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Background : Datas from China suggest that patients with cancer have more severe outcome in case of covid-19 infection. Patients with haematological disease have often immunosuppression, due to the underlying disease and to their treatment. Methods: We recorded the consecutive patients usually treated in our haematology department diagnosed with COVID-19 infection between March 10th to April 30th. To evaluate the impact of the pandemic, we compare the activity of our department during two twenty working-days periods: March 20th to April 17th (“Covid month”) and February 18th to March 16th 2020 (“Covid-free month”). Results: Fifty patients treated in our haematology department had a COVID-19 infection, diagnosed with PCR or CT-scanner. Half of them were still on chemotherapy treatment, 30% were on survey after treatment and 20% were on a “watch and wait” strategy. Sixteen patients ( 30%) evolved to an acute respiratory syndrome with a fatal outcome in ten cases. (20%). The severity of the disease prompted us to change the organization of our department to protect our patients. We followed international recommendation and delayed non urgent procedure. this allowed a reduction of 10% of our activity. Moreover, we managed to treat 25% of our patients coming usually in outpatient clinic with tele-health. Thanks to hospital-at-home, these patients could receive their treatment and stay safe at home. Conclusion: This retrospective study give an insight of how covid-19 outbreak will change cancer care.

Background Optimal dosing of antibiotics is critical in immunocompromised patients suspected to have an infection. Data on pharmacokinetics (PK) of meropenem in patients with haematological malignancies are scarce. Objectives To optimize dosing regimens, we aimed to develop a PK population model for meropenem in this population. Methods Patients aged ≥18 years, hospitalized in the haematology department of our 1500 bed university hospital for a malignant haematological disease and who had received at least one dose of meropenem were eligible. Meropenem was quantified by HPLC. PK were described using a non-linear mixed-effect model and external validation performed on a distinct database. Monte Carlo simulations estimated the PTA, depending on renal function, duration of infusion and MIC. Target for free trough concentration was set at >4× MIC. Results Overall, 88 patients (181 samples) were included, 66 patients (75%) were in aplasia and median Modification of Diet in Renal Disease (MDRD) CLCR was 117 mL/min/1.73 m2 (range: 35–359). Initial meropenem dosing regimen ranged from 1 g q8h to 2 g q8h over 30 to 60 min. A one-compartment model with first-order elimination adequately described the data. Only MDRD CLCR was found to be significantly associated with CL. Only continuous infusion achieved a PTA of 100% whatever the MIC and MDRD CLCR. Short duration of infusion ( Conclusions In patients with malignant haematological diseases, meropenem should be administered at high dose (6 g/day) and on continuous infusion to reach acceptable trough concentrations.

Myelodysplastic syndromes (MDS) and MDS/myeloproliferative neoplasms (MDS/MPN) can be associated with giant cell arteritis (GCA). In this nationwide study by the "French Network of dysimmune disorders associated with hemopathies" (MINHEMON) the objective was to evaluate characteristics, treatment and outcome of GCA MDS-MDS/MPN.Retrospective analysis of patients that presented a MDS or MDS/MPN associated with GCA. Treatment efficiency, relapse-free and overall survival of GCA MDS-MDS/MPN were compared to GCA alone.Twenty-one patients with GCA MDS-MDS/MPN were included with median age 76 [42-92], M/F ratio 2.5, 8 MDS with multilineage dysplasia (38%), 4 chronic myelomonocytic leukemia (19%), at low or intermediate risk according to IPPS and IPSS-R. The prevalence of headaches, jaw claudication and anterior ischemic optic neuropathy was significantly lower in patients with GCA MDS-MDS/MPN compared to idiopathic GCA (14.3%, 0% and 0% versus 30%, 25%, and 25%, respectively; p .05). Other clinical and histology findings were similar. All GCA patients received steroid therapy as first-line treatment. Complete or partial response was observed in 14 GCA MDS-MDS/MPN patients (66.7%), of whom 6 (28.6%) received combined immunosuppressive therapies (versus 10% of idiopathic GCA; p = .07). Relapse incidence was similar in the two groups. Steroid dependence was more frequent among GCA MDS-MDS/MPN patients (12 (57%) versus 18 (22.5%); p .05). Relapse-free and steroid-free survivals were significantly decreased in GCA MDS-MDS/MPN patients (log rank 0.002 and 0.049 respectively), but not overall survival.Characteristics of GCA MDS-MDS/MPN seem different than idiopathic GCA, with a distinct clinical phenotype and poorer outcome with a higher risk of steroid dependence and relapse.

International audience; Background: Multiparametric flow cytometry (MFC) was recently reported to be a helpful additional tool in the diagnosis of myelodysplastic syndromes (MDS). However, numerous aberrancies have been reported that makes their evaluation difficult as part of a routine diagnosis. Methods: Here, we validated a 1-tube panel for the evaluation of granulocytic and monocytic maturation by MFC and correlated our findings with diagnosis and prognosis of MDS. A total of 251 samples with MDS suspicion were prospectively analyzed and compared to an internal reference database leading to the calculation of the Diff score. Results: The associated specificity and sensitivity values of this scoring system were 92.1% and 60.4% in a first learning cohort and 96.7% and 65.2% in a second independent validation cohort. The combination of the Diff score with the concomitantly calculated Ogata score increased the sensitivity to 74.2% and 78.3% in the learning and validation cohorts, respectively. Finally, a normal Diff score in MDS patients was associated with a significant prolonged progression-free survival. Conclusions: Taken together, the present data indicate that our strategy is a sensitive and specific MFC tool for the diagnosis of MDS-related cytopenia(s) which could be also useful for predicting evolution of these diseases.

Recent years have witnessed a dramatic improvement in multiple myeloma (MM) patient care with a current median life expectancy of 6 to 10 years dependent on age. High-dose melphalan followed by aut...

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for an ongoing global pandemic. Phase III trials have demonstrated excellent efficacies of mRNA vaccines against SARS-CoV-2 in large population studies (Baden LR, NEJM, 2021; Polack FP, NEJM, 2020). Immunosuppressed individuals such as chronic lymphocytic leukemia (CLL) patients are at risk for a suboptimal response to 2 vaccine doses (Herishanu Y, Blood, 2021). The French National Authority for Health recommends the use of a third dose in immunosuppressed patients. However, seroconversion rate after the triple-dose vaccine is not yet known. The objective of our study was to evaluate SARS-CoV-2 antibody responses after the first, second and third doses of the BNT162b2 and mRNA-1273 vaccines. Data were collected from 17 French Innovative Leukemia Organization (FILO) investigating centers and the French CLL patients' association (SILLC). SARS-CoV-2 IgG anti-Spike levels were measured at 4-6 weeks after each vaccine dose. A total of 530 patients and 14 controls were included in the study. Vaccine response was evaluated post-dose 1 for 158 CLL patients, post-dose 2, for 506 patients and post-dose 3 for 66 patients. Peripheral blood lymphocyte subsets were studied post-dose 2 by flow cytometry in 80 CLL patients and 14 controls. The median age of the patients was 71 years (range 37-93), 218 (40%) were treatment-naïve (TN), 136 (26%) had a prior CLL treatment and 176 (34%) were on therapy. Post-dose 1, the global response rate was 27% (43/158). TN patients had a response rate of 34% (23/67), similar to those who had a prior CLL treatment (33%,12/36), and higher compared to on-therapy patients (15%, 8/55, P=0.02). Post-dose 2, the global response rate was 52% (265/506). TN patients had the highest response rate of 72% (151/210) compared to previously treated patients, mostly by immunochemotherapy (60%, 78/130, P=0.02) and on-therapy patients (22%, 36/166, P65 years (OR 0.55, 95% CI 0.33-0.92, P=0.02), ongoing CLL treatment (OR 0.13, 95% CI 0.07-0.23, P Flow cytometry results suggest a differential balance of the T CD4+ cell subpopulations in Binet stage A and in patients on targeted therapy compared to healthy controls. Post-dose 2 seronegative patients were proposed a third dose and to date, 66 have been tested for the antibody response 4-6 weeks post-dose 3. The post-dose 3 response rate was 42% (28/66). TN patients and previously treated patients had a significantly higher response rate (57%, 16/28) compared to on-therapy patients (32%, 12/38, P=0.03). We further analyzed patients tested post-dose 2 with the Abbott Architect SARS-CoV-2 IgG anti-Spike assay (n=24). Those who achieved seroconversion after the third dose (n=10) had significantly higher titers post-dose 2 (median 12, IQR 3.0-40.8) compared to those who remained seronegative (n=14) (median 2.2, IQR 0.5-5.1, p An additional cohort of 40 CLL patients who presented a SARS-CoV-2 infection prior to vaccination participated to the study and was analyzed independently. All patients achieved seroconversion after infection and a single dose of vaccine, even though 30% (n=12) had an ongoing CLL treatment. In conclusion, double-dose mRNA vaccination generated a humoral response in 52% of our CLL cohort and a third dose induced seroconversion in 42% of the patients who remained seronegative after the second dose. The major independent predictor of negative antibody response was ongoing treatment with BTKi. The strongest boost to immune response against the virus seems to be SARS-CoV-2 infection, as a substantial increase in anti-Spike antibodies was observed in all CLL patients with prior infection, after a single dose vaccination. Figure 1 Figure 1. Disclosures Letestu: Janssen: Research Funding, Speakers Bureau; Roche: Speakers Bureau; AbbVie: Research Funding, Speakers Bureau. Dartigeas: Astra-Zeneca: Membership on an entity's Board of Directors or advisory committees, Other: travel grants/Congress; Abbvie: Membership on an entity's Board of Directors or advisory committees, Other: travel grants/Congress; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: travel grants/Congress. Laribi: Astellas Phama, Inc.: Other: Personal Fees; BeiGene: Other: Personal Fees; AstraZeneca: Other: Personal Fees; IQONE: Other: Personal Fees; AbbVie: Other: Personal Fees, Research Funding; Takeda: Other: Personal Fees, Research Funding; Novartis: Other: Personal Fees, Research Funding; Le Mans Hospital: Research Funding; Jansen: Research Funding. Cymbalista: Lilly-LOXO: 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; ASTRA ZENECA: 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; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Introduction: TP53 gene mutations (m TP53), found in up to 20% of MDS or AML pts and 30-40% of therapy-related (TR) MDS/AML cases, represent a distinct molecular cohort with poor outcomes. Hypomethylating agents (HMA) are the frontline standard of care, with CR rates of ~20% and median OS of < 12 months. APR-246 is a novel, first-in-class small molecule that reactivates the mutant p53 protein and targets cellular redox balance, ultimately inducing apoptosis and ferroptosis in m TP53 cancer cells. We previously reported the Phase 2 results of 2 parallel trials of APR-246+AZA (Sallman et al and Cluzeau et al., JCO 2021). We now report analyses of the combined Phase 2 cohorts and long-term follow-up. Methods: This is a multicenter, international collaboration of the US MDS clinical research consortium and the GFM of HMA-naïve m TP53 higher-risk MDS, MDS/MPN and oligoblastic AML (≤ 30% blasts) pts (NCT03072043/NCT03588078). Pts received APR-246 4500mg IV (days 1-4) + AZA 75 mg/m 2 SC/IV x 7 days (days 4-10 or 4-5 and 8-12) in 28-day cycles. Primary objective was CR rate by International Working Group (IWG) 2006 criteria. Secondary objectives included ORR, OS, outcome following allogeneic hematopoietic stem cell transplant (allo-HSCT), with serial high depth next generation sequencing (NGS, 0.1% cutoff) for evaluation of measurable residual disease (MRD). Results: As of July 15, 2021, 100 pts had been enrolled with a median age of 68 years (range, 34-87; 47% male). By WHO, 74 pts had MDS, 22 AML-MRC and 4 CMML/MDS-MPN; 83% complex karyotype (CK) and 88% were CK and/or biallelic for TP53 mutations; 92% had a TP53 missense mutation in the DNA binding domain. In 63 pts, TP53 was the only mutation detected (i.e. isolated m TP53). Median time on treatment was 6 cycles (1-25+) with 5 pts ongoing and 23 pts who proceeded to allo-HSCT. Non-hematologic treatment (Tx)-related adverse events (AEs) in ≥20% of pts included nausea/vomiting (58%), ataxia (26%), and dizziness (23%). Neurologic AEs were reversible in 100% of cases. Febrile neutropenia occurred in 37% of pts. Thirty and 60-day mortality was 1% (n=1) and 7% (n=7), respectively. Dose reductions of APR-246 and AZA occurred in 16% and 1% of pts, respectively, with only 1 treatment discontinuation due to a treatment-related AE. By intention-to-treat (ITT) analysis, ORR by IWG was 69% with 43 CR, 1 PR, 10 marrow CR (mCR)+HI, 9 HI alone, and 6 with mCR. Of non-responders, 6 had stable disease and 7 pts had progressive disease. The median duration of CR/PR was 10.6 months (95% CI 8.8-12.3, 23+ months ongoing). CR/PR rate for MDS was 49% (36/74), 36% for AML (8/22) and 0% for MDS/MPN (0/4) with an ORR rate of 70%/64%/75%, respectively. Isolated m TP53 was predictive for a higher CR rate (52% vs 30%; P=.04). Patients who had biallelic TP53 or CK had a significantly higher CR rate vs pts without (49% vs 8%; P=0.01). On serial TP53 NGS using a VAF cutoff of 5%, 40 pts achieved NGS negativity with 6 pts MRD negative (VAF < 0.1%). Of NGS negative pts (TP53 VAF At data-cutoff by ITT analysis with a median follow up of 27.8 months, median OS was 11.8 months (95% CI 9.4-14.3). Pts undergoing allo-HSCT had a median OS of 16.1 months (95% CI 14-18.1). Impact of response and NGS clearance was evaluated by landmark analysis at 6 months. Pts achieving CR/PR or NGS negativity had improved OS (15.8 vs 10.1 months; P=0.002; Fig 1A). Additionally, pts who became MRD negative had a 2-year OS of 50% vs 23% (P=0.21). Although allo-HSCT was not predictive of OS in the overall cohort by landmark analysis (14.7 vs 14.4 months; P=0.15; Fig 1B), significant OS improvement was noted in allo-HSCT pts based on CR/PR or NGS negativity (P=0.002; Fig 1C). Notably, pts who achieved CR/PR/NGS negativity and were bridged to allo-HSCT had a median OS that was not reached (95% CI 10.4-NR) vs 9.1 months (95% CI 7.4-NR) in allo-HSCT pts who did not achieve this response (P=0.01). Conclusions: In this international, combined analysis of P2 APR-246+AZA pts, the combination was well-tolerated with high response rates in m TP53 MDS/AML. Quality of response and NGS negativity strongly predicted OS, particularly in the setting of allo-HSCT, validating NGS clearance as a critical biomarker of allo-HSCT outcomes in m TP53 pts. Figure 1 Figure 1. Disclosures Sallman: Intellia: Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kite: Membership on an entity's Board of Directors or advisory committees; Aprea: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees; Magenta: Consultancy; Shattuck Labs: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Syndax: Membership on an entity's Board of Directors or advisory committees; Incyte: Speakers Bureau; Agios: Membership on an entity's Board of Directors or advisory committees. Komrokji: BMS: Honoraria, Speakers Bureau; JAZZ: Honoraria, Speakers Bureau; Abbvie: Honoraria, Speakers Bureau; Novartis: Honoraria; Geron: Honoraria; Acceleron: Honoraria; Agios: Honoraria, Speakers Bureau. DeZern: Taiho: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees. Sebert: BMS: Consultancy; Abbvie: Consultancy. Steensma: Novartis: Current Employment. Roboz: Astellas: Consultancy; Otsuka: Consultancy; Blueprint Medicines: Consultancy; AbbVie: Consultancy; Bayer: Consultancy; Glaxo SmithKline: Consultancy; Celgene: Consultancy; Bristol Myers Squibb: Consultancy; Helsinn: Consultancy; Janssen: Consultancy; Novartis: Consultancy; Jasper Therapeutics: Consultancy; MEI Pharma - IDMC Chair: Consultancy; Janssen: Research Funding; AstraZeneca: Consultancy; Jazz: Consultancy; Amgen: Consultancy; Daiichi Sankyo: Consultancy; Mesoblast: Consultancy; Agios: Consultancy; Pfizer: Consultancy; Astex: Consultancy; Actinium: Consultancy; Roche/Genentech: Consultancy. Sekeres: BMS: Membership on an entity's Board of Directors or advisory committees; Takeda/Millenium: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Sweet: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; AROG: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Bristol Meyers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees. Kuykendall: Incyte: Consultancy; Novartis: Honoraria, Speakers Bureau; Prelude: Research Funding; PharmaEssentia: Honoraria; CTI Biopharma: Honoraria; Celgene/BMS: Honoraria, Speakers Bureau; BluePrint Medicines: Honoraria, Speakers Bureau; Abbvie: Honoraria; Protagonist: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Recher: Agios: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS/Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astellas: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Honoraria; Janssen: Honoraria; Jazz: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; MaatPharma: Research Funding; Macrogenics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Raffoux: ASTELLAS: Consultancy; ABBVIE: Consultancy; PFIZER: Consultancy; CELGENE/BMS: Consultancy. Padron: Incyte: Research Funding; BMS: Research Funding; Blueprint: Honoraria; Kura: Research Funding; Taiho: Honoraria; Stemline: Honoraria. Attar: Aprea Therapeutics: Current Employment, Current equity holder in publicly-traded company. Kantarjian: Amgen: Honoraria, Research Funding; KAHR Medical Ltd: Honoraria; BMS: Research Funding; AbbVie: Honoraria, Research Funding; Ascentage: Research Funding; Pfizer: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Astellas Health: Honoraria; Jazz: Research Funding; Aptitude Health: Honoraria; Astra Zeneca: Honoraria; Ipsen Pharmaceuticals: Honoraria; NOVA Research: Honoraria; Precision Biosciences: Honoraria; Immunogen: Research Funding; Daiichi-Sankyo: Research Funding; Taiho Pharmaceutical Canada: Honoraria. List: Precision BioSciences: Current Employment, Current equity holder in publicly-traded company; Aileron Therapeutics: Consultancy; CTI Biosciences: Consultancy; Halia Therapeutics: Consultancy, Current holder of individual stocks in a privately-held company. Ades: Celgene: Honoraria, Research Funding; Abbvie: Honoraria; Takeda: Honoraria; Novartis: Honoraria; JAZZ: Honoraria. Lancet: BerGenBio: Consultancy; Celgene/BMS: Consultancy; Millenium Pharma/Takeda: Consultancy; Jazz: Consultancy; Astellas: Consultancy; Daiichi Sankyo: Consultancy; ElevateBio Management: Consultancy; Agios: Consultancy; AbbVie: Consultancy. Fenaux: Janssen: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; JAZZ: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Celgene/BMS: Honoraria, Research Funding; Syros Pharmaceuticals: Honoraria.

Although anti-CD38 monoclonal antibodies have improved the prognosis of relapsed/refractory multiple myeloma (RRMM), some patients still experience early relapses with poor outcomes. This present study evaluated the predictive value of FDG PET/CT parameters for RRMM prior to initiating anti-CD38 treatment. We included 38 consecutive RRMM patients who underwent a PET/CT scan treated at our institution at relapse. The median PFS was 12.5 months and the median OS was not reached. 42% of the patients had an initial ISS score of 1, 37% of 2, and 21% of 3. The presence of &gt, 3 focal lesions (FLs, n = 19) and the ISS score were associated with inferior PFS (p = 0.0036 and p = 0.0026) and OS (p = 0.025 and p = 0.0098). Patients with &gt, 3 FLs had a higher initial ISS score (p = 0.028). In multivariable analysis, the ISS score and &gt, 3 FLs were independent prognostic factors for PFS (p = 0.010 and p = 0.025 respectively), and combined they individualized a high-risk group with a median PFS and OS of 3.1 months and 8.5 months respectively vs. not reached for the other patients. The presence of &gt, 3 FLs on PET was predictive of survival outcomes in patients with RRMM treated using CD38 targeted therapy. Combined with the initial ISS, an ultra-high-risk RRMM population can thus be identified.

Mutational analyses performed following acquired ibrutinib resistance have suggested that chronic lymphocytic leukemia (CLL) progression on ibrutinib is linked to mutations in Bruton tyrosine kinase (BTK) and/or phospholipase Cγ2 (PLCG2) genes. Mutational information for patients still on ibrutinib is limited. We report a study aimed to provide a “snapshot” of the prevalence of mutations in a real-life CLL cohort still on ibrutinib after at least 3 years of treatment. Of 204 patients who initiated ibrutinib via an early-access program at 29 French Innovative Leukemia Organization (FILO) centers, 63 (31%) were still on ibrutinib after 3 years and 57 provided a fresh blood sample. Thirty patients had a CLL clone ≥0.5 × 109/L, enabling next-generation sequencing (NGS); BTK and PLCG2 mutations were detected in 57% and 13% of the NGS samples, respectively. After median follow-up of 8.5 months from sample collection, the presence of a BTK mutation was significantly associated with subsequent CLL progression (P = .0005 vs no BTK mutation). Our findings support that mutational analysis should be considered in patients receiving ibrutinib who have residual clonal lymphocytosis, and that clinical trials are needed to evaluate whether patients with a BTK mutation may benefit from an early switch to another treatment.

Mutational analyses performed following acquired ibrutinib resistance have suggested that chronic lymphocytic leukemia (CLL) progression on ibrutinib is linked to mutations in Bruton tyrosine kinase (

Introduction La neuropathie amyloide AL, une cause rare d’atteinte nerveuse peripherique, associe generalement une atteinte distale symetrique et une dysautonomie. Nous rapportons une presentation atypique, essentiellement caracterisee par une plexopathie unilaterale. Observation Une patiente de 74 ans consulte en hematologie pour alteration de l’etat general, polyadenopathie et bicytopenie. L’anamnese revele des paresthesies du territoire C8 gauche depuis 2 ans. L’immunofixation montre un pic monoclonal IgM lambda et la biopsie osteomedullaire pose le diagnostic de maladie de Waldenstrom. La patiente est traitee par alkylant puis anti-CD20, permettant la regression de l’infiltrat medullaire. Au cours de la meme annee apparait neanmoins un deficit moteur des territoires C5 a T1 gauches ainsi qu’une paralysie du nerf III gauche. Les IRM cerebrale et orbitaire sont normales. L’EMG met en evidence une baisse des amplitudes sensitives dans le territoire plexique gauche et des traces neurogenes dans les muscles correspondants. L’IRM du rachis cervical et l’etude du LCR sont normaux. L’IRM des plexi brachiaux revele une atteinte bilaterale, plurisegmentaire et confluente, d’allure inflammatoire. La PET-TDM est normale. La patiente est traitee par immunoglobulines IV. La poursuite de la degradation clinique et neurophysiologique fait pratiquer une biopsie des glandes salivaires, laquelle revele des depots d’amylose AL, et une biopsie du nerf radial, qui confirme le diagnostic de neuropathie amyloide. Discussion La plexopathie est une presentation rare d’atteinte neurologique amyloide, pouvant initialement etre consideree comme une neuropathie inflammatoire. La poursuite de l’aggravation sous immunoglobulines IV doit faire reconsiderer le diagnostic. Une fois le diagnostic de neuropathie amyloide AL etabli, le traitement repose sur la prise en charge de la pathologie hematologique sous-jacente, meme s’il ne permet que rarement la stabilisation clinique. Conclusion La neuropathie amyloide AL est une affection rare, dont la presentation peut s’averer trompeuse. Elle peut etre revelee par une plexopathie monomelique et comporter l’atteinte de paires crâniennes. Conclusion Image 1 : Depots Rouge Congo sur biopsie nerveuse, Dr Maisonobe.

We would like to report a study on solitary plasmacytoma of the bone (SPB) treatment.SPB is a rare plasma cell dyscrasia characterized by a single bone tumor with no evidence of other lesions or mu...

Somatic mutations contribute to the heterogeneous prognosis of chronic myelomonocytic leukemia (CMML). Hypomethylating agents (HMAs) are active in CMML, but analyses of small series failed to identify mutations predicting response or survival. We analyzed a retrospective multi-center cohort of 174 CMML patients treated with a median of 7 cycles of azacitidine (n = 68) or decitabine (n = 106). Sequencing data before treatment initiation were available for all patients, from Sanger (n = 68) or next generation (n = 106) sequencing. Overall response rate (ORR) was 52%, including complete response (CR) in 28 patients (17%). In multivariate analysis, ASXL1 mutations predicted a lower ORR (Odds Ratio [OR] = 0.85, p = 0.037), whereas TET2mut/ASXL1wt genotype predicted a higher CR rate (OR = 1.18, p = 0.011) independently of clinical parameters. With a median follow-up of 36.7 months, overall survival (OS) was 23.0 months. In multivariate analysis, RUNX1mut (Hazard Ratio [HR] = 2.00, p = .011), CBLmut (HR = 1.90, p = 0.03) genotypes and higher WBC (log10(WBC) HR = 2.30, p = .005) independently predicted worse OS while the TET2mut/ASXL1wt predicted better OS (HR = 0.60, p = 0.05). CMML-specific scores CPSS and GFM had limited predictive power. Our results stress the need for robust biomarkers of HMA activity in CMML and for novel treatment strategies in patients with myeloproliferative features and RUNX1 mutations., Highlights • TET2mut/ASXL1wt genotype predicts higher complete response rate and prolonged survival in CMML with hypomethylating agents. • Conversely, RUNX1mut and CBLmut genotypes are associated with poorer outcome, independently of higher leukocyte count. • CPSS and GFM prognostic scores showed modest performance when calculated at initiation of hypomethylating agents. Somatic mutations contribute to the heterogeneous prognosis of chronic myelomonocytic leukemia (CMML). Hypomethylating agents (HMAs) are active in CMML. Response and survival in MDS and AML patients treated with HMAs is difficult to predict. We explore the predictive role of recurrent somatic mutations in a large retrospective cohort of 174 HMA-treated CMMLs. Consistent with MDS studies, we report a higher response rate in TET2mut/ASXL1wt patients. We also identify a CMML-specific molecular pattern (RUNX1mut or CBLmut) associated with shorter survival. Our results can inform treatment decision in CMML, for instance by using HMAs prior to transplant in TET2mut/ASXL1wt patients.

Primary central nervous system lymphoma (PCNSL) is a rare topographic variant of diffuse large B-cell lymphoma (DLBCL). While prognostic scales are useful in clinical trials, no dynamic prognostic marker is available in this disease. We report here the prognostic value of early metabolic response by 18F-FDG PET scanner (PET) in 25 newly diagnosed immunocompetent PCNSL patients. Induction treatment consisted of four cycles of Rituximab, Methotrexate and Temozolamide (RMT). Based on patient's general condition, consolidation by high-dose Etoposide and Aracytine was given to responding patients. Brain MRI and PET were performed at diagnosis, after two and four cycles of RMT, and after treatment completion. Two-year progression-free (PFS) and overall survival (OS) were 62% and 74%, respectively for the whole cohort. Best responses after RMT induction were 18 (72%) complete response (CR)/CR undetermined (CRu), 4 (16%) partial response, 1 (4%) progressive disease and 2 (8%) stable disease. Response evaluation was concordant between MRI and PET at the end of induction therapy. Nineteen patients (76%) had a negative PET2. Predictive positive and negative values of PET2 on end-of-treatment (ETR) CR were 66.67% and 94.74%, respectively. We observed a significant association between PET2 negativity and ETR (p = 0.001) and longer PFS (p = 0.02), while having no impact on OS (p = 0.32). Two years PFS was 72% and 33% for PET2- and PET2+ patients, respectively (p < 0.02). PET2 evaluation may help to early define a subgroup of CR PCNSL patients with a favorable outcome.

Introduction : TP53 mutated (TP53m) MDS and AML have very poor outcome irrespective of the treatment received, including 40% responses (20% CR) with azacitidine (AZA) with short response duration and a median overall survival (OS) of about 8 months (Bejar, Blood 2014). APR-246 is a prodrug spontaneously converted to methylene quinuclidinone (MQ), a Michael acceptor that binds covalently to cysteines in mutant p53, leading to protein reconformation that reactivates its pro apoptotic and cell cycle arrest functions. The combination of AZA and APR 246 showed promising results in a phase Ib study in TP53m MDS (Sallman, ASH 2018). We report interim results of a GFM phase 2 study of AZA+ APR-246 in TP53m MDS and AML, conducted in parallel with a similar US MDS consortium study. Patients and Methods : The study included hypomethylating agent (HMA) naïve and not previously allografted intermediate, high or very high IPSS-R TP53m MDS and AML adult patients. Patients received APR-246 4500 mg IV /d (6 hour infusions) (days 1-4) followed by AZA 75 mg/m²/d (days 4-10) in 28 day cycles. Response (primary endpoint, assessed by IWG 2006 for MDS and ELN criteria for AML) was evaluated after 3 and 6 cycles in the intent to treat (ITT) population, ie all patients who had received any protocol treatment, and in patients who had at least a blood and bone marrow evaluation after cycle 3 (evaluable population). Allo-SCT, when possible, was proposed after 3 to 6 cycles, and treatment with reduced APR 246 and AZA doses could be continued after allo-SCT. Results : 53 patients were enrolled between Sept 2018 and July 2019 in 7 GFM centers, with a median age of 73 years (range 44-87), and M/F: 28/25. 34 patients had MDS (including 74% very high IPSS-R) and 19 had AML. IPSS-R cytogenetic risk was very poor in 30/34 MDS, and unfavorable in 18/19 AML, complex in 89% of the patients. Median baseline mutated TP53 VAF was 21% (range 3-76). Nineteen of the 53 patients had been included at least 7 months before date of analysis (25 July 2019), had received protocol treatment and were thus potentially evaluable for response after 6 treatment cycles (ITT population). One of them died after only one cycle from an unrelated cause (cerebral ischemic stroke), and 2 during the third cycle (from bleeding and sepsis, respectively). In the remaining 16 patients (evaluable population per protocol), the response rate was 75% including 9 (56%) CR, 3 (19%) marrow CR or stable disease with hematological improvement (HI), and 4 treatment resistance. In the ITT population, the response rate was 63%, including 47% CR, and 16% stable or marrow CR+ HI. Among CR patients, complete cytogenetic CR and negative NGS for TP53 mutation (VAF cutoff of 2%) were achieved in 7/9 (78%) and 8/8 (100%), respectively. So far, 1 patient has undergone allo-SCT. All 53 patients had received at least one treatment cycle, and no increased myelosuppression, compared with AZA alone, was apparent. Treatment related AEs observed in ≥ 20% of patients were febrile neutropenia in 19 (36%) and neurological AEs in 21 (40%) of the patients. The latter, reviewed with a neurological team, were mainly grade 1 or 2 and consisted of ataxia (n=13), sometimes associated with cognitive impairment (n=4), suggesting a cerebellar origin. Other patients experienced acute confusion (n=4), isolated dizziness (n=3) and facial paresthesia (n=1). Neurological AEs reached grade III in 3 cases (1 acute confusion, 2 ataxia). Occurrence of neurological AEs was correlated with lower glomerular filtration rate at treatment onset (p Conclusion : In this very high-risk elderly population of TP53m MDS and AML, generally with complex karyotype, a promising 56% CR rate at 6 cycles was reached in the evaluable population with AZA+ APR 246 combination, with deep molecular remission in all CR patients. We observed manageable neurologic AEs, mainly in elderly patients with reduced renal function, who therefore require close monitoring and dose reduction if necessary. An update regarding safety and efficacy in the 53 patients, including survival data, will be available at the meeting. A phase III international trial comparing AZA alone and AZA+ APR 246 in TP53m MDS is ongoing. Disclosures Cluzeau: Abbvie: Consultancy; Jazz Pharma: Consultancy; Menarini: Consultancy. Peterlin:AbbVie Inc: Consultancy; Astellas: Consultancy; Jazz Pharma: Consultancy; Daiichi-Sankyo: Consultancy. Recher:Daiichi-Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; chugai: Research Funding; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Agios: Research Funding; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Astellas Pharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz Pharmaceuticals: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Stamatoullas:Celgene: Honoraria; Takeda: Consultancy. Berthon:JAZZPHARMACEUTICAL: Other: DISCLOSURE BOARD; CELGEN: Other: DISCLOSURE BOARD; PFIZER: Other: DISCLOSURE BOARD. Sallman:Celyad: Membership on an entity's Board of Directors or advisory committees. Ades:Amgen: Research Funding; Astellas: Membership on an entity's Board of Directors or advisory committees; Silence Therapeutics: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Jazz: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Helsinn Healthcare: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Fenaux:Celgene Corporation: Honoraria, Research Funding; Astex: Honoraria, Research Funding; Jazz: Honoraria, Research Funding; Aprea: Research Funding.

l-asparaginase (L-ase) is a major drug used to treat acute lymphoblastic leukemia (ALL) [1]. L-ase kills leukemic cells by depleting circulating asparagine pools related to its asparaginase activit...

Sustained Leukemia-Free State and Molecular Response to Sorafenib in a Patient With Chronic Myelomonocytic Leukemia in Transformation Driven by Homozygous FLT3-ITD Malignant Hematopoiesis Olivier Kosmider, Nicolas Chapuis, Sophie Kaltenbach, Romain Coriat, Pascaline Boudou Rouquette, Lise Willems, Virginie Chesnais, Isabelle Radford-Weiss, Valerie Bardet, Patrick Mayeux, Jerome Tamburini, Michaela Fontenay, Didier Bouscary

International audience; Primary bone diffuse large B-cell lymphoma (PB-DLBCL) is a rare DLBCL location variant. We treated 76 PB-DLBCL patients by immuno-chemotherapy, resulting in an 84% sustained complete remission rate and a 78.9% survival over a 4.7-year median follow-up period. Ann Arbor stage IV and high age-adjusted international prognostic index were predictive of adverse outcome in univariate analysis. In multivariate analysis using a Cox model, only aa-IPI predicted long-term survival. While based on a limited number of cases, we suggested that radiotherapy may be useful as a consolidation modality in PB-DLBCL. We also suggested that positron emission tomography/CT scan should be interpreted with caution due to a persistent [18F]fluorodeoxyglucose [18FDG] uptake of bone lesions even after remission in some in PB-DLBCL patients. Our study based on a homogeneous cohort of PB-DLBCL patients confirmed the favorable outcome of this DLBCL variant and support the implementation of prospective clinical trials in this disease.

Myelodysplastic syndromes (MDSs) are hematopoietic stem cell disorders in which recurrent mutations define clonal hematopoiesis. The origin of the phenotypic diversity of non-del(5q) MDS remains unclear. Here, we investigated the clonal architecture of the CD34+CD38- hematopoietic stem/progenitor cell (HSPC) compartment and interrogated dominant clones for MDS-initiating cells. We found that clones mainly accumulate mutations in a linear succession with retention of a dominant subclone. The clone detected in the long-term culture-initiating cell compartment that reconstitutes short-term human hematopoiesis in xenotransplantation models is usually the dominant clone, which gives rise to the myeloid and to a lesser extent to the lymphoid lineage. The pattern of mutations may differ between common myeloid progenitors (CMPs), granulomonocytic progenitors (GMPs), and megakaryocytic-erythroid progenitors (MEPs). Rare STAG2 mutations can amplify at the level of GMPs, from which it may drive the transformation to acute myeloid leukemia. We report that major truncating BCOR gene mutation affecting HSPC and CMP was beneath the threshold of detection in GMP or MEP. Consistently, BCOR knock-down (KD) in normal CD34+ progenitors modifies their granulocytic and erythroid differentiation. Clonal architecture of the HSPC compartment and mutations selected during differentiation contribute to the phenotypic heterogeneity of MDS. Defining the hierarchy of driver mutations provides insights into the process of transformation and may guide the search for novel therapeutic strategies.

Clostridium difficile (C. difficile) infection was observed in 13% of recipients after hematopoietic stem cell transplantation (HSCT), mainly in the first month posttransplantation. Risk factors were cord blood as the source of stem cells, acute graft-versus-host disease (GVHD), and total body irradiation (TBI). No association was found with an increased risk of mortality. The purpose of this study was to evaluate the incidence, risk factors, and outcome of C. difficile infection (CDI) after HSCT. We conducted a single-center, retrospective, cohort study on all patients who received an allogeneic HSCT from January 2004 to December 2007. All patients with diarrhea in the first year after HSCT were tested for the presence of C. difficile in stools. Among the 407 assessable patients, 53 presented at least 1 CDI in the first year post-HSCT. The total incidence rate was 5.6 cases of CDI per 10,000 patient-days. Fifty percent of cases were diagnosed in the first month after HSCT, and 95% occurred during the first 6 months. Fewer than 5% of patients with CDI had severe diarrhea and severe complications were never observed. TBI in the conditioning regimen, cord blood as the source of stem cells, and acute graft-versus-host disease (aGVHD) were independently associated with CDI. Six patients (11%) had a recurrence of CDI. Four patients required second-line treatment with vancomycin. With a median follow-up of 22 months, the 2-year overall survival rates were similar between patients who presented a CDI and those who did not. CDI was observed in approximately 13% of recipients after HSCT, mainly in the first month posttransplantation and was associated with CB, aGVHD, and TBI. CDI was not associated either with severe complications or with an increased risk of mortality in this large cohort of patients.

Purpose: The growth and survival of acute myeloid leukemia (AML) cells are enhanced by the deregulation of signaling pathways such as phosphoinositide 3-kinase (PI3K)/Akt and mammalian target of rapamycin (mTOR). Major efforts have thus been made to develop molecules targeting these activated pathways. The mTOR serine/threonine kinase belongs to two separate complexes: mTORC1 and mTORC2. The mTORC1 pathway is rapamycin sensitive and controls protein translation through the phosphorylation of 4E-BP1 in most models. In AML, however, the translation process is deregulated and rapamycin resistant. Furthermore, the activity of PI3K/Akt and mTOR is closely related, as mTORC2 activates the oncogenic kinase Akt. We therefore tested, in this study, the antileukemic activity of the dual PI3K/mTOR ATP-competitive inhibitor NVP-BEZ235 compound (Novartis). Experimental Design: The activity of NVP-BEZ235 was tested in primary AML samples (n = 21) and human leukemic cell lines. The different signaling pathways were analyzed by Western blotting. The cap-dependent mRNA translation was studied by 7-methyl-GTP pull-down experiments, polysomal analysis, and [3H]leucine incorporation assays. The antileukemic activity of NVP-BEZ235 was tested by analyzing its effects on leukemic progenitor clonogenicity, blast cell proliferation, and survival. Results: The NVP-BEZ235 compound was found to inhibit PI3K and mTORC1 signaling and also mTORC2 activity. Furthermore, NVP-BEZ235 fully inhibits the rapamycin-resistant phosphorylation of 4E-BP1, resulting in a marked inhibition of protein translation in AML cells. Hence, NVP-BEZ235 reduces the proliferation rate and induces an important apoptotic response in AML cells without affecting normal CD34+ survival. Conclusions: Our results clearly show the antileukemic efficiency of the NVP-BEZ235 compound, which therefore represents a promising option for future AML therapies. Clin Cancer Res; 16(22); 5424–35. ©2010 AACR.

Mammalian target of rapamycin (mTOR) is a protein kinase implicated in the regulation of various cellular processes, including those required for tumor development, such as the initiation of mRNA translation, cell-cycle progression and cellular proliferation. In a wide range of hematological malignancies, the mTORC1 signaling pathway has been found to be deregulated and has been designed as a major target for tumor therapy. Given that pre-clinical studies have clearly established the therapeutic value of mTORC1 inhibition, numerous clinical trials of rapamycin and its derivates (rapalogs) are ongoing for treatment of these diseases. At this time, although disease stabilization and tumor regression have been observed, objective responses in some tumor types have been modest. Nevertheless, some of the mechanisms underlying cancer-cell resistance to rapamycin have now been described, thereby leading to the development of new strategy to efficiently target mTOR signaling in these diseases. In this review, we discuss the rationale for using mTOR inhibitors as novel therapies for a variety of hematological, malignancies with a focus on promising new perspectives for these approaches.

Fusarium species cause rare and severe infections. Their incidence is increasing in immunocompromised patients but they are also observed in healthy hosts. Because of the rapid dissemination of infection and the frequent resistance of Fusarium species to antifungal drugs, histopathologic evidence of hyphae is very helpful to obtain the diagnosis rapidly. We report the clinical and pathological features of two patients with initial cutaneous lesions. Cutaneous early biopsies showed microvessel involvement with hyphae and thrombosis. Fusarium infection was confirmed by skin culture. Hyphae within a microvessel thrombus in the skin were highly suggestive of disseminated fungal infection. These pathological features enabled to establish an early diagnosis and to start efficient antifungal treatment. In early cutaneous biopsies of immunocompromised patients, the presence of cutaneous vessel thrombosis can suggest a fungal infection and may help to start specific therapy without delay for these life-threatening infections.

// Anna Raimbault 1, 2, 3, 4, 5, * , Cecile Pierre-Eugene 1, * , Alexandra Rouquette 6 , Celine Deudon 1 , Lise Willems 7 , Nicolas Chapuis 1, 2, 3, 4, 5 , Stephanie Mathis 1, 2, 3, 4, 5 , Claudia Kunz 8 , Harald Fricke 8 , Olivier Kosmider 1, 2, 3, 4, 5 , Valerie Bardet 1, 2, 3, 4, 5 , Michaela Fontenay 1, 2, 3, 4, 5 , on behalf of the Groupe Francophone des Myelodysplasies 1 Assistance Publique-Hopitaux de Paris, Service d’Hematologie Biologique, Hopitaux Universitaires Paris Centre, Hopital Cochin, Paris, France 2 Universite Paris Descartes, Faculte de Medecine, Paris, France 3 Institut National de la Sante et de la Recherche Medicale (INSERM) U1016, Paris, France 4 Centre National de la Recherche Scientifique, Unite Mixte de Recherche 8104, Paris, France 5 Institut Cochin, Department of Development, Reproduction and Cancer, Paris, France 6 Departement d’Epidemiologie et de Biostatistiques, Hopitaux Universitaires Paris Centre, Paris, France 7 Assistance Publique-Hopitaux de Paris, Service d’Hematologie Clinique, Hopitaux Universitaires Paris Centre, Hopital Cochin, Paris, France 8 APOGENIX, GmbH, Heidelberg, Germany * These authors have contributed equally to this work Correspondence to: Michaela Fontenay, e-mail: michaela.fontenay@inserm.fr Keywords: myelodysplastic syndromes, erythropoiesis, CD95, CD95 ligand, anemia Received: September 07, 2015 Accepted: January 02, 2016 Published: February 18, 2016 ABSTRACT CD95, a member of the death receptor family initiates a caspase-dependent apoptosis, when activated by its ligand CD95L, thought to negatively regulate erythrocyte production in the bone marrow. We have previously shown that CD95 is overexpressed in two thirds of patients with a lower risk myelodysplastic syndrome (MDS) and that resistance to erythropoiesis-stimulating agents (ESA) is linked to poor residual erythropoiesis. In the present study, we show that CD95 overexpression and previous transfusion are independent predictive factors of ESA resistance. To investigate an alternative therapeutic strategy of anemia in ESA-resistant patients, we have conducted a preclinical study of the effects of APG101, a fusion protein consisting of the extracellular domain of human CD95 and the Fc region of human IgG1 on MDS erythropoiesis in vitro . APG101 increases the number of burst-forming unit-erythroid (BFU-E) progenitors derived from CD34 + progenitors in liquid culture and improves overall proliferation rate of erythroid precursors by inhibiting apoptosis. APG101 rescues BFU-E growth in MDS patients presenting with attrition of erythroid progenitors at baseline, independently of CD95 or CD95L expression level. Our data show that overexpression of CD95 at diagnosis is a hallmark of ESA resistance and that severe impairment of erythropoiesis is predictive of erythroid response to APG101 in vitro . These data provide a rationale for further clinical investigation of APG101 in an attempt to treat anemia in lower risk MDS patients.

Cancer cells require glutamine to adapt to increased biosynthetic activity. The limiting step in intracellular glutamine catabolism involves its conversion to glutamate by glutaminase (GA). Different GA isoforms are encoded by the genes GLS1 and GLS2 in humans. Herein, we show that glutamine levels control mitochondrial oxidative phosphorylation (OXPHOS) in acute myeloid leukemia (AML) cells. Glutaminase C (GAC) is the GA isoform that is most abundantly expressed in AML. Both knockdown of GLS1 expression and pharmacologic GLS1 inhibition by the drug CB-839 can reduce OXPHOS, leading to leukemic cell proliferation arrest and apoptosis without causing cytotoxic activity against normal human CD34(+) progenitors. Strikingly, GLS1 knockdown dramatically inhibited AML development in NSG mice. The antileukemic activity of CB-839 was abrogated by both the expression of a hyperactive GAC(K320A) allele and the addition of the tricarboxyclic acid cycle product α-ketoglutarate, indicating the critical function of GLS1 in AML cell survival. Finally, glutaminolysis inhibition activated mitochondrial apoptosis and synergistically sensitized leukemic cells to priming with the BCL-2 inhibitor ABT-199. These findings show that targeting glutamine addiction via GLS1 inhibition offers a potential novel therapeutic strategy for AML.

Hemophagocytic lymphohistiocytosis (HLH) diagnosed in the course of acute myeloid leukemia (AML) is generally triggered by treatment-induced infections. AML-induced HLH is a very rare situation for which no diagnostic or therapeutic guidelines are available. We report the occurrence of HLH in an AML5 post-transplant relapse. In our case, the absence of detectable pathogen and the parallel evolution between HLH and leukemia burden suggested a direct link between AML and HLH. We suggest that the diagnostic of AML-related HLH should be promptly considered in front of unexplained fever, cytopenia, liver dysfunction or neurological symptoms as therapeutic intervention is urgent in this life-threatening situation.

Background Primary immune thrombocytopenia is not a rare event during pregnancy, and it must be carefully managed to avoid hemorrhagic complications for the mother. After failure of first-line treatments, the teratogenicity and toxicity of other therapeutic agents limit the available options and treatment. Cases We describe the cases of two pregnant patients with corticosteroid-refractory immune thrombocytopenia who were successfully treated by romiplostim, a thrombopoietin receptor agonist, without any fetal or maternal complications. Conclusion Romiplostim may represent an important alternative treatment choice during pregnancy for immune thrombocytopenia cases refractory to first-line therapy, especially because of its speed of action and high efficacy. Nevertheless, further data are required to provide definitive evidence of its safety for newborns.

Cancer cells require nutrients and energy to adapt to increased biosynthetic activity, and protein synthesis inhibition downstream of mammalian target of rapamycin complex 1 (mTORC1) has shown promise as a possible therapy for acute myeloid leukemia (AML). Glutamine contributes to leucine import into cells, which controls the amino acid/Rag/mTORC1 signaling pathway. We show in our current study that glutamine removal inhibits mTORC1 and induces apoptosis in AML cells. The knockdown of the SLC1A5 high-affinity transporter for glutamine induces apoptosis and inhibits tumor formation in a mouse AML xenotransplantation model. l-asparaginase (l-ase) is an anticancer agent also harboring glutaminase activity. We show that l-ases from both Escherichia coli and Erwinia chrysanthemi profoundly inhibit mTORC1 and protein synthesis and that this inhibition correlates with their glutaminase activity levels and produces a strong apoptotic response in primary AML cells. We further show that l-ases upregulate glutamine synthase (GS) expression in leukemic cells and that a GS knockdown enhances l-ase–induced apoptosis in some AML cells. Finally, we observe a strong autophagic process upon l-ase treatment. These results suggest that l-ase anticancer activity and glutamine uptake inhibition are promising new therapeutic strategies for AML.

Introduction Myelodysplastic syndromes (MDS) are clinically diverse malignant disorders of aging with a propensity to evolve to acute myeloid leukemia (AML) or bone marrow failure. In early MDS, whole genome sequencing identified mutations distributed in few clones. Evidence have been provided for the existence of a MDS-initiating cell in cases harboring a 5q deletion. However, the clonal heterogeneity and its consequences on the phenotypic diversity of non-del(5q) MDS is little documented. Here we focused on studying the hierarchical organization and the functionality of clones defined by molecular profiling. The clonal architecture of the CD34+CD38- hematopoietic stem/progenitor cell (HSPC) compartment was investigated and dominant clones were examined as MDS-initiating cells. Material and methods Bone marrow (BM) samples were obtained from 20 patients with non-del(5q) MDS enrolled in the national Programme Hospitalier de Recherche Clinique MDS-04 after informed consent in accordance with ethics committee guidelines. BM samples, cytaphereses from age-matched healthy individuals and cord bloods were used as controls. Targeted NGS of a selected panel of 39 genes was used to define the mutational landscape on BM mononuclear cells (MNC). To study the clonal architecture at the HSPC level, single CD34+CD38- cells were seeded in 96-well plates coated with MS-5 stromal cells and cultured in H5100 MyeloCult medium (StemCell Technologies, Vancouver, Canada) with cytokines for six weeks. For long-term culture-initiating cell (LTC-IC) assays, CD34+ progenitors were cultured for six weeks on MS-5-coated plates without cytokines and then tested for colony-forming cells. For clonogenic assays, CD34+CD38- cells were seeded in methylcellulose for two weeks. All animal experimentations were performed in NSG mice. Results In the 20 cases of non-del(5q) MDS, genomic lesions were traced down to single CD34+CD38- HSPC-derived colonies. Clonal organization was mostly linear in 13/17 patients and branched in 4 cases with retention of a dominant subclone. The clone detected in LTC-IC compartment and that reconstituted short-term human hematopoiesis in xenotransplantation models was usually the dominant clone, which gave rise to the myeloid and to a lesser extent to the lymphoid lineage. Other mutations not detected in LTC-IC can appear in CD34+CD38- compartment or at the level of lineage-committed progenitors. The pattern of mutations may differ between common myeloid (CMP), granulo-monocytic (GMP) and megakaryocytic-erythroid (MEP) progenitors. For instance, a major truncating BCOR gene mutation affecting HSPC and CMP was beneath the threshold of detection in GMP or MEP. Consistently, BCOR knockdown by shRNA in normal CD34+ progenitors impaired their granulocytic and erythroid differentiation. By contrast, a STAG2 gene mutation, not detected in CMP or MEP, amplified in a GMP, which drove the transformation to AML. Conclusion In the present study, we characterized the first genetic hits that initiate disease in a dominant clone of the CD34+CD38- HSPC compartment, which exhibits LTC-IC activity and reconstitutes human short-term hematopoiesis in NSG mice. The genetic heterogeneity in non-del(5q) MDS arises within the HSPC compartment and in lineage-committed progenitors which ultimately support the transformation into AML. The clonal architecture of HSPC compartment and mutations selection along differentiation contribute to the phenotype of MDS. Defining the hierarchy of driver mutations provides insights into the process of transformation, and may guide the search for novel therapeutic strategies. Disclosures No relevant conflicts of interest to declare.

Background: Myelofibrosis (MF) is the less frequent Philadelphia-negative myeloproliferative neoplasms (MPN). We have included in a nationwide database primary (P), post-polycythemia (PPV) and post-essential thrombocythemia (PET) MF diagnosed in France since 2005. Methods: Inclusion criteria were: diagnostic of MF after 2005; according strictly to WHO (bone marrow biopsy mandatory); informed consent. The registry was launched in Oct. 2013, and 26 hematology centers included patients (pts). Summary statistics were reported, namely median [Interquartile range, IQR] or percentage. Baseline characteristics were compared across IPSS groups using chi-square test or Mann and Whitney test. Kaplan-Meier survival curves were plotted and compared by the log-rank test. Results: At time of analysis (June 2016) a total of 527 pts were included in the registry, complete baseline data were available in 499 (95%), and follow-up (FU) data in 433 (87%). Median [IQR] age and M/F sex ratio were 71 [63-78] years and 315/184 (1.7), respectively (resp). 301 (60%) pts had PMF, 182 (36%) had secondary MF (including 64 PPVMF and 118 PETMF) and 16 had pre-fibrotic MF. Five percent of pts had a familial history of hematologic malignancy, and 22% a history of thrombosis or hemorrhage. Splenomegaly was present in 386 (77%) with a median [IQR] spleen size of 4 cm [1-8] below costal margin, and was symptomatic in 11% of pts. Constitutional symptoms were present in 107 (21%) (weight loss in 56, night sweats in 61, fever in 14), and ECOG score was 0, 1, 2, and 3 in 53%, 36%, 11% and 0.3% of pts, resp. Median [IQR] Hemoglobin, WBC and platelet counts were 109 g/L [94-122], 9.3 G/L [5.7-16.0] and 257 G/L [138-430], resp. Circulating blast cells were present in 41%, LDH was above normal value in 95% of pts, median EPO level was 54 [11 - 57] U/L. Grade of fibrosis (WHO) was 1, 2, and 3 in 2%, 66% and 32% of pts, resp. Karyotype was done in 321 pts, normal in 173 (54%), abnormal with favorable prognostic value in 89 (30%) and unfavorable in 30 (10%) (29 failures). A total of 461 (92%) pts had molecular testing: 60% were JAK2V617F positive, 4% had MPL and 7% had CALR mutations, and 99 (28%) over the 352 pts with triple testing were triple negative. IPSS risk categories were low, int-1, int-2 and high in 68 (14%), 168 (34%), 158 (32%), and 105 (21%) pts, resp. In addition to constitutional symptoms, there was a significant increase in the prevalence of clinical signs across IPSS categories (from low to high risk): symptomatic spleen (p=0.016) -though no difference in spleen size was found (p=0.18)-, early satiety (p=0.013), ECOG score (p= 0.0001), bone pain (p=0.002). Moreover, among biological parameters, there was an increase across IPSS groups in WBC (p=0.029), LDH (p=0.0007), ferritin (p=0.003), circulating CD34+ cells (p=0.020), EPO level (p=0.035). In contrast, a decrease was seen for hemoglobin and platelets (p=0.0001 for both). Lastly, frequency of grade 3 fibrosis increased with IPSS (p=0.043), while no evidence of difference was found regarding abnormal karyotype and mutational pattern. Median FU was 33 months [9-63 months]. Among those 433 pts with FU data, median FU was 38 months [19-68], and 124 (29 %) pts had died at the time of analysis, including 13%, 17%, 31%, and 40% of pts from the Low, Int-1, Int-2, and High risk groups, resp (p= 0.0001, figure 1). In the 450 pts with treatment data, treatments received during FU included cytoreductive drug (41%), Jak-inhibitors (35%), Interferon alpha (18%), IMIDs (4%). Splenectomy was performed in only 14 (3%) pts. Forty percent of pts received packed red blood cells, and 12% platelets transfusions. 49 (11%) patients participated in a clinical trial, and 27 (6%) were allografted. Conclusion: This is the first analysis of the French MF observatory after inclusion of more than 500 pts diagnosed and treated during the past 10 years. Complete baseline data and follow-up information available for the majority of pts should allow for new studies of outcomes and influence of clinical and biological parameters, as well as reassessment of prognostic models in the era of new targeted therapies. Figure 1 Comparison of overall survival according to IPPS Figure 1. Comparison of overall survival according to IPPS Figure 2 Figure 2. Disclosures Etienne: Pfizer: Speakers Bureau; BMS: Speakers Bureau; ARIAD: Speakers Bureau; novartis: Consultancy, Speakers Bureau. Tavitian:Novartis: Membership on an entity's Board of Directors or advisory committees. Ugo:Novartis: Membership on an entity's Board of Directors or advisory committees. Kiladjian:Novartis: Honoraria, Research Funding; AOP Orphan: Membership on an entity's Board of Directors or advisory committees, Research Funding.

The mammalian target of rapamycin (mTOR) and the phosphoinositide 3-kinase (PI3K) signaling pathways are commonly deregulated in cancers and promote cellular growth, proliferation, and survival. mTOR is part of two complexes, mTORC1 and mTORC2, with different biochemical structures and substrates specificity. PI3K/AKT activation may result from genetic hits affecting different components of the pathway, whereas the mechanisms leading to constitutive mTORC1 activation remain globally unknown. The connections between the PI3K and mTOR kinases are multiple and complex, including common substrates, negative feedback loops, or direct activation mechanisms. First-generation allosteric mTOR inhibitors (eg, rapamycin) are mainly active on mTORC1 and mostly display cytostatic anti-tumor activity. Recently, second-generation catalytic mTOR inhibitors targeting both mTOR complexes 1 and 2 have been developed. Some of them also inhibit class IA PI3K. Here, we highlight recent data generated with these new inhibitors against cancer cells and their potential as anti-cancer drugs.

The serine/threonine kinase mammalian target of rapamycin (mTOR) is crucial for cell growth and proliferation, and is constitutively activated in primary acute myeloid leukemia (AML) cells, therefore representing a major target for drug development in this disease. We show here that the specific mTOR kinase inhibitor AZD8055 blocked mTORC1 and mTORC2 signaling in AML. Particularly, AZD8055 fully inhibited multisite eIF4E-binding protein 1 phosphorylation, subsequently blocking protein translation, which was in contrast to the effects of rapamycin. In addition, the mTORC1-dependent PI3K/Akt feedback activation was fully abrogated in AZD8055-treated AML cells. Significantly, AZD8055 decreased AML blast cell proliferation and cell cycle progression, reduced the clonogenic growth of leukemic progenitors and induced caspase-dependent apoptosis in leukemic cells but not in normal immature CD34+ cells. Interestingly, AZD8055 strongly induced autophagy, which may be either protective or cell death inducing, depending on concentration. Finally, AZD8055 markedly increased the survival of AML transplanted mice through a significant reduction of tumor growth, without apparent toxicity. Our current results strongly suggest that AZD8055 should be tested in AML patients in clinical trials.

The FOXO transcription factors are involved in multiple signaling pathways and have tumor-suppressor functions. In acute myeloid leukemia (AML), deregulation of oncogenic kinases, including Akt, extra-signal–regulated kinase, or IκB kinase, is frequently observed, which may potentially inactivate FOXO activity. We therefore investigated the mechanism underlying the regulation of FOXO3a, the only FOXO protein constantly expressed in AML blast cells. We show that in both primary AML samples and in a MV4-11/FOXO3a-GFP cell line, FOXO3a is in a constant inactive state due to its cytoplasmic localization, and that neither PI3K/Akt nor extra-signal–regulated kinase–specific inhibition resulted in its nuclear translocation. In contrast, the anti-Nemo peptide that specifically inhibits IKK activity was found to induce FOXO3a nuclear localization in leukemic cells. Furthermore, an IKK-insensitive FOXO3a protein mutated at S644 translocated into the nucleus and activated the transcription of the Fas-L and p21Cip1 genes. This, in turn, inhibited leukemic cell proliferation and induced apoptosis. These results thus indicate that IKK activity maintains FOXO3a in the cytoplasm and establishes an important role of FOXO3a inactivation in the proliferation and survival of AML cells. The restoration of FOXO3a activity by interacting with its subcellular distribution may thus represent a new attractive therapeutic strategy for AML.

Finding an effective treatment for acute myeloid leukemia (AML) remains a challenge, and all cellular processes that are deregulated in AML cells should be considered in the design of targeted therapies. We show in our current study that the LKB1/AMPK/TSC tumor suppressor axis is functional in AML and can be activated by the biguanide molecule metformin, resulting in a specific inhibition of mammalian target of rapamycin (mTOR) catalytic activity. This induces a multisite dephosphorylation of the key translation regulator, 4E-BP1, which markedly inhibits the initiation step of mRNA translation. Consequently, metformin reduces the recruitment of mRNA molecules encoding oncogenic proteins to the polysomes, resulting in a strong antileukemic activity against primary AML cells while sparing normal hematopoiesis ex vivo and significantly reducing the growth of AML cells in nude mice. The induction of the LKB1/AMPK tumor-suppressor pathway thus represents a promising new strategy for AML therapy.

Background Alterations in the PI3K/Akt pathway are found in a wide range of cancers and the development of PI3K inhibitors represents a promising approach to cancer therapy. Constitutive PI3K activation, reflecting an intrinsic oncogenic deregulation of primary blast cells, is detected in 50% of patients with acute myeloid leukemia. However, the mechanisms leading to this activation are currently unknown. As we previously reported IGF-1 autocriny in acute myeloid leukemia cells, we investigated whether IGF-1 signaling was involved in the constitutive activation of PI3K. Design and Methods We analyzed the IGF-1/IGF-1R signaling pathway and PI3K activity in 40 acute myeloid leukemia bone marrow samples. Specific inhibition of IGF-1/IGF-1R signaling was investigated using neutralizing anti-IGF-1R, anti-IGF-1 antibodies or IGF-1 short interfering RNA. The anti-leukemic activity of the neutralizing anti-IGF-1R was tested by analyzing its effects on leukemic progenitor clonogenicity, blast cell proliferation and survival. Results In all samples tested, we found that functional IGF-1R was constantly expressed in leukemic cells. In the acute myeloid leukemia samples with PI3K activation, we found that the IGF-1R was constitutively phosphorylated, although no IGF-1R activating mutation was detected. Specific inhibition of IGF-1R signaling with neutralizing anti-IGF-1R strongly inhibited the constitutive phosphorylation of both IGF-1R and Akt in 70% of the PI3K activated samples. Moreover, both incubation with anti-IGF-1 antibody and IGF-1 short interfering RNA inhibited Akt phosphorylation in leukemic cells. Finally, neutralizing anti-IGF-1R treatment decreased the clonogenicity of leukemic progenitors and the proliferation of PI3K activated acute myeloid leukemia cells. Conclusions Our current data indicate a critical role for IGF-1 autocriny in constitutive PI3K/Akt activation in primary acute myeloid leukemia cells and provide a strong rationale for targeting IGF-1R as a potential new therapy for this disease.

The PI3K/AKT and mTOR signaling pathways are activated in acute myeloid leukemia, including in the more immature leukemic populations. Constitutive PI3K activation is detectable in 50% of acute myeloid leukemia samples whereas mTORC1 is activated in all cases of this disease. In leukemic cells, the PI3K activity relates to the expression of the p110delta isoform of class IA PI3K. Constitutive PI3K activation is the result of autocrine IGF-1/IGF-1R signaling in 70% of acute myeloid leukemia samples but specific inhibition of this pathway does not induce apoptosis. Specific inhibition of PI3K/AKT or mTORC1 alone in vitro has anti-leukemic effects which are essentially exerted via the suppression of proliferation. However, as mTORC1 activation is independent of PI3K/AKT in acute myeloid leukemia, dual PI3K and mTOR inhibitors may induce apoptosis in blast cells. Moreover, mTORC1 inhibition using sirolimus overactivates PI3K/AKT via the upregulation of IRS2 expression and by favoring IGF-1/IGF-1R autocrine signaling. Recent data also indicate that mTORC1 does not control protein translation in acute myeloid leukemia. These results open the way for the design of direct inhibitors of protein synthesis as novel acute myeloid leukemia therapies and also for the development of second generation mTOR inhibitors (the TORKinhibs).

The deregulation of translation markedly contributes to the malignant phenotype in cancers, and the assembly of the translation initiating complex eIF4F is the limiting step of this process. The mammalian Target of Rapamycin Complex 1 (mTORC1) is thought to positively regulate eIF4F assembly and subsequent oncogenic protein synthesis through 4E-BP1 phosphorylation. We showed here that the translation inhibitor 4EGI-1 decreased the clonogenic growth of leukemic progenitors and induced apoptosis of blast cells, with limited toxicity against normal hematopoiesis, which emphasize the importance of translation deregulation in acute myeloid leukemia (AML) biology. However, the mTORC1 inhibitor RAD001 (a rapamycin derivate) did not induce AML blast cell apoptosis. We herein demonstrated that mTORC1 disruption using raptor siRNA or RAD001 failed to inhibit 4E-BP1 phosphorylation in AML. Moreover, RAD001 failed to inhibit eIF4F assembly, to decrease the proportion of polysome-bound c-Myc mRNA, and to reduce the translation-dependent accumulation of oncogenic proteins. We identified the Pim-2 serine/threonine kinase as mainly responsible for 4E-BP1 phosphorylation on the S65 residue and subsequent translation control in AML. Our results strongly implicate an mTORC1-independent deregulation of oncogenic proteins synthesis in human myeloid leukemogenesis. Direct inhibition of the translation initiating complex thus represents an attractive option for the development of new therapies in AML.

The phosphatidylinositol 3-kinase (PI3K)/Akt and mammalian target of rapamycin complex 1 (mTORC1) signaling pathways are frequently activated in acute myelogenous leukemia (AML). mTORC1 inhibition with RAD001 induces PI3K/Akt activation and both pathways are activated independently, providing a rationale for dual inhibition of both pathways. PI-103 is a new potent PI3K/Akt and mTOR inhibitor. In human leukemic cell lines and in primary blast cells from AML patients, PI-103 inhibited constitutive and growth factor-induced PI3K/Akt and mTORC1 activation. PI-103 was essentially cytostatic for cell lines and induced cell cycle arrest in the G1 phase. In blast cells, PI-103 inhibited leukemic proliferation, the clonogenicity of leukemic progenitors and induced mitochondrial apoptosis, especially in the compartment containing leukemic stem cells. In contrast, apoptosis was not induced with RAD001 and IC87114 association, which specifically inhibits mTORC1 and p110delta activity, respectively. PI-103 had additive proapoptotic effects with etoposide in blast cells and in immature leukemic cells. Interestingly, PI-103 did not induce apoptosis in normal CD34(+) cells and had moderate effects on their clonogenic and proliferative properties. Here, we demonstrate that multitargeted therapy against PI3K/Akt and mTOR with PI-103 may be of therapeutic value in AML.

The phosphatidylinositol 3-kinase (PI3K)/Akt and mTORC1 pathways are frequently activated, representing potential therapeutic targets in acute myeloid leukemia (AML). In 19 AML samples with constitutive PI3K/Akt activation, the rapamycin derivative inhibitor everolimus (RAD001) increased Akt phosphorylation. This mTOR C1-mediated Akt up-regulation was explained by an insulin-like growth factor-1 (IGF-1)/IGF-1 receptor autocrine loop: (1) blast cells expressed functional IGF-1 receptors, and IGF-1-induced Akt activation was increased by RAD001, (2) a neutralizing anti-IGF-1R α-IR3 monoclonal antibody reversed the RAD001-induced Akt phosphorylation, and (3) autocrine production of IGF-1 was detected in purified blast cells by quantitative reverse transcription-polymerase chain reaction and immunofluorescence. This RAD001-induced PI3K/Akt up-regulation was due to an up-regulated expression of the IRS2 adaptor. Finally, we observed that concomitant inhibition of mTORC1 and PI3K/Akt by RAD001 and IC87114 induced additive antiproliferative effects. Our results suggest that dual inhibition of the mTORC1 complex and the IGF-1/IGF-1R/PI3K/Akt pathway in AML may enhance the efficacy of mTOR inhibitors in treatment of this disease.

Successful outcome of a disseminated adenovirus infection 6 years after allogeneic bone marrow transplantation

Abstract 4786 Background Chronic myelomonocytic leukemia (CMML) is a rare clonal hematopoietic stem cell disorder whom biology remains unclear.CMML is associated with many different somatic mutations in genes involved in key cellular processes including signaling (N/K-Ras, CBL, JAK2); differentiation (RUNX1, NPM1, CEBPa); epigenetic regulation (TET2, ASXL1, IDH1/2, EZH2, DNMT3A); and RNA splicing (SRSF2, U2AF1, SF3B1 and ZRSR2). FLT3 mutations are very rare but provide the rationale for FLT3 tyrosine kinase inhibitor use to treat this disease. We report the case of a 60-years-old patient diagnosed with a hepatocarcinoma metastasis which legitimized the introduction of anti-angiogenic therapy using the VEGF-R2 inhibitor, sorafenib. The patient was addressed to the hematology department with a myeloproliferative-like CMML in transformation. We show here that the molecular analyses of this hematological disorders allow us to use sorafenib as a targeted therapy to inhibit the consequences of a FLT3-ITD mutation. Methods Cytogenetic analysis and genome wide array-based comparative genomic hybridization (aCGH) were performed at diagnosis. The reference standard used for aCGH was matched genomic constitutional DNA (CD3+ T cells sorted from a blood sample). Serum samples collected from the patient before or under treatment with sorafenib were assessed for their plasma inhibitory activity by western blotting analyses of signaling molecules downstream the FLT3-ITD mutation. Genomic DNA samples extracted from BMMCs and peripheral blood (PB) cells at diagnosis were screened for mutations in 18 classical genes. To monitor the FLT3-ITD mutation, the exon 15 of FLT3 was amplified by a specific PCR using a 6FAM-labeled forward primer. Results The patient developed hyperleucocytosis (48.2 G/L) with neutrophilia (30.4 G/L), monocytosis (11.6 G/L) and basophilia (0.5 G/L) in January 2011. The BM was hypercellular with granulocytic and monocytic proliferation, dysgranulopoiesis and dysmegacaryopoiesis. Blast cells plus promonocytes accounted for 30% of the nucleated BM cells, leading to a diagnosis of AML secondary to CMML in the WHO classification BM karyotype identified no clonal abnormalities and aCGH analysis of BMMCs produced normal findings. BM and PB cells were screened for mutations in 18 CMML-associated genes. Only two abnormalities were identified: a 27 base pair (bp) insertion FLT3-ITD mutation (exon 15) detected in BM cells with near complete disappearance of the wild type (WT) FLT3 allele (FLT3-ITD/FLT3-WT ratio at 9.62) and a classical heterozygous mutation (dupG) was found in the exon 12 of ASXL1. ASXL1 and FLT3-ITD mutations were not detected in purified CD3+ T lymphocytes. Five months after sorafenib introduction, PB was strictly normal and BM examination demonstrated normal richness, blast cells and promonocytes accounting for 2% of the nucleated BM cells but persistent moderate dysgranulopoiesis and dysmegakaryopoiesis, indicative of complete remission. At this time, the FLT3-ITD/FLT3-WT ratio was 1.66 and 0.58 in the BM and PB, respectively. In January 2012, the WBC profile was still normal and a BM smear only showed moderate dysgranulopoiesis. On the molecular side, FLT3-ITD mutation was undetectable, indicative of complete molecular response. But ASXL1 mutation was evident at all time points. The serum of the patient, obtained before and under sorafenib was tested on cell line harboring FLT3-ITD mutation. Constitutive FLT3 Y591, Akt S473, STAT5 Y694 and ERK1/2 T202/Y204 phosphorylations were fully inhibited in the presence of the serum extracted under sorafenib treatment. Conclusion Our patient clearly had a myeloproliferative-CMML driven by an homozygous FLT3-ITD mutation. This is the first report of such a CMML patient achieving sustained CR and CMR after treatment with an FLT3-ITD tyrosine kinase inhibitor. In this case, the ASXL1 mutation remained detectable upon sorafenib treatment after the suppression of FLT3-ITD-driven malignant hematopoiesis, suggesting that it arose from a FLT3-WT subclone that contributed to the CMML phenotype with some dysplastic feature. In conclusion, we propose that mutations in the FLT3 gene should be examinated in all CMML cases, even their low frequency because FLT3 TKI may induce dramatic and sustained responses without significant toxicity and eventually allow for allogenic transplantation. Disclosures: No relevant conflicts of interest to declare.

Abstract 1024 Poster Board I-46 The treatment of acute myeloid leukemia (AML) still represents a challenge. As the growth and survival of AML cells are enhanced by the deregulation of signaling pathways such as PI3K, ERK/MAPK or mTOR, major efforts are made to develop targeted molecules against these activated pathways. The mTOR serine/threonine kinase belongs to two separate complexes, mTORC1 and mTORC2. The mTORC1 complex, defined by the interaction between mTOR and raptor, is inhibited by rapamycin in most models. It controls mRNA translation through the phosphorylation of the physiological translation repressor 4E-BP1. A constitutive activation of mTORC1 is usually detected in primary AML cells, indicating this pathway as a major target for AML therapy. However, inhibition of mTORC1 with rapamycin has only modest effects in this disease (Recher, Beyne-Rauzy et al., Blood 2005; Xu, Thompson et al.,Blood 2005). Accordingly, we recently showed that the translation process is deregulated and rapamycin resistant in AML, although specifically targeting translation with the 4E-BP1 mimetic 4EGI-1 markedly impairs AML cells survival (Tamburini, Green et al., Blood 2009). The mTORC2 complex is defined by the interaction between rictor and mTOR and is generally reported as resistant to rapamycin. An emerging role for mTORC2 has recently been rose in cancer biology, including in AML, in part through its ability to activate the oncogenic kinase Akt by phosphorylation on S473 (Zeng, Sarbassov dos et al., Blood 2007). In AML, the PI3K and mTOR activities are closely connected: inhibition of mTORC1 activates an IGF-1/IGF-1R autocrine loop that overactivates PI3K but mTORC1 activity is PI3K-independent (Tamburini, Chapuis et al., Blood 2008). These results strongly suggest a rational for simultaneous inhibition of PI3K and mTOR to enhance the killing of AML cells (Park, Chapuis et al., Leukemia 2008; Tamburini, Chapuis et al., Blood 2008). The NVP-BEZ235 compound (Novartis®) is an ATP-competitive inhibitor specific of PI3K and mTOR kinases, actually in phase I/II trial in oncology. We tested for the first time NVP-BEZ235 in 3 human AML cell lines (MV4-11, MOLM-14 and OCI-AML3) and in primary AML samples (n=10). This compound inhibited PI3K and mTOR signaling without off-target effects against other kinases usually activated in AML cells (ERK1/2 and STAT5). In contrast to rapamycin, NVP-BEZ235 dose-dependently inhibited the catalytic activity of mTOR as attested by inhibition of the mTOR autophosphorylation site on S2481. Consequently, NVP-BEZ235 fully inhibited the rapamycin-resistant phosphorylation of the translation repressor 4E-BP1 on T37/46, T70 and S65 residues. This resulted in a marked inhibition of mRNA translation in AML cells, attested by (i) an inhibition of the assembly of the translation initiating complex eIF4F, (ii) a shift from large to small polysomes in NVP-BEZ235-treated AML cells and (iii) a decreased expression of the oncogenic cap-dependant proteins Bcl-XL, c-myc and cyclinD1. Moreover, to study the effects of NVP-BEZ235 on mTORC2 activity independently of Akt, we investigated the regulation of the mTORC2 substrate paxillin (Jacinto, Loewith et al., Nat Cell biol 2004). We first confirmed that paxillin Y118 residue was a substrate for mTORC2 activity in primary AML cells as the siRNA-mediated rictor knockdown dramatically inhibited this phosphorylation event. In primary AML samples, NVP-BEZ235 inhibited paxillin Y118 phosphorylation in a dose-dependent way and this closely correlated to the inhibition of Akt S473 phosphorylation. Targeting the catalytic activity of mTOR represses therefore both mTORC1 and mTORC2 activity. Accordingly, the NVP-BEZ235 compound had marked anti-leukemic activity in AML. Indeed, it strongly reduced the proliferation of AML cells and blocked the cell-cycle as attested by a decrease of AML cells in S-phase and an accumulation in G1-phase. Finally, NVP-BEZ235 induced an important apoptotic response in AML blast cells but its effects on normal hematopoiesis were limited ex vivo. Overall, NVP-BEZ235 strongly inhibited protein synthesis and induced the killing of AML cells through the catalytic inhibition of the oncogenic PI3K and mTOR kinases. Given these results, NVP-BEZ235 may be tested urgently in clinical trials in AML. Disclosures: No relevant conflicts of interest to declare.