Alison Sehgal

DNMT3A and IDH mutations in acute myeloid leukemia and other myeloid malignancies: associations with prognosis and potential treatment strategies

The development of effective treatment strategies for most forms of acute myeloid leukemia (AML) has languished for the past several decades. There are a number of reasons for this, but key among them is the considerable heterogeneity of this disease and the paucity of molecular markers that can be used to predict clinical outcomes and responsiveness to different therapies. The recent large-scale sequencing of AML genomes is now providing opportunities for patient stratification and personalized approaches to treatment that are based on individual mutational profiles. It is particularly notable that studies by The Cancer Genome Atlas and others have determined that 44% of patients with AML exhibit mutations in genes that regulate methylation of genomic DNA. In particular, frequent mutation has been observed in the genes encoding DNA methyltransferase 3A (DNMT3A), isocitrate dehydrogenase 1 (IDH1) and isocitrate dehydrogenase 2 (IDH2), as well as Tet oncogene family member 2. This review will summarize the incidence of these mutations, their impact on biochemical functions including epigenetic modification of genomic DNA and their potential usefulness as prognostic indicators. Importantly, the presence of DNMT3A, IDH1 or IDH2 mutations may confer sensitivity to novel therapeutic approaches, including the use of demethylating agents. Therefore, the clinical experience with decitabine and azacitidine in the treatment of patients harboring these mutations will be reviewed. Overall, we propose that understanding the role of these mutations in AML biology will lead to more rational therapeutic approaches targeting molecularly defined subtypes of the disease.

You eat what you are: autophagy inhibition as a therapeutic strategy in leukemia.

A deeper understanding of the role of autophagy, literally ‘self-eating’, in normal and cancer cell biology has emerged over the last few years. Autophagy serves as a vehicle for cells to respond to various stressors including genomic, hypoxic and nutrient stress, and to oppose mechanisms of ‘programmed’ cell death. Here, we review not only mechanisms of cell death and cell survival but also the early successes in applying autophagy inhibition strategies in solid tumors using the only currently available clinical inhibitor, oral hydroxychloroquine. In acute leukemia, currently available chemotherapy drugs promote cell death and demonstrate clinical benefit, but relapse and subsequent chemotherapy resistance is common. Increasing preclinical data suggest that autophagy is active in leukemia as a means of promoting cell survival in response to chemotherapy. We propose coupling autophagy inhibition strategies with current cytotoxic chemotherapy and discuss synergistic combinations of available anti-leukemic therapies with autophagy inhibition. Furthermore, novel autophagy inhibitors are in development and promise to provide new therapeutic opportunities for patients with leukemia.

DNMT3A mutational status affects the results of dose-escalated induction therapy in acute myelogenous leukemia

Purpose: DNA methyltransferase 3A (DNMT3A) is one of the commonly mutated genes in acute myelogenous leukemia (AML). Reports on the prognostic significance of DNMT3A mutations have been inconsistent, and most of the data are available only for patients 60 years of age or younger. We hypothesized that this inconsistency is due to an interaction between the dose of anthracycline used in induction therapy and DNMT3A status. We studied whether patients with DNMT3A-mutated AML treated with standard dose anthracyclines had an inferior survival compared with patients with other mutation profiles or those who received high-dose therapy. Experimental Design: A total of 152 patients in this retrospective cohort study (median age, 54 years) with de novo AML underwent induction therapy and next-generation sequencing of 33 commonly mutated genes in hematologic malignancies, including DNMT3A, FLT3-ITD, NPM1, and IDH1/2. Cox regression was used to know whether those with DNMT3A mutations who were treated with standard dose anthracycline had inferior survival. Results: DNMT3A mutations, found in 32% of patients, were not associated with an inferior survival. Dose escalation of anthracycline in the induction regimen was associated with improved survival in those with DNMT3A mutations but not those with wild-type DNMT3A. Patients with DNMT3A mutations who received standard dose induction had shorter survival time than other patient groups (10.1 months vs. 19.8 months, P = 0.0129). This relationship remained significant (HR, 1.90; P = 0.006) controlling for multiple variables. Conclusions: Patients with DNMT3A-mutated AML have an inferior survival when treated with standard-dose anthracycline induction therapy. This group should be considered for high-dose induction therapy. Clin Cancer Res; 21(7); 1614–20. ©2015 AACR.

Programmed death-1 checkpoint blockade in acute myeloid leukemia

Introduction: Immune checkpoints are regulatory pathways induced in activated T lymphocytes that regulate antigen responsiveness. These immune checkpoints are hijacked by tumors to promote dysfunction of anti-tumor effector cells and consequently of tumor escape from the host immune system. Areas covered: Programmed death-1/programmed death ligand (PD-1/PDL-1), a checkpoint pathway, has been extensively investigated in leukemia mouse models. Expression of PD-1 on the surface of activated immune cells and of its ligands, PD-L1 and PD-L2, on leukemic blasts has been documented. Clinical trials with PD-1 inhibitors in patients with hematological malignancies are ongoing with promising clinical responses. Expert opinion: Therapy of hematological cancers with antibodies blocking inhibitory receptors is expected to be highly clinically effective. Checkpoint inhibitory receptors and their ligands are co-expressed on hematopoietic cells found in the leukemic milieu. Several distinct immunological mechanisms are likely to be engaged by antibody-based checkpoint blockade. Co-expression of multiple inhibitory receptors on hematopoietic cells offers an opportunity for combining blocking antibodies to achieve more effective therapy. Up-regulation of receptor/ligand expression in the leukemic milieu may provide a blood marker predictive of response. Finally, chemotherapy-induced up-regulation of PD-1 on T cells after conventional leukemia therapy creates a solid rationale for application of checkpoint blockade as a follow-up therapy.

Leukapheresis in patients newly diagnosed with acute myeloid leukemia

Hyperleukocytosis is present in 5 to 20 percent of patients with newly diagnosed acute myeloid leukemia (AML). The management of hyperleukocytosis, when symptoms of leukostasis occur, includes intensive supportive care and interventions for rapid cytoreduction. Leukapheresis is a rapid and effective means of cytoreduction and has been used in AML patients. In the current study, we evaluated the outcomes of 68 newly diagnosed AML patients that underwent leukapheresis and the effects of leukapheresis on various laboratory parameters. A total of 127 leukapheresis cycles were performed. The median number of leukapheresis cycles was 2 (range, 1-8). The overall survival for all patients was 4.2 months (95% CI 1.2-9.7 months). The median overall survival for patients who achieved complete remission after induction chemotherapy was significantly higher (19.1 months [95% CI 12.1-41.8 months]) than patients that did not achieve complete remission (0.46 months [95% CI 0.33-0.99 months]). Stepwise logistic regression demonstrated that elevated number of peripheral blasts, low platelet count and elevated bilirubin at AML diagnosis were predictive of death within a week. Leukapheresis was effective in reducing the peripheral blood leukocytes and leukemia blasts and was a safe procedure with regard to organ function, coagulation parameters, red blood cells and platelet count. The high initial response rates in newly diagnosed AML patients fit to receive intensive chemotherapy suggest that leukapheresis could be beneficial in reducing the complications associated with hyperleukocytosis until systemic intensive chemotherapy commences.

IV pentamidine for primary PJP prophylaxis in adults undergoing allogeneic hematopoietic progenitor cell transplant.

IV pentamidine for primary PJP prophylaxis in adults undergoing allogeneic hematopoietic progenitor cell transplant

A Modified Integrated Genetic Model for Risk Prediction in Younger Patients with Acute Myeloid Leukemia

Background Although cytogenetics-based prognostication systems are well described in acute myeloid leukemia (AML), overall survival (OS) remains highly variable within risk groups. An integrated genetic prognostic (IGP) model using cytogenetics plus mutations in nine genes was recently proposed for patients ≤60 years to improve classification. This model has not been validated in clinical practice. Methods and Findings We retrospectively studied 197 patients with newly diagnosed de novo AML. We compared OS curves among the mutational profiles defined by the IGP model. The IGP model assigned patients with intermediate cytogenetics as having favorable, intermediate or unfavorable mutational profiles. The IGP model reassigned 50 of 137 patients with intermediate cytogenetics to favorable or unfavorable mutational profiles. Median OS was 2.8 years among 14 patients with intermediate cytogenetics and favorable mutational profiles (mutant NPM1 and mutant IDH1 or IDH2) and 1.3 years among patients with intermediate mutational profiles. Among patients with intermediate cytogenetics labeled as having unfavorable mutational profiles, median OS was 0.8 years among 24 patients with FLT3-ITD positive AML and high-risk genetic changes (trisomy 8, TET2 and/or DNMT3A) and 1.7 years among 12 patients with FLT3-ITD negative AML and high-risk mutations (TET2, ASXL1 and/or PHF6). OS for patients with intermediate cytogenetics and favorable mutational profiles was similar to OS for patients with favorable cytogenetics (p = 0.697) and different from patients with intermediate cytogenetics and intermediate mutational profiles (p = 0.028). OS among patients with FLT3-ITD positive AML and high-risk genetic changes was similar to patients with unfavorable cytogenetics (p = 0.793) and different from patients with intermediate IGP profile (p = 0.022). Patients with FLT3-ITD negative AML and high-risk mutations, defined as ‘unfavorable’ in the IGP model, had OS similar to patients with intermediate IGP profile (p = 0.919). Conclusions The IGP model was not completely validated in our cohort. However, mutations in six out of the nine genes can be used to characterize survival (NPMI, IDH1, IDH2, FLT3-ITD, TET2, DNMT3A) and allow for more robust prognostication in the patients who are re-categorized by the IGP model. These mutations should be incorporated into clinical testing for younger patients outside of clinical trials, in order to guide therapy.

Acute Cholecystitis Is a Common Complication after Allogeneic Stem Cell Transplantation and Is Associated with the Use of Total Parenteral Nutrition

The incidence and risk factors for acute cholecystitis after allogeneic hematopoietic stem cell transplantation (HSCT) are not well defined. Of 644 consecutive adult transplants performed at our institution between 2001 and 2011, acute cholecystitis occurred in the first year of transplant in 32 patients (5.0%). We conducted 2 retrospective case-control studies of this population to determine risk factors for cholecystitis after HSCT and to evaluate the performance of different methods of imaging to diagnosis cholecystitis in patients undergoing HSCT compared with non-HSCT patients. In the HSCT population, development of cholecystitis was associated with an increased 1-year overall mortality rate (62.5% versus 19.8%, P < .001). The risk of developing cholecystitis was higher in patients who received total parenteral nutrition (TPN) (adjusted odds ratio, 3.41; P = .009). There was a trend toward more equivocal abdominal ultrasound findings in HSCT recipients with acute cholecystitis compared with nontransplant patients (50.0% versus 30.6%, P = .06). However, hepatobiliary iminodiacetic acid (HIDA) scans were definitively positive for acute cholecystitis in most patients in both populations (80.0% of HSCT recipients versus 77.4% of control subjects, P = .82). In conclusion, acute cholecystitis is a common early complication of HSCT, the risk is increased in patients who receive TPN, and it is associated with high 1-year mortality. In HSCT recipients with findings suggestive of acute cholecystitis, especially those receiving TPN, early use of HIDA scan may be considered over ultrasound.

Peri‐transplant Clostridium difficile infections in patients undergoing allogeneic hematopoietic progenitor cell transplant

Clostridium difficile infections (CDI) remain the leading cause of infectious diarrhea among hospitalized patients in this country. Patients with hematologic malignancies, especially those who undergo hematopoietic progenitor cell transplants are particularly at risk for developing CDI. One hundred and forty seven consecutive allogeneic hematopoietic progenitor cell transplants were analyzed for peri‐transplant Clostridium difficile infections (PT‐CDI). Sixteen patients (11%) developed PT‐CDI (Median time = 7 days after transplant). The probability for developing PT‐CDI during the peri‐transplant period was 12.3%. History of CDI was strongly associated with the development of PT‐CDI (P = 0.008) (OR = 5.48) (P = 0.017). These patients also developed PT‐CDI much earlier than in those without a history (median 1 day vs. 8 days, P = 0.03). The probability for developing PT‐CDI for those with a history was 39%. There was a trend toward significance (P = 0.065) between matched related donor grafts and the development of PT‐CDI (OR = 0.245) (P = 0.08). Age, sex, diagnosis, transplant preparative regimens, Graft‐versus‐host disease (GVHD) prophylaxis, grade 3/4 acute GVHD, or use of antimicrobials within 8 weeks of transplant were not associated with PT‐CDI. Non‐CDI‐related deaths occurred in one patient in the PT‐CDI group and nine in the group without PT‐CDI. In the remaining 139 patients, the length of hospital stay for those with PT‐CDI was significantly longer than those without (mean 27 days vs. 22 days; P = 0.02). Am. J. Hematol. 91:291–294, 2016.

Inferior outcome after allogeneic transplant in first remission in high-risk AML patients who required more than two cycles of induction therapy.

While some patients with high‐risk acute myeloid leukemia (AML) require one or two cycles of induction chemotherapy to achieve a complete remission (CR), others require more than two cycles. We examined the outcomes of patients with high‐risk AML who received allogeneic HPC transplant in CR1. Forty five consecutive high‐risk AML patients in CR1 were included. All 45 patients had adverse cytogenetics, FLT 3 mutations, or secondary AML. Group A patients (n = 33) received one or two cycles, and Group B (n = 12) three or more cycles of induction chemotherapy. The patients were comparable in age, sex, white cell count at presentation, and time from diagnosis and from last chemotherapy to transplant. The 100‐day mortality rate was higher in Group B patients (50% vs. 9%, P = 0.006). They had a higher non‐relapse mortality (33% vs. 6%, P = 0.035) and a longer length of hospital stay from the day of stem cell infusion (median 21 vs. 20, P = 0.02; third quartile 22 vs. 28, P = 0.02). There was also a trend toward inferior event‐free survival and overall survival. High‐risk AML patients undergoing allogeneic transplant in CR1 after three or more cycles of induction chemotherapy have an inferior outcome and higher mortality when compared to those who only needed one or two cycles of induction chemotherapy. Novel strategies are needed to reduce the transplant‐related mortality in high‐risk AML patients needing more than two cycles of induction chemotherapy prior to allogeneic transplant in CR1. Am. J. Hematol. 90:715–718, 2015.