Induction therapy for elderly patients with acute myeloid leukemia

Homoharringtonine enhances cytarabine-induced apoptosis in acute myeloid leukaemia by regulating the p38 MAPK/H2AX/Mcl-1 axis

Acute myeloid leukaemia (AML) is a fatal haematopoietic malignancy and is treated with the conventional combination of cytarabine (Ara-C) and daunorubicin (Dau). The survival rate of AML patients is lower due to the cardiotoxicity of daunorubicin. Clinically, homoharringtonine (HHT) plus Ara-C has been reported to be equally effective as Dau plus Ara-C in some types of AML patients with less toxic effects. We utilized the clinical use of homoharringtonine in combination with Ara-C to test its combination mechanism. We found that the insensitivity of AML cells to cytarabine-induced apoptosis is associated with increased Mcl-1 stability and p38 inactivation. HHT downregulates Mcl-1, phosphorylates H2AX and induces apoptosis by activating p38 MAPK. Inactivation of p38 through inhibitors and siRNA blocks apoptosis, H2AX phosphorylation and Mcl-1 reduction. HHT enhances Ara-C activation of the p38 MAPK signalling pathway, overcoming Ara-C tolerance to cell apoptosis by regulating the p38/H2AX/Mcl-1 axis. The optimal ratio of HHT to Ara-C for synergistic lethality in AML cells is 1:4 (M/M). HHT synergistically induces apoptosis in combination with Ara-C in vitro and prolongs the survival of xenografts. We provide a new mechanism for AML treatment by regulating the p38 MAPK/H2AX/Mcl-1 axis to improve cytarabine therapy.

Venetoclax with decitabine vs intensive chemotherapy in acute myeloid leukemia: A propensity score matched analysis stratified by risk of treatment-related mortality

Hypomethylating agents (HMA) with venetoclax is a new standard for older/unfit patients with acute myeloid leukemia (AML). However, it is unknown how HMA with venetoclax compare to intensive chemotherapy (IC) in patients who are "fit" or "unfit" for IC. We compared outcomes of older patients with newly diagnosed AML receiving 10-day decitabine with venetoclax (DEC10-VEN) vs IC. DEC10-VEN consisted of daily venetoclax with decitabine 20 mg/m² for 10 days for induction and decitabine for 5 days as consolidation. The IC cohort received regimens containing cytarabine ≥1 g/m² /d. A validated treatment-related mortality score (TRMS) was used to classify patients at high-risk or low-risk for TRM with IC. Propensity scores were used to match patients to minimize bias. Median age of the DEC10-VEN cohort (n = 85) was 72 years (range 63-89) and 28% patients were at high-risk of TRM with IC. The comparator IC group (n = 85) matched closely in terms of baseline characteristics. DEC10-VEN was associated with significantly higher CR/CRi compared to IC (81% vs 52%, P < .001), and lower rate of relapse (34% vs 56%, P = .01), 30-day mortality (1% vs 24%, P < .01), and longer overall survival (OS; 12.4 vs 4.5 months, HR = 0.48, 95%CI 0.29-0.79, P < .01). In patients at both at high-risk and low-risk of TRM, DEC10-VEN showed significantly higher CR/CRi, lower 30-day mortality, and longer OS compared to IC. Patients at both high-risk and low-risk of TRM had comparable outcomes with DEC10-VEN. In conclusion, DEC10-VEN offers better outcomes compared to intensive chemotherapy in older patients with newly diagnosed AML, particularly in those at high-risk of TRM.

Enasidenib for the treatment of acute myeloid leukemia

INTRODUCTION

In August 2017, the United States Federal Drug Administration (FDA) approved enasidenib (Idhifa, Celgene/Agios) for adults with relapsed and refractory acute myelogenous leukemia (AML) with an IDH2 mutation. Enasidenib targets cells with mutant copies of isocitrate dehydrogenase-2 (IDH2), inhibiting the oncometabolite 2-hydroxyglutarte (2-HG) formed by the mutant IDH2. Areas covered: We review the studies leading to enasidenib's approval, as well as common side effects and safety issues experienced during the clinical trials. There is a focus on the diagnosis and treatment of these side effects including differentiation syndrome. Expert commentary: We are experiencing a revolution in the understanding of the mechanism of AML. A majority of the effort has been concentrated on targeting gene mutations or pathway activations with precision therapeutics. Enasidenib is beneficial in a patient population that previously had limited treatment options. However, given the fact that enasidenib is a highly specific inhibitor of an early stable mutation, it is questionable whether a strategy of targeting a single mutation or pathway in relapsed AML will allow for better than the 20% complete remission (CR) rate observed with this therapy. The proper role for single mutation targeting in AML needs to be carefully considered.

Heteronemin, a marine natural product, sensitizes acute myeloid leukemia cells towards cytarabine chemotherapy by regulating farnesylation of Ras

Cytarabine is a conventionally used chemotherapeutic agent for treating acute myeloid leukemia (AML). However, chemoresistance, toxic side-effects and poor patient survival rates retard the efficacy of its performance. The current study deals with the chemosensitization of AML cells using heteronemin, a marine natural product towards cytarabine chemotherapy. Heteronemin could effectively sensitize HL-60 cells towards sub-toxic concentration of cytarabine resulting in synergistic toxicity as demonstrated by MTT assay and [3H] thymidine incorporation studies, while being safe towards healthy blood cells. Flow cytometry for Annexin-V/PI and immunoblotting for caspase cleavage proved that the combination induces enhancement in apoptosis. Heteronemin being a farnesyl transferase inhibitor (FTI) suppressed cytarabine-induced, farnesyl transferase-mediated activation of Ras, as assessed by Ras pull-down assay. Upon pre-treating cells with a commercial FTI, L-744,832, the synergism was completely lost in the combination, confirming the farnesyl transferase inhibitory activity of heteronemin as assessed by thymidine incorporation assay. Heteronemin effectively down-regulated cytarabine-induced activation of MAPK, AP-1, NF-κB and c-myc, the down-stream targets of Ras signaling, which again validated the role of Ras in regulating the synergism. Hence we believe that the efficacy of cytarabine chemotherapy can be improved to a significant extent by combining sub-toxic concentrations of cytarabine and heteronemin.

Inhibition of Mnk enhances apoptotic activity of cytarabine in acute myeloid leukemia cells

Cytarabine (Ara-C) is a first line clinical therapeutic agent for treatment of acute myeloid leukemia (AML). However, this therapy is limited due to high rate of resistance and relapse. Recent research has revealed that the poor prognosis and resistance to Ara-C in AML were associated with its abnormally activated MAPK pathways. In this study, we showed a strong synergistic effect of Ara-C with either our Mnk inhibitor (MNKI-8e) or short hairpin RNA (shRNA) mediated knockdown of Mnks in MV4-11 AML cells. We investigated the underlying mechanisms for this synergism. We showed that both MNKI-8e and Mnk shRNAs enhanced the ability of Ara-C to induce apoptosis. We found that Ara-C increased the phosphorylation of Erk1/2, p38 and eIF4E, which correlated with an enhanced level of anti-apoptotic Mcl-1 protein. Inhibition of Mnk activity suppressed the Ara-C-induced MAPK activity, and thus enhanced apoptosis in MV4-11 cells. Taken together, our study suggests that MAPK-Mnk-eIF4E pathway plays a critical role in Ara-C-treated MV4-11 cells and targeting Mnk may be a promising therapeutic strategy for sensitizing leukemic cells to Ara-C therapy.

A phase I dose escalation study of oral bexarotene in combination with intravenous decitabine in patients with AML

The response rate of non-M3 acute myeloid leukemia (AML) to all trans retinoic acid has been limited. Using Affymetrix expression arrays, we found that in diverse AML blasts RXRA was expressed at higher levels than RARA and that mouse Ctsg-PML-RARA leukemia responded to bexarotene, a ligand for RXRA. We therefore performed a phase I study of combination bexarotene and decitabine in elderly and relapsed AML patients. We found that this combination was well tolerated, although outcomes were modest (1 CRi, and 3 PR among 19 patients). Correlative studies found that patients with clinical response had increased differentiation to bexarotene both in vivo and ex vivo, suggesting that pre-treatment analysis might identify a more susceptible subgroup of patients.

Outcomes of elderly de novo acute myeloid leukemia treated by a risk-adapted approach based on age, comorbidity, and performance status

Several criteria to define fitness for induction chemotherapy in elderly acute myeloid leukemia (AML) have been proposed; however, no studies have reported outcomes according to the application of a risk-adapted approach. We treated 256 consecutive patients with elderly AML (≥60 years) with a risk-adapted approach based on age, comorbidity score (CS), and performance status (ECOG). Eighty-five low-risk patients (age ≤ 65 years and ECOG 0-1 with CS < 2), 86 intermediate-risk patients (age > 65 years or ECOG = 2 with CS < 2), and 85 high-risk patients (ECOG > 2 or CS ≥ 2) were treated with induction chemotherapies, including standard intensive regimens, abbreviated-scheduled regimens, and modified low-dose cytarabine with oral etoposide (mLDAC), respectively. Overall response rates (ORR; complete response and complete response with incomplete recovery) for these three groups were 71.8%, 60.5%, and 41.2%, respectively, without a significant difference in early death rate (17.6%, 25.6%, 23.5%, P = 0.415). Among three abbreviated-scheduled regimens, a gemtuzumab ozogamicin (GO)-containing regimen (n = 43) showed a similar ORR rate (72.1%) to the intensive regimen. After achieving remission, 142 patients went on postremission treatments, including reduced-intensity allogeneic transplantation (RIC, n = 41), standard consolidation (n = 71), and repeated mLDAC (n = 30) according to donor availability, age, ECOG, and CS. Multivariate analyses revealed that not only RIC, but also repeated mLDAC, resulted in significantly superior survival outcomes to standard consolidation independent of age, ECOG, and CS. Clinical benefits of mLDAC for high-risk patients and abbreviated induction with GO for intermediate-risk patients should be confirmed with further studies. Our results also suggest that RIC should be actively considered in elderly AML as a postremission treatment.

The Development of Novel Therapies for the Treatment of Acute Myeloid Leukemia (AML)

Acute myeloid leukemia (AML) is nearly always a fatal malignancy. For the past 40 years, the standard of care remains a combination of cytarabine and an anthracycline known as 7 + 3. This treatment regimen is troubled by both low survival rates (10% at 5 years) and deaths due to toxicity. Substantial new laboratory findings over the past decade have identified many cellular pathways that contribute to leukemogenesis. These studies have led to the development of novel agents designed to target these pathways. Here we discuss the molecular underpinnings and clinical benefits of these novel treatment strategies. Most importantly these studies demonstrate that clinical response is best achieved by stratifying each patient based on a detailed understanding of their molecular abnormalities.

Induction chemotherapy versus palliative treatment for acute myeloid leukemia in a consecutive cohort of elderly patients

A retrospective survey of 210 consecutive patients aged ≥ 65 years (median age 69 years, range 65-88 years) with acute myeloid leukemia (AML) diagnosed at a single center over a 6-year period (January 2001 to December 2006) is presented. De novo AML was diagnosed in 179 (85.2 %) patients and 31 (14.7 %) patients had a secondary AML. Twenty-three patients had M0 (11 %), 36 M1 (17.15 %), 57 M2 (27.1 %), eight M3 (3.8 %), 45 M4 (21.4 %), 31 M5 (14.8 %), one M6 (0.5 %), one M7 (0.5 %), and eight patients had unclassified myeloid leukemia (3.8 %) according to French-American-British (FAB) Study Group Classification. Eight patients with M3 (acute promyelocytic leukemia) were excluded from the study. Cytogenetic analysis was performed in 172/202 (85 %) patients. The normal karyotype was found in 81/172 (47 %), high risk aberrations in 32/172 (18.6 %), and favorable karyotype in 13/172 (7.5 %) patients. Supportive and palliative therapies were applied in 115 (56.9 %) patients, a no induction chemotherapy (NIC) group, and 87 (43.1 %) patients received induction chemotherapy (IC group). Complete remission (CR) was achieved in 45/87 (51.7 %) in the IC group and in 5/115 (4.3 %) in the NIC group of patients. After a median follow up of 4 years, 194 (96 %) patients died. The variables significantly associated with a longer overall survival (OS) by univariate analysis were an age of <75 years, a better ECOG performance status (PS) (p = 0.000, CI 95.0 %, 1.358-2.049), a serum LDH activity <600 U/l (p = 0.000, CI 95.0 %, 1.465-2.946), lower white blood cell (WBC) count at diagnosis (p = 0.011, CI 95.0 %, 1.102-2.100), lower comorbidity HCT-CI index (p = 0.000, CI 95 % 2.209-3.458), absence of splenomegaly (p = 0.015, CI 95.0 %, 1.082-2.102) and hepatomegaly (p = 0.008, CI 95.0 %, 1.125-2.171), and no preceding nonhematological malignancy. Multivariate analysis showed that significant factors affecting OS in the IC group were achievement of CR (p = 0.000), the ECOG PS (p = 0.045) and the ECOG PS (p = 0.000), and HCT-CI (p = 0.000) in the NIC group of elderly patients. The present study suggests that a subgroup of elderly patients with both ECOG PS and HCT-CI ≤ 2 at presentation may be eligible for intensive induction chemotherapy.

Addition of lomustine to idarubicin and cytarabine improves the outcome of elderly patients with de novo acute myeloid leukemia: a report from the GOELAMS

PURPOSE

No significant improvement in treatment outcome has been seen in elderly patients with acute myeloid leukemia (AML) over the past 20 years. This retrospective analysis investigated the prognostic factors for complete remission (CR) and survival in older patients with AML.

PATIENTS AND METHODS

The study involved 847 patients older than 60 years enrolled onto three trials carried out in France between 1995 and 2005. Induction therapy consisted of idarubicin (8 mg/m(2), days 1 through 5) and cytarabine (100 mg/m(2), days 1 through 7; group I, 339 patients) or the same drugs plus lomustine (200 mg/m(2) orally on day 1; group II, 508 patients). Consolidation therapy consisted of anthracycline and cytarabine courses at lower doses, preceded or not by a first course of intermediate-dose cytarabine.

RESULTS

The rate of CR was significantly higher in patients in group II compared with group I (68% v 58%; P = .002). The rate of toxic death was similar in the two groups. In multivariate analysis, two prognostic factors were linked to CR: nonadverse cytogenetic (P < .003) and addition of lomustine to induction chemotherapy (P = .002). Median overall survival was significantly improved in patients treated with lomustine (median and SE, 12.7 +/- 2.2 months v 8.7 +/- 2.7 months; P = .004). In multivariate analysis, five prognostic factors positively affected overall survival: addition of lomustine (P = .002), age < or = 69 years (P < .001), Eastern Cooperative Oncology Group performance status lower than 2 (P = .002), French-American-British subgroup 1/2 (P = .02), and nonadverse cytogenetic (P < .001).

CONCLUSION

Lomustine improves the rate of CR and survival in elderly patients with de novo AML when added to standard induction therapy.

Understanding and Targeting the Eukaryotic Translation Initiation Factor eIF4E in Head and Neck Cancer

The eukaryotic translation initiation factor eIF4E is elevated in about 30% of human malignancies including HNSCC where its levels correlate with poor prognosis. Here, we discuss the biochemical and molecular underpinnings of the oncogenic potential of eIF4E. Studies in human leukemia specimens, and later in a mouse model of prostate cancer, strongly suggest that cells with elevated eIF4E develop an oncogene dependency to it, making them more sensitive to targeting eIF4E than normal cells. We describe several strategies that have been suggested for eIF4E targeting in the clinic: the use of a small molecule antagonist of eIF4E (ribavirin), siRNA or antisense oligonucleotide strategies, suicide gene therapy, and the use of a tissue-targeting 4EBP fusion peptide. The first clinical trial targeting eIF4E indicates that ribavirin effectively targets eIF4E in poor prognosis leukemia patients and more importantly leads to striking clinical responses including complete and partial remissions. Finally, we discuss the relevance of these findings to HNSCC.