Combination Of Cytarabine Research Articles

Clofarabine Plus Low-Dose Cytarabine For The Treatment Of Patients Withhigher-Risk Myelodysplastic Syndrome (MDS) Who Have Been Relapsing After, Or Are Refractory To, Hypomethylator Agent Therapy

▪ BackgroundTreatment with hypomethylating agents (HMA) such as azacitidine and decitabine has changed the overall outcome of patients with MDS. Failure to responed to or relapse from treatment with HMA carries a poor outcome and no approved therapy for these patients exists. Clofarabine is a second generation nucleoside analog with single agent activity in MDS. AimThis is a phase II trial to evaluate the safety and activity of the combination of clofarabine and low dose cytarabine in the treatment of patients with high risk MDS who failed prior HMA therapy. Material and MethodEligible were adults older than 18 years with MDS who have had no response, progressed, or relapsed following at least 4 cycles of therapy with either azacitidine and/or decitabine. Patients were required to have an ECOG performance status of </=2 at the time of study entry. Responses were defined according to IWG 2006 criteria. Induction therapy consisted of clofarabine 15 mg/m2 IV daily X 5 days (days 1-5) and cytarabine 20 mg SC twice daily X 7 days (days 1-7). Patients could receive up to 3 induction cycles as long as they tolerated the therapy and had stable disease. Responding patients proceeded with consolidation therapy with clofarabine 15 mg/m2IV daily X 3 days (days 1-3) and cytarabine 20 mg SC twice daily X 5 days (days 1-5) for a maximum of 12 cycles. Cycles were repeated every 4 to 8 weeks depending on hematopoietic recovery and resolution of toxicities. ResultsBetween January 2012 and March 2013, 29 patients were enrolled. The clinical characteristics are summarized in Table 1. Twenty four patients were evaluable for response (5 patients were too early for response). The overall response rate (ORR) was 50% (8 [33%] achieved complete remission (CR)/ complete remission with incomplete platelets recovery (CRp)/marrow CR, and 4 [17%] had stable disease with hematological improvement). With a median follow up of 4.9 months (range, 1.9-16.7), the median overall survival (OS) was 4.8 months (range, 0.5-13.5). Most toxicities were grade </= 2 and included: elevated liver enzymes in 41% of the patients, elevated bilirubin (38%), rash (28%), nausea (31%), headache (24%), and febrile neutropenia (28%). Grade >/= 3 toxicities included: elevated liver enzymes (3%) and elevated bilirubin (3%). Four-week mortality was 12%.Table 1Patient characteristicsN(%) / [range]Total29Median age, year6959-78Age > 65GenderMale2069Female931Prior chemotherapy931Prior radiotherapy724Performance status0-125862414DiagnosisRAEB1448RAEB-T1139CMML413IPSS scoreIntermediate-127Intermediate-21448High1345Cytogenetic analysisDiploid1345-5/5q- and -7/7q-414-5/5q- (sole)27-7/7q- (sole)13+82711q abnormalities13Miscellaneous621Median WBC X 1093.00.6-81.0Median hemoglobin g/dL9.12.8-13.6Median platelets x 10947.04.0-187.0Median bone marrow blasts %16.07.0 - 28Median peripheral blood blasts %3.00 - 22 ConclusionThe combination of clofarabine and low-dose cytarabine has an ORR of 50% in patients with MDS who failed prior therapy with HMA. The study continues to accrue and updated results with longer follow up will be presented at the meeting. Disclosures:Off Label Use: Clofarabine use in MDS. Faderl:Sanofi-Aventis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Targeting The Wee1 Kinase With MK-1775 For Treatment Of Acute Myeloid Leukemia In The Down Syndrome Population

Approximately one seventh of pediatric acute myeloid leukemia (AML) patients also have Down Syndrome (DS), or constitutional trisomy 21. DS AML is considered to be a unique disease from non-DS AML, due in part to a high prevalence of somatic GATA1 mutations and a megakaryocytic phenotype (AMKL). In contrast to the non-DS population, DS AML is generally associated with a very favorable prognosis. However, treatment of this disease is not without complications. Adverse drug effects are significant within this population, especially with up to half of patients possessing congenital heart abnormalities. Furthermore, for those patients who suffer either an induction failure or relapse, prognoses are dismal (Taga T. et al., Blood, 120: 1810-1815, 2012) including the outcomes after stem cell transplant (Hitzler JK. et al., Biol Blood Marrow Transplant, 19:893-897, 2013). Therefore, less toxic and more efficacious therapies are needed for this population.Recently, chemotherapeutic targeting of cell cycle checkpoints has emerged as an exciting possibility, with many clinical trials underway. The wee1 kinase has been identified as a potential target in many malignancies, including leukemia. It is responsible for inhibiting CDK1 and CDK2 by adding phosphate groups at amino acid residue tyrosine 15 (Y15), which is necessary for subsequent checkpoint activation by checkpoint proteins (e.g. CHK1). The development of a wee1-specific inhibitor, MK-1775, has allowed investigations into its use alone or in combination with classical chemotherapeutics as treatment for many types of cancer, with favorable results thus far. However, there is some controversy with regards to the mechanism by which it enhances cell death.In this preclinical work we used DS AML cell lines to investigate the potential use of MK-1775, both alone and in combination with cytarabine, to improve outcomes in DS AML patients. The two cell lines, CMK and CMY, were derived from DS AMKL patients and both harbor GATA1 mutations. CMK was derived from a patient who relapsed after initial treatment and CMY was derived from a patient who experienced an induction failure. The CMY line displays significant resistance to multiple different classes of chemotherapy drugs including nucleoside agents (e.g. cytarabine) and anthracyclines. We found that MK-1775 alone was able to cause growth inhibition and apoptosis at clinically relevant doses in both cell lines, independent of sensitivity to cytarabine or other agents. This effect was greatly enhanced by the addition of cytarabine. Addition of 250nM MK-1775 was able to reduce the cytarabine IC50 9- and 45-fold in CMK and CMY cells, respectively. Combination indices (CI) for this combination ranged from 0.66-0.95 and 0.50-0.94 in CMK and CMY, respectively.The combination of MK-1775 and cytarabine was able to synergistically induce apoptosis as measured by annexinV/propidium iodide (PI) staining. Addition of MK-1775 was able to decrease inhibitory CDK1 and CDK2 Y15 phosphorylation induced by cytarabine treatment. Interestingly, treatment with MK-1775 increased DNA damage induced by cytarabine as measured by γH2AX signal on western blots. Furthermore, this damage was induced primarily in S-phase, as measured by γH2AX/PI dual-staining and flow-cytometry. Finally, to aid with the clinical translation of this work, the dose- and time-dependency of MK-1775 treatment on CDK1 and CDK2 Y15 phosphorylation was determined. Briefly, even low doses (100nM) of MK-1775 were able to reduce CDK1 and CDK2 Y15 phosphorylation after only four hours. However, this inhibitory phosphorylation was able to return after only 1 hour, suggesting that treatment with MK-1775 must be continued during cytarabine therapy.In conclusion, these data support the combination of MK-1775 and cytarabine for the treatment of DS AML, including possible relapsed/refractory cases which have a very poor prognosis. Combining MK-1775 with cytarabine was able to synergistically induce apoptosis in both cell lines, possibly by increasing DNA damage and decreasing inhibition of CDK1 and CDK2. Disclosures:No relevant conflicts of interest to declare.

Phase II, Open Label, Randomized Comparative Trial Of Ondansetron Alone Versus The Combination Of Ondansetron Plus Aprepitant For The Prevention Of Nausea and Vomiting In Patients (Pts) With Hematological Malignancies Receiving Regimens Containing High Dose Cytarabine

▪ BackgroundChemotherapy induced nausea and vomiting can be a significant problem for pts with acute myeloid leukemia (AML) receiving induction chemotherapy causing deterioration in quality of life. Cytarabine-containing regimens are the cornerstone for the management of AML and cytarabine is a moderate emetic risk chemotherapy agent. Combination of cytarabine with other chemotherapeutic agent can substantially worsen nausea and vomiting. Ondansetron has been used for nausea control in pts receiving chemotherapy. Aprepitant is a P/neurokinin-1 (NK1)-receptor antagonist approved for use in combination with a 5-HT3-receptor antagonist and dexamethasone for the prevention of acute and delayed chemotherapy-induced nausea and vomiting. We explored whether the combination of two drugs with different mechanisms of action may improve the control of nausea in pts with AML receiving cytarabine-based induction. MethodsPts with AML, high-risk MDS or CML blast phase receiving induction chemotherapy with cytarabine at a dose of ≥1 g/m2/day for at least 3 days were randomized to: Arm 1) Ondansetron 8mg IV 30 minutes before high dose cytarabine followed by ondansetron 24mg IV continuous infusion daily until 6-12 hours after the end of last chemotherapy infusion. Arm 2) Aprepitant 125mg PO plus ondansetron 8mg IV 30 minutes before high dose cytarabine followed by ondansetron 24mg IV continuous infusion daily until 6-12 hours after the end of last chemotherapy, plus aprepitant 80 mg PO daily and to continue for 1 day after last dose of chemotherapy. Pts were followed for 72 hrs post chemotherapy. A diary was used by the pts to record daily number of episodes of nausea and /or vomiting experienced during the study, as well as to record any need of extra medications for escape nausea. Complete response was defined as no emesis episodes and no use of rescue medication during the study period. Partial response was defined as ≤ 1 episode of emesis during the entire study period, no use of rescue medication during the study period, and no more than moderate nausea (NCI grade 2). ResultsForty nine pts were enrolled in each arm. Fifty seven percent were men in arm 1 and 55% men in arm 2. The median age was 53yrs (ranges, 30-68) in arm 1 and 49yrs (ranges, 21-70) arm 2. Caucasians were 83% in arm 1 and 76% in arm 2. African American and Hispanics were 10 % and 6% respectively in arm 1 and 8% and 12% in arm 2. Among the population studied 96% were diagnosed with AML in each arm. MDS 2% in arm 1 and 4% in arm 2. Fourteen percent received Idarubicin with cytarabine (Ara-C) in each arm. Twenty percent in ondansetron (OND) arm and 16% in ondansetron plus aprepitant (OND+APREP) arm receive Ara-C combined with Fludarabin. Ara-C in combination with anthracycline plus nucleoside analogues was given to 49% of pts in each arm. Ten percent in arm 1 received Ara-C with anthracycline and targeted therapy, 8% in arm 2 receive similar combination. Forty two pts on OND arm and 41 pts in the OND+APREP arm were evaluable for efficacy. Patient in the OND+APREP arms achieved higher overall response rates (complete plus partial responses) as shown in Figure 1, but the difference was not statistically significant (OND 67%, OND+APREP 80%; P= 0.11). More than 75% of pts overall were free of nausea on Days 1 and 2. On days 6 and 7 higher proportion of pts in OND+APREP arm were free from nausea than OND arm. Overall 36% of pts required rescue medications, 38% in OND arm and 34% in OND+APREP arm. Among them 14% of pts required rescue more than once; 19% in the OND arm and 10% in OND+APREP arm, as shown in Figure 2. Requirement of rescue medications on Days 2 and 3 were fewer in OND+APREP arm 7% and 5% respectively compare to 21% and 16% in the ondansetron arm (P = 0.06 and P=0.07).Most common adverse events were headache and diarrhea. Twenty percent of pts in OND arm and 19% in OND+APREP arm reported to have NCI grade 2 headache (P= 0.56). Five percent of pts in ondansetron arm and 12% in ondansetron plus aprepitant arm had grade 2 diarrhea (P=0.19). ConclusionsThe daily assessment of emesis and nausea did not show statistically significant differences between the study arms but there was a clear trend towards better responses in ondansetron plus aprepitant arm with more overall response rates and lower use of rescue medications. Further larger studies are warranted to further define the benefits of this combination of antiemetic drugs. [Display omitted] [Display omitted] Disclosures:No relevant conflicts of interest to declare.

The Long-Term Outcome Of Adult Patients With Acute Myeloid Leukemia NPM+ and FLT3/ITD- Is Not Significantly Improved By The Application Of An Allogeneic Stem Cell Transplantation

▪ IntroductionThe discovery of the NPM mutation in acute myeloid leukemia (AML) allowed to identify a distinct entity with intermediate-good prognosis particularly when the FLT3/ITD mutation is absent. The most appropriate consolidation treatment of these patients upon the achievement of the first complete remission has not been established yet and the role of allogeneic stem cell transplantation (SCT) is still debated. Aimto assess long-term outcome of adult patients with NPM positive acute myeloid leukemia according to type and intensity of consolidation therapy. Patients and methodsBetween May 2000 and February 2012, 1155 patients were enrolled into two consecutive, prospective Northern Italy Leukemia Group (NILG) trials (00/01 and 02/06). Six-hundred sixty nine were studied for NPM mutation and 218 (33%) proved positive (by immunohistochemistry or by molecular analysis) (Falini et al, Haematologica. 2007 Apr;92(4):519-32). Median age of NPM+ patients was 50 years (range 16-72) and 134 (61%) were female. Median WBC was 33.3 x 10^9/L (range 0.9-313.9), 71 (33%) had myelomonocytic leukemia (FAB M4), and 211 (96%) had de novo AML. According to the European Leukemia Net (ELN) classification, cytogenetic risk groups were: normal 178 (82%), intermediate 26 (12%), unfavorable 2 (1%) and unknown 12 (5%). Eighty-two (38%) patients had a concurrent FLT3/ITD mutation and 31 (14%) a FLT3/TKD mutation. According to cytogenetics and additional risk factors (late response, WBC count >50x10^9/L, FAB class M0/6/7, hepato/splenomegaly, MDS-related/secondary AML, FLT3/ITD mutation), patients were stratified in standard (SR) and high (HR) risk groups.In both studies the remission induction was based on combination of cytarabine with idarubicin. Post-remission therapy was allogeneic SCT in HR while high-dose cytarabine or busulfan/cyclophosphamide with autologous SCT was given to SR patients. The molecular evaluation of minimal residual disease (MRD) was planned after induction, before the post-remission consolidation and the follow-up. ResultsComplete remission (CR) was achieved in 196/218 (90%) NPM+ patients. One hundred sixty-eight out of 196 remitters (86%) received post-remission consolidation therapy: allogeneic SCT 72 (37%), high dose Ara-C 74 (38%), autologous SCT 14 (7%), other therapy 8 (4%); 28 patients did not receive consolidation due to early relapse (n=24), CR death (n=3), and loss to follow-up (n=1). With a median follow-up of 1.8 years (range 0.008-12.66), 99 CR patients (50.5%) were alive in 1st CR, 13 (6.5%) died of complications, and 84 (43%) had recurrent AML. In a cumulative analysis, 5-year overall and disease-free survival were 46% (OS) and 43% (DFS), respectively. In univariate analysis FLT3/ITD mutation (n=82) affected negatively 5-year OS (29% vs. 49%, P < .0001) and DFS (27% vs. 46%, P < .0001), whereas FLT3/TDK mutation did not. In patients with FLT3/ITD mutation able to receive consolidation therapy (n=49), the application of allogeneic SCT improved DFS significantly (55% vs. 18%, P = .03) and reduced the cumulative incidence of relapse (CIR) (39% vs. 81%, P = .026). In patients with NPM+ and FLT3/ITD- AML, the risk of relapse after high dose cytarabine or autologous SCT (n=68) was more than doubled compared to that observed after allogeneic SCT (n=42) (50% vs. 23%, P= .08) (Figure). However, DFS (48% vs. 69.5%, p= .17), and OS (60% vs. 72%, p= .80) were not significantly different since allogeneic SCT was associated with higher treatment related mortality, albeit effective in the salvage of some relapsed patients. In multivariate analysis, FLT3/ITD mutation was the most powerful factor that unfavorably affected OS, DFS and CIR, while age > 55 years negatively affected OS and DFS. No other clinical factor was predictive for relapse in FLT3- patients. The relationship between MRD and clinical outcome is currently being studied and will be presented. ConclusionsOur data indicate that allogeneic SCT is the most active post-remission treatment for NPM+ AML, but its benefit over chemotherapy may be limited in patients without FLT3/ITD. For this reason the evaluation of MRD could help identify the patients for whom an allogeneic SCT should be preferable. [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Personalizing Therapies With Ex Vivo Pharmacological Responses May Uncover The Differences Between IDA-DNR-MIT Among European AML Protocols

Background and objectivesProtocols for acute myeloid leukemia (AML) 1st line patients are centered on the combination of Cytarabine and an anthracycline; Idarubicin (IDA), Daunorubicin (DNR), or Mitoxantrone (MIT). Patients may be treated with IDA, DNR, or MIT depending on the country of residence, because multiple clinical trials have not found significant differences among them. A new Personalized Medicine (PM) test developed by Vivia Biotech based on pharmacological responses in patient samples (ex vivo) is uncovering individual responses to these treatments. Our objective is to explore whether a significant % of individual patients may respond differently to IDA vs DNR vs MIT treatments, in spite that of their “on average” similar response shown by clinical trials. Patients and MethodsMulticenter, prospective, non-interventional study of the PETHEMA group for treatment of AML. Bone Marrow (BM) samples were collected at diagnosis for 160 AML patients. Samples were incubated for 48 hours in 96-well plates, each well containing different drugs or drug combinations, each at 8 different concentrations, enabling calculation of dose response curves for each single drug (CYT, IDA, DNR, MIT) and combination used in treatments (CYT-IDA, CYT-DNR, CYT-MIT). Drug response was evaluated as depletion of AML malignant cells in each well after 48 hours incubations. Annexin V-FITC was used to quantify the ability of the drugs to induce apoptosis. Malignant cells were identified with monoclonal antibodies and light scatter properties. 1) We use the whole bone marrow sample, retaining the erythrocyte population and serum proteins, during the entire incubation period; and after 48 h leukocytes are isolated prior to evaluation by flow cytometry. 2) We have pioneered development of a proprietary automated flow cytometry platform called ExviTech. 3) Pharmacological responses are calculated using pharmacokinetic population models. ResultsFigure left panel shows dose responses for both IDA (red) and DNR (blue) in 125 AML patient samples. Although their average curves (thick red & blue) are similar, the interpatient variability of either drug is quite large. We hypothesized that some patients could show very differential sensitivities to both drugs, as illustrated by the green arrow where a patient sample is resistant to DNR (right shifted dose response curve) but sensitive to IDA (left shifted dose response curve). To identify these cases Figure right panel shows a comparison of the potency IDA vs DNR. Potency is represented by their EC50 (concentration that kills 50% of the cells). Most dots tend to line up, but red dots represent patient samples with a difference in potency between these drugs >30%. Repeating this exercise for IDA-MIT and DNR-MIT to cover all alternatives among the 3 anthracyclines identifies 40% of patients samples with >30% different potency among IDA-DNR-MIT. Repeating this exercise with the combination treatments CYT-IDA, CYT-DNR, CYT-MIT increases to 58% the population of patients whose samples have a differential sensitivity to these anthracyclines. A fraction of this 57% of patients may benefit in if treatment selection among these 3 treatments were to be aided by this ex vivo testing sensitivities. To identify which fraction would benefit we would need a trial specifically designed. ConclusionsThis preliminary results show that Vivia's PM test seems able to identify a subset of AML patients who's ex vivo pharmacological response to anthracycline drugs is significantly different. Because this ex vivo test accurately predicts the clinical response to CYT-IDA, if these selective anthracycline ex vivo responses translate to clinical responses, a fraction of this 57% subpopulation could benefit significantly from receiving 1st or 2nd line treatments based on either IDA, DNR, MIT, and their combinations. Hence this approach stands for European integration of treatment protocols, based on ex vivo individual responses data rather than nationality. [Display omitted] Disclosures:Primo:Vivia Biotech: Employment. Hernandez-Campo:Vivia Biotech: Employment. Rojas:Vivia Biotech: Employment. Bennett:Vivia Biotech: Employment. Liebana:Vivia Biotech: Employment. Lopez:Vivia Biotech: Employment. Ballesteros:Vivia Biotech: Equity Ownership.

Pharmacodynamic Analysis Of The Inhibitory Potency Of The Tyrosine Kinase Inhibitor Midostaurin In Combination With Intensive Chemotherapy Including Allogeneic Hematopoietic Stem Cell Transplantation Followed By Maintenance Therapy In FLT3-ITD Positive Acute Myeloid Leukemia In The Ongoing AMLSG 16-10 Trial

BackgroundActivating mutations in the receptor tyrosine kinase FLT3 occur in roughly 30% of acute myeloid leukemia (AML) patients (pts), implicating FLT3 as a potential target for kinase inhibitor therapy. The multi-targeted kinase inhibitor midostaurin (PKC412) shows potent activity against FLT3 as a single agent but also in combination with intensive chemotherapy. Besides its mere presence, the allelic ratio as well as ITD insertion site within the FLT3 gene had been reported as prognostic factors in FLT3-ITD positive AML. Furthermore, pharmacokinetic analyses revealed clinically important interactions between potent CYP3A4 inhibitors, such as azoles, and midostaurin. AimsTo evaluate the pharmacodynamic activity of midostaurin measured as inhibition of the degree of phosphorylated FLT3 (pFLT3) in correlation to co-medication and outcome data. MethodsThe study includes intensively treated adults (age 18-70 years) with newly diagnosed FLT3-ITD positive AML enrolled in the ongoing single-arm phase-II AMLSG 16-10 trial (NCT: NCT01477606). Pts with acute promyelocytic leukemia are not eligible. The presence of FLT3-ITD is analyzed by Genescan-based fragment-length analysis (allelic ratio >0.05 required to be FLT3-ITD positive). Induction therapy consists of daunorubicin (60 mg/m², d1-3) and cytarabine (200 mg/m², continuously, d1-7); midostaurin 50 mg twice daily is applied from day 8 onwards until 48h before start of the next treatment cycle. For consolidation therapy, pts proceed to allogeneic hematopoietic stem cell transplantation (HSCT) as first priority; if allogeneic HSCT is not possible pts receive three cycles of age-adapted high-dose cytarabine in combination with midostaurin from day 6 onwards. In all pts maintenance therapy for one year is intended. A total sample size of n=142 is planned to show an improvement in event-free survival from 25% after 2 years to 37.5%. Plasma inhibitory activity assay (PIA) for pFLT3 is performed as previously described (Levis MJ, et al. Blood 2006; 108:3477-83). For PIA, measured time points include day 15 of induction therapy, the end of each treatment cycle and every three months during maintenance therapy. ResultsTo date, 72 pts (median age, 54.5 years; range, 29-69 years) have been included and PIA was performed so far in 37 pts during induction therapy. Median pFLT3 inhibition after one week of midostaurin intake measured on day 15 of cycle 1 (C1D15) was 57.5% (range, 14.2-93.7%) with 2 of 31 pts showing inhibition >85%. At the end of the first induction cycle (C1end), median inhibition was 60.3% (range, 0-99.8%); here, 6 of 37 pts had an inhibition >85%. Co-medication with azoles was present in 7 of 23 pts at C1D15 and 13 of 28 pts at C1end. There was no significant difference in pFLT3 inhibition either on C1D15 (p=0.79) or at C1end (p=0.70) between pts on (median pFLT3 inhibition: 52.5%) or off (median pFLT3 inhibition 57.5%) azoles. Response data were available in 56 pts: complete remission (CR) was achieved in 78.5%; rates of early death and refractory disease (RD) were 9% and 12.5%, respectively. In first analyses, there was no difference in pFLT3 inhibition in pts achieving CR (n=30) as compared to those with RD (n=3; p=0.99). In contrast to our previously published data from three historical trials without a FLT3 inhibitor which showed that high allelic ratio was associated with low CR rates (Kayser S, et al. Blood 2009;114:2386-92), in the current trial CR rates remained high (81.5%) despite of a high allelic ratio above the median (>0.58). In addition, we did not see a negative prognostic impact of ITD insertion site within the tyrosine kinase domain of the FLT3 gene (p=0.99). Analyses are currently ongoing, measurement of FLT3 ligand levels and evaluation of pharmacokinetics of midostaurin are also intended. ConclusionsThe addition of 50 mg midostaurin twice daily to intensive induction therapy resulted in a moderate pFLT3 inhibition during induction therapy. Nonetheless, CR rates are promising, especially in pts with unfavorable FLT3-ITD characteristics. Concomitant azoles do not appear to significantly influence pFLT3 inhibitory activity of midostaurin. Disclosures:Levis:Ambit Biosciences: Consultancy. Schlenk:Ambit: Honoraria; Chugai: Research Funding; Novartis: Research Funding; Pfizer: Research Funding; Amgen: Research Funding.

Stem Cell Transplant Versus Chemotherapy in Older Adults with Acute Myelogenous Leukemia In First Remission

▪ IntroductionOptimal therapy for older adults with acute myelogenous leukemia (AML) who achieve remission following induction chemotherapy has not been determined. Options include consolidation chemotherapy (CC) or stem cell transplant (SCT) if an appropriate donor is identified. In order to determine whether SCT improved overall survival (OS) or whether associated toxicity was increased, we performed a retrospective study comparing SCT with CC in this older age group. MethodsAll adult patients ages 60 to 75 years with AML in 1st remission (CR1) who underwent a SCT at MSKCC between 2001 and 2013 were reviewed and compared to age-matched patients with AML who achieved CR1 and received CC. A landmark analysis at 3 months following CR1 was used to compare OS for the 2 patient groups. Only SCT patients transplanted by landmark time were included in the analysis. Overall survival was compared using Kaplan-Meier methodology. ResultsSixty-eight patients were identified for the SCT group. Thirty-two patients were identified for the CC group (Table). Stem cell sources included: peripheral blood (n=63), cord blood (n=4) and bone marrow (n=1). Fifty-six patients received a T cell depleted transplant (32 with ClinMACsTM and 24 with IsolexTM ) and 12 received an unmodified product. Conditioning regimens were busulfan/melphalan/ fludarabine (n=54), melphalan/fludarabine (n=4), cyclophosphamide/fludarabine/thiotepa/ TBI (n=4), fludarabine/busulfan (n=3), busulfan/melphalan (n=2) and thiotepa/fludarabine/TBI (n=1). Donors included matched unrelated (n=28), matched related (n=25), mismatched unrelated (n=11) and mismatched cord blood (n=4). For patients in the CC group, induction chemotherapy included cytarabine in combination with either idarubicin (n=21), daunorubicin (n=10), or mitoxantrone plus etoposide (n=1). Forty-four patients received their transplant by the 3 month landmark and 30 patients in the CC group were alive at the landmark and were included in the OS analysis.Patient Characteristics:SCTCCNumber of patients6832Median age at SCT or CC65 (60-75)65 (60-69)Males/Females41/2718/14Median F/U in mos (range)19 (1-83)22 (11-75)Number of deaths within 100 days of SCT or 1st cycle CC6 (9%)2 (6%) [Display omitted] Deaths in the SCT group included 4 patients from infection, 1 from treatment-related toxicity, and 1 from relapsed disease. The estimated OS at 2 years in the landmark groups were 64% in the SCT group and 42% in the CC group (p=0.04). ConclusionsRecognizing the inherent bias when retrospective studies compare SCT and CC, these data support the use of SCT for older patients with AML in CR1 who have an appropriate donor. Despite the older age, there was a statistically significant better OS with low 100 day mortality for those patients who underwent SCT. Disclosures:No relevant conflicts of interest to declare.

Fludarabine and Cytarabine Based Induction Therapy Is Associated With High Response Rate and Durable Remission With Low Treatment Related Mortality In Elderly Patients With Core-Binding Factor AML (CBF-AML)

BackgroundCore-binding factor (CBF) AML is associated with high response rate and favorable prognosis when treated with intensive chemotherapy (IC) including intermediate to high dose cytarabine (IHDAC). However, IC can be associated with high treatment-related mortality in elderly patients (pts). Combination of anthracycline and IHDAC in older (age ≥ 60) pts with CBF-AML can result in 88% complete remission (CR) rate but be associated with approximately 10% early treatment-related mortality (Prebet, Boissel et al. JCO, 2009). Thus, there is an urgent need to reduce treatment-related mortality while maintaining the response in this pt population. Our previous study showed that fludarabine and cytarabine based induction regimens, which do not include anthracycline, were highly effective in CBF-AML.(Borthakur, Kantarjian et al. Cancer, 2008), We investigated the response and treatment-related mortality of regimens based on this combination in elderly pts with CBF-AML. MethodsPreviously untreated CBF-AML pts (defined by the presence of t(8;21) or inv(16) ), ages ≥ 60, who received induction treatment under one of the clinical trials at MD Anderson (ID02-266 or 2007-0147) using fludarabine and cytarabine combination without conventional anthracycline were eligible for the analysis. Planned induction comprised of either FA (fludarabine 30 mg/m2 IV daily x 5 days followed by cytarabine 2g/m2 IV daily on the same days), FLAG (GCS-F 5µg/kg subcutaneously daily from day -1 to 5 in addition to FA), or FLAG+GO (gemtuzumab ozogamicin 3mg/m2 IV on day 1 in addition to FLAG). Consolidation therapy was given with the same regimen with reduced dose for total 6 cycles if tolerated. ResultIn total, 34 pts (23 [68%] with inv(16) and 9[32%] with t(8;21)) were eligible for the analysis. Three (9%) pts received FA induction, whereas 18 (53%) and 13 (38%) received FLAG or FLAG+GO induction, respectively. Twenty six (76%) pts received full dose of induction regimen, whereas 8 (24%) pts received reduced dose of induction (from 20%-50% dose reduction). Thirty two (94%) pts were able to receive consolidation therapy for the median 5 cycles (range: 1-6). The median age of the cohort was 68 (range: 60-88). Seven (21%) pts had ECOG performance status (PS) ≥ 2. Twelve (35%) pts had other cytogenetic abnormalities in addition to CBF alteration. None of the pts tested had c-kit mutation (0/16). Other pt demographics are also described in Table 1. [Display omitted] CR and CR without platelet recovery (CRp) were documented in 30 (88%) and 3 (9%) pts, respectively (overall response rate [ORR] = 98%). Two of the 33 responders required 2 cycles to achieve the response. Early treatment related mortality at 4 weeks and 8 weeks was documented in 1 (3%) and 2 (6%) pts, respectively (both pts received FLAG). Ten out of 11 pts on FLAG+GO regimen with available follow up q-PCR data, achieved ≥3 log reduction in leukemia associated fusion transcript ratio by 3 cycles of therapy.Six pts relapsed and one opted for stem cell transplant in remission. Median overall survival (OS) in the entire cohort was 47.9 months. The median relapse free survival (RFS: defined as time interval from CR/CRp to relapse or death) was 47.4 months (95% CI: 21.6-73.1, Figure 1), whereas 1 year and 2 year RFS rate was 73% and 63%, respectively. In an analysis subgrouped by the pt demographics, RFS was significantly worse in pts with PS ≥ 2 (vs. PS < 2, P = 0.03). Howerve, there was no statistical difference in RFS between 1) different age group (age < 70 vs. ≥ 70), 2) inv(16) vs. t(8;21), 3) additional cytogenetics, 4) induction regimen, and 5) presence of molecular alterations (FLT3-ITD, RAS, or NPM1 mutations). [Display omitted] DiscussionInduction therapy with fludarbine and cytarabine based combination regimen is highly effective (ORR 98%), provides durable remissions and is associated with low treatment-related mortality (3% in 4 weeks, 6% in 8 weeks) in elderly (age ≥ 60) pts with CBF-AML. Our findings suggest that anthracycline could be omitted from induction treatment in this pt population. Disclosures:No relevant conflicts of interest to declare.

A Phase II Expansion Study Of Vorinostat In Combination With Idarubicin and Cytarabine For Patients With Acute Myelogenous Leukemia (AML) With FLT3 Molecular Alterations

BackgroundThe combination of vorinostat, idarubicin and cytarabine (IA+vorinostat) is associated with high response rate in patients with newly diagnosed acute myelogenous leukemia (AML) or higher-risk myelodysplastic syndromes (MDS) (JCO 2012;30:2204). In that study, presence of FLT3-ITD was associated with 100% overall response rate (ORR) in 11 patients. To confirm the efficacy of this combination, we extended the phase II study to treat 2 additional cohorts: one for patients with newly diagnosed (untreated cohort) and the other with relapsed and refractory (R/R cohort) AML or higher-risk MDS with FLT3 alteration (both ITD and D835 mutation). MethodsPatients with the above diagnosis, ages 15 to 65 years, with appropriate organ function (measured cardiac ejection fraction ≥ 50%, serum creatinine ≤ 2 mg/dl, total bilirubin ≤ 2 mg/dl, and GPT/GOT ≤ 2.5 x upper limit of normal) whose eastern cooperative group (ECOG) defined performance status ≤ 2 were eligible for the study. Study treatment comprised of vorinostat 500 mg orally three times a day (days 1 to 3), idarubicin 12 mg/m2 intravenously (IV) daily x 3 days (days 4 to 6), and cytarabine 1.5 g/m2 IV as a continuous infusion daily x 3 - 4 days (days 4 to 7). Patients in remission could be treated with five cycles of consolidation therapy with lower dose combination and up to 12 months of maintenance therapy with single-agent vorinostat. ResultUntreated cohort included 26 patients, whereas 13 patients were treated in R/R cohort (total 39 patients). Thirty six patients had de novo AML, 1 had de novo MDS and 2 had therapy-related AML. For the R/R patients, the median number of prior therapies was 3 (range: 1-6). The median age of the entire study group was 49 (range: 19-64) and 17 (44%) were male. Among the patients whose cytogenetic result were available, 20 (51%) patients had normal and 15 (39%) had abnormal karyotype. By Medical Research Council (MRC) criteria, 30 (77%) patients had intermediate risk and 9 (23%) had poor risk karyotype. Thirty three (85%) patients had FLT3-ITD only, 4 (10%) had both FLT3-ITD and D835 mutation, and 2 (5%) had D835 mutation only. Seventeen (44%) patients had NPM1 mutation.In untreated cohort (N = 26), CR and CRp were documented in 21 (80%) and 2 (8%) patients, respectively (ORR = 88%). In R/R cohort (N = 13), overall response (OR) was observed in 4 (30%) patients (CR in 2 [15%] and CRp in 2[15%]). Of those 4 patients who had OR in R/R cohort, 2 patients were refractory to other high-dose cytarabine-based regimen. The median duration of CR or CRp was 9.2 months (range: 0.1-48.4) in untreated cohort and was 2.9 months (range: 1.6-4.7) in R/R cohort. Twelve (46%) patients in the untreated cohort were bridged to stem cell transplant (SCT) while they were in 1st CR. None of the patients in R/R cohort were bridged to SCT. No difference in response was observed in 1) younger (Age < 60) vs. older patients, 2) normal vs. abnormal karyotype, 3) intermediate vs. poor risk cytogenetics by MRC criteria, 4) presence of RAS mutation, 5) presence of NPM1 mutation, or 6) de novo vs. therapy-related disease.The median overall survival (OS) was 21.7 months (95% CI: 8.1-35.3) in the untreated cohort and was 4.9 months (95% CI: 0.1-10.4) in the R/R cohort. Early treatment related mortality (defined by the death within 4 weeks of the induction) was documented in 1 (4%) patient in the untreated cohort and 2 (15%) patients in the R/R cohort. Toxicity profiles were similar to that reported in the original phase II study (JCO 2012;30:2204). DiscussionVorinostat in combination with IA provides high response rate and durable remission in previously untreateed AML or higher risk MDS patients with FLT3 alteration but is less effective in patients with R/R disease. Phase III randomized study of IA+/- vorinostat in previously untreated AML patients is ongoing (SWOG S1203). Disclosures:Off Label Use: vorinostat in MDS and AML. Cortes:Ambit: Research Funding; Astellas: Research Funding; Argo: Research Funding; Novartis: Research Funding.

Long Term Molecular Response To Triple Therapy With High Doses Imatinib In Patients With Chronic Myeloid Leukemia

IntroductionImatinib 400 mg daily is considered the best initial therapy for patients with chronic myeloid leukemia (CML) in the chronic phase (CP). However, only minorities of patients have a complete molecular remission (CMR) Another agent has antileukemic activity against Bcr-Abl-positive cells like Ara-C and interferon, the association of this drugs and imatinib in CML was evaluated in several trials with an increase in molecular response.The aim of this study was to evaluate the major molecular response (MMR) at 12 months with triple treatment schedule, analyze the evolution of these patients and general and hematologic toxicity. Material and MethodsPatients diagnosed with CML at the Hospital General de Zona #35 in Juarez, Mexico were included. Eligibility criteria were adults with diagnosis of CML chronic phase on triple regimen for at least 12 months: Pegylated interferon-α 2a 90mcgrs via subcutaneous / week for 4 weeks + PO imatinib 800 mgs a day for 30 days + 20 mgs/mt2 cytarabine from day 1 to 10 subcutaneus. Patients were stratified according to Sokal score at diagnosis. The molecular analysis was performed in Quest diagnostic laboratory by means of real-time quantitative polymerase-chain-reaction (RT-PCR) results are expressed as a percent ratio of BCR-ABL1 to ABL1 and further adjusted to the international scale (IS) since august 2012.Patients could have received previous treatment for CML, with the exception of bone marrow transplantation. All patients provided written informed consent. This study was conducted in accordance with the Declaration of Helsinki.Molecular and adverse events were assessed. An analysis of molecular response at 12 months was planned and follows up patients with MMR every year. A MMR was defined a Bcr-Abl 0.1% or less and complete molecular response (CMR) as undetectable. Hematological toxicity was assessed according WHO scale. Results41 patients completed the first 12 months in therapy, with a mean age of 44.4 years (17 to 71) 51% male and 49% female, the median and ranges of hemoglobin levels, leukocyte and platelet counts at diagnosis were 10.2 g/dl (5.1-16.0), 209.000 μL3 (10,600 - 529.000) and 565.500 μL (130.000 to 4,272,000) respectively. The percentages of cases by Sokal risk group were 70.7% low, 24.4% intermediate and 4.9% high risk.The Median follow up time was 58 months (range 14 to 120). At 12 months the number of patients who were in MMR was 27 (65.9%) including 8 (19.5%) with no BCR-ABL detectable. Median duration of triple therapy exposure at first year was 24 Weeks (range 12 to 32)Responses by Sokal score were 62%, 70% and 100% for low, intermediate and high respectively. Adverse events occurred in 88% cases; 33% of patients has at least one adverse event (AE) 42% 2 EA and 28% 3 EA, the most important EA was gastrointestinal. (table 1) 43.9% of patients has Hematological toxicity III-IVMedian follow up time of patients in RMM was 64 months (range16-120) 2 patients were no evaluable. Patients who have RMM at 12 months 50% achieve a CMR at last follow up, 33% continues in RMM and 17% loss molecular response. Patients with CMR 72% have undetectable bcr-abl, 14% have loss molecular response and 14% in MMR ConclusionsIn this group of patients MMR was achieved in a higher proportion of cases at 12 months of treatment which is important in the long-term prognosis. Side effects grade 3 and 4 hematologic and non-hematologic were significant in this series of cases appearing in 44 and 88% respectively, which requires close monitoring of patients. The combination of interferon α2a, cytarabine and high-dose imatinib induces a MMR of 66% at 12 months of treatment, a 28%, 56% and 16% in MMR, CMR and loss molecular response respectively at last follow up.Table 1Adverse eventsAdverse eventn%Gastrointestinal2261Bone pain1644Cutaneous1028Liver toxicity1028Fluid retention822Infection720Nervous system central617Fever26Cramps13Psychiatric13Clinical files n =36 Disclosures:No relevant conflicts of interest to declare.

Longer Follow-Up Of The Combination Of Clofarabine, Idarubicin, and Cytarabine (CIA) As Frontline Therapy For Patients Younger Than 61 Years With Newly Diagnosed Acute Myeloid Leukemia (AML)

Abstract Background Clofarabine is a second generation nucleoside analogue with activity in adults with AML. In a phase II trial of clofarabine in combination with idarubicin and cytarabine in newly diagnosed patients (pts) with acute myeloid leukemia (AML) &lt;/= 60 years old, the overall response rate (ORR) was 79%. The combination was well tolerated with low induction mortality. Compared to historical pts who were treated with idarubicin and cyarabine (IA), the overall survival (OS) and event-free survival (EFS) were significantly longer for CIA treated pts and mainly for pts &lt;/= 40 years old. Aim To report a longer follow up of this study. Patients and Methods Eligible were adults between 18-60 years old with newly diagnosed AML with adequate renal (creatinine &lt;/= 1.0 mg/dL) and hepatic (bilirubin &lt;/= 1.5 x upper limit of normal, [SGPT and/or SGOT] &lt;/= 2.5 x ULN) functions. Ptswere excluded for ECOG PS &gt; 2, cardiac ejection fraction &lt; 45%, or active and uncontrolled infection. For the first 30 pts, induction therapy consisted of Clofarabine 22.5 mg/m2 iv daily (days 1-5), Idarubicin 6 mg/m2 daily (days 1-3), and Cytarabine 0.75 g/m2 daily (days 1-5). From pt 31 onward, induction doses were amended to Clofarabine 20 mg/m2 x 5, Idarubicin 10 mg/m2 x 3, and Cytarabine 1 g/m2 x 5. Pts who did not achieve a complete remission (CR) following induction could receive one re-induction course. Pts in CR/CRp continued with up to 6 consolidation cycles with Clofarabine 22.5 mg/m2 x 3, Idarubicin 6 mg/m2 X 2, and Cytarabine 0.75 g/m2 x 3, subsequently amended to Clofarabine 15 mg/m2 x 3, Idarubicin 8 mg/m2 x 2, and Cytarabine 0.75 g/m2x 3. Results From April 2010 until February 2012, 57 pts were evaluable. With median follow up of 21.5 months (1.5-33.4), the median OS was 27.4 months, median relapse-free survival was not reached, and median EFS was 11.5 months. Patients &lt;/= 40 years who received CIA had a better OS (HR 0.43, CI 0.24-0.75, P = 0.007), and better EFS (HR 0.43, CI 0.24-0.75, P = 0.007) compared to pts &gt; 40 years. Compared to a historical cohort of pts treated with IA, CIA continued to show superior OS (HR 0.8, CI 0.51-1.27, P = 0.043). In multivariate analysis, CIA retained its prognostic value on OS even when transplant was added as time dependent covariate (HR 0.84, CI 0.53-1.33, P = 0.04). Pts &lt;/= 40 years had superior OS (HR 0.15, CI 0.03-0.65, P= 0.039) when they were treated with CIA compared to IA. Conclusion A longer follow up of the CIA combination in newly diagnosed pts with AML &lt;/= 60 continues to show OS benefit compared to IA alone. Patients &lt;/=40 years continue to benefit the most from this combination regardless of transplant. A randomized trial to compare this combination to standard therapy in AML is needed to further investigate the role of this combination in AML. Disclosures: Off Label Use: Clofarabine use in AML. Kantarjian:Sanofi-Aventis: Research Funding. Ravandi:Sanofi-Aventis: Research Funding. Faderl:Sanofi-Aventis: Membership on an entity’s Board of Directors or advisory committees, Research Funding.

Elacytarabine Is More Effective Preclinically Than Cytarabine In Combination With Daunorubicin In Primary Patient Xenografts Of AML

Acute myeloid leukemia (AML) is a heterogeneous disease with poor prognosis. The overall survival rate in AML patients has changed little in the last 20 years with overall survival rates for young patients (< 60 years) remaining at 35%. However, for elderly patients (> 60 years), survival is less than 10%. Despite the fact that AML represents one of the most molecularly characterized malignancies, the standard therapeutic option is unaltered in the last 15 years i.e. we still solely rely upon a combination of anthracycline and Cytarabine (Ara-C) as the cornerstone of induction therapy.Recently many potentially drugable targets have been discovered and while responses have been observed, these are generally amongst sub-sets of patients with good to intermediate prognostic factors and most often in combination with conventional therapy. Elacytarabine (ELA; CP-4055) is a fatty acid derivative (elaidic acid ester) of Ara- C, currently in undergoing phase II clinical trial as second-course remission-induction therapy in combination with anthracycline.In this study we determined the maximum tolerated dose for the combination of ELA with Daunorubicin (DAN) in immunodeficient NOD-scid-IL2Rγcnull (NSG) mice. Subsequently, we compared the preclinical efficacy of the combination of ELA (30 mg/kg; q.d.x5) or Ara-C (500 mg/kg; q.d.x2) with DAN (2.5 mg/kg; q.d.x3) in a primary patient xenograft model of refractory AML following relapse after Ara-C+DAN therapy (n = 24). Efficacy was evaluated employing a novel time-domain imaging strategy utilizing targeted monoclonal antibodies conjugated to near infrared dye that specifically recognize and bind to epitopes on AML cells enabling non-invasive monitoring of disease progression following therapy. Similarly, bone marrow aspirates were assayed for AML content by flow cytometry (CD45+/34+/33+) and IHC analysis.The combination of ELA and DAN was well tolerated in NSG mice xenografted with primary patient AML cells. While longitudinal near infrared optical imaging of AML disease dissemination illustrated lower disease burden in Ara-C + DAN treated mice than controls (p<0.05), those treated with ELA+DAN demonstrated significantly reduced disease progression, both in comparison to controls (p<0.001) and Ara-C+DAN (p<0.01) treated NSG mice. Flow cytometry analysis of bone marrow aspirates revealed similar reductions in ELA treated mice. Ultimately, combination of ELA+DAN exhibited significant increases in mean survival time (45 ± 4.6 days) over control (31.6 ± 1.7 days; p<0.0001) and Ara-C+DAN treated NSG mice (39 ± 3.2 days; p<0.039).ELA is more effective preclinically than Ara-C in combination with DAN in primary patient xenografts of refractory AML. ELA was found to be well tolerated and significantly increased survival in combination with Daunorubicin. Despite withdrawal of Elacytarabine as a single agent (following Phase III clinical trial earlier this year in relapsed and refractory AML versus investigators choice of treatment) our preclinical results demonstrate combined therapy of ELA+DAN may promise enhanced survival advantages over current standard therapy for AML patients. Disclosures:Popa:KinN Therapeutics AS: Employment. Gjertsen:KinN Therapeutics AS: Membership on an entity's Board of Directors or advisory committees. McCormack:KinN Therapeutics AS: Membership on an entity's Board of Directors or advisory committees.

Efficacy and Relative Costs Of Re-Induction Chemotherapy With Clofarabine and Cytarabine For Adults With AML

IntroductionChemotherapy for adults with Acute Myeloid Leukemia (AML) has undergone little change in 30 years. Unfortunately, many patients relapse following an initial response to chemotherapy, and there is no standard salvage chemotherapy regimen in AML. There have been no randomized trials comparing various intensive re-induction regimens (i.e., MEC – Mitoxantrone/cytarabine/etoposide; FLAG-Ida – Fludarabine/cytarabine/idarubicin/g-csf; CLAG – cladribine/cytarabine/g-csf), and reported rates of complete remission (CR) with these regimens range from 25-60%. The only potentially curative therapy for relapsed AML is an allogeneic stem cell transplant (SCT), and SCT outcomes are improved for patients in second CR compared to those transplanted with refractory disease. Clofarabine is a second-generation purine analog, inhibiting ribonucleotide reductase and DNA polymerase. The CLASSIC I trial randomized older patients with relapsed/refractory AML to either clofarabine/cytarabine to low-dose cytarabine, with improved CR (35%) and event-free survival and no significant difference in overall survival. Single arm clinical trials with a combination of clofarabine and cytarabine report CR rates of 25-60% in the setting of relapsed AML. Our institution has treated patients with relapsed or refractory AML with the clofarabine/cytarabine regimen off clinical trial from September, 2011, to January, 2013. Here, we report the outcomes in the context of chemotherapy drug costs (Table 1). MethodsWe conducted a retrospective chart review of 20 consecutive adult patients with AML treated at the University of Kansas Medical Center from September, 2011 to January, 2013, with the combination of clofarabine (40mg/m2/day days 1-5) followed 4 hours later by cytarabine (1g/m2/day days 1-5). Data collected included age, sex, AML cytogenetics, number of prior therapies, remission rates, toxicities, number of patients proceeding on to stem cell transplant and length of hospitalization. ResultsThe median age was 67 years (range 34-74) with a male predominance (12/20 patients) and average of 2 prior therapies (range 1-3). Cytogenetics at diagnosis are available for 18 patients: 11 with poor risk; 6 with intermediate risk; 1 with favorable risk (normal cytogenetics, NPM1 mutated). We observed a 30% CR rate, with 5/6 patients in CR going on to SCT (one patient who achieved CR had evidence of leukemia recurrence at evaluation for planned SCT). The average length of stay was 33 days (5-70). Three patients had short hospitalizations (less than 14 days) or outpatient administration of chemotherapy and all three required re-admission for neutropenic fever and /or sepsis. Seven patients underwent SCT following clofarabine and cytarabine re-induction: 5 in CR and 2 with active disease at the time of SCT. Six patients received an allogeneic SCT at our institution, 5 in CR and 1 with active disease; 1 patient received SCT at another institution. One patient had relapse of AML following SCT in CR2 at day 128 post-SCT. The other 4 patients in CR at time of SCT remain alive without relapse at 215, 293, 608 and 647 days after clofarabine/cytarabine. The patient who was transplanted with active leukemia died 113 days after clofarabine/cytarabine. One patient who did not achieve CR but had a decrease in blast percentage continues to receive decitabine monthly and is alive after 14 doses at the time of this writing despite lack of CR. DiscussionOur single institution experience with clofarabine/cytarabine for refractory or relapsed AML a CR rate of 30%, consistent with published literature. It also allowed 5 patients to receive SCT in CR2, and of those, 4 remain alive and in remission; one additional patient remains alive although with residual leukemia. However, length of hospitalization was 33 days and there is significant underlying drug cost disparity. The regimen of clofarabine and cytarabine is effective in inducing CR in adult patients with relapsed and refractory AML, albeit at a higher drug-specific cost than other regimens.Table 1Drug and vial sizeCost/vialTypical re-induction dose for 2m2 patientCost/re-induction courseCladribine 10mg$46010mg × 5 days$2300Clofarabine 20mg$300780mg × 5 days$60,140Cytarabine 1000mg$262000mg × 5 days$260Etoposide 100mg$12200mg × 5 days$120Fludarabine 50mg$12160mg × 5 days$1210Mitoxantrone 20mg$16916mg × 5 days$676 Disclosures:No relevant conflicts of interest to declare.

Combination of fludarabine, amsacrine, and cytarabine followed by reduced-intensity conditioning and allogeneic hematopoietic stem cell transplantation in patients with high-risk acute myeloid leukemia

Sequential use of chemotherapy and reduced-intensity conditioning (RIC) with allogeneic stem cell transplantation (SCT) has been proposed to improve the treatment outcomes in patients with high-risk acute myeloid leukemia (AML). Here, we present our experience with this procedure in a cohort of 60 AML patients with primary induction failure (n = 9); early, refractory, or ≥ second relapse (n = 41); or unfavorable cytogenetics (n = 10). A combination of fludarabine (30 mg/m²/day), cytarabine (2 g/m²/day), and amsacrine (100 mg/m²/day) for 4 days was used. After 3 days of rest, RIC was carried out, consisting of 4 Gy total body irradiation, antithymocyte globulin (ATG-Fresenius), and cyclophosphamide (fludarabine, amsacrine, and cytarabine (FLAMSA)-RIC protocol). Prophylactic donor lymphocyte infusions (pDLIs) were given in patients with complete remission (CR) and without evidence of graft-versus-host disease ≥120 days after SCT. The median time of neutrophil engraftment was 17 days. CR was achieved in 47 of 60 patients (78%). Eleven patients received pDLIs resulting in long-term CR in eight of them. Non-relapse mortality after 1 and 3 years was 25 and 28%, respectively. With a median follow-up of 37 months (range, 10-69), 3-year overall survival and 3-year progression-free survival were 42 and 33%, respectively. In a multivariate analysis, dose of CD34(+) cells >5 × 10⁶/kg (p = 0.005; hazard ratio (HR) = 0.276), remission of AML before SCT (p = 0.044; HR = 0.421), and achievement of complete chimerism after SCT (p = 0.001; HR = 0.205) were significant factors of better overall survival. The use of the FLAMSA-RIC protocol in suitable high-risk AML patients results in a long-term survival rate of over 40%.

Aurora B inhibitor barasertib and cytarabine exert a greater‐than‐additive cytotoxicity in acute myeloid leukemia cells

Barasertib, an aurora B inhibitor, terminates cell division, introduces polyploidy, and consequently causes apoptosis. In the present study, we evaluated the effect of the combination of barasertib and cytarabine (ara-C), a key agent for leukemia chemotherapy, on leukemic cells in vitro. Human leukemia HL-60 cells and HL-60/ara-C20 cells, a 20-fold ara-C-resistant variant, were used. The 50% growth inhibitory concentrations of an active metabolite of barasertib, barasertib-hydroxyquinazoline-pyrazol-aniline (Barasertib-HQPA), and ara-C were 51 nM and 300 nM for HL-60 cells and 70 nM and 5300 nM for HL-60/ara-C20 cells, respectively. Barasertib-HQPA induced polyploidy with a subsequent induction of sub-G1 phase apoptosis, indicating the M-phase specific cytotoxicity. Cells treated with the S-phase specific ara-C accumulated in S phase and subsequently died through apoptosis. When HL-60 cells were treated with barasertib-HQPA and ara-C in combination, a greater-than-additive apoptosis was induced. This enhancement was obtained when the cells were treated with barasertib-HQPA prior to ara-C (37.9% sub-G1) or with both concurrently (31.2% sub-G1), but not with ara-C prior to barasertib-HQPA (17.8% sub-G1). The combination effects were similarly obtained in HL-60/ara-C20 cells with 19.7% sub-G1 for barasertib-HQPA→ara-C, 18.4% sub-G1 for both concurrently, and 13.8% sub-G1 for ara-C→barasertib-HQPA, and another leukemic U937 cells with 25.4% sub-G1 for barasertib-HQPA→ara-C, 28.2% sub-G1 for both concurrently, and 16.0% sub-G1 for ara-C→barasertib-HQPA. Barasertib-HQPA inhibited aurora B autophosphorylation and histone H3 phosphorylation in all the cell lines. Barasertib-HQPA did not inhibit DNA synthesis, allowing ara-C incorporation into DNA for its cytotoxicity. Thus, barasertib-HQPA and ara-C provided a greater-than-additive cytotoxicity in leukemic cells in vitro.

Abstract 3274: Combination of elacytarabine and daunorubicin is significantly more effective than combination of cytarabine and daunorubicin in primary patient xenografts of AML.

Abstract Background: The overall survival rate in patients with acute myeloid leukaemia has changed little in the last 20 years with overall survival rates for young patients (60 years, survival statistics are less than 10% being cured (2). Although AML has become one of the most molecularly characterised malignancies, the core therapeutic option remains unchanged in the last 15 years i.e. We continue to be solely reliant upon a combination of anthracycline and Cytarabine (Ara-C) as the cornerstone of induction therapy. Recently many potentially drugable targets have been revealed (3-7) and while responses have been observed, these are generally amongst sub-sets of patients with good to intermediate prognostic factors and most often in combination with conventional therapy. Aims and methods: Elacytarabine (ELA; CP-4055) is a fatty acid derivative of Ara-C, currently in undergoing phase II and phase III clinical trial as second-course remission-induction therapy and in late stage AML, respectively. In this study we determined the MTD for the combination of ELA in combination with Daunorubicin (DAN) in NSG mice. Subsequently, we compared the preclinical efficacy of the combination of ELA (30 mg/kg; q.d.x5) or Ara-C (500 mg/kg; q.d.x2) with DAN (2.5 mg/kg; q.d.x3) in primary xenografts in NSG mice (n = 24) from relapsed (Ara-C+DAN) AML patients. Employing a novel time-domain imaging strategy (8) we non-invasively monitored disease progression following therapy. Similarly marrow aspirates were assayed for AML content by flow cytometry and IHC analysis. Results: The combination of ELA and DAN was well tolerated in NSG mice xenografted with primary patient AML cells. While longitudinal near infrared optical imaging of AML disease burden illustrated lower disease burden in Ara-C + DAN treated mice than controls (p&amp;lt;0.05), those treated with ELA+DAN demonstrated significantly reduced disease burden, both in comparison to controls (p&amp;lt;0.001) and Ara-C+DAN (p&amp;lt;0.01) treated mice. Flow cytometry analysis of bone marrow aspirates revealed similar reductions in ELA treated mice. Ultimately, combination of ELA+DAN exhibited significant increases in mean survival time (45 ± 4.6 days) over control (31.6 ± 1.7 days; p&amp;lt;0.0001) and Ara-C+DAN treated mice (39 ± 3.2 days; p&amp;lt;0.039). Conclusions: The combination of ELA+DAN is well tolerated and significantly increase survival in comparison to Ara-C+DAN in primary patient xenografts of refractory AML. 1. Rowe JM, et al. Blood 2010; 116: 3147-56. 2. Burnett AK. Rev Clin Exp Hematol 2002; 6: 26-45; discussion 86-7. 3. Nencioni A et al. Leukemia 2007; 21: 30-6. 4. Bruserud O et al. Expert Opin Ther Targets 2006; 10: 51-68. 5. Burnett AK et al. Hematology Am Soc Hematol Educ Program 2007: 429-34. 6. Doepfner KT et al. Crit Rev Oncol Hematol 2007; 63: 215-30. 7. Tang R et al. BMC Cancer 2009; 9: 199. 8. McCormack E et al. Blood 2012; In Press. Citation Format: Tereza Osdal, Lars P. Jordheim, Mihaela Popa, Lene M. Vikebø, Andre Sulen, Siv Lise Bedringaas, Marit Liland Sandvold, Birgitte Booij, Øystein Bruserud, Bjørn Tore Gjertsen, Charles Dumontet, Emmet McCormack. Combination of elacytarabine and daunorubicin is significantly more effective than combination of cytarabine and daunorubicin in primary patient xenografts of AML. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3274. doi:10.1158/1538-7445.AM2013-3274

Abstract LB-92: RVX-2135 is a novel, orally bioavailable epigenetic BET inhibitor that synergizes with cytarabine and idarubicin to inhibit proliferation of acute myeloid leukemia cells.

Abstract Current treatment of acute myeloid leukemia (AML) often includes a combination of intravenous cytarabine (Ara-C) and an anthracycline such as idarubicin. Bromodomain and extra-terminal domain (BET) proteins contain two bromodomains that bind to acetylated lysines in histones and regulate gene transcription by an epigenetic mechanism. Here we describe a novel small molecule BET inhibitor, RVX-2135, which selectively binds recombinant BET bromodomains of BRD2, BRD3, and BRD4 but not non-BET bromodomains. RVX-2135 inhibited BRD2, BRD3, and BRD4 dual bromodomains binding to acetylated histones in vitro with sub to low micromolar IC50 values. In the human AML cell line MV4-11, RVX-2135 displaced BET proteins from chromatin and significantly reduced expression of c-MYC and BCL-2 mRNAs, with IC50s of 4 and 5 μM, respectively. RVX-2135 inhibited proliferation of cultured MV4-11 cells with an IC50 value of 6 μM, and induced cell cycle arrest and apoptosis. In vivo, nude mice bearing MV4-11 xenografts were treated orally with RVX-2135 at doses of 75 and 120 mg/kg b.i.d, and showed tumor growth inhibition of 77 and 92% respectively. There was a corresponding inhibition of c-MYC and BCL-2 mRNA expression in the xenograft tumors. In combination therapy in vitro, RVX-2135 synergized with idarubicin and cytarabine, with Chou-Talalay's combination indices of 0.17 and 0.18, respectively. The synergistic effect also translated into increased apoptosis when cytarabine was combined with RVX-2135. Similar data were seen with BET inhibitors from different chemical scaffolds, suggesting that this may represent a promising new class of drugs for AML. Citation Format: Eric Campeau, Ravi Jahagirdar, Jin Wu, Emily M. Gesner, Olesya Kharenko, Raymond Yu, Sarah Attwell, Henrik C. Hansen, Gregory S. Wagner, Kevin G. McLure, Peter R. Young. RVX-2135 is a novel, orally bioavailable epigenetic BET inhibitor that synergizes with cytarabine and idarubicin to inhibit proliferation of acute myeloid leukemia cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-92. doi:10.1158/1538-7445.AM2013-LB-92

High-dose imatinib versus high-dose imatinib in combination with intermediate-dose cytarabine in patients with first chronic phase myeloid leukemia: a randomized phase III trial of the Dutch-Belgian HOVON study group

Despite the revolutionary change in the prognosis of chronic myeloid leukemia (CML) patients with the introduction of imatinib, patients with resistant disease still pose a considerable problem. In this multicenter, randomized phase III trial, we investigate whether the combination of high-dose imatinib and intermediate-dose cytarabine compared to high-dose imatinib alone, improves the rate of major molecular response (MMR) in newly diagnosed CML patients. This study was closed prematurely because of declining inclusion due to the introduction of second generation tyrosine kinase inhibitors and only one third of the initially required patients were accrued. One hundred nine patients aged 18-65years were randomly assigned to either imatinib 800mg (n = 55) or to imatinib 800mg in combination with two successive cycles of cytarabine 200mg/m(2) for 7days (n = 54). After a median follow-up of 41months, 67% of patients were still on protocol treatment. The MMR rate at 12months was 56% in the imatinib arm and 48% in the combination arm (p = 0.39). Progression-free survival was 96% after 1year and 89% after 4years. Four-year overall survival was 97%. Adverse events grades 3 and 4 were more common in the combination arm. The addition of intermediate-dose of cytarabine to imatinib did not improve the MMR rate at 12months. However, the underpowering of the study precludes any definitive conclusions. This trial is registered at www.trialregister.nl (NTR674).

The combination of rituximab, bendamustine, and cytarabine for heavily pretreated relapsed/refractory cytogenetically high‐risk patients with chronic lymphocytic leukemia

Treatment of patients with B-cell chronic lymphocytic leukemia (CLL) relapsed/refractory (R/R) to conventional treatments is particularly challenging. The combination of bendamustine and cytarabine has demonstrated distinct and synergistic mechanisms of action in preclinical studies on cell lines and primary tumor cells of several B-cell lymphomas, including 17p deleted or TP53 mutated CLL. The efficacy of rituximab (375 mg/m(2) , Day 1), plus bendamustine (70 mg/m(2) , days 1-2), and cytarabine (800 mg/m(2) , Day 1-3; R-BAC), every 28 days for up to four courses, was evaluated in a pilot trial enrolling 13 patients with very selected high-risk R/R CLL. All patients (median age 60 years, range 53-74) had symptomatic Binet stage B or C active disease requiring treatment, were characterized by adverse cytogenetics (17p deletion, 11q deletion, or both), unmutated immunoglobulin heavy-chain variable region, and were heavily pretreated (1-5, median three previous lines). Overall, R-BAC was well tolerated with limited non-hematological toxicity. Major toxicities were transient Grade 3/4 neutropenia and thrombocytopenia in 84% and 85% of patients, respectively. Overall response rate (OR) was 84%, including complete and partial response in 38% and 46% of patients, respectively. Patients with 17p deletion had an OR of 78%. After a median follow-up of 17 months, median progression-free survival was 16 months while median overall survival (OS) was not reached (1-year OS: 75 ± 13%). R-BAC is an active regimen in R/R heavily pretreated high-risk patients with CLL, representing an option for the treatment of patients that are usually refractory to standard therapy.

Multiplexed mAbs: a new strategy in preclinical time-domain imaging of acute myeloid leukemia

AbstractAntibodies play a fundamental role in diagnostic immunophenotyping of leukemias and in cell-targeting therapy. However, this versatility is not reflected in imaging diagnostics. In the present study, we labeled anti–human mAbs monochromatically against selected human myeloid markers expressed on acute myeloid leukemia (AML) cells, all with the same near-infrared fluorochrome. In a novel “multiplexing” strategy, we then combined these mAbs to overcome the limiting target-to-background ratio to image multiple xenografts of AML. Time-domain imaging was used to discriminate autofluorescence from the distinct fluorophore-conjugated antibodies. Imaging with multiplexed mAbs demonstrated superior imaging of AML to green fluorescent protein or bioluminescence and permitted evaluation of therapeutic efficacy with the standard combination of anthracycline and cytarabine in primary patient xenografts. Multiplexing mAbs against CD11b and CD11c provided surrogate imaging biomarkers of differentiation therapy in an acute promyelocytic leukemia model treated with all-trans retinoic acid combined with the histone-deacetylase inhibitor valproic acid. We present herein an optimizedapplication of multiplexed immunolabeling in vivo for optical imaging of AML cellxenografts that provides reproducible, highly accurate disease staging and monitoring of therapeutic effects.