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Key Points First report of an FLT3-targeted therapy added to nonintensive chemotherapy that has improved survival in older FLT3-ITD patients with AML.Quizartinib is well tolerated, improves response and survival in older FLT3-ITD AML patients and merits consideration in future therapies. Now amended as text above., Visual Abstract, Survival for older patients with acute myeloid leukemia (AML) unsuitable for intensive chemotherapy is unsatisfactory. Standard nonintensive therapies have low response rates and only extend life by a few months. Quizartinib is an oral Fms-like tyrosine kinase 3 (FLT3) inhibitor with reported activity in wild-type patients. As part of the AML LI trial, we undertook a randomized evaluation of low-dose ara-C (LDAC) with or without quizartinib in patients not fit for intensive chemotherapy. Overall, survival was not improved (202 patients), but in the 27 FLT3-ITD patients, the addition of quizartinib to LDAC improved response (P = .05) with complete remission/complete remission with incomplete haematological recovery for quizartinib + LDAC in 5/13 (38%) vs 0/14 (0%) in patients receiving LDAC alone. Overall survival (OS) in these FLT3-ITD+ patients was also significantly improved at 2 years for quizartinib + LDAC (hazard ratio 0.36; 95% confidence intervals: 0.16, 0.85, P = .04). Median OS was 13.7 months compared with 4.2 months with LDAC alone. This is the first report of an FLT3-targeted therapy added to standard nonintensive chemotherapy that has improved survival in this population. Quizartinib merits consideration for future triplet-based treatment approaches. This trial was registered at www.clinicaltrials.gov as ISRCTN #ISRCTN40571019 and EUDRACT @2011-000749-19.

The survival of acute myeloid leukaemia (AML) patients aged over 60 has been suboptimal historically, whether they are treated using hypomethylating agents, low-dose cytarabine (LDAC) or venetoclax-based regimens. Progress is being made, however, for subgroups with favourable molecular or cytogenetic findings. Arginine metabolism plays a key role in AML pathophysiology. We report the only randomised study of LDAC with recombinant arginase BCT-100 versus LDAC alone in older AML patients unsuitable for intensive therapy. Eighty-three patients were randomised to the study. An overall response rate was seen in 19.5% (all complete remission [CR]) and 15% (7.5% each in CR and CR without evidence of adequate count recovery [CRi]) of patients in the LDAC+BCT-100 and LDAC arms respectively (odds ratio 0.73, confidence interval 0.23-2.33; p = 0.592). No significant difference in overall or median survival between treatment arms was seen. The addition of BCT-100 to LDAC was well tolerated.

Despite the approval of 8 new drugs for acute myeloid leukemia (AML) since 2017, the disease remains challenging, given the significant toxicity associated with available treatments and relatively low cure rates, especially in older adults. Although advantageous for patients, self-congratulatory rejoicing about the new agents would be extremely premature. Questions abound about the need for a specific versus less specific FLT3 inhibitor (eg, midostautin) in the upfront setting and whether a single agent (gilteritnib), albeit better than chemotherapy, is sufficient for relapsed disease. Is the new liposomal formulation of daunorubicin/cytarabine better than ‘3 + 7’ only in secondary AML? Should only those newly diagnosed patients with core binding factor AML routinely receive gemtuzumab ozogamicin? The isocitrate dehydrogenase inhibitors were approved based on non-randomized data; thus, one wonders whether single-agent isocitrate dehydrogenase inhibitor therapy is appropriate for relapsed patients. Glasdegib, an orally available hedgehog inhibitor, is approved in conjunction with low-dose cytarabine in unfit patients but is rarely used in favor of a combination of hypomethylating agents or low-dose cytarabine with venetoclax, which are hopeful newly approved combinations for the older and/or unfit previously untreated. Perhaps venetoclax-based combinations should be more widely used, but the data is currently lacking. Thus, a temperate approach, more clinical research, and a critical analysis of the available data remain important in this “optimistic” new era of AML therapeutics.

The prognosis for younger patients with relapsed acute myeloid leukaemia (AML) is generally dismal. Allogeneic stem cell transplantation is the preferred therapy for these patients. As part of the UK NCRI AML17 trial, daunorubicin/clofarabine (DClo) was compared with fludarabine, cytarabine, granulocyte colony-stimulating factor with idarubicin (FLAG-Ida) in 311 patients designated high-risk following course one of induction therapy, which has previously been reported. We now report the results of the same randomisation in patients who were refractory to two induction courses or subsequently relapsed. A total of 94 relapsed or refractory AML patients, usually less than 60 years of age and with mainly favourable or intermediate-risk cytogenetics, were randomised to receive up to three courses of DClo or FLAG-Ida, with the aim of proceeding to transplant. Complete remission was achieved in 74% of patients with no difference between the arms. Overall, 57% of patients received a transplant with no difference between the arms, likewise overall survival at five years showed no significant difference (21% for DClo vs. 22% for FLAG-Ida). No patient who did not receive a transplant survived beyond 21months. A stratified analysis including the 311 post course 1 high-risk patients who underwent the same randomisation showed a consistent treatment benefit for FLAG-Ida.

Acute myeloid leukemia (AML) is a hematological malignancy with an undefined heritable risk. Here we perform a meta-analysis of three genome-wide association studies, with replication in a fourth study, incorporating a total of 4018 AML cases and 10488 controls. We identify a genome-wide significant risk locus for AML at 11q13.2 (rs4930561; P = 2.15 × 10−8; KMT5B). We also identify a genome-wide significant risk locus for the cytogenetically normal AML sub-group (N = 1287) at 6p21.32 (rs3916765; P = 1.51 × 10−10; HLA). Our results inform on AML etiology and identify putative functional genes operating in histone methylation (KMT5B) and immune function (HLA)., Genome wide association studies in cancer are used to understand the heritable genetic contribution to disease risk. Here, the authors perform a genome wide association study in European patients with acute myeloid leukemia and identify loci associated with risk of developing the disease.

Acute myeloid leukemia (AML) is a hematological malignancy with an undefined heritable risk. Here we performed a meta-analysis of three genome-wide association studies, with replication in a fourth study, incorporating a total of 4018 AML cases and 10488 controls. We identified a genome-wide significant risk locus for AML at 11q13.2 (rs4930561; P = 2.15 × 10-8; KMT5B). We also identified a genome-wide significant risk locus for the cytogenetically normal AML sub-group (N=1287) at 6p21.32 (rs3916765; P = 1.51 × 10-10; HLA). Our results inform on AML etiology by identifying putative functional genes operating in histone methylation (KMT5B) and immune function (HLA).

BackgroundAcute myeloid leukaemia (AML) is a heterogeneous disease where outcome is substantially influenced by age. Over the last 30-40 years, significant improvements have been made in survival for younger patients (those under 60). However, with the median age of the disease at diagnosis at 65 years, outcome in older patients has improved much less. Additionally, many elderly patients are not considered suitable for intensive chemotherapy and the current standard treatment is considered unsatisfactory. MethodsLI1 will evaluate several relevant therapeutic questions in AML patients over 60 years of age for whom intensive chemotherapy is not considered suitable. Patients are invited to enter a randomized comparison of standard therapy (LD Ara-C) versus a novel treatment. A number of different treatment options are available at any one time, but there is no comparison between novel agents. If, at initial review, a novel agent is deemed unlikely to demonstrate the required improvement, it may be removed from the protocol and replaced with another novel agent, via protocol amendment. Agents are initially entered into a phase II comparison against standard of care - where an agent is considered promising at interim review (based on remission rates), the randomisation may be extended to a fully powered phase III comparison based on survival. Agents which may prolong survival or improve remission rates will also be required to demonstrate equivalence or better of quality of life in patients – therefore, quality of life assessments are undertaken throughout, in each arm. DiscussionEven when less intensive treatment options are delivered, the outcomes are not satisfactory. The NCRI AML working group has a strong network, required for delivery of this trial program. The UK network is augmented by international collaborative groups, most notably from New Zealand and Denmark. The use of the Pick-a-Winner design improves efficiency and speed of review of the available novel agents with the aim of benefitting the increasing number of patients in this age group.Trial registration: ISCRTN40571019, EUDRACT2011-000479-19 (12th May 2011)

Since the comprehensive recommendations for the management of acute promyelocytic leukemia (APL) reported in 2009, several studies have provided important insights, particularly regarding the role of arsenic trioxide (ATO) in frontline therapy. Ten years later, a European LeukemiaNet expert panel has reviewed the recent advances in the management of APL in both frontline and relapse settings in order to develop updated evidence- and expert opinion–based recommendations on the management of this disease. Together with providing current indications on genetic diagnosis, modern risk-adapted frontline therapy, and salvage treatment, the review contains specific recommendations for the identification and management of the most important complications such as the bleeding disorder APL differentiation syndrome, QT prolongation, and other all-trans retinoic acid– and ATO-related toxicities, as well as recommendations for molecular assessment of the response to treatment. Finally, the approach to special situations is also discussed, including management of APL in children, elderly patients, and pregnant women. The most important challenges remaining in APL include early death, which still occurs before and during induction therapy, and optimizing treatment in patients with high-risk disease.

Background: Many patients with Acute Myeloid Leukemia (AML) diagnosed after 60 years of age are not considered suitable for intensive remission induction chemotherapy, either due to co-morbidities or frailty associated with advanced age. Despite treatment with either a hypomethylating agent or low-dose cytarabine arabinoside (LDAC), survival is usually poor, with 1-year survival after LDAC of 24-37% in NCRI AML16 and historical arms of LI-1. Combination therapy with additional agents represents an attractive option, and has the potential to improve patient outcomes without substantially increasing toxicity. Lenalidomide (Revlimid TM) is an immunomodulatory drug, used to treat myeloma, and some cases of myelodysplastic syndrome, and has potent antineoplastic, anti-angiogenic, anti-inflammatory and pro-erythropoietic properties. Early-phase trials of lenalidomide in AML have demonstrated clinical activity with acceptable toxicity. Aim: To assess the efficacy and tolerability of LDAC+lenalidomide versus LDAC alone in patients aged 60+ unsuitable for intensive therapy. The aim was to double 2-year survival from 11% to 22% (HR 0.69). Methods: LI-1 was an international multicentre, multi-arm, randomised phase II trial developed to study the efficacy and tolerability of novel non-intensive therapies in AML using a "pick a winner" design. LDAC was given at 20mg BD SC on days 1-10 of each course. Lenalidomide was administered orally once daily in a flat 10mg dose for 21 days, where day 1 is day 1 of LDAC with courses occurring at 5-week intervals for courses 1-4. Patients considered to be benefitting after 4 courses, i.e. in remission or stable disease, could continue to receive treatment until disease progression, either with LDAC+lenalidomide at 6-week intervals, or lenalidomide only at 4-week intervals if patient had experienced significant toxicity. Toxicities were recorded using CTCAEv3. Primary objectives included overall survival (OS), complete remission (CR + CRi) achievement, reasons for failure, duration of response (CR/CRi), relapse rates and deaths in first CR. Secondary objectives included toxicity, supportive care requirements, and Quality of Life assessments (measured using EORTC QLQ-30, EQ5D and HADS tools). Results: Between Jan-17 and Jun-19, 202 patients from Denmark (8%), New Zealand (16%) and the UK (76%) were randomised. Median age was 78 years (range 62-89). Overall, 58% were male; 76% de novo AML, 20% secondary AML, and 4% high risk MDS; 1% favourable, 66% intermediate, 19% adverse and 14% unknown cytogenetics; WHO performance status 0 for 15%, 1 for 58%, 2 for 22% and 3 for 5%. Median of 2 courses (range 0-24; mean 3.28) was delivered in LDAC arm and 1 course in LDAC+lenalidomide arm (range 0-25; mean 3.48). Overall response (CR/CRi) was achieved in 40/202 patients (20%), (LDAC+lenalidomide 25%, LDAC 14%, OR 0.45 (0.22, 0.93), P=0.031). 30-day mortality was not significantly increased (19% in both arms); and 2-year OS showed no significant difference (14% vs 11.5%, HR 0.94 (0.69, 1.29, P=0.719). Median OS was 3.5 vs 4.6 months; HR 0.96 (0.71, 1.30), P=0.80. 1-year OS for patients that didn't enter CR/CRi was 6.8% for LDAC+lenalidomide vs 16.9% for LDAC (P=0.028). Cause of death for the majority of patients was resistant/recurrent disease: 45(53%) vs 47(58%). Most adverse events (AEs) were grade 1/2 in both arms. During cycle 1, there were 78 vs 51 grade 3/4 AEs in the LDAC+lenalidomide and LDAC arms, respectively (P=0.02). This included 5 thrombotic events in the LDAC+lenalidomide arm (4 grade 3 and 1 grade 4) and none in the LDAC arm. In course 1, supportive care requirements were higher in terms of both days of antibiotics (7 vs 3; p=0.001) and hospitalisation days (11 vs 6.5; p=0.005) for the LDAC+lenalidomide arm. There was no difference in transfusion requirements. Conclusions: Despite improving the CR/CRi rate, the combination of lenalidomide+LDAC did not improve OS, relapse-free survival or time in remission in elderly patients with AML. The addition of lenalidomide to LDAC resulted in increased toxicity, including episodes of thrombosis, as well as increased supportive care requirements. Alternative strategies to improve survival for elderly patients with AML remain a significant clinical need. Acknowledgements: We are grateful to Blood Cancer UK for funding the trial and Celgene for providing drug and additional support for this IIS. Fig 1: OS All patients Figure 1 Figure 1. Disclosures Copland: Astellas: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Incyte: Honoraria, Research Funding, Speakers Bureau; Jazz: Honoraria, Speakers Bureau; Cyclacel Ltd: Research Funding. Russell: Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Speakers Bureau; Astellas: Membership on an entity's Board of Directors or advisory committees; Jazz: Research Funding, Speakers Bureau. OffLabel Disclosure: Off label use of lenalidomide in combination with low dose cytarabine will be discussed in the setting of elderly unfit AML.

Background: Among patients with Acute Myeloid Leukaemia (AML) over the age of 60, a considerable number are not considered suitable for intensive remission-induction chemotherapy. Survival in these patients is poor, whether they are treated using hypomethylating agents or low-dose ara-C (LDAC). The possibility of combination therapy with additional agents represents an attractive option. Arginine metabolism plays a key role in AML pathogenesis (Mussai et al. Blood 2013); BCT-100 is a pegylated recombinant human arginase that leads to a rapid depletion in extracellular and intracellular arginine concentrations resulting in G0/G1 arrest, and subsequent death by necrosis. BCT-100 demonstrates significant activity as single-agent against AML cell lines, AML xenografts and primary AML blasts from newly diagnosed or relapsed patients (Mussai et al. Blood 2015). Importantly BCT-100 is synergistic in combination with cytarabine. Aims: To assess the efficacy of LDAC+BCT100 versus LDAC alone in patients aged 60+ unsuitable for intensive therapy, in a "pick a winner" design. This design allows several treatments to be assessed simultaneously in a randomised fashion, with the aim of doubling 2-year survival from 11% to 22% (HR 0.69), with interim assessments after 50 and 100 patients per arm are recruited. Methods: LDAC was given at 20mg BD SC on days 1-10 of each course. Patients randomised to the combination received LDAC as above with BCT-100 1600U/kg on Days 1, 8, 15 and 22 as a 1-hour intravenous infusion. Courses occurred at 4-6 week intervals. Toxicities were recorded using CTCAE version 3. Pharmacokinetic and biomarker samples were assessed in BCT-100 patients. Results here are based upon median follow-up of 3.8 months (range: 0.1 - 20.6 months) Results: Between September 2018 and December 2020, 83 patients were randomised. The trial was prematurely closed due to the COVID pandemic and did not reach the pre-planned first evaluation. Median age was 76.7 years (range 62-88). Overall, 65% were male; 70% de novo AML, 23% secondary AML, and 6% high risk MDS; 2% favourable, 59% intermediate, 23% adverse and 15% unknown/unreported cytogenetics. Median of 2 courses was delivered in either arm (mean 2 LDAC, 2 LDAC+BCT, range for both: 1-12). BCT-100 leads to a depletion of arginine from baseline in the majority of patients. Overall response (CR/CRi) was achieved in 12/81 patients (15%), (LDAC+BCT-100 15%, LDAC 15%, R 1.03 (0.30, 3.51),P=0.963). Thirty-day mortality was not significantly increased (18% vs 11%, HR 1.71 (0.50, 5.84), P=0.393; and 1-year survival showed no evidence of a difference (31% vs 30%, HR 1.28 (0.72, 2.25). Median overall survival time was 3.8 vs 6.4months; overall survival HR 1.11 (0.64, 1.90), P=0.715. The most common cause of death was resistant/recurrent disease: 12(46%) vs 16(59%). BCT-100 was not associated with any haematological toxicity; although rare grade 3/4 cardiac and hepatic events were reported, these were not significantly increased with BCT-100. Summary: The addition of BCT-100 to LDAC did not improve response rate or survival. BCT-100 was well tolerated with an acceptable toxicity profile. Further clinical evaluation of BCT-100 induced arginase depletion continues in a variety of malignancies. Acknowledgements: We are grateful to Blood Cancer UK for funding the trial and Bio-Cancer Treatment International for providing drug and additional support for this Investigator Initiated Study. Figure 1. OS All patients Figure 1 Figure 1. Disclosures Knapper: Jazz: Consultancy, Speakers Bureau; Pfizer: Consultancy, Speakers Bureau; Astellas: Ended employment in the past 24 months, Speakers Bureau; Novartis: Consultancy, Research Funding, Speakers Bureau. McMullin: Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Other: clinical trial support, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AOP Orphan: Research Funding, Speakers Bureau. Copland: Incyte: Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; Cyclacel Ltd: Research Funding; Astellas: Honoraria, Speakers Bureau; Jazz: Honoraria, Speakers Bureau. Russell: Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Speakers Bureau; Astellas: Membership on an entity's Board of Directors or advisory committees; Jazz: Research Funding, Speakers Bureau.

Background: Therapeutic resistance and treatment tolerance vary greatly in patients with AML, likely due to the advanced age and genetic diversity in pharmacokinetics of those affected. Undoubtedly, tools to accurately predict outcomes of individual therapies for patients could inform decision-making and improve response rates. To this end, several scoring systems have been developed aimed at identifying patients at high risk of poor outcome after intensive chemotherapy. Similar tools for use after non-intensive therapies are currently not available. As such therapies are increasingly effective and more widely utilized we sought to develop tools to predict early death and survival for patients treated with non-intensive therapies. Patients and Methods: We developed prediction models for all-cause death by day 28, 42, 56, and 100 from enrollment using data from 796 patients enrolled on MRC/NCRI trial LI-1, which we then validated in a cohort of 540 patients treated on SWOG trials S0432, S0703, and S1612. Treatments included: Low dose Ara-C (LDAC) alone, sapacitabine alone and LDAC in combination with vosaroxin, tosedostat or ganetespib (MRC/NCRI); Azacytidine (AZA) alone, tipifarnib alone, and AZA in combination with mylotarg, midostaurin, and nivolumab (SWOG). The following covariates were available in the MRC/NCRI and SWOG cohorts to build multivariable logistic regression models (quantitative unless specified otherwise): age, performance status (PS; 0-1 vs. 2-4), secondary AML (vs. de novo AML or high-risk myelodysplastic syndrome), white blood cell and platelet counts, and percentage of bone marrow blasts - all assessed at enrollment. The regression coefficients from the model fit in the MRC/NCRI cohort were used to derive a score and applied to each patient in the SWOG cohort. The models' prognostic accuracies were assessed using the area under the receiver operating characteristic curve (AUC). For the MRC/NCRI cohort, additional covariates were available: cytogenetic risk (per Grimwade 2011), FLT3-ITD, and NPM1 mutation and patient-reported outcomes using the QLQ-C30 instrument. Logistic regression models with these covariates were fit and optimism-corrected AUC estimated to assess prognostic performance for early death. Results: Both patient cohorts were largely composed of older individuals (median age of 75 [range: 60-91] for MRC/NCRI and 77 [60-94] for SWOG, respectively. A substantial subset in each had a PS of 2-4 (MRC/NCRI: 20%; SWOG: 37%) and/or secondary AML (MRC/NCRI: 26%; SWOG: 41%). Overall, the ability to predict early death either by day 28, 42, 56, or 100 was limited in the MRC/NCRI cohort. Subscales of the QLQ-C30 had univariate AUC=0.67, the highest among all covariates evaluated. Multivariable models with just clinical covariates had optimism-corrected AUCs ranging from 0.63-0.65; adding cytogenetic risk and FLT3-ITD and NPM1 mutation status led optimism-corrected AUCs ranging from 0.64-0.66; addition of two QLQ-C30 subscales (fatigue and appetite loss) led to optimism-corrected AUCs ranging from 0.66-0.69. The SWOG cohort did not collect QLQ-C30 or mutational data on all patients and only the clinical multivariable models could be evaluated. The models had a similar performance in the SWOG cohort with AUCs ranging from 0.65-0.68. Conclusion: Our ability to predict early death in older patients treated with lower intensity AML therapies is limited with routinely available clinical variables. Inclusion of cytogenetic risk, FLT3-ITD, and NPM1 mutation status minimally improved the prognostic accuracy as did some of the QLQ-C30 subscales. Our data highlight the difficulties in predicting outcomes with non-intensive AML therapy with routinely available baseline clinical information. Improving the clinical utility of these models may require more complete characterization of patient comorbidities (including frailty index, cognitive function, renal and hepatic function, comorbidity scores) or additional PRO measures since some QLQ-C30 subscales had the strongest univariate signals. Support: NIH/NCI grants CA180888 and CA180819; Blood Cancer UK grant 13041 and Cardiff University. Figure 1 Figure 1. Disclosures Assouline: Novartis: Honoraria, Research Funding; Amgen: Current equity holder in publicly-traded company, Research Funding; Gilead: Speakers Bureau; Johnson&Johnson: Current equity holder in publicly-traded company; Jewish General Hospital, Montreal, Quebec: Current Employment; Eli Lilly: Research Funding; Roche/Genentech: Research Funding; Takeda: Research Funding; BeiGene: Consultancy, Honoraria, Research Funding; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria. Erba: AbbVie Inc; Agios Pharmaceuticals Inc; Astellas; Bristol Myers Squibb; Celgene, a Bristol Myers Squibb company; Daiichi Sankyo Inc; Genentech, a member of the Roche Group; GlycoMimetics Inc; Incyte Corporation; Jazz Pharmaceuticals Inc; Kura Oncology; Nov: Other: Advisory Committee; AbbVie Inc: Other: Independent review committee; AbbVie Inc; Agios Pharmaceuticals Inc; Bristol Myers Squibb; Celgene, a Bristol Myers Squibb company; Incyte Corporation; Jazz Pharmaceuticals Inc; Novartis: Speakers Bureau; AbbVie Inc; Agios Pharmaceuticals Inc; ALX Oncology; Amgen Inc; Daiichi Sankyo Inc; FORMA Therapeutics; Forty Seven Inc; Gilead Sciences Inc; GlycoMimetics Inc; ImmunoGen Inc; Jazz Pharmaceuticals Inc; MacroGenics Inc; Novartis; PTC Therapeutics: Research Funding. Walter: Jazz: Research Funding; Pfizer: Consultancy, Research Funding; Selvita: Research Funding; Amphivena: Consultancy, Other: ownership interests; Agios: Consultancy; Astellas: Consultancy; BMS: Consultancy; Genentech: Consultancy; Janssen: Consultancy; Kite: Consultancy; Macrogenics: Consultancy, Research Funding; Immunogen: Research Funding; Celgene: Consultancy, Research Funding; Aptevo: Consultancy, Research Funding; Amgen: Research Funding. Othus: Daiichi Sankyo: Consultancy; Celgene: Other: Data safety monitoring board; Merck: Consultancy; Biosight: Consultancy; Glycomimetics: Other: Data safety monitoring board.

The clinical benefit of adding FMS-like tyrosine kinase-3 (FLT3)-directed small molecule therapy to standard first-line treatment of acute myeloid leukemia (AML) has not yet been established. As part of the UK AML15 and AML17 trials, patients with previously untreated AML and confirmed FLT3-activating mutations, mostly younger than 60 years, were randomly assigned either to receive oral lestaurtinib (CEP701) or not after each of 4 cycles of induction and consolidation chemotherapy. Lestaurtinib was commenced 2 days after completing chemotherapy and administered in cycles of up to 28 days. The trials ran consecutively. Primary endpoints were overall survival in AML15 and relapse-free survival in AML17; outcome data were meta-analyzed. Five hundred patients were randomly assigned between lestaurtinib and control: 74% had FLT3-internal tandem duplication mutations, 23% FLT3-tyrosine kinase domain point mutations, and 2% both types. No significant differences were seen in either 5-year overall survival (lestaurtinib 46% vs control 45%; hazard ratio, 0.90; 95% CI 0.70-1.15; P = .3) or 5-year relapse-free survival (40% vs 36%; hazard ratio, 0.88; 95% CI 0.69-1.12; P = .3). Exploratory subgroup analysis suggested survival benefit with lestaurtinib in patients receiving concomitant azole antifungal prophylaxis and gemtuzumab ozogamicin with the first course of chemotherapy. Correlative studies included analysis of in vivo FLT3 inhibition by plasma inhibitory activity assay and indicated improved overall survival and significantly reduced rates of relapse in lestaurtinib-treated patients who achieved sustained greater than 85% FLT3 inhibition. In conclusion, combining lestaurtinib with intensive chemotherapy proved feasible in younger patients with newly diagnosed FLT3-mutated AML, but yielded no overall clinical benefit. The improved clinical outcomes seen in patients achieving sustained FLT3 inhibition encourage continued evaluation of FLT3-directed therapy alongside front-line AML treatment. The UK AML15 and AML17 trials are registered at www.isrctn.com/ISRCTN17161961 and www.isrctn.com/ISRCTN55675535 respectively.

With a few subgroups as exceptions, such as younger patients with more favorable genetic disease, improvement in the treatment of acute myeloid leukemia has been slow. There is a possibility that improving the quality of remission can reduce the risk of relapse. Escalation of daunorubicin dose, addition of Ab-directed chemotherapy, and alternative nucleoside analogs in induction may displace the longstanding standard of “3 + 7” daunorubicin + cytarabine (Ara-C) as induction, and several prognostic factors are emerging that enable a more personalized approach to postinduction treatment, in particular, which patients should be offered allogeneic transplantation in first remission. In addition to providing prognostic information, molecular characterization provides potential therapeutic targets and, in some cases, an opportunity to more precisely monitor residual disease. With few exceptions, the predictive value of prognostic factors (ie, what therapy to adopt) has yet to be established. A major challenge is the treatment of older patients with acute myeloid leukemia (AML), who represent the majority of patients with this disease. Only about half of older AML patients will enter complete remission (CR) with conventional chemotherapy and, of these, most will relapse within 2 years. Little impact has been made on these dismal outcomes over the past 3 decades, and new treatments and approaches to trial design are required. Another population of concern is older AML patients who are not considered to be fit for an intensive approach based on concerns about their ability to withstand the consequences of treatment. This group is not easy to define objectively, but age represents a useful surrogate because it is associated with more chemoresistant disease and medical comorbidity. Older patients represent a therapeutic challenge, but several new treatments may offer some potential to improve their situation.

The acute myeloid leukaemia (AML)14 trial addressed four therapeutic questions in patients predominantly aged over 60 years with AML and High Risk Myelodysplastic Syndrome: (i) Daunorubicin 50 mg/m2 vs. 35 mg/m2; (ii) Cytarabine 200 mg/m2 vs. 400 mg/m2 in two courses of DA induction; (iii) for part of the trial, patients allocated Daunorubicin 35 mg/m2 were also randomized to receive, or not, the multidrug resistance modulator PSC-833 in a 1:1:1 randomization; and (iv) a total of three versus four courses of treatment. A total of 1273 patients were recruited. The response rate was 62% (complete remission 54%, complete remission without platelet/neutrophil recovery 8%); 5-year survival was 12%. No benefits were observed in either dose escalation randomization, or from a fourth course of treatment. There was a trend for inferior response in the PSC-833 arm due to deaths in induction. Multivariable analysis identified cytogenetics, presenting white blood count, age and secondary disease as the main predictors of outcome. Although patients with high Pgp expression and function had worse response and survival, this was not an independent prognostic factor, and was not modified by PSC-833. In conclusion, these four interventions have not improved outcomes in older patients. New agents need to be explored and novel trial designs are required to maximise prospects of achieving timely progress.

As therapy for hematologic malignancy evolves, new regimens and novel agents that target specific cellular processes allow a more optimistic prognosis for many patients. Bortezomib and tipifarnib are two new, targeted treatments for hematologic malignancies. Bortezomib, a proteasome inhibitor, has shown impressive efficacy in patients with relapsed multiple myeloma and as initial treatment, including before autologous stem cell transplantation. It has been studied as monotherapy and in combination with standard treatments such as dexamethasone, and with newer agents such as the immunomodulators thalidomide and lenalidomide; response is encouraging, even in patients who have relapsed after previously receiving components of a regimen as single agents. Bortezomib is generally well tolerated, including in combination with novel and conventional agents. Tipifarnib is a specific inhibitor of farnesyltransferase. Clinical trials in patients with high-risk acute leukemias and myelodysplastic syndromes have demonstrated good efficacy with tipifarnib. Continued investigation with these new, targeted treatments will further define their use as treatment options in patients with hematologic cancer.

Acute myeloid leukemia (AML) is characterized by developmental arrest, which is thought to arise from transcriptional dysregulation of myeloid development programs. Hematopoietic stem and progenitor cells (HSPCs) isolated from human blood are frequently used as a normal comparator in AML studies. Previous studies have reported changes in the transcriptional program of genes involved in proliferation, differentiation, apoptosis, and homing when HSPCs were expanded ex vivo. The intrinsic functional differences between quiescent and dividing CD34+ HSPCs prompted us to determine whether fresh or cytokine-induced cord blood-derived CD34+ HSPCs are a more appropriate normal control compared to AML blasts. Based on principal component analysis and gene expression profiling we demonstrate that CD34+ HSPCs that do not undergo ex vivo expansion are transcriptionally similar to minimally differentiated AML blasts. This was confirmed by comparing the cell cycle status of the AML blasts and the HSPCs. We suggest that freshly isolated CD34+ HSPCs that do not undergo ex vivo expansion would serve as a better control to identify novel transcriptional targets in the AML blast population.

Summary Older adult patients (≥60 years) with acute myeloid leukaemia (AML) are generally considered to be poor‐risk and there is limited information available regarding risk stratification based on molecular characterization in this age group, particularly for the double‐mutant CEBPA (CEBPA DM) genotype. To investigate whether a molecular favourable‐risk genotype can be identified, we investigated CEBPA, NPM1 and FLT3 status and prognostic impact in a cohort of 301 patients aged 60 years or more with intermediate‐risk cytogenetics, all treated intensively. Overall survival (OS) at 1 year was highest in the 12 patients (4%) that were CEBPA DM compared to the 76 (28%) with a mutant NPM1 and wild‐type FLT3 (NPM1 MUT FLT3 WT) genotype or all other patients (75%, 54%, 33% respectively), with median survival 15·2, 13·6 and 6·6 months, although the benefit was short‐term (OS at 3 years 17%, 29%, 12% respectively). Combination of the CEBPA DM and NPM1 MUT FLT3 WT genotype patients defined a molecular group with favourable prognosis (P

Modifying induction therapy in acute myeloid leukemia (AML) may improve the remission rate and reduce the risk of relapse, thereby improving survival. Escalation of the daunorubicin dose to 90 mg/m 2 has shown benefit for some patient subgroups when compared with a dose of 45 mg/m 2, and has been recommended as a standard of care. However, 60 mg/m 2 is widely used and has never been directly compared with 90 mg/m 2. As part of the UK National Cancer Research Institute (NCRI) AML17 trial, 1206 adults with untreated AML or high-risk myelodysplastic syndrome, mostly younger than 60 years of age, were randomized to a first-induction course of chemotherapy, which delivered either 90 mg/m 2 or 60 mg/m 2 on days 1, 3, and 5 combined with cytosine arabinoside. All patients then received a second course that included daunorubicin 50 mg/m 2 on days 1, 3, and 5. There was no overall difference in complete remission rate (73% vs 75%; odds ratio, 1.07 [0.83-1.39]; P = .6) or in any recognized subgroup. The 60-day mortality was increased in the 90 mg/m 2 arm (10% vs 5% (hazard ratio [HR] 1.98 [1.30-3.02]; P = .001), which resulted in no difference in overall 2-year survival (59% vs 60%; HR, 1.16 [0.95-1.43]; P = .15). In an exploratory subgroup analysis, there was no subgroup that showed significant benefit, although there was a significant interaction by FLT3 ITD mutation. This trial is registered at http://www.isrctn.com as #ISRCTN55675535.

The development of new treatments for older patients with acute myeloid leukemia is an active area, but has met with limited success. Vosaroxin, a quinolone-derived intercalating agent has several properties that could prove beneficial. Initial clinical studies showed it to be well-tolerated in older patients with relapsed/refractory disease. In vitro data suggested synergy with cytarabine (Ara-C). To evaluate vosaroxin, we performed 2 randomized comparisons within the “Pick a Winner” program. A total of 104 patients were randomized to vosaroxin vs low-dose Ara-C (LDAC) and 104 to vosaroxin + LDAC vs LDAC. When comparing vosaroxin with LDAC, neither response rate (complete recovery [CR]/complete recovery with incomplete count recovery [CRi], 26% vs 30%; odds ratio [OR], 1.16 (0.49-2.72); P = .7) nor 12-month survival (12% vs 31%; hazard ratio [HR], 1.94 [1.26-3.00]; P = .003) showed benefit for vosaroxin. Likewise, in the vosaroxin + LDAC vs LDAC comparison, neither response rate (CR/CRi, 38% vs 34%; OR, 0.83 [0.37-1.84]; P = .6) nor survival (33% vs 37%; HR, 1.30 [0.81-2.07]; P = .3) was improved. A major reason for this lack of benefit was excess early mortality in the vosaroxin + LDAC arm, most obviously in the second month following randomization. At its first interim analysis, the Data Monitoring and Ethics Committee recommended closure of the vosaroxin-containing trial arms because a clinically relevant benefit was unlikely.

The relative efficacy and toxicity of the chemotherapeutic agents thioguanine (6TG) and etoposide (VP16) were assessed by a randomized comparison of the DAT (daunorubicin, cytarabine, thioguanine) versus ADE (daunorubicin, cytarabine, etoposide) regimens in the Medical Research Council's 10th acute myeloid leukaemia trial (MRC AML 10), which was open to patient entry from May 1988 to April 1995. In this, the largest reported trial of AML therapy to date, 1,857 eligible patients, mostly less than 56 years old, were randomized: 929 (including 143 children under 15 years old) were allocated to DAT and 928 (143 children) to ADE. The two groups were well matched for presentation features. The complete remission (CR) rate was 81% with DAT and 83% with ADE (P = .3). The percentages of remitters achieving remission after 1, 2, or more than 2 courses were 70%, 22%, and 8% for DAT and 74%, 21%, and 5% for ADE. The percentages failing to achieve a CR due to resistant disease were 11% with DAT versus 9% with ADE (P = .07). There was a slightly higher death rate in CR during consolidation chemotherapy with ADE (9%) than with DAT (6%) (P = .06). Patients receiving DAT took slightly but significantly longer to recover from neutropenia and thrombocytopenia but the median number of days in hospital were similar in each group. ADE patients experienced slightly more severe nonhematologic toxicity. There was also no significant difference between the groups in the longer-term measures of efficacy: disease-free survival at 6 years from CR was 42% (±4) for DAT and 43% (±4) for ADE (P = .8); relapse rate at 6 years was 50% (±4) for DAT and 49% (±5) for ADE (P = .6); survival at 6 years was 40% (±4) for both DAT and ADE (P = .9). Subgroup analysis failed to show any benefit for etoposide in patients with monocytic or myelomonocytic disease, or in any other diagnostic subgroup. In conclusion, DAT and ADE both achieve high remission rates and good long-term survival, and are equally effective chemotherapy regimens for the treatment of AML patients aged up to 55 years.

The BCR/ABL1 fusion gene, usually carried by the Philadelphia chromosome (Ph) resulting from t(9;22)(q34;q11) or variants, is pathognomonic for chronic myeloid leukaemia (CML). It is also occasionally found in acute lymphoblastic leukaemia (ALL) mostly in adults and rarely in de novo acute myeloid leukaemia (AML). Array Comparative Genomic Hybridization (aCGH) was used to study six Ph(+)AML, three bi-lineage and four Ph(+)ALL searching for specific genomic profiles. Surprisingly, loss of the IKZF1 and/or CDKN2A genes, the hallmark of Ph(+)ALL, were recurrent findings in Ph(+)AML and accompanied cryptic deletions within the immunoglobulin and T cell receptor genes. The latter two losses have been shown to be part of 'hot spot' genome imbalances associated with BCR/ABL1 positive pre-B lymphoid phenotype in CML and Ph(+)ALL. We applied Significance Analysis of Microarrays (SAM) to data from the 'hot spot' regions to the Ph(+)AML and a further 40 BCR/ABL1(+) samples looking for differentiating features. After exclusion of the most dominant markers, SAM identified aberrations unique to de novo Ph(+)AML that involved relevant genes. While the biological and clinical significance of this specific genome signature remains to be uncovered, the unique loss within the immunoglobulin genes provides a simple test to enable the differentiation of clinically similar de novo Ph(+) AML and myeloid blast crisis of CML.

The role of specific cytochrome P450 (P450) isoforms in the formation of adducts of 7,12-dimethylbenz ( a )anthracene metabolites and membrane proteins has been investigated in vitro with microsomal fractions prepared from rats pretreated with various isoenzyme selective inducers. The effects of isoenzyme selective inhibitors were also evaluated. Adduct formation was shown to be mediated by P450 catalysed reactions but was unaltered, relative to untreated animals, in membranes from pyrazole- and clofibrate-treated animals suggesting that CY P2E1 and CYP4A1 are not involved in this process. However, adduct formation was significantly increased in microsomes from Sudan III-,phenobarbital-and dexamethasone-treated rats, suggesting the involvement of the CYP1A, CYP2B and CYP3A subfamilies, respectively. These conclusions were further supported by the finding that adduct formation in these microsomes could be inhibited by the isoenzyme-selective inhibitors α-naph-thoflavone, metyrapone and troleandomycin, respectively.

Diagnostic cytogenetic abnormalities are considered important prognostic factors in patients with acute myeloid leukaemia (AML). However, the prognostic assessments have mainly been derived from patients with AML aged60 years. Two recent studies of AML patients of 60 years and older proposed prognostic classifications with distinct discrepancies. To further study the prognostic value of cytogenetic abnormalities in this patient population, we have evaluated cytogenetic abnormalities in a series of 293 untreated patients with AML aged 60 years and older, included in a randomised phase 3 trial, also in relation to patient characteristics and clinical outcome. The most frequently observed cytogenetic abnormality was trisomy 8 (+8), in 31 (11%) patients. Abnormalities, such as -5, 5q-, abn(17p) and abn(17q), were almost exclusively present in complex karyotypes. A relatively favourable outcome was only observed in five patients with core-binding factor abnormalities t(8;21) and inv(16)/del(16)/t(16;16). However, most of the other evaluated cytogenetic abnormalities, such as 5q-, -7, +8, abn(17p), abn(17q), and complex aberrations expressed a more adverse prognosis when compared with patients with AML aged 60 years and older with a normal karyotype. Large studies to confirm the prognosis of individual cytogenetic aberrations are warranted.

The optimum chemotherapy schedule for reinduction of patients with high-risk acute myeloid leukemia (relapsed, resistant/refractory, or adverse genetic disease) is uncertain. The MRC AML (Medical Research Council Acute Myeloid Leukemia) Working Group designed a trial comparing fludarabine and high-dose cytosine (FLA) with standard chemotherapy comprising cytosine arabinoside, daunorubicin, and etoposide (ADE). Patients were also randomly assigned to receive filgrastim (G-CSF) from day 0 until neutrophil count was greater than 0.5 × 109/L (or for a maximum of 28 days) and all-trans retinoic acid (ATRA) for 90 days. Between 1998 and 2003, 405 patients were entered: 250 were randomly assigned between FLA and ADE; 356 to G-CSF versus no G-CSF; 362 to ATRA versus no ATRA. The complete remission rate was 61% with 4-year disease-free survival of 29%. There were no significant differences in the CR rate, deaths in CR, relapse rate, or DFS between ADE and FLA, although survival at 4 years was worse with FLA (16% versus 27%, P = .05). Neither the addition of ATRA nor G-CSF demonstrated any differences in the CR rate, relapse rate, DFS, or overall survival between the groups. In conclusion these findings indicate that FLA may be inferior to standard chemotherapy in high-risk AML and that the outcome is not improved with the addition of either G-CSF or ATRA.

The prognostic significance of FLT3 mutations in acute promyelocytic leukemia (APL) is not firmly established and is of particular interest given the opportunities for targeted therapies using FLT3 inhibitors. We studied 203 patients with PML-RARA–positive APL; 43% of the patients had an FLT3 mutation (65 internal tandem duplications [ITDs], 19 D835/I836, 4 ITD+D835/I836). Both mutations were associated with higher white blood cell (WBC) count at presentation; 75% of the patients with WBC counts of 10 × 109/L or greater had mutant FLT3. FLT3/ITDs were correlated with M3v subtype (P < .001), bcr3 PML breakpoint (P < .001), and expression of reciprocal RARA-PML transcripts (P = .01). Microarray analysis revealed differences in expression profiles among patients with FLT3/ITD, D835/I836, and wild-type FLT3. Patients with mutant FLT3 had a higher rate of induction death (19% vs 9%; P = .04, but no significant difference in relapse risk (28% vs 23%; P = .5) or overall survival (59% vs 67%; P = .2) at 5 years. In in vitro differentiation assays using primary APL blasts (n = 6), the FLT3 inhibitor CEP-701 had a greater effect on cell survival/proliferation in FLT3/ITD+ cells, but this inhibition was reduced in the presence of ATRA. Furthermore, in the presence of CEP-701, ATRA-induced differentiation was reduced in FLT3/ITD+ cells. These data carry implications for the use of FLT3 inhibitors as frontline therapy for APL.