Sorafenib plus intensive chemotherapy in newly diagnosed FLT3-ITD AML: a randomized, placebo-controlled study by the ALLG.

Sorafenib maintenance improves outcomes after hematopoietic cell transplant (HCT) for patients with FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) acute myeloid leukemia (AML). Although promising outcomes have been reported for sorafenib plus intensive chemotherapy, randomized data are limited. This placebo-controlled, phase 2 study (ACTRN12611001112954) randomized 102 patients (aged 18-65 years) 2:1 to sorafenib vs placebo (days 4-10) combined with intensive induction: idarubicin 12 mg/m2 on days 1 to 3 plus either cytarabine 1.5 g/m2 twice daily on days 1, 3, 5, and 7 (18-55 years) or 100 mg/m2 on days 1 to 7 (56-65 years), followed by consolidation and maintenance therapy for 12 months (post-HCT excluded) in newly diagnosed patients with FLT3-ITD AML. Four patients were excluded in a modified intention-to-treat final analysis (3 not commencing therapy and 1 was FLT3-ITD negative). Rates of complete remission (CR)/CR with incomplete hematologic recovery were high in both arms (sorafenib, 78%/9%; placebo, 70%/24%). With 49.1-months median follow-up, the primary end point of event-free survival (EFS) was not improved by sorafenib (2-year EFS 47.9% vs 45.4%; hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.51-1.51; P = .61). Two-year overall survival (OS) was 67% in the sorafenib arm and 58% in the placebo arm (HR, 0.76; 95% CI, 0.42-1.39). For patients who received HCT in first remission, the 2-year OS rates were 84% and 67% in the sorafenib and placebo arms, respectively (HR, 0.45; 95% CI, 0.18-1.12; P = .08). In exploratory analyses, FLT3-ITD measurable residual disease (MRD) negative status (<0.001%) after induction was associated with improved 2-year OS (83% vs 60%; HR, 0.4; 95% CI, 0.17-0.93; P = .028). In conclusion, routine use of pretransplant sorafenib plus chemotherapy in unselected patients with FLT3-ITD AML is not supported by this study.

Determinants of fatal bleeding during induction therapy for acute promyelocytic leukemia in the ATRA era.

Acute promyelocytic leukemia (APL) is commonly complicated by a complex coagulopathy. Uncertainty remains as to which markers of bleeding risk are independent predictors. Drawing from 5 large clinical trials that included all-trans retinoic acid (ATRA) as part of induction, we assessed known determinants of bleeding at baseline and evaluated them as potential predictors of hemorrhagic death (HD) in the first 30 days of treatment. The studies included were ALLG APML3 (single arm of ATRA + idarubicin ± prednisone), ALLG APML4 (single arm of ATRA + idarubicin + arsenic trioxide + prednisone), CALGB C9710 (single arm of ATRA + cytarabine + daunorubicin), Eastern Cooperative Oncology Group-American College of Radiology Imaging Network (ECOG-ACRIN) E2491 (intergroup I0129, consisting of daunorubicin + cytarabine vs ATRA), and SWOG S0521 (single-arm induction of ATRA + cytarabine + daunorubicin). A total of 1009 patients were included in the original trials, of which 995 had sufficient data to be included in our multivariate analysis. In this final cohort, there were 37 HD cases during the first 30 days following induction, for an estimated cumulative incidence of 3.7% (95% confidence interval [CI], 2.6% to 5.0%). Using multivariate Cox proportional hazards regression, the hazard ratio of HD in the first 30 days was 2.17 (95% CI, 0.84-5.62) for an ECOG performance status of 3-4 vs 0-2 and 5.20 (95% CI, 2.70-10.02) for a white blood cell count of ≥20 000/µL vs <20 000/µL. In this large cohort of APL patients, high white blood cell count emerged as an independent predictor of early HD.

Optimal approach for high-risk acute promyelocytic leukemia.

PURPOSE OF REVIEW: Clinical outcomes for patients with acute promyelocytic leukemia (APL) have improved dramatically in the last 25 years, but a small proportion still die early during induction or relapse after achieving remission. This review examines features that define increased risk of treatment failure in APL, and summarizes strategies that are currently available to minimize that risk. RECENT FINDINGS: In the last few years, a targeted approach has progressively been adopted in the initial therapy of APL, with increasing reliance on the combination of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). The goals of treatment are to minimize early and late disease-related and therapy-related complications, and to ultimately eliminate relapses and resistant disease entirely. The relative contributions of treatment-induced terminal differentiation and leukemia-specific fusion protein degradation in the elimination of APL have also been clarified. SUMMARY: High-risk APL, traditionally defined by an initial white cell count exceeding 10 × 109/l, has proven to be almost as amenable to disease eradication as low-risk and intermediate-risk APL, provided treatment includes ATRA, ATO and some chemotherapy. Improved understanding of the pathogenesis of APL and the associated coagulopathy has the potential to further minimize the risk of failure by reducing induction deaths and relapses.

All-trans-retinoic acid, idarubicin, and IV arsenic trioxide as initial therapy in acute promyelocytic leukemia (APML4).

The treatment of acute promyelocytic leukemia has improved considerably after recognition of the effectiveness of all-trans-retinoic acid (ATRA), anthracycline-based chemotherapy, and arsenic trioxide (ATO). Here we report the use of all 3 agents in combination in an APML4 phase 2 protocol. For induction, ATO was superimposed on an ATRA and idarubicin backbone, with scheduling designed to exploit antileukemic synergy while minimizing cardiotoxicity and the severity of differentiation syndrome. Consolidation comprised 2 cycles of ATRA and ATO without chemotherapy, followed by 2 years of maintenance with ATRA, oral methotrexate, and 6-mercaptopurine. Of 124 evaluable patients, there were 4 (3.2%) early deaths, 118 (95%) hematologic complete remissions, and all 112 patients who commenced consolidation attained molecular complete remission. The 2-year rate for freedom from relapse is 97.5%, failure-free survival 88.1%, and overall survival 93.2%. These outcomes were not influenced by FLT3 mutation status, whereas failure-free survival was correlated with Sanz risk stratification (P[trend] = .03). Compared with our previously reported ATRA/idarubicin-based protocol (APML3), APML4 patients had statistically significantly improved freedom from relapse (P = .006) and failure-free survival (P = .01). In conclusion, the use of ATO in both induction and consolidation achieved excellent outcomes despite a substantial reduction in anthracycline exposure. This trial was registered at the Australian New Zealand Clinical Trials Registry (www.anzctr.org.au) as ACTRN12605000070639.

Role of arsenic trioxide in acute promyelocytic leukemia.

Acute promyelocytic leukemia (APL) is a unique subtype of acute myeloid leukemia that is characterized by distinct clinical, morphological, cytogenetic, and molecular abnormalities. It is associated with a striking risk of early hemorrhagic death due to disseminated intravascular coagulation and hyperfibrinolysis. The prognosis of APL has improved dramatically following the introduction of all-trans retinoic acid (ATRA) and its combination with anthracycline-based chemotherapy during induction and consolidation. Patients with high-risk APL, defined by a white cell count >10 × 10(9)/L at diagnosis, also appear to benefit from the addition of intermediate- or high-dose cytarabine during consolidation. Arsenic trioxide (ATO) has proved to be even more effective than ATRA as a single agent, and is now routinely used for the treatment of the 20%-30% of patients who manifest disease relapse after initial treatment with ATRA and chemotherapy. ATO has a toxicity profile that differs considerably from that of both ATRA and cytotoxic chemotherapy, and accordingly presents its own specific challenges during treatment. Optimizing a strategy for the incorporation of ATO into initial therapy is currently the focus of several cooperative group trials, with an emphasis on minimizing or even eradicating the use of chemotherapy. ATRA plus ATO without chemotherapy appears to be adequate during induction and consolidation for patients with standard-risk APL, but triple therapy that includes limited anthracycline or gemtuzumab ozogamicin (GO) during induction is required for high-risk APL. Uncertainty still exists regarding the minimum amount of chemotherapy and number of consolidation cycles necessary, the optimal scheduling of ATO, and the potential utility of oral ATO administration. Although prolonged oral maintenance therapy is usually included in most current APL treatment protocols, its value remains controversial, and the superior anti-leukemic efficacy of ATO-based therapy may facilitate its elimination in the future.

Applying molecular measurable residual disease testing in acute myeloid leukaemia.

Molecular testing in acute myeloid leukaemia (AML) has continued to dramatically advance in recent years, facilitating the ability to detect residual disease at exponentially lower levels. With the advent of the recently updated ELN consensus recommendations, there is increasing complexity to ordering and interpreting measurable residual disease (MRD) assays in AML. We outline the technology itself in conjunction with the relevant testing timepoints, clinically significant thresholds and potential prognostic and therapeutic significance of MRD testing for the major molecular targets in AML. This practical overview should assist haematologists in incorporating molecular MRD assays routinely into their personalised AML clinical management.

Treatment of refractory pyoderma gangrenosum with intravenous immunoglobulin.

We report a patient with pyoderma gangrenosum successfully treated with intravenous immunoglobulin. He had previously been treated for 4 years with high-dose corticosteroids and had developed insulin-dependent diabetes mellitus. Multiple corticosteroid-sparing agents had failed or were contraindicated. He developed no adverse effects from intravenous immunoglobulin, which allowed reduction of his prednisone to 3 mg/day, and his ulcer has completely healed.

Curative strategies in APL.

In the 60 years since the recognition of acute promyelocytic leukemia as a distinct entity, outcomes for patients have improved dramatically. This has occurred partly because of improvements in supportive care, and partly because treatment has diverged from reliance on standard antileukemic chemotherapy to the use of agents that are specifically targeted at the molecular events responsible for initiating and maintaining the disease. However early death remains a significant barrier to cure, especially for patients who fall outside the selection biases imposed by clinical trials. This review will focus on changes to clinical practice that have been adopted to reduce the risk of failure.

CD300f epitopes are specific targets for acute myeloid leukemia with monocytic differentiation.

Antibody-based therapy in acute myeloid leukemia (AML) has been marred by significant hematologic toxicity due to targeting of both hematopoietic stem and progenitor cells (HSPCs). Achieving greater success with therapeutic antibodies requires careful characterization of the potential target molecules on AML. One potential target is CD300f, which is an immunoregulatory molecule expressed predominantly on myeloid lineage cells. To confirm the value of CD300f as a leukemic target, we showed that CD300f antibodies bind to AML from 85% of patient samples. While one CD300f monoclonal antibody (mAb) reportedly did not bind healthy hematopoietic stem cells, transcriptomic analysis found that CD300f transcripts are expressed by healthy HSPC. Several CD300f protein isoforms exist as a result of alternative splicing. Importantly for antibody targeting, the extracellular region of CD300f can be present with or without the exon 4-encoded sequence. This results in CD300f isoforms that are differentially bound by CD300f-specific antibodies. Furthermore, binding of one mAb, DCR-2, to CD300f exposes a structural epitope recognized by a second CD300f mAb, UP-D2. Detailed analysis of publicly available transcriptomic data indicated that CD34+ HSPC expressed fewer CD300f transcripts that lacked exon 4 compared to AML with monocytic differentiation. Analysis of a small cohort of AML cells revealed that the UP-D2 conformational binding site could be induced in cells from AML patients with monocytic differentiation but not those from other AML or HSPC. This provides the opportunity to develop an antibody-based strategy to target AMLs with monocytic differentiation but not healthy CD34+ HSPCs. This would be a major step forward in developing effective anti-AML therapeutic antibodies with reduced hematologic toxicity.

A blood dendritic cell vaccine for acute myeloid leukemia expands anti-tumor T cell responses at remission.

Only modest advances in AML therapy have occurred in the past decade and relapse due to residual disease remains the major challenge. The potential of the immune system to address this is evident in the success of allogeneic transplantation, however this leads to considerable morbidity. Dendritic cell (DC) vaccination can generate leukemia-specific autologous immunity with little toxicity. Promising results have been achieved with vaccines developed in vitro from purified monocytes (Mo-DC). We now demonstrate that blood DC (BDC) have superior function to Mo-DC. Whilst BDC are reduced at diagnosis in AML, they recover following chemotherapy and allogeneic transplantation, can be purified using CMRF-56 antibody technology, and can stimulate functional T cell responses. While most AML patients in remission had a relatively normal T cell landscape, those who had received fludarabine as salvage therapy have persistent T cell abnormalities including reduced number, altered subset distribution, failure to expand, and increased activation-induced cell death. Furthermore, PD-1 and TIM-3 are increased on CD4T cells in AML patients in remission and their blockade enhances the expansion of leukemia-specific T cells. This confirms the feasibility of a BDC vaccine to consolidate remission in AML and suggests it should be tested in conjunction with checkpoint blockade.

Use of arsenic trioxide in remission induction and consolidation therapy for acute promyelocytic leukaemia in the Australasian Leukaemia and Lymphoma Group (ALLG) APML4 study: a non-randomised phase 2 trial.

BACKGROUND: Initial treatment of acute promyelocytic leukaemia traditionally involves tretinoin (all-trans retinoic acid) combined with anthracycline-based risk-adapted chemotherapy, with arsenic trioxide being the treatment of choice at relapse. To try to reduce the relapse rate, we combined arsenic trioxide with tretinoin and idarubicin in induction therapy, and used arsenic trioxide with tretinoin as consolidation therapy. METHODS: Patients with previously untreated genetically confirmed acute promyelocytic leukaemia were eligible for this study. Eligibilty also required Eastern Cooperative Oncology Group performance status 0-3, age older than 1 year, normal left ventricular ejection fraction, Q-Tc interval less than 500 ms, absence of serious comorbidity, and written informed consent. Patients with genetic variants of acute promyelocytic leukaemia (fusion of genes other than PML with RARA) were ineligible. Induction comprised 45 mg/m(2) oral tretinoin in four divided doses daily on days 1-36, 6-12 mg/m(2) intravenous idarubicin on days 2, 4, 6, and 8, adjusted for age, and 0·15 mg/kg intravenous arsenic trioxide once daily on days 9-36. Supportive therapy included blood products for protocol-specified haemostatic targets, and 1 mg/kg prednisone daily as prophylaxis against differentiation syndrome. Two consolidation cycles with tretinoin and arsenic trioxide were followed by maintenance therapy with oral tretinoin, 6-mercaptopurine, and methotrexate for 2 years. The primary endpoints of the study were freedom from relapse and early death (within 36 days of treatment start) and we assessed improvement compared with the 2 year interim results. To assess durability of remission we compared the primary endpoints and disease-free and overall survival at 5 years in APML4 with the 2 year interim APML4 data and the APML3 treatment protocol that excluded arsenic trioxide. This study is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12605000070639. FINDINGS: 124 patients were enrolled between Nov 10, 2004, and Sept 23, 2009, with data cutoff of March 15, 2012. Four (3%) patients died early. After a median follow-up of 4·2 years (IQR, 3·2-5·2), the 5 year freedom from relapse was 95% (95% CI 89-98), disease-free survival was 95% (89-98), event-free survival was 90% (83-94), and overall survival was 94% (89-97). The comparison with APML3 data showed that hazard ratios were 0·23 (95% CI 0·08-0·64, p=0·002) for freedom from relapse, 0·21 (0·07-0·59, p=0·001) for disease-free survival, 0·34 (0·16-0·69, p=0·002) for event-free survival, and 0·35 (0·14-0·91, p=0·02) for overall survival. INTERPRETATION: Incorporation of arsenic trioxide in initial therapy induction and consolidation for acute promyelocytic leukaemia reduced the risk of relapse when compared with historical controls. This improvement, together with a non-significant reduction in early deaths and absence of deaths in remission, translated into better event-free and overall survival. FUNDING: Phebra.

Have all-trans retinoic acid and arsenic trioxide replaced all-trans retinoic acid and anthracyclines in APL as standard of care.

Until recently, the standard of care in the treatment of APL has involved the combination of all-trans retinoic acid with anthracycline-based chemotherapy during both induction and consolidation. Additionally, the intensity of consolidation chemotherapy has evolved according to a universally accepted relapse-risk stratification algorithm based on the white cell and platelet counts at presentation. That standard of care is being challenged by the increasing incorporation of arsenic trioxide into front-line treatment protocols, based on two complementary observations. The first is the undoubted anti-leukaemic activity of arsenic trioxide as shown in the relapsed and refractory setting, and in the initial management of low- and intermediate-risk patients. The second is an improved understanding of the action of both all-trans retinoic acid and arsenic trioxide in mediating APL cell eradication, with increasing recognition that PML-RARA fusion protein degradation rather than direct induction of terminal differentiation is the primary mechanism for their ability to eliminate leukaemia initiating cells. As a result, we believe the standard of care for initial therapy in APL is shifting towards an all-trans retinoic acid plus arsenic trioxide-based approach, with additional chemotherapy reserved for patients with high-risk disease.

Diagnosis and molecular monitoring of acute promyelocytic leukemia using DzyNA reverse transcription-PCR to quantify PML/RARalpha fusion transcripts.

BACKGROUND: PML/RARalpha fusion transcripts provide a readily accessible marker for diagnosis of acute promyelocytic leukemia (APL) and for monitoring response to therapy. Survival rates are improved by therapies guided by such monitoring. We assessed the potential of DzyNA reverse transcription-PCR (RT-PCR) for measurement of PML/RARalpha fusion transcripts. METHODS: Parallel single-tube DzyNA RT-PCR protocols were developed to allow real-time fluorescent quantification of PML/RARalpha fusion transcripts and a low abundance control transcript, normal BCR. Calibration curves, generated using cell line RNA, allowed estimation of these transcripts in RNA from patients with APL at various stages of the disease. RESULTS: DzyNA RT-PCR calibration curves were linear for both transcripts over a broad range and demonstrated interassay variations of 12% (mean, 658 ng) and 10% (mean, 263 ng), respectively. The protocols detected low concentrations of transcripts and resolved twofold dilutions. PML/RARalpha mRNA was quantified in 10 patients at diagnosis and in 1 patient over a 7-year period. Monitoring of transcript concentrations effectively reflected the disease course in one patient and demonstrated that an increase in PML/RARalpha transcripts can be detected 4-6 months before hematologic relapse, with no false-positive results. CONCLUSION: DzyNA RT-PCR has potential for use in clinical practice as a tool for diagnosis of APL and forsubsequent monitoring of minimal residual disease and detection of molecular relapse.