS was better in FIT&UNFIT pts in the ASCT (ITT) group than in the NO ASCT group: median 35,6 months vs 25,8 months; p 0,04, HR 0,54, 95%CI 0,31-0,97. However, in the ASCT (ITT) group, the age group 65-69 years fared better than pts ³70 years (51,5 vs 27,7 months, p 0,0037; HR 0.34, 95% CI 0.17-0.7). Indeed, in IMWG UNFIT patients aged ³70, the PFS of the ASCT (ITT) group was comparable to NO ASCT group (18 vs 27 months, p 0,33) whereas in UNFIT pts aged 65-69, PFS was superior in pts treated more intensively by physician choice: 43,3 months in ASCT (ITT) arm vs 18,4 months in NO ASCT (p 0.01, HR 0.03; 95%CI 0.003-0.24). Conclusion: In an unselected series of elderly MM pts aged 65-75 and undergoing ASCT according to clinical judgement the outcome of ASCT pts was better than those of NO ASCT. CCI and HCT-CI score proved of little help for better identifying the best candidates to ASCT. Conversely the IMWG frailty score would be of help in identifying the category of UNFIT pts aged 70-75 whose outcome with ASCT selected by clinical judgement was no better than with less intensive treatments. Table 1: Disclosures Belotti: Amgen: Other: Advisory Board; Celgene: Other: Advisory Board. Cattaneo:GILEAD: Other: Advisory Board. Rossi:TEVA: Other: ADVISORY BOARD; CELGENE: Other: ADVISORY BOARD; SANOFI: Other: ADVISORY BOARD; MUNDIPHARMA: Honoraria; ABBVIE: Other: ADVISORY BOARD; JANNSEN: Other; PFIZER: Other: ADVISORY BOARD; ROCHE: Other: Advisory Board; NOVARTIS: Honoraria; SANDOZ: Honoraria; GILEAD: Other: ADVISORY BOARD; BMS: Honoraria; JAZZ: Other: ADVISORY BOARD; AMGEN: Other: ADVISORY BOARD.

Introduction Multiple myeloma (MM) can be associated with paraskeletal (PP) or extramedullary (EMP) plasmocytomas (PL). Although PLs are relatively frequent, even at diagnosis, our knowledge on the subject mainly relies on small case series or single center experiences. Remarkably, little is known regarding the role of new drugs on MM with PL. Aim To perform a meta-analysis of 8 EMN-GIMEMA studies focused on the description of PLs characteristics, clinical outcome, and response to new drugs. The trials involved in this meta-analysis have the following identification codes: EUDRACT 2005-00473041, NCT01093196, NCT01063179, NCT01091831, NCT01857115, NCT01190787, NCT00551928, NCT01346787. Patients A total of 2332 newly diagnosed MM patients have been included in the analysis, and 267 (11.4%) had a PL, defined as PP in 243 (10.4%), EMP in 12 (0.5%), and not classified in 12 (0.5%) patients. PLs were evaluated with different techniques as PET, CT, NMR or physical examination accordingly to their site and local guidelines. PP and EMP were single in 195, and multiple in 60 cases, and their median size was 4 cm (range 1-26 cm). Median age at diagnosis was 68 years (range 18-87) in PL, and 69 years (range 25-91) in non-PL patients; male patients were 149 (55.8%) in PL and 1007 (48.8) in non-PL patients. ISS stage in PL and non-PL patients was as follows: stage I in 119 (44.6%) and 682 (33.0%), stage II in 89 (33.3%) and 792 (38.3%), stage III in 38 (14.2%) and 508 (24.6%), unknown in 21 (7.8%) and 83 (4.0%) patients, respectively. Cytogenetics was available in 166 PL, and 1528 non-PL patients, and high risk status, defined as having t(4;14) or t(14;16) or del(17p), was observed in 51 (30.7%) PL, and 446 (21.6%) non-PL patients. PL and non-PL patients received treatment with the following drugs: bortezomib in 65 (24.3%) and 598 (29.0%), lenalidomide in 182 (68.1%) and 1366 (66.1%), and carfilzomib in 20 (7.5%) and 101 (4.9%), respectively. Autologous stem cell transplantation (ASCT) was performed in 112 (41.9%) PL and 782 (37.9) non-PL patients. PL and non-PL patients received maintenance in 108 (40.4%) and 815 (39.5%), continuous treatment in 128 (47.9%) and 1007 (48.7%), and fixed-duration treatment in 31 (11.6%) and 243 (11.7%) cases, respectively. Results With a median follow-up of 62 months (IQ range 34-75) in PL and 65 months (IQ range 40-77) in non-PL patients, 4-years overall survival (OS) was 56% in PL and 67% in non-PL patients (p3 cm PL, 53% ≤3 cm PL vs 67% in non-PL), and a 5 cm threshold (55% >5 cm PL, 57% ≤5 cm PL vs 67% in non-PL), neither by the number of PLs (58% single PL, 50% multiple PLs vs 67% in non-PL), or the onset site (57% PP, 55% EMP vs 67% in non-PL). Four-years OS in PL patients treated with either bortezomib or carfilzomib was 44%; it was 56% in patients treated with lenalidomide; in non-PL patients was 62% when treated with bortezomib or carfilzomib, or 65% when treated with lenalidomide. Four-year progression-free survival (PFS) was 26% in PL and 27% in non-PL patients. In patients that received maintenance, the 4-years PFS from maintenance start was 24% in PL and 30% in non-PL patients. When considering the PFS-2, i.e. the PFS calculated from the treatment start to the time of second relapse/progression, the median time was 42.3 months (95% CI, 36.3 - 51.5) in PL and 46.4 months (95% CI, 44.1 - 48.9) in non-PL patients. Conclusions Our meta-analysis studied the largest number of newly diagnosed MM patients with PL so far reported. We observed that in patients treated with new generation therapies incorporating new drugs, the detrimental effect of PL at diagnosis is limited. The 4-years OS is modestly reduced for PL patients, while we observed that PSF and PFS-2 were similar in PL and non-PL patients, suggesting that effective treatment can overcome the unfavorable prognostic significance of PLs. We also observed that lenalidomide is effective in patients with MM and PL, as are bortezomib and carfilzomib. Disclosures Montefusco: Janssen: Other: Advisory Board; Amgen: Other: Advisory Board; Celgene: Other: Advisory Board. Gay:Roche: Other: Advisory Board; Seattle Genetics: Other: Advisory Board; BMS: Honoraria; Janssen: Honoraria; Celgene: Honoraria, Other: Advisory Board; Amgen: Honoraria; Takeda: Honoraria, Other: Advisory Board. De Paoli:Gilead: Other: Advisory Board; Celgene: Other: Advisory Board; Amgen: Other: Advisory Board; Janssen: Other: Advisory Board. Di Raimondo:Celgene: Honoraria; Takeda: Honoraria, Research Funding. Patriarca:Janssen: Other: advisory role; Celgene: Other: advisory role & travel, accommodations, expenses; MSD Italy: Other: advisory role; Medac: Other: travel, accommodations, expenses; Jazz: Other: travel, accommodations, expenses. Musto:Amgen: Honoraria; BMS: Honoraria; Takeda: Honoraria; Janssen: Honoraria; Celgene: Honoraria. Cavo:GlaxoSmithKline: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Ballanti:BMS: Honoraria; Amgen: Honoraria; Janssen: Honoraria; Celgene: Honoraria. Hajek:Takeda: Consultancy, Honoraria, Research Funding; Bristol Myers Squibb: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Novartis: Research Funding. Offidani:Amgen: Honoraria, Other: Advisory Board; Takeda: Honoraria, Other: Advisory Board; Janssen: Honoraria, Other: Advisory Board; Celgene: Honoraria, Other: Advisory Board; Bristol-Myers Squibb: Honoraria, Other: Advisory Board. Corradini:Gilead: Honoraria, Other: Advisory Board & Lecturer; Amgen: Honoraria, Other: Advisory Board & Lecturer; Takeda: Honoraria, Other: Advisory Board & Lecturer; Celgene: Honoraria, Other: Advisory Board & Lecturer; Roche: Honoraria, Other: Advisory Board & Lecturer; Sanofi: Honoraria, Other: Advisory Board & Lecturer; Sandoz: Other: Advisory Board; Novartis: Honoraria, Other: Advisory Board & Lecturer; Abbvie: Honoraria, Other: Advisory Board & Lecturer; Janssen: Honoraria, Other: Lecturer. Boccadoro:Janssen: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; AbbVie: Honoraria; Bristol-Myers Squibb: Honoraria, Research Funding; Mundipharma: Research Funding; Amgen: Honoraria, Research Funding; Sanofi: Honoraria, Research Funding; Celgene: Honoraria, Research Funding.

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.

Background: Survival rates of multiple myeloma (MM) patients (pts) has improved over the past few years, but patients inevitably relapse and become more resistant to subsequent treatments. Carfilzomib and Pomalidomide were both approved for the treatment of relapsed/refractory MM (RRMM). Combinations including a proteasome inhibitor (PI) plus an immunomodulator (IMiD), such as Bortezomib-Lenalidomide-Dexamethasone (VRD) or Carfilzomib-Lenalidomide-Dexamethasone (CRD), showed a very high response rate with an acceptable toxicity. Moreover, in the CHAMPION1 study (Berenson et al Blood 2016), the weekly infusion of Carfilzomib showed to be as effective as the twice schedule. In this phase I/II study we assessed for the first time weekly Carfilzomib plus Pomalidomide and low dose Dexamethasone (wKPd) for the treatment of RRMM. Here we report preliminary results. Methods: the primary objective of the phase I part of the trial was to determine the maximum tolerated dose (MTD) of wKPd combination. The primary objective of the phase II was to determine the rate of partial response (PR). Patients with RRMM, who received 1-3 prior lines of treatments and were refractory to Lenalidomide were eligible. Treatment consisted of 28-day cycles of oral Pomalidomide at fixed dose of 4 mg on days 1-21 (1 week off), oral or intravenous (iv) Dexamethasone 40 mg on days 1,8,15,22 and iv Carfilzomib at escalating doses on days 1,8,15. Escalation started at the dose of 36 mg/m2 (0 level) and used a standard 3+3 schema based on dose-limiting toxicities (DLTs) occurring in cycle 1. Treatment was continued until relapse or intolerance. Results: A total of 57 patients were enrolled in 6 Italian centers. Fifty-two patients could be evaluated for this analysis (5 patients did not complete the first cycle yet). The median age was 62 years with a median time from diagnosis of 4 years. 17/39 (44%) of patients were considered high risk according to cytogenetic abnormalities [at least one among t (4;14) t (14;16) and deletion chromosome 17 (del17) detected by FISH]. In the phase I of the trial 15 patients were enrolled. The first 3 patients at the dose level 0 of Carfilzomib did not experience any DLT. In the next cohort with Carfilzomib 20/45 mg/m2 a G3 hypertension and a sudden death occurred. According to the protocol, 3 more patients were enrolled at dose level 0: 1 patient experienced G3 atrial fibrillation, 2 patients ≥ G3 hypertension. Considering the serious adverse events (SAEs) occurred, the trial was temporary stopped to evaluate the benefit of continuing the study. All the DLTs were cardiologic and occurred in patients with a prior history of cardiac disease. As per protocol, they were evaluated with ECG and echocardiogram before the enrolment and were considered eligible for the study. The safety committee established new procedures for the evaluation of cardiac function of potentially eligible patients, including 24 h continuing pressure monitoring before the enrolment and serial measurement of blood pressure during and after Carfilzomib infusions. Six more patients were enrolled at dose level -1 (Carfilzomib 20/27 mg/m2) and none experienced a DLT. The MTD was established at dose level -1 with Carfilzomib 20/27 mg/m2, Pomalidomide 4 mg and Dexamethasone 40 mg. In the phase II portion of the trial, 42 patients were enrolled. Considering both phase I and II portions of the study, the most frequent drug related, grade ≥ 3 AEs were hematologic (65% of neutropenia and 13% of thrombocytopenia) and cardiologic (17%, mainly hypertension). We recorded only 4% of infection and ≥ G3 peripheral neuropathy. The overall response rate (ORR) of phase I/II portions was 58% (30/52) including 25% (13/52) of ≥ very good partial remission (VGPR). The ORR of high risk patients was 44% (7/16) including 19% (3/16) of ≥ VGPR. With a median follow-up of 10 months, median progression free survival (PFS) was 9.5 months and the median overall survival was not reached. Conclusions: This is the first phase I/II trial that combined weekly Carfilzomib with Pomalidomide and Dexamethasone. This combination was highly effective in RRMM. After a median follow-up of 10 months, wKRd showed a double median PFS in comparison with Pomalidomide-low dose dexamethasone (Sanmiguel et al Lancet Oncology 2013): 9.5 vs 4 months respectively, confirming the efficacy of combining a PI with an IMiD. An updated analysis will be presented at the meeting. Disclosures Bringhen: BMS: Honoraria; Celgene: Honoraria; Janssen-Cilag: Honoraria; Amgen: Other: ADVISORY BOARD; Mundipharma: Other: ADVISORY BOARD; Karyopharm: Other: ADVISORY BOARD. Larocca:Celgene: Honoraria; Janssen-Cilag: Honoraria; Bristol-Myers Squibb: Honoraria; Amgen: Honoraria. Gaidano:Karyopharm: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Speakers Bureau; Gilead: Consultancy, Honoraria, Speakers Bureau; Morphosys: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Speakers Bureau; Roche: Consultancy, Honoraria, Speakers Bureau. Oliva:Amgen: Honoraria; Celgene: Honoraria; Takeda: Honoraria. Sonneveld:Amgen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding. Palumbo:Janssen Cilag: Honoraria; Takeda: Employment, Honoraria. Boccadoro:Janssen: Honoraria, Research Funding; BMS: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Abbivie: Honoraria; Mundipharma: Research Funding; SANOFI: Honoraria, Research Funding; CELGENE: Honoraria, Research Funding.

Background Graft versus host disease (GVHD) is a common complication of allogeneic stem cell transplantation (allo-SCT), and represents its major cause of morbidity and mortality. Some “classical” patient-, donor- and transplant characteristics, such as age, gender disparity, donor type, HLA-match, and source of stem cells, have been reported as predictors for acute and chronic GVHD. However, no studies analysed these “classical” variables together with parameters of metabolic and endocrine functions, which may potentially influence the immune system. Thus, patient-and transplant variables together with index of liver and thyroid function, and some parameters of protein and lipid metabolism were retrospectively evaluated at different time points after transplantation, in order to identify possible predictors of acute and chronic GVHD and to calculate a risk score. Methods Clinical and transplant characteristics, number and type of infections before and after SCT were analysed in 161 patients. The following variables were also analysed pre-SCT, at day +7,+14,+21,+28, at + 3 and +6 months: LDH, parameters of liver function; parameters of protein and lipid metabolism (serum albumin, urea, total protein, cholesterol, triglycerides); thyroid function tests; autoimmune parameters (anti-nuclear, anti-DNA, anti-cardiolipin antibodies); body mass index. A 2-step multivariate analysis was performed using principal component analysis (PCA) and Cox regression analysis, in order to solve the problem of the high number of variables (metabolic, patients- and transplant related) in comparison with the relatively limited and heterogeneous pool of patients. Based on the regression coefficient of Cox analysis for each significant predictor, a scoring system for acute and chronic GVHD was calculated. Results In multivariate analysis, diagnosis of Myelodisplastic Syndrome or Chronic Myeloid Leukemia (HR 4,9; p=0.0004), conditioning regimen including Total Body Irradiation (HR 3,3; p=0.0003), and pre transplantation urea > 34 mg/dl with +21 day urea > 54 mg/dl (HR 2,6; p=0.0008) were evidenced as predictors for acute GVHD. Score values for each factor are 2, 1, and 1, respectively. Hence, the score, obtained by the sum of the three score values, ranged from 0 to 4. The probability of acute GVHD ranged from 8% (score 0) to 98% (score 4). Female donor (HR 5,1; p=0.0008), pre-SCT TSH values ≥ 2 mU/L with +28 day urea ≥ 39 mg/dl (HR 3,3; p=0.02), +6 month total protein < 5,5 g/dl with gamma-GT ≥ 347 U/L (HR 7,8, p=0.0001) resulted predictors for moderate/severe chronic GVHD, with score values of 1, 1, and 2 respectively. Risk of chronic GVHD at +6,5 month ranged from 3% (score 0) to 97% (score 4). Discussion Our study evidenced that factors other than “classical” ones may be associated to GVHD. Our scoring system includes routine-parameters (urea, total protein, gamma-GT,TSH), which are easily available in clinical practice. Urea levels depend on the balance between protein intake, endogenous catabolism and urinary excretion. The inflammatory microenvironment of GVHD promotes muscle catabolism, hence, urea levels do increase. Increased urea levels could be an indirect index of increased uremic toxins as well, which may stimulate the production of pro-inflammatory cytokines and the activation of leukocytes. On the other hand, increased urea levels and uremic toxins could derive from a dysregulated metabolism of the gut microbiome, which may influence immune system. Our findings, which require a prospective validation, suggest the usefulness a deeper study of the complex network between metabolic/endocrine functions and immune system, in order to develop a holistic approach of the transplant management. Disclosures No relevant conflicts of interest to declare.

8011 Background: MRD detection is a sensitive tool to measure response in MM. We assessed MRD by MFC in newly diagnosed MM patients (pts) enrolled in the EMN02/HO95 phase 3 trial. Methods: Pts were ≤65 years old and received Bortezomib-Cyclophosphamide-Dexamethasone (VCD) induction, intensification with Bortezomib-Melphalan-Prednisone (VMP) vs High-Dose-Melphalan (HDM) followed by stem cell transplant, consolidation with Bortezomib-Lenalidomide-Dexamethasone (VRD) vs no consolidation, and Lenalidomide maintenance. MRD analysis was performed in pts achieving at least a very good partial response (VGPR) before starting maintenance (after HDM, VMP or VRD) and during maintenance every 6-12 months; samples were centralized to 3 European labs. MFC was performed on bone marrow according to Euroflow-based methods (8 colors, 2 tubes) with a sensitivity of 10-5. Quality checks were performed to compare sensitivity and to show correlation between protocols (Hofste op Bruinink D ASH 2016 abstract 2072). Results: 316 pts were evaluable before maintenance: median age was 57 years, 18% (57/316) pts had ISS III and 22% (70/316) had high risk cytogenetic (HR-C) defined as having at least one among del17, t(4;14) or t(14;16); 63% (199/316) had received HDM and 37% (117/316) VMP; thereafter 51% (160/316) had received VRD. 76% (239/316) were MRD negative (MRD-) of whom 64% (153/239) received HDM vs 36% (86/239) VMP, with a median follow-up time of 30 months from MRD enrolment. 3-year PFS was 50% in MRD positive (MRD+) vs 77% in MRD- pts (HR: 2.87, p < 0.001). Subgroup analyses were performed to evaluate the risk factors for MRD+ according to baseline characteristics and therapies: HR-C was the most important risk factor (HR 9.87, interaction-p = 0.001). Finally, 48% of MRD+ pts at pre-maintenance who had a second MRD evaluation after at least 1 year of lenalidomide became MRD-. Conclusions: MRD by MFC is a strong prognostic factor in MM pts receiving intensification with novel agents or transplant; lenalidomide maintenance further improved depth of response; HR-C is the most important prognostic factor in MRD+ pts. Clinical trial information: NCT01208766.

Background: Although a complete remission (CR) can be achieved in 70-80% of newly diagnosed acute myeloid leukemia (AML) patients, relapses occur in up to the 50% of cases. Thus, minimal residual disease (MRD) monitoring is a major issue for early detection of patients at high-risk of treatment failure and relapse. Aim: to dynamically evaluate WT1 pan-leukemic molecular marker of MRD in patients with AML. Matherial and methods: 107 newly diagnosed AML patients consecutively treated between 2010 and 2013 were monitored with quantitative WT-1 from bone marrow (BM) and peripheral blood (PB) at baseline, after induction, after the first consolidation course, before allogeneic stem cell transplantation (allo-SCT), at the 3rd and the 6th month after transplantation Results: At diagnosis, 104/107 (97%) had increased PB and BM WT1 levels assessed according to the ELN assay. Eighty-eight out of 107 patients (82%) achieved a complete remission (CR) after induction, 30/88 (34%) relapsed during follow up and 24/107 (22%) were addressed to allogeneic stem cell transplantation (allo-SCT). By univariate analysis, PB-WT > 50x10^4/ABL and BM-WT1 > 250x10^4/ABL after induction (PB: p=0.02; BM: p=0.04), after consolidation (PB: p=0.003), at the end of treatment (PB and BM: p=0.001), at 3rd month of follow up (PB and BM: p=0.005) and at 6th month of follow up (PB: p=0.005) were associated with a reduced overall survival (OS). By multivariate analysis, a BM-WT1 > 250 x 10^4/ABL at the end of treatment was significantly associated with a reduced OS. In order to adapt the cut-off of WT1 in our series of patients, we considered WT1 levels as continuous variables and categorized them at approximately the 25th, 50th, and 75th percentile. A cut-off of PB-WT1 > 25x10^4/ABL and BM-WT1 > 125x10^4/ABL at the end of the treatment program was identified as correlated with reduced leukemia-free survival (LFS) and OS (p=0.001). Similarly, and restricting the analysis on the 24 patients allo-transplanted in CR, 8/11 (73%) with pre-transplant PB-WT1 ≥ 5 and 4/13 (31%) with PB-WT1 < 5 relapsed, respectively (p=0.04). The incidence of relapse was higher in AML patients with PB-WT1 ≥ 5 measured at 3rd (56% vs 38%; p=0.43) and 6th month (71% vs 20%; p=0.03) after allo-SCT. Interestingly, 5/5 (100%) patients with pre-transplant PB-WT1 ≥ 5 who never reduced this level at 3rd or 6th month after allo-SCT experienced a disease recurrence. Conclusions: our data, although retrospectively collected, show that WT1 monitoring may be useful to predict the relapse in AML patients. Acknowledgments: This work was supported in part by Banca di Credito Cooperativo di Pompiano e Franciacorta and Lions Club Bassa Bresciana Association. Disclosures Russo: Celgene: Research Funding; Gilead: Research Funding; Novartis: Consultancy.

Introduction. Allogeneic haematopoietic stem cell transplantation (HSCT) is a potentially curative option for several haematological diseases. Its efficacy relies primarily on the Graft-versus-tumor (GVT) effect, which is promoted by donor immune cells. However, GVT partially overlaps with Graft versus Host disease (GvHD), the most common cause of morbidity and mortality in HSCT, since they may share immune effector cells and antigen targets, such as minor histocompatibility antigens. The development of a functional immune system is one of the main factors influencing the clinical outcome of HSCT. Immune deficiency as well as the effect of GVT/GvHD imbalance can expose patients to a high risk of opportunistic infections and disease relapse. Many studies analyzed immune reconstitution after HSCT both retrospectively and prospectively. However, immune parameters that univocally associate with GVHD or GVT have not been identified yet. In this study, lymphocyte subsets together with index of thymic and bone marrow output were evaluated at different time points, in order to identify possible indicators/predictors of GVHD and ineffective GVT. Methods. Prospective evaluations of immune reconstitution were performed in 37 patients before SCT, at 30, 90, 180 days and 1 year after SCT. CD4+/CD8+ naïve, central memory, effector memory, terminally differentiated effector memory cells, subsets of regulatory T-lymphocytes, immature B cells, naïve, switched and unswitched memory B cells, memory double negative (IgD-CD27-) B cells were analysed by flow cytometry. Analysis of thymic and bone marrow output was performed by detection of T cell receptor excision circles (TRECs) and kappa-deleting recombination circles (KRECs). TRECs and KRECs were simultaneously quantified by a duplex quantitative Real-Time PCR. A 2-step multivariate analysis was performed using principal component analysis (PCA) and Cox regression analysis, to solve the problem of the high number of variables (immunological, patients- and transplant related) in comparison with the relatively limited and heterogeneous pool of patients. Results. Twelve patients developed acute GVHD (median time: 28 days, range 17-120). Chronic GVHD was observed in 8 patients (median time: 6 months, range 4-8). In multivariate analysis, acute GVHD correlated positively with values of regulatory central memory T-cells (HR 1, 24; p=0,0006) and negatively with values of regulatory naïve T-cells (HR 0,52; p=0,006) at day +30. CD4+ effector memory T-cells at day +90 were positively associated with chronic GVHD (HR 1,3; p=0,04). The relapse rate (27%; median time: 5,5 months, range 3-12) was used as clinical index of ineffective GVT. The following cluster of immunological parameters at day +90 correlated positively with relapse: CD8+ effector memory cells, immature B cells, mature, naïve, switched memory B cells, memory double negative (IgD-CD27-) B cells, and KRECs (HR 2,4; p=0,006). Discussion Different clusters of immunological parameters were evidenced as predictors of GVHD and ineffective GVT, allowing a clear-cut distinction between these immunological reactions. The non-univocal association of regulatory T-cells with GVHD may be explained by the relative efficiency of different subsets of regulatory T-cells (naïve>central memory regulatory), as shown in some experimental models. Increased values of CD8+ effector memory cells could be an early sign of ineffective GVL. Imbalance toward a lymphocyte B-response, and especially toward “senescent” memory (IgD-CD27-) B cells, could promote tolerance to tumor cells. The validation of these clusters of immunological parameters as specific early indicators of GVHD or GVT could potentially allow the development of pre-emptive and targeted therapies. Disclosures No relevant conflicts of interest to declare.

To evaluate if WT1 expression may predict relapse after allo-SCT, we analyzed WT1 levels on peripheral blood (PB) and bone marrow (BM) before and after allo-SCT in 24 AML patients with WT1 overexpression at diagnosis. Five copies of WT1/ABL × 104from PB were identified as the threshold value that correlated with relapse after allo-SCT. The same correlation was not identified when WT1 expression was assessed from bone marrow (BM). Eight out of 11 (73%) patients with a pre-allo-SCT PB-WT1 ≥ 5 and 4/13 (31%) patients with a pre-allo-SCT PB-WT1 < 5 relapsed, respectively (P= 0.04). The incidence of relapse was higher in patients with PB-WT1 ≥ 5 measured after allo-SCT, at the 3rd (56% versus 38%;P= 0.43) and at the 6th month (71% versus 20%;P= 0.03). Patients with pretransplant PB-WT1 < 5 had significantly better 2-year OS and LFS than patients with a PB-WT1 ≥ 5 (81% versus 0% and 63% versus 20%) (P= 0.02). Our data suggest the usefulness of WT1 monitoring from PB to predict the relapse in allotransplanted AML patients and to modulate the intensity of conditioning and/or the posttransplant immunosuppression in an attempt to reduce the posttransplant relapse risk.

Introduction: Immunoglobulin light chain amyloidosis (AL) may occur in association with a recognizable plasma cell (PC) clone diagnostic for multiple myeloma (MM) both with CRAB symptoms (AL-CRAB) and without them but with more than 10% marrow PCs (AL-PCMM). Prognosis of AL-CRAB and AL-PCMM was significantly poorer than AL in a large retrospective study by the Mayo Clinic (Kourelis et al, JCO 2013). Treatment with autologous stem cell transplantation (ASCT) improved the 5-y overall survival (OS) rates of all the three entities by approximately 40%. Therefore it is debated if patients with AL should receive more MM-oriented treatment including ASCT and if patients with AL-PCMM or AL-CRAB should receive the same treatment as MM patients. Aims: to contribute to this debate we analysed the outcome of patients with amyloidosis treated at our center according to their underlying disease: AL, AL-PMCC and AL-CRAB. Furthermore, we analysed the outcome according to the use of ASCT as part of first line treatment strategy. Methods: Of 53 patients newly diagnosed between Jan 1999 to June 2016 (median age 62 years), 19 (36%) were affected by AL, whereas 23 (43%) presented with AL-PCMM and 11 (21%) with AL-CRAB. Of 53 patients 18 (34%) underwent first line ASCT (21% of AL patients, 35% of AL-PCMM and 55% of AL-CRAB patients), upfront (6) or following induction chemotherapy (12). The 35 patients (66%) who didn't receive ASCT were treated with CyBorD regimen (21), melphalan-dexamethasone (8), VMP (4) or lenalidomide-dexamethasone (2). Risk groups were identified as follows: cTnI >0.1ng/ml and/or ECOG PS ³3: high risk; age ²65 years with normal cTnI levels, ECOG PS 50ml/min: low risk. Intermediate risk patients were defined if not meeting criteria for high or low risk. Mayo Stage classification (Dispenzieri et al, JCO 2004) was also applied to stratify risk categories. MM diagnosis was made according to IMWG criteria. Haematological and organ response (OR), OS and event free survival (EFS: time to 2nd line therapy or death) were analysed. Results: the proportion of high risk patients was 37%, 44% and 18% in AL, AL-PCMM and AL-CRAB, respectively, whereas the proportion of Mayo stage III patients was 47%, 30% and 9% for each subgroup. Median dFLC was similar (150, 150 and 146, respectively), such as baseline NT-proBNP (1318, 1301 and 1396). No difference was observed in terms of haematologic and organ response between patients with AL only or with concomitant MM: overall response rate (ORR) and complete remission (CR) were 63% and 37% in AL only patients and 88% and 32% if concomitant MM was present, whereas organ response was 47% and 56%, respectively. Similar results were seen among high risk or Mayo Stage III patients between the two subgroups. Haematologic response was similar between patients receiving ASCT in first line treatment and patients who did not: ORR and CR rates were 89% and 44% in the ASCT group and 71% and 29% in the no ASCT group, respectively. However, OR was significantly higher in the ASCT group (83% vs 37%, p 0.0014). Toxicity was manageable in both groups. After a median follow up of 32 months no significant difference was seen overall between AL only and AL with concomitant MM in terms of EFS (65% vs 85% at 2 years, respectively; HR 1,46, 95% CI 0,64-3,35) and OS (71% vs 87% at 2 years, respectively; HR 2,28, 95% CI 0,75-6,95). ASCT significantly improved both EFS and OS, comparing patients receiving or not transplantation (EFS 87% vs 64% at 2 years, p 0,013; HR 0,41, 95% CI 0,21-0,83; OS 100% vs 71% at 2 years, p 0,005; HR 0,23, 95% CI 0,08-0,64, see Figure 1). Of note, in patients achieving OR, similar OS was observed regardless of having received ASCT or not. Our data confirm the survival advantage with ASCT reported by Kourelis et al. The better outcome observed in AL with concomitant MM may be due to the more frequent use of a transplant strategy in first line treatment for AL-MM at our institution. Conclusion: We confirm that selected patients with AL AL-PCMM and AL-CRAB may have a survival advantage when receiving ASCT. These results may be related to the higher OR rates obtained with ASCT and to the improvement in OS in patients achieving OR. As no difference in terms of treatment response were observed between different underlying diseases, our study also supports the use of conventional MM treatment therapies incorporating high doses of melphalan followed by ASCT also for patients with AL Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Introduction and aim of the study: monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) have a distinct risk of evolving towards symptomatic multiple myeloma (MM) but it is widely accepted that they should not be treated until clinical evolution. The clinical presentation of symptomatic MM includes severe complications like acute renal failure, spinal cord compression by vertebral collapse, pathologic bone fractures which cannot be completely avoided even by strict follow-up of MGUS/SMM patients. The recent availability of effective and less toxic therapies has fueled renewed interest in the identification of prognostic models able to predict the risk of impending progression of MGUS/SMM patients to symptomatic MM and criteria for MM defining events have been recently broadened to allow an earlier start of treatment even in asymptomatic patients (Rajkumar SV et al, Lancet Oncol 2014). However, from a clinical perspective it would be more important to prevent the development of severe MM related complications by treating those MGUS/SMM considered at high risk of developing them. To this end, we have analyzed known risk factors for MGUS/SMM progression and other disease biomarkers in order to identify those able to consistently predict an high risk of "severe MM" development. Methods: we retrospectively analyzed 67 patients with symptomatic MM with a known previous history of MGUS/SMM, referred to our division from 1985 to December 2014 (23 males, 44 females; median age at MGUS/MM diagnosis 60 years). Focusing on the first assessment of their asymptomatic disease, we compared patients who subsequently developed severe CRAB criteria (Bladé J et al, Hematol Oncol Clin North Am. 2007), defined as having at least one of the following: hypercalcemia > 11.5mg/dL, creatinine > 4mg/dL, Hb < 8 mg/dL, severe bone lesions characterized by pathological fractures or causing spinal nerve compression, and called "severe MM" with patients who lacked severe CRAB symptoms at MM diagnosis, in order to identify risk factors for "severe MM" during its asymptomatic phase. Variables analyzed for comparison were: involved/uninvolved free light chains (FLC) ratio, monoclonal component (MC) quantification, presence of evolving pattern of MC (defined as an increase in the level of MC of at least 10% in 6 months), presence of immunoparesis, LDH levels, 24h-urinary protein levels, Ig isotype and bone marrow plasma cells percentage. Frequency of follow up was also considered (every 6 months or more). Time to treatment start (TTTS) from MGUS/SMM diagnosis, progression free survival (PFS) from first line treatment and overall survival (OS) were also calculated. Results: median 24-hour urine protein levels were significantly higher in MGUS/SMM patients who subsequently developed "severe MM", compared with patients without severe CRAB symptoms at MM diagnosis (140 vs 90mg/24h, p 0.022, see Figure 1), with an increased risk of severe myeloma related complications for MGUS/SMM patients with more than 200mg/24h urine proteins (Odds Ratio 2.65, p 0.037). Risk was highest in 4 MGUS/SMM patients with 24h-urinary protein levels higher than 1500mg (Odds Ratio 8.43, p 0.030) who invariably developed "severe MM". No difference were found comparing other variables. Of note, there was no difference between the two subgroups in terms of median TTTS (5.3 vs 8.3 years for MGUS patients and 1.7 vs 1.6 years for SMM, respectively), PFS ( 24.4 vs 32.2 months, respectively) and OS (nr vs 4.36), although a higher early mortality was observed in patients with "severe MM" (2 y OS 69% vs 93%). Conclusions: increased 24h-urinary protein levels (> 200mg) in MGUS/SMM patients are associated with a higher risk of the occurrence of severe CRAB symptoms at MM progression. Further data with larger series of patients are needed to better define the best predictive threshold for "severe MM". However, patients with more than 1500mg/24h urinary protein loss represent a small subgroup of MGUS/SMM patients who should better start treatment while still asymptomatic. Figure 1. 24h-urinary protein (mg) levels in the asymptomatic phase Figure 1. 24h-urinary protein (mg) levels in the asymptomatic phase Disclosures No relevant conflicts of interest to declare.

Abstract 4676 Introduction Myeloproliferative diseases (MPDs) are a group of haematological disorders characterized by the hyper proliferation of different blood cells in peripheral blood and other hematopoietic organs. The clinical heterogenity of these neoplasms reflects the different gene pathways involved, most of which are only partially known. Given the genetic homology and the physiological similarity to mammals, zebrafish has emerged as an ideal model to study human normal and malignant haematopoiesis. In the last decade several oncogenes involved in the development of hematopoietic neoplasms have been used to model leukemia in zebrafish with the aim to discovery new molecular pathways involved in malignant transformation. Despite the first encouraging results these experimental models failed to fully recapitulate human myeloproliferative disorders. Methods We took advantage of the Gal4/UAS binary system to induce the expression of human oncogenic HRASV12G in the zebrafish hematopoietic compartment. We used a specific transgenic line that drives oncogene expression in zebrafish early hematopoietic progenitors under control of the FLI.1 (Friend Leukemia virus Integration 1) promoter. Results We observed the development of a myelo-erythroid proliferative disease in few days in zebrafish transgenic larva. The pathological phenotype is characterized by the expansion of the hematopoietic tissue, an increased expression of myelo-erythroid specific genes (PU.1, gata1, mpx, c-mpl) associated with a slight increase of staminality markers (lmo2, scl, c-myb, runx.1), and a higher number of l-plastin expressing cells. Moreover blood smear of pathological larva displayed leukemic blasts and the arrest of erythrocyte differentiation whereas kidney marrow of juvenile fish displayed abnormal myelopoiesis characterized by the increase of erythro-myeloid progenitors. We found that the pathological phenotype is associated with a down regulation of the Notch pathway as shown by the decreased gene expression of notch pathways target genes (notch1, notch3, her6). Furthermore we discovered a novel set of genes involved in neoplastic transformation induced by HRASV12 expression through RNA-Seq analysis of pathological larva. Conclusions The expansion of the zebrafish hematopoietic compartment characterized by the hyper-proliferation of the myelo-erythroid progenitors that we found in this model reproduces some of the pathological features of human myeloproliferative disorders. This study showed that forcing oncogene expression in the hemogenic endothelial cells induces the transdifferentiation of the early hemogenic pluripotent stem cells into abnormal myeloerythoid progenitors by repressing the Notch pathways. Transcriptome analysis identified a number of potential effectors of this transformation. Disclosures: No relevant conflicts of interest to declare.

Abstract 4711 Background: Myeloproliferative diseases (MPDs) are a group of hematological malignancies characterized by the abnormal increase of different blood cells in peripheral blood and in other hematological organs. The molecular pathways involved in disease pathogenesis and progression as well as in drug sensitivity and resistance are not fully elucidated yet. Given the physiological similarity to mammals, the zebrafish (ZF) could accelerate the study of the molecular basis of these diseases. In the last decade several human leukaemia associated oncogenes have been transiently over-expressed in ZF embryos in order to perturb the myelo-erythroid compartment, with the aim to create experimental models to discover new molecular pathways that can became potential targets for new chemical compounds. Methodogy: We took advantage of the binary Gal4/UAS system to express oncogenic human HRAS in the ZF hematopoietic compartment. We used the tg(MAZe) driver line, a specific transgenic line that allows random mosaic expression of Gal4-VP16 after heat shock(hs) treatment(1). This driver line was mated with a tg(UAS:eGFP-HRASV12)(2) responder line in order to mimic somatic events leading to human oncogene expression. Results: Surprisingly a single heat shock at 30hpf, (referred here as HRASV12hs) induces human HRASV12 expression in hematopoietic progenitors as judged by the expansion of the hematopoietic tissue. Histological analysis showed an increased number of monocytes/macrophages. Blood smear of HRASV12hs larvae showed the expansion of blasts and myeloid precursors. Quantitative analysis of gene expression highlights a remarkable increase of myelo-erythroid restricted genes associated with a slight increase of staminality markers (pu1, mpx, lmo2, mpl, CD41 and c-myb). Moreover fish raised to adulthood developed hyper-plastic kidney marrow, the site of definitive haematopoiesis, the equivalent of mammalian bone marrow. Conclusions and Future Perspectives: The combination of hyper-proliferation of blood cells associated with the expansion of the hematopoietic compartment that we found in this model reproduces the pathological features of human myeloproliferative disorders. This study shows that it is possible to drive the expression of leukemia associated oncogenes to the hematopoietic compartment in developing ZF thus reproducing some of the features of human blood malignancies in an in vivo model. Our Group is now testing different driver lines in order to induce oncogene expression in earliest hematopoietic progenitors and is focusing on different responder lines expressing human oncogenes involved in hematopoietic malignancies. Disclosures: No relevant conflicts of interest to declare.