Search

The addition of midostaurin, a FLT3-inhibitor, to intensive chemotherapy (IC) was previously shown to improve outcome of younger patients with FLT3-mutated AML. The toxicity and efficacy of adding midostaurin to IC in patients not originally included in the RATIFY study or with intensified daunorubicin dosing are unknown. We conducted a retrospective, multi-center, historical-control study to characterize the safety and efficacy of adding midostaurin to IC in a “real-world” setting. Sixty-nine adult patients were included in the analysis (midostaurin n = 34, historical controls n = 35) with a mean follow-up of 18.4 (± 15) months. Median age of patients was 60 (range 26–82) years; 32% and 20% of patients were > 65 and 70 years, respectively. No differences in baseline characteristics were noted between the groups. Midostaurin was administered with 90 mg/m2 daunorubicin in 29% of patients; One-third of patients experienced dose reductions/interruptions during midostaurin therapy. Overall toxicity was comparable between the midostaurin and control groups.CR/CRi rates were higher in patients treated with midostaurin compared with controls (80% vs. 57%, p = 0.047) and significantly more patients in the midostaurin group were transplanted in first remission (95% vs. 68%, p = 0.04).Median OS and DFS were higher in the midostaurin vs. control group (not reached vs. 11 months (p = 0.085) and 13 vs. 6 months (p = 0.09), respectively). In our analysis, midostaurin was not associated with increased toxicity including in older patients, in those with secondary AML or when administered with intensified daunorubicin dosage. Higher remission rates in the midostaurin group and increased transplantation rates in first CR were associated with a trend towards better outcomes.

Background: Venetoclax-based combinations were recently approved to treat patients (pts) with acute myeloid leukemia (AML) ineligible for intensive chemotherapy. Limited prospective 'real-world' data is available on treatment patterns of venetoclax-based therapy in routine clinical practice. We investigated patterns of patient selection, efficacy, toxicity, patient related outcome and post-remission management in a nationwide multicenter prospective observational trial. Methods: Newly diagnosed pts with AML were enrolled at the time of venetoclax-based therapy initiation from 10 medical centers in Israel. Demographic, clinical and patient-related baseline characteristics were documented. Treatment patterns, safety and efficacy outcomes are reported. Results: Between August 12, 2019, and June 17, 2021(data cut) ,127 AML pts were enrolled to receive venetoclax based therapy. Baseline patient and disease characteristics are reported in Table 1. The main reasons for physician's choice of venetoclax-based therapy were age ≥75, comorbidities and ECOG ≥2 (patient related factors) in 76% of cases and adverse disease biology predicting poor response to intensive chemotherapy (disease related factors) in 24% of cases. Most pts started therapy in an inpatient setting, 82 (64.6%) with a median hospitalization duration of 14 days, while 44 pts (34.6%) started therapy as out pts. Pts received a median of 3.8 cycles of therapy (range 1-21). Most pts (97%) received venetoclax in combination with hypomethylating agents. The full dose of 400mg QD after a median ramp-up duration of 3 days was achieved in 88% of the pts. Dose interruptions and dose modifications during follow-up occurred in 59 (46%) and 30 (24%) of pts, respectively. To allow for adequate follow up for response assessment, efficacy analysis was limited to pts enrolled prior to December 31, 2020, and included 108 pts with a median follow-up of 8 months (range 1-20). As of data cut, 93 pts completed cycle 1 of therapy, 66 pts completed cycle 3 and 39 pts completed cycle 6. 29 pts (27%) are still active on treatment. Best composite complete remission [CCR = complete remission (CR) plus CR with incomplete count recovery (CRi)] was achieved in 62 (57%) pts. CCR rates were assessed in different pre-defined subgroups. Best CCR in pts selected for therapy based on disease-related and patient-related factors were 70% and 54% respectively. Best CCR in pts with AML arising from MPN and pts with other AML were 45% and 58% respectively. Estimated median overall survival (OS) of all pts was 9.6 months (range 7.4-10.6) (Figure 1). Achieving CCR was associated with a superior probability for survival. Estimated median OS was 13.6 months (range 10.6 - not reached) in pts achieving CCR and 4.2 months (range 1.2-10.3) in non-CCR (p Allogeneic transplantation following venetoclax based treatment was offered to 16 (26%) pts with a median age of 71 years (range 43-77). Last documented response prior to transplant was CR in 5 (32%) pts, CRi 9 (56%), MLFS 1 (6%) and PR in 1 (6%) patient. Among grade ≥3 AEs were febrile neutropenia in 28% and infections in 21% of pts. Clinical and laboratory tumor lysis syndrome (TLS) was documented in 2 and 4 pts, respectively. Antifungal prophylaxis was administered in 20% of pts and granulocyte colony-stimulating factor (GCSF) support was used in 17% of pts in response. Early death rate at 30 and 60 days were 7% and 13%, respectively. Conclusion: This prospective real-world analysis reveals unique patterns of patient selection and venetoclax treatment utilization in a medical system with wide access for this indication. Venetoclax-based therapies are effective and associated with manageable toxicity, including in AML patient populations that were excluded from previous registration trials with comparable CCR and early death rates. Factors associated with patient selection in the 'real-world' setting and immature follow up data most probably led to a shorter estimated median OS in this analysis as compared to controlled trials. The REVIVE study continues to expand and is expected to provide additional insights on treatment patterns, management as well as clinical and patient related outcomes. Figure 1 Figure 1. Disclosures Wolach: Janssen: Consultancy; Novartis: Consultancy; Amgen: Research Funding; Astellas: Consultancy; Abbvie: Consultancy, Honoraria, Research Funding; Neopharm: Consultancy. Levi: AbbVie: Consultancy, Research Funding. Lavie: AbbVie: Membership on an entity's Board of Directors or advisory committees, Other: Fees for lectures; BMS: Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Other: Fees for lectures; Roche: Other: Fees for lectures; Novartis: Other: Fees for lectures. Tavor: AbbVie: Consultancy. Hellmann: AbbVie: Consultancy. Tadmor: Janssen: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding. Zuckerman: Gilead Sciences: Honoraria, Speakers Bureau; Novartis: Honoraria; Janssen: Honoraria; Cellect Biotechnology: Honoraria; BioSight Ltd: Honoraria; AbbVie: Honoraria; Orgenesis Inc.: Honoraria. Stemer: AbbVie: Consultancy. Berelovich: AbbVie: Current Employment, Current equity holder in publicly-traded company. Ofek: AbbVie: Current Employment, Current equity holder in publicly-traded company. Frankel: AbbVie: Current Employment, Current equity holder in publicly-traded company. Grunspan: AbbVie: Current Employment, Other: May hold equity. Ofran: Medison Israel: Consultancy; Pfizer: Consultancy; Astellas: Consultancy; AbbVie: Consultancy; Janssen: Consultancy. Moshe: Novartis: Membership on an entity's Board of Directors or advisory committees, Other: Lectures; Astellas: Membership on an entity's Board of Directors or advisory committees, Other: Lectures; AbbVie: Membership on an entity's Board of Directors or advisory committees, Other: Lectures.

Background: The outcome of elderly patients with Acute Myeloid Leukemia (AML) is poor and treatment options in these high-risk groups are limited. Recently, venetoclax combinations with hypomethylating agents or low dose cytarabine were approved to treat patients with AML ineligible for intensive chemotherapy. However limited prospective data is available on the safety and efficacy of venetoclax treatment in routine clinical practice. Israel is among the first countries to have approved venetoclax-based combinations as first line therapy for AML and this treatment is fully reimbursed via the national health system. Here we present the initial results of a prospective, multicenter, nationwide trial that sought to assess the use of venetoclax-based therapy in a real-world setting. Methods: A prospective observational nationwide multicenter trial. Newly diagnosed patients with AML were enrolled at the time of venetoclax-based therapy initiation. Demographic, clinical and patient-related baseline characteristics were documented. Treatment patterns, safety and efficacy outcomes are reported. Patient related outcomes were assessed at baseline and after cycle 3 using the EQ-5D-5L and EORTC QLQ-C30 questionnaires. Results: A total of 70 patients were enrolled between August 2019 and June 2020 (data cut off) with a median age of 75 years (range 45-88) and a median follow-up of 74 days (8-232). Two-thirds of patients were males (62.9%). Over one-quarter (28.6%) of patients had an ECOG performance status of 2 or higher; the median modified Charlson Comorbidity Index (CCI) was 0 (range 1-4) with 27.1% with a CCI ≥2. De-novo AML was documented in 44.3%, secondary AML was diagnosed in 52.8% (secondary to MDS (27.1%), MPNs (11.4%) and therapy related AML (14.3%)). European LeukemiaNet (ELN) risk category was favorable, intermediate and adverse in 8.6%, 30% and 42.9%, respectively (Table 1). Time from diagnosis to initiation of therapy was 8 days (median, range 1-38). The main reasons for choosing venetoclax-based low intensity therapy as reported by treating physicians were patient related factors (mainly age>75 years, performance status) in the majority of cases and adverse disease biology predicting poor response to intensive chemotherapy in 17.1%. Of the 57 patients with available data, 38 (67%) initiated therapy in an inpatient setting with a median hospitalization duration of 12 days (range 1-62 days) and 19 (33%) patients started therapy as outpatients. By data cutoff, of 63 patients that initiated therapy 45, 23 and 7 patients completed cycle 1, cycle 3 and cycle 6 assessments, respectively. Complete remission (CR) or CR with incomplete count recovery (CRi) was achieved in 23/44 (52.3%) patients that were assessed for best response. Of responding patients, 6 (23%, 5 CRi and 1 Partial Remission (PR)) went on to receive an allogeneic transplantation (median age 70.5 years). Ninety percent of patients received venetoclax in combination with hypomethylating agents (azacytidine n=56, decitabine n=1). The full dose of 400mg was administered in 87% of cases with a median ramp-up duration of 3 days. Dose interruptions, dose modifications and dose discontinuations during follow-up were frequent and occurred in 41%, 35% and 27%, respectively. During therapy 63.5% of patients experienced adverse events (AE) of any grade; severe AE's were recorded in 41.3% of patients. Febrile neutropenia was documented in 22.2% and Tumor Lysis Syndrome (TLS) was documented in 2 patients (grade 2; 3.2%). Early death rates at 30 and 60 days were 6.3% and 11.1%, respectively. Conclusion: In the real-world setting venetoclax-based therapies are effective and associated with manageable toxicity including in the outpatient setting. In routine practice patient-related factors and disease-related factors (disease-risk) both seem to play a role in choice of therapy. Venetoclax treatment in real-life practice in Israel appears to follow general recommendations, is tolerable with approximately 90% of patients achieving target dose. These observational data are expected to provide information on patient selection patterns, efficacy and safety and patient related outcomes in patients not in clinical trial. Table Disclosures Wolach: AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Fees for lectures and Consultancy, Research Funding; Astellas: Consultancy, Honoraria, Other: Fees for lectures and Consultancy; Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Other: Fees for lectures and Consultancy; Amgen: Other: Fees for lectures and Consultancy; Janssen: Other: Fees for lectures and Consultancy. Levi:Abbvie Inc: Consultancy, Research Funding. Canaani:Abbvie: Consultancy, Honoraria, Research Funding. Tadmor:AbbVie: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Sanofi: Consultancy, Speakers Bureau; Medison: Consultancy, Speakers Bureau; Neopharm: Consultancy, Speakers Bureau; 6. Novartis Israel Ltd., a company wholly owned by Novartis Pharma AG: Consultancy, Speakers Bureau. Tavor:Abbvie: Consultancy, Honoraria, Research Funding. Hellmann:Abbvie: Research Funding. Stemer:Abbvie: Research Funding. Cohen:Abbvie Inc: Current Employment, Current equity holder in publicly-traded company. Afik:Abbvie Inc: Current equity holder in publicly-traded company. Ofek:Abbvie Inc: Current Employment. Banayan:Abbvie Inc: Current Employment, Current equity holder in publicly-traded company. Kan:Abbvie Inc: Current Employment, Current equity holder in publicly-traded company. Grunspan:Abbvie Inc: Current Employment, Current equity holder in publicly-traded company. Ofran:AbbVie: Membership on an entity's Board of Directors or advisory committees. Moshe:Astellas: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria, Research Funding.

The combination of daunorubicin and cytarabine is the cornerstone of induction therapy for acute myeloid leukemia (AML). Little data are available on the optimal chemotherapy regimen for patients with AML and advanced renal failure, with some authors recommending administration of reduced daunorubicin doses. We report the case of a 54-year-old AML patient on chronic hemodialysis who was treated with a modified induction regimen with reduced-dose daunorubin. Daunorubicin levels were measured during the treatment schedule. Although daunorubicin terminal t1/2 appears to be unaffected in hemodialysis patients, the estimated 0-23 h area under the curve was comparable with that of patients receiving full-dose daunorubicin. Therefore, dose adjustment in this patient group may be prudent.

Evaluation of early response during induction therapy for acute myeloid leukemia (AML) is used for prognostication and re-induction strategy, yet the optimal evaluation time point is unknown. Clearance of bone marrow (BM) blasts by day 14 of therapy does not ensure remission; thus, some patients requiring re-induction are neglected. This study aimed to examine the role of earlier BM evaluation during induction for predicting remission and overall survival. Results of BM testing on the 5th and 14th day of intensive induction were prospectively compared in 127 adult patients with AML. Re-induction was given, based on Day 14 results, to 25 patients. Reduction of the BM blast count to

Introduction Azacitidine (AZA) dose reduction is a common practice in cytopenic patients. However, a correlation between AZA dose and infection complications has never been studied. Patients and Methods Higher-risk patients with myelodysplastic syndrome or acute myeloid leukemia treated with AZA in 18 Israeli hospitals between the years 2008 and 2011 were included in a former national survey. To reveal the effect of AZA dosage on infection risk we limited our analysis to the infection rate after the first AZA dose alone. We excluded subsequent cycles of AZA from the analysis, because infectious events during these cycles might be related to other cofactors such as disease response to AZA therapy. Results After the first AZA cycle, infectious events were more frequent after doses of 75 mg/m 2 for 7 days than 75 mg/m 2 for 5 days (36/106 [34%] and 10/67 [14.9%], respectively; P = .008), regardless of the patient's age. Of the 46 recorded infectious events, the causative pathogen was identified as bacterial in 25 (54.3%) and as viral or fungal in 2 (4.3%) and 2 (4.3%) cases, respectively. No pathogen was identified in 17 (37%) cases. Infections were significantly more prevalent among patients who presented with platelet counts P = .012) and poor risk cytogenetics (40.7% vs. 19.8%; P = .008). Conclusion Reduction of AZA dose might decrease infection rate and therefore should be considered in patients with high infection risk.

Introduction: The phase III RATIFY study (Stone et al, NEJM 2017) demonstrated that the addition of the FLT3 inhibitor midostaurin to intensive induction and consolidation courses improves outcome in younger FLT3-positive AML patients. The toxicity and efficacy profile of adding midostaurin to chemotherapy in patients not originally included in the RATIFY study is unknown. We sought to characterize midostaurin use in a 'real-world' setting. Methods: Patients (>18 years) with FLT3-positive AML (ITD/TKD) were eligible to receive midostaurin through the Novartis extended access program that was launched in Israel in April 2016. In order to control for toxicity and efficacy outcomes in the midostaurin-treated patients, a historical control cohort was created that included patients with FLT3-positive AML from 2 participating centers that were not treated with midostaurin (all patients diagnosed after January 2015). Data were extracted from electronic patient records and were collected from several medical centers in Israel. Base-line characteristics, disease- and patient- specific parameters as well as relapse-rates and overall survival were analyzed and compared between the midostaurin treated and untreated cohorts. We used Cox regression to analyze predictors for survival. This study was approved by the Institutional Review Board. Results: Thirty-five patients were included in the analysis. The median age of the patients was 62 years (range 27-78); 40% and 20% of patients were over the age of 65 and 70 years, respectively. FLT3-ITD mutations were detected in 32 patients (91%) and 3 patients had TKD mutations (9%). Eight patients (23%) had secondary leukemia, 83% had normal karyotype and 57% were NPM1-mutated. No differences were noted between the midostaurin-treated group (n=21) and the historical control cohort (n=14) in terms of age, gender, leukemia ontogeny, cytogenetics, presenting blood counts, extramedullary involvement, performance status and comorbidity scales. More patients in the midostaurin group were found to be NPM1-mutated (66 vs. 44%, p=0.03). Furthermore, no differences were noted between the groups in terms of daunorubicin dose for induction (45, 60 and 90 mg/m2/dayin 20, 30 and 50% of patients, respectively), number of consolidations (median number of cycles - 2), cytarabine dose or allogeneic transplantation rate (45 and 36% in the midostaurin and control group, respectively). The full 14 day midostaurin course was given in most patients during induction (73%). In 5 patients midostaurin was initiated only at the post-induction courses due to technical delays in drug supply. Only 4 patients experienced dose reductions or interruptions during therapy: 3 during induction (septic shock, drug interaction and QT prolongation) and 1 during consolidation (new onset atrial fibrillation). Toxicity was comparable between the cohorts. Febrile neutropenia during induction was noted in 95 and 93% of patients in the midostaurin and control groups, respectively. Time to neutrophil and platelet recovery were also comparable (25 vs. 24 days and 24 vs. 20 days in the midostaurin and control groups respectively). Other toxicities were uncommon and not significantly different between the groups. CR/CRi rates were 85% and 58% in the midostaurin and control cohorts, respectively (p=0.17). The median follow-up time for surviving patients in the midostaurin and control cohorts were 426 and 517 days, respectively (p=0.55). During follow-up, 7 deaths occurred in the midostaurin group and 9 in the control arm. Median survival was not reached for the midostaurin treated group and was 281 days for the control group (Figure 1, p=0.42). Nine and 6 patients in remission relapsed in the midostaurin and control group, respectively, translating into a relapse-rate of 53% and 86%, respectively (p=0.19). No difference in early death rate was noted between the groups. The only factor that significantly affected overall survival in the COX-regression analysis was white blood cell count at diagnosis (p=0.03). Conclusions: In the off-trial setting, midostaurin is administered across all age groups and various FLT3-positive subtypes. In this 'real-life' setting, midostaurin is well tolerated and does not significantly add to the toxicity of chemotherapy. Longer follow-up and more patients are needed to assess the efficacy of adding midostaurin to chemotherapy in this group of patients. Figure 1. Figure 1. Disclosures Ofran: Novartis: Other: Served on a Novartis advisory board.

Evaluation of early response during induction therapy for acute myeloid leukemia (AML) is used for prognostication and re-induction strategy, yet the optimal evaluation time point is unknown. Clearance of bone marrow (BM) blasts by day 14 of therapy does not ensure remission; thus, some patients requiring re-induction are neglected. This study aimed to examine the role of earlier BM evaluation during induction for predicting remission and overall survival. Results of BM testing on the 5th and 14th day of intensive induction were prospectively compared in 127 adult patients with AML. Re-induction was given, based on Day 14 results, to 25 patients. Reduction of the BM blast count to5% as early as by the fifth day of induction was more specifically associated with the achievement of remission compared to Day 14 (88.2% vs. 60%, respectively). Rapid responders have a better 3-year overall survival (OS). Day 5 results are a stronger predictor of OS by multivariate analysis and better segregate long-term survivors than the Day 14th BM count (66% vs. 30%, P = 0.0001 and 48% vs. 37%, respectively, P = 0.04). The Day 5 evaluation of BM carries significant clinical information. The benefit of prescribing re-induction based on such early evaluation should be prospectively studied.

Hypomethylating agents have become the standard therapy for patients with high-risk myelodysplastic syndrome (MDS). In Israel, azacitidine (AZA) is routinely used. Yet, infectious complications are common during AZA therapy. The current study was aimed to evaluate the incidence and predisposing risk factors for infections in AZA-treated patients. This retrospective study included patients treated with AZA in 18 Israeli medical institutions between 2008 and 2011. Data on 184 patients [157 high-risk MDS and 27 acute myeloid leukemia (AML)], with a median age of 71.6 (range 29-92) were recorded. Overall, 153 infectious events were reported during 928 treatment cycles (16.5%) administered to 100 patients. One hundred fourteen, 114/153 (75%) events required hospitalization and 30 (19.6%) were fatal. In a univariate analysis, unfavorable cytogenetics, low neutrophil, hemoglobin (Hb) and platelet (PLT) counts were found to be associated with infections (24.4% vs. 12.9%, P < 0.0001; 27% vs. 13.5%, P < 0.0001; 20.4% vs. 11%, P < 0.0001 and 29.2% vs. 14.2%, P < 0.0001, respectively). In multivariate analysis, only low Hb level, low PLT count, and unfavorable cytogenetics remained significant. Prior to therapy, poor cytogenetics, PLT count below 20 × 10⁹/L and neutrophil count below 0.5 × 10⁹/L were predictive of the risk of infection during the first two cycles of therapy. In conclusion, patients with unfavorable cytogenetics, presenting with low neutrophil and PLT counts, are susceptible to infections. Evaluation of infection risk should be repeated prior to each cycle. Patients with poor cytogenetics in whom AZA is prescribed despite low PLT count are particularly at high risk for infections and infection prophylaxis may be considered.

Ponatinib is an oral tyrosine kinase inhibitor (TKI) that has been designed to be effective also in patients who harbor the TKI-refractory threonine to isoleucine mutation at position 315 (T315I). In December 2014 the drug was granted an accelerated approval by the FDA, based on the promising results from the phase II PACE (Ponatinib Ph ALL and CML evaluation) trial. In this trial, 56% of previously treated patients who had resistance to or unacceptable side effects from dasatinib or nilotinib achieved a major cytogenetic response, including 70% of patients with the T315I mutation. Albeit the PACE trial convincingly demonstrated the efficacy of ponatinib, the wide use of the drug has been limited due to safety matters and in particular arterial thrombotic complications, reported in up to 17% of patients. Currently, there is very little real-life information regarding the use of ponatinib outside of clinical trials. The purpose of this study is to characterize patients with chronic myeloid leukemia (CML) who received ponatinib and to assess the effectiveness and safety profile of ponatinib outside of clinical trials. Between 4.2011 and 7.2015 (51 months) 24 patients with CML received ponatinib in 7 medical centers in Israel. We reviewed the medical records of these patients and asked their physicians to rank the quality of life of their patients on a 1 to 5 scale. Prior to ponatinib therapy, patients were treated for a median of 55 months (range: 1 to 215) with 1 to 3 different TKIs (median: 3). In addition 13 patients received at least one course of chemotherapy or interferon and 2 underwent allogeneic bone marrow transplantation. Screening for mutations at the DNA binding domain was performed at least once during the pre-ponatinib follow-up time in most patients (67%, N=16). Mutations were detected in 11 patients (69%) and the T315I mutation was detected in 8 of those. The median age when starting ponatinib was 44 years (rang: 23 to 79). Most patients had advanced disease and their disease was classified as either accelerated (21%, N=5) or blast crisis (41%, N=10) when they started ponatinib. Based on the medical history, 48% were at-risk to develop vascular complications either because of prior cerebrovascular event or myocardial infarction (18%) or because of vascular risk factors (30%). Baseline ECG and cardiac ECHO studies were available in 11 patients. Only two had signs of prior MI in ECG and none had significant structural or functional pathology. At time of analysis the median duration of follow up was 6 months (range Conclusions: In real- life setting ponatinib is generally used as a last resort. In our cohort, it was almost exclusively given to patients who experienced failure to previous TKIs. The only exceptions were 2 patients who received ponatinib for suboptimal molecular response and achieved MMR when switched to ponatinib. Only one third of patients tolerated the recommended dose of 45mg. Yet, response rate was still relatively high, suggesting that a daily dose of 30mg might be appropriate. With only 6 months of follow-up we documented 3 cardiovascular events (12%) that prompted discontinuation of the drug and only one patient had a significant prior vascular risk. The high response rate and overall contribution to quality of life in patients with very few alternatives, who already experienced failure of other TKIs, support the use of this treatment for patients with advanced disease. Disclosures Raanani: Novartis: Other: Advisory Board, Research Funding; BMS: Other: Advisory Board; Ariad: Other: Advisory Board; Pfizer: Other: Advisory Board. Lavie:Pfizer: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Rozovski:Novartis: Other: Advisory board.

Rapid eradication of blasts from peripheral blood during induction therapy in AML is associated with remission and overall survival. We prospectively evaluated the value of a bone marrow (BM) examination on day 5 of induction therapy in unselected newly diagnosed AML patients assigned for intensive induction. Seventy nine patients were enrolled during a 29-months period in six medical centers in Israel. BM blasts were evaluated by two independent observers and in most cases with the support of FACS analysis. Induction protocols administrated were 3+7 with daunorubicin 60 or 90 mg/m2 or clofarabine 40mg/m2 for five days [58 (73%), 10(13%) and 11(14%) patients, respectively]. Patients’ median age was 59 (range 22-78) years. Among surviving patients the actual follow-up time was longer than 9 months in 25(48%) patients and longer than 12 months in 16 (30%) patients. Cytogenetic results are available for 70 patients [2(3%), 47(67) and 21(30%) with standard, intermediate and poor risk, respectively]. Flt3ITD mutation was present in 11(13.9%) patients and NPM1 mutation, in 12 who presented with normal karyotype and were negative for FLT3-ITD. Treatment protocol was not altered on the basis of day 5 BM examination which was repeated on day 12-14. Residual disease (>10% blasts) was detected and a re-induction protocol (repeat 3+7 at doses of 60 or 45mg/m2 at day 14 or clofarabine 30mg/m2 on day 21) was administered in 20(25%) patients. Overall, 50(72%) patients achieved remission (CR1). Post-remission therapies varied according to patient age and risk factors. Overall, 29(37%) patients underwent allogeneic stem cell transplantation. During the study period, 27(34.2%) patients succumbed, 5(6.3%) during induction, 8(10%) while in remission and 12(15%) following relapse. Day 5 blast counts higher than 10% of all BM nucleated cells predicted for the identification of residual leukemia on day 14 regardless of BM cellularity. Moreover, day 5 counts lower than 10% of all BM nucleated cells predicted for the achievement of CR1 with a single induction course. The 10% cutoff for BM day 5 blast count accurately identified these patients with a sensitivity of 80% and specificity of 74%. Kaplan Meir analysis demonstrated superior overall survival (OS) and lower relapse rate (figure 1a&b) of rapid responders than those with more than 10% blasts in day 5 BM. The 2-year anticipated OS is 80% and 35% (p=0.05), respectively. For the 50 patients who achieved CR1, the predicted 2-year relapse rate was as low as 8% for patients with a low day 5 BM blast count and 82% in the group of higher day 5 BM blasts (p=0.004).Figure 1Figure 1. Bone marrow day 5 aspiration was not always informative and in seven cases where biopsy was not available the blast content couldn’t be assessed. Of the 72 patients with a valid day 5 blasts count, 24 (33%) were rapid responders in whom blasts were less than 10% of BM nucleated cells. On day 14, a lower than 10%, blast count was recognized in 54% of patients. However, 11/16 (69%) of patients who despite high blast counts at day 5 had a low count at day 14, either failed to achieve remission or relapsed. Only 5 patients presented with a low blast count at day 5 had a day 14 blasts count higher than 10%. Rapid response on day 5 was not associated with age or molecular status; yet, there was a trend (p=0.08) towards lower frequency of poor cytogenetics among these patients. Surprisingly, mean presenting WBC was higher among rapid responders. Conclusion Bone marrow blast count on the fifth day of induction during chemotherapy is a powerful predictor of AML prognosis, irrespective of other pre-treatment risk factors. Larger studies, with longer follow up are required to determine its role in clinical management. Disclosures: No relevant conflicts of interest to declare.