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Purpose

To determine the efficacy and toxicity of the combination of sorafenib, cytarabine, and idarubicin in patients with acute myeloid leukemia (AML) younger than age 65 years.

Patients and Methods

In the phase I part of the study, 10 patients with relapsed AML were treated with escalating doses of sorafenib with chemotherapy to establish the feasibility of the combination. We then treated 51 patients (median age, 53 years; range, 18 to 65 years) who had previously untreated AML with cytarabine at 1.5 g/m2 by continuous intravenous (IV) infusion daily for 4 days (3 days if > 60 years of age), idarubicin at 12 mg/m2 IV daily for 3 days, and sorafenib at 400 mg orally twice daily for 7 days.

Results

Overall, 38 (75%) patients have achieved a complete remission (CR), including 14 (93%) of 15 patients with mutated FMS-like tyrosine kinase-3 (FLT3; the 15th patient had complete remission with incomplete platelet recovery [CRp]) and 24 (66%) of 36 patients with FLT3 wild-type (WT) disease (three additional FLT3-WT patients had CRp). FLT3-mutated patients were more likely to achieve a CR than FLT3-WT patients (P = .033). With a median follow-up of 54 weeks (range, 8 to 87 weeks), the probability of survival at 1 year is 74%. Among the FLT3-mutated patients, 10 have relapsed and five remain in CR with a median follow-up of 62 weeks (range, 10 to 76 weeks). Plasma inhibitory assay demonstrated an on-target effect on FLT3 kinase activity.

Conclusion

Sorafenib can be safely combined with chemotherapy, produces a high CR rate in FLT3-mutated patients, and inhibits FLT3 signaling.

Purpose

To compare the antitumor efficacy of three different anthracyclines in combination with cytarabine and etoposide in adult patients with newly diagnosed acute myeloid leukemia (AML).

Patients and Methods

We randomly assigned 2,157 patients (age range, 15 to 60 years) to receive intensive induction-consolidation chemotherapy containing either daunorubicin, idarubicin, or mitoxantrone. After achieving complete remission (CR), patients were assigned to undergo either allogeneic or autologous stem-cell transplantation (SCT), depending on the availability of a sibling donor.

Results

The overall CR rate (69%) was similar in the three groups. Autologous SCT was performed in 37% of cases in the daunorubicin arm versus only 29% and 31% in mitoxantrone and idarubicin, respectively (P < .001). However, the disease-free survival (DFS) and survival from CR were significantly shorter in the daunorubicin arm: the 5-year DFS was 29% versus 37% and 37% in mitoxantrone and idarubicin, respectively. The proportion of patients who underwent allogeneic SCT (22%) was equivalent in the three treatment groups, and the outcome was similar as well: the 5-year overall survival rates were 34%, 34%, and 31%, respectively.

Conclusion

In adult patients with AML who do not receive an allogeneic SCT, the use of mitoxantrone or idarubicin instead of daunorubicin enhances the long-term efficacy of chemotherapy.

Background

Patients with acute myeloid leukemia (AML) are often neutropenic as a result of their disease. Furthermore, these patients typically experience profound neutropenia following induction and/or consolidation chemotherapy and this may result in serious, potentially life-threatening, infection. This randomized, double-blind, phase 2 clinical trial compared the efficacy and tolerability of pegfilgrastim with filgrastim for assisting neutrophil recovery following induction and consolidation chemotherapy for de novo AML in patients with low-to-intermediate risk cytogenetics.

Methods

Patients (n = 84) received one or two courses of standard induction chemotherapy (idarubicin + cytarabine), followed by one course of consolidation therapy (high-dose cytarabine) if complete remission was achieved. They were randomized to receive either single-dose pegfilgrastim 6 mg or daily filgrastim 5 μg/kg, beginning 24 hours after induction and consolidation chemotherapy.

Results

The median time to recovery from severe neutropenia was 22.0 days for both pegfilgrastim (n = 42) and filgrastim (n = 41) groups during Induction 1 (difference 0.0 days; 95% CI: -1.9 to 1.9). During Consolidation, recovery occurred after a median of 17.0 days for pegfilgrastim versus 16.5 days for filgrastim (difference 0.5 days; 95% CI: -1.1 to 2.1). Therapeutic pegfilgrastim serum concentrations were maintained throughout neutropenia. Pegfilgrastim was well tolerated, with an adverse event profile similar to that of filgrastim.

Conclusion

These data suggest no clinically meaningful difference between a single dose of pegfilgrastim and multiple daily doses of filgrastim for shortening the duration of severe neutropenia following chemotherapy in de novo AML patients with low-to-intermediate risk cytogenetics.

Trial registration

Clinicaltrials.gov NCT00114764

Primary pulmonary leiomyosarcoma (LMS) is a very unusual tumor. Although LMS has well-known metastatic potential, cutaneous metastasis is a remarkably uncommon. Exposure to cytotoxic agents could lead to “therapy-related myeloid neoplasm” (t-MN). Starting from 2008, the World Health Organization (WHO) has adopted the term to cover the spectrum of malignant diseases previously known as therapy-related acute myeloid leukemia (t-AML), therapy-related myelodysplastic syndrome (t-MDS) and therapy-related myelodysplastic/myelo- proliferative neoplasm (t-MDS/MPN). We described the onset of t-MDS and progression to t-AML in one case diagnosed as primary pulmonary LMS with cutaneous metastasis. This patient achieved complete remission (CR) after three courses of IA regimen chemotherapy (idarubicin 5 mg/d, d 1-3; cytarabine 100 mg/d, d 1-5) and 1 course of HA chemotherapy regimen (homoharringtonine 3 mg/d, d 1-3; cytarabine 100 mg/d, d 1-7). This case presents the natural course of therapy-related neoplasm and provides therapeutic experience for t-AML.

Background

It is unknown whether patients with nonleukemic myeloid sarcoma (MS) and those with acute myeloid leukemia (AML) have similar responses to anti-AML treatment. We addressed this question by matching MS patients with analogous AML patients and comparing their clinical outcomes.

Methods

We identified 23 consecutive MS and 1720 consecutive AML patients who presented at The University of Texas M. D. Anderson Cancer Center from 1990 to 2004. All AML patients and 16 MS patients received cytarabine plus idarubicin or fludarabine as induction remission therapy. We matched treated MS and AML patients according to cytogenetics, age, Zubrod performance status, and time of treatment. Event-free survival (EFS) and overall survival (OS) were compared using Kaplan-Meier analyses.

Results

Complete response rates were 69% in MS and 57% in AML (p=0.45). The respective 2-year EFS and OS rates were 32% and 18% (p=0.08) and 43% and 29% (p=0.11). Matches could be found for 14 MS patients, who were paired repeatedly with 91 AML patients to produce 94 matches (3 AML patients were matched twice). EFS was longer in 56 MS pair-mates, shorter in 26, and similar in 12 (p=0.01, Fisher exact test). OS analyses gave similar results.

Conclusions

Anti-AML therapy is highly effective in patients with non-leukemic MS. This study emphasizes the need to treat patients with non-leukemic MS with AML-type therapy.

Background

Pediatric acute myeloid leukemia (AML) remains a challenging disease to treat even with intensified cytarabine-based chemotherapy. Histone deacetylases (HDACs) have been reported to be promising therapeutic targets for treating AML. However, HDAC family members that are involved in chemotherapy sensitivities remain unknown. In this study, we sought to identify members of the HDAC family that are involved in cytarabine sensitivities, and to select the optimal HDACI that is most efficacious when combined with cytarabine for treating children with AML.

Methodology

Expression profiles of classes I, II, and IV HDACs in 4 pediatric AML cell lines were determined by Western blotting. Inhibition of class I HDACs by different HDACIs was measured post immnunoprecipitation. Individual down-regulation of HDACs in pediatric AML cells was performed with lentiviral shRNA. The effects of cytarabine and HDACIs on apoptosis were determined by flow cytometry analysis.

Results

Treatments with structurally diverse HDACIs and HDAC shRNA knockdown experiments revealed that down-regulation of both HDACs 1 and 6 is critical in enhancing cytarabine-induced apoptosis in pediatric AML, at least partly mediated by Bim. However, down-regulation of HDAC2 may negatively impact cytarabine sensitivities in the disease. At clinically achievable concentrations, HDACIs that simultaneously inhibited both HDACs 1 and 6 showed the best anti-leukemic activities and significantly enhanced cytarabine-induced apoptosis.

Conclusion

Our results further confirm that HDACs are bona fide therapeutic targets for treating pediatric AML and suggest that pan-HDACIs may be more beneficial than isoform-specific drugs.

Purpose

RAS mutations occur in 12% to 27% of patients with acute myeloid leukemia (AML) and enhance sensitivity to cytarabine in vitro. We examined whether RAS mutations impact response to cytarabine in vivo.

Patients and Methods

One hundred eighty-five patients with AML achieving complete remission on Cancer and Leukemia Group B study 8525 and randomly assigned to one of three doses of cytarabine postremission were screened for RAS mutations. We assessed the impact of cytarabine dose on cumulative incidence of relapse (CIR) of patients with (mutRAS) and without (wild-type; wtRAS) RAS mutations.

Results

Thirty-four patients (18%) had RAS mutations. With 12.9 years median follow-up, the 10-year CIR was similar for mutRAS and wtRAS patients (65% v 73%; P = .31). However, mutRAS patients receiving high-dose cytarabine consolidation (HDAC; 3 g/m2 every 12 hours on days 1, 3, and 5 or 400 mg/m2/d × 5 days) had the lowest 10-year CIR, 45%, compared with 68% for wtRAS patients receiving HDAC and 80% and 100%, respectively, for wtRAS and mutRAS patients receiving low-dose cytarabine (LDAC; 100 mg/m2/d × 5 days; overall comparison, P < .001). Multivariable analysis revealed an interaction of cytarabine dose and RAS status (P = .06). After adjusting for this interaction and cytogenetics (core binding factor [CBF] AML v non-CBF AML), wtRAS patients receiving HDAC had lower relapse risk than wtRAS patients receiving LDAC (hazard ratio [HR] = 0.67; P = .04); however, mutRAS patients receiving HDAC had greater reduction in relapse risk (HR = 0.28; P = .002) compared with mutRAS patients treated with LDAC.

Conclusion

AML patients carrying mutRAS benefit from higher cytarabine doses more than wtRAS patients. This seems to be the first example of an activating oncogene mutation favorably modifying response to higher drug doses in AML.

The sensitization of leukemia cells with hematopoietic growth factors can enhance the cytotoxicity of chemotherapy in acute myeloid leukemia (AML). Therefore, the current trial attempted to evaluate the efficacy of granulocyte colony-stimulating factor (G-CSF) priming in remission induction chemotherapy with an intensified dose of Ara-C for newly diagnosed AML. Patients with newly diagnosed AML were randomly assigned to receive idarubicin (12 mg/m2/24 hr, days 1-3) plus Ara-C (500 mg/m2/12 hr, days 4-8) with G-CSF (250 µg/m2/d, days 3-7) (IAG group) or standard idarubicin (12 mg/m2/24 hr, days 1-3) plus Ara-C (100 mg/m2/12 hr, days 1-7) without G-CSF (IA group). There were no significant differences in sex, age, subtype, or cytogenetic risk between the two groups. Complete remission was achieved in 15 patients (88.2%) from the IAG group and in 14 patients (82.4%) from the IA group (p=0.31). The median time to complete remission was 26 vs. 31 days (p=0.779) for the IA and IAG groups, respectively. The median time to neutrophil recovery (>1×109/L) and platelet recovery (>20×109/L) did not differ significantly between the two groups (26 vs. 26 days, p=0.338; 21 vs. 16 days, p=0.190, respectively). After a median follow-up of 682 days, the 3-year overall survival rate for the IA group was 64.7%, whereas that for the IAG group was 45.6% (p=0.984). No improved clinical outcomes were observed for the AML patients subjected to intensified remission induction with G-CSF priming when compared with standard induction chemotherapy.

We report a rare case of granulocytic sarcoma infiltrating the bile duct in a patient with acute myeloid leukemia. A 23-year-old man presented with jaundice and weight loss. A peripheral blood smear revealed blast cells, and the results of an examination of bone marrow aspirate were consistent with acute myeloid leukemia. The bilirubin level increased gradually after induction chemotherapy with cytarabine. Magnetic resonance cholangiopancreatography (MRCP) revealed dilatation of the intrahepatic bile ducts and smooth tapering off at the level of the common hepatic bile duct. Endoscopic retrograde cholangiopancreatography (ERCP) also revealed diffuse narrowing of the proximal common hepatic bile duct. Obstructive jaundice resolved after endoscopic nasobiliary drainage. Remission induction chemotherapy with cytarabine and idarubicin was administered, and the patient remained complete hematological remission with normal liver function tests.

Acute megakaryoblastic leukemia (AMKL) is a type of acute myeloid leukemia (AML), in which majority of the blasts are megakaryoblastic. De novo AMKL in adulthood is rare, and carries very poor prognosis. We here report a 45-year-old woman with de novo AMKL with BCR/ABL rearrangement and der(16)t(1;16)(q21;q23) translocation but negative for t(9;22) Ph chromosome. Upon induction chemotherapy consisting of homoharringtonine, cytarabine and daunorubicin, the patient achieved partial hematological remission. The patient was then switched to imatinib plus one cycle of CAG regimen (low-dose cytarabine and aclarubicin in combination with granulocyte colony-stimulating factor), and achieved complete remission (CR). The disease recurred after 40 days and the patient eventually died of infection. To the best of our knowledge, this is the first report of de novo AMKL with p210 BCR/ABL and der(16)t(1;16)(q21;q23) translocation but not t(9;22) Ph chromosome.

Acute myeloid leukemia (AML) is a clonal disease originating from myeloid progenitor cells with a heterogeneous genetic background. High-dose cytarabine is used as the standard consolidation chemotherapy. Oncogenic RAS mutations are frequently observed in AML, and are associated with beneficial response to cytarabine. Why AML-patients with oncogenic RAS benefit most from high-dose cytarabine post-remission therapy is not well understood. Here we used bone marrow cells expressing a conditional MLL-ENL-ER oncogene to investigate the interaction of oncogenic RAS and chemotherapeutic agents. We show that oncogenic RAS synergizes with cytotoxic agents such as cytarabine in activation of DNA damage checkpoints, resulting in a p53-dependent genetic program that reduces clonogenicity and increases myeloid differentiation. Our data can explain the beneficial effects observed for AML patients with oncogenic RAS treated with higher dosages of cytarabine and suggest that induction of p53-dependent differentiation, e.g. by interfering with Mdm2-mediated degradation, may be a rational approach to increase cure rate in response to chemotherapy. The data also support the notion that the therapeutic success of cytotoxic drugs may depend on their ability to promote the differentiation of tumor-initiating cells.

Cytarabine resistance characterizes relapsed and refractory acute myelogenous leukemia (AML). Restoration of cytarabine sensitivity can potentially improve treatment outcome in this setting. Acquired hypermethylation of gene promoters and associated silencing of gene expression has been implicated in chemo resistance, and drug-induced hypomethylation can improve sensitivity to cytarabine in vitro. We conducted an adaptively randomized study of a combination of azacitidine, a hypomethylating agent, and cytarabine in 34 patients with AML. The combination administered in a concomitant fashion is safe at full doses of azacitidine and cytarabine, without unexpected toxicities. However, in this advanced AML population, it was difficult to deliver more than one cycle of therapy, and minimal anti-leukemia activity was seen in patients with relapsed/refractory disease. Complete remission was achieved in 2 of 6 minimally pre-treated patients. We conclude that the combination of azacitidine and cytarabine is feasible but has limited activity in relapsed/refractory AML.

Because no conclusive evidence as to the efficacy of maintenance chemotherapy in acute myelogenous leukemia (AML) existed, a study to obtain such information was done. Twenty-six adult patients with AML in whom complete remission had been achieved following induction chemotherapy were randomly assigned to receive either maintenance chemotherapy consisting of cytarabine and 6-thioguanine for two days each month or to receive no maintenance therapy. The data showed a significant difference in remission duration between the two groups, with median remission lengths for the maintained and unmaintained groups being 10.3 and 6.7 months, respectively (p<.05). In 46 percent of the maintained patients there were remissions lasting longer than 11 months, whereas in none of the unmaintained patients was there such a prolonged remission. No significant drug-induced toxicity was observed. That the prolonged exposure to these chemotherapeutic agents, which were also used in our induction program, did not adversely affect the rate of successful reinduction therapy was shown by identical 50 percent complete remission rates for second inductions in both groups. In patients with palpable splenomegaly at the time of diagnosis, there was no prolongation of remission with maintenance therapy. These data indicate the potential utility of maintenance chemotherapy for prolonging remission duration in acute myelogenous leukemia.

Summary

Smoking adversely affects hematopoietic stem cell transplantation outcome. We asked whether smoking affected outcome of newly diagnosed acute myeloid leukemia (AML) patients treated with chemotherapy. Data were collected on 280 AML patients treated with high-dose cytarabine and idarubicin-containing regimens at Roswell Park Cancer Institute who had smoking status data at diagnosis. Patients’ gender, age, AML presentation (de novo vs. secondary), white blood cell (WBC) count at diagnosis, karyotype and smoking status (never vs. ever) were analyzed. Among the 161 males and 119 females with a median follow-up of 12.9 months, 101 (36.1%) had never smoked and 179 (63.9%) were ever smokers. The proportion of patients between never and ever smokers was similar with respect to age, AML presentation, WBC count at diagnosis or karyotype based on univariate analysis of these categorical variables. Never smokers had a significantly longer overall survival (60.32 months) compared to ever smokers (30.89; p=0.005). In multivariate analysis incorporating gender, age, AML presentation, WBC count, karyotype, and smoking status as covariates, age, karyotype and smoking status retained prognostic value for overall survival. In summary, cigarette smoking has a deleterious effect on overall survival in AML.

XIAP, a potent caspase inhibitor, is highly expressed in acute myeloid leukemia (AML) cells and contributes to chemoresistance. A multi-center phase 1/2 trial of XIAP antisense oligonucleotide AEG35156 in combination with idarubicin/cytarabine was conducted in 56 patients with relapsed/refractory AML. Herein we report the pharmacodynamic studies of the patients enrolled at M. D. Anderson Cancer Center. A total of 13 patients were enrolled in our institution: five in phase 1 (12–350 mg/m2 AEG35156) and eight in phase 2 (350 mg/m2 AEG35156) of the protocol. AEG35156 was administered on 3 consecutive days and then weekly up to a maximum of 35 days. Blood samples were collected from patients on days 1 through 5 and on day 28–35 post-chemotherapy for detection of XIAP levels and apoptosis. AEG35156 treatment led to dose-dependent decreases of XIAP mRNA levels (42–100% reduction in phase 2 patients). XIAP protein levels were reduced in all five samples measured. Apoptosis induction was detected in 1/4 phase 1 and 4/5 phase 2 patients. Importantly, apoptosis was most pronounced in CD34+38− AML stem cells and all phase 2 patients showing apoptosis induction in CD34+38− cells achieved response. We conclude that at 350 mg/m2, AEG35156 is effective in knocking down XIAP in circulating blasts accompanied by the preferential induction of apoptosis in CD34+38− AML stem cells.

Summary

The most effective post-remission treatment to maintain complete remission (CR) in adults aged between 46 and 60 years with acute myeloid leukaemia (AML) is uncertain. Previously untreated patients with AML in CR after induction chemotherapy with daunorubicin and cytarabine were randomized between two intensive courses of consolidation therapy containing high-dose cytarabine, combined with amsacrine or daunorubicin and a standard consolidation and maintenance therapy containing standard dose cytarabine and daunorubicin. One hundred fifty-eight CR patients were assigned to the intensive group and 157 patients to the standard group. After a median follow-up of 7.5 years, the 4-year survival rate was 32 % in the intensive group versus 34 % in the standard group (P = 0.29). In the intensive group, the 4-year relapse incidence was lower than in the standard group: 55 and 75 %, respectively (P = 0.0003), whereas treatment-related mortality incidence was higher: 22 versus 3 % (P < 0.0001). Two intensive consolidation courses containing high-dose cytarabine as post-remission treatment in patients with AML aged between 46 and 60 years old did not translate in better long-term outcome despite a 20 % lower relapse incidence. Better supportive care and prevention of treatment-related complications may improve the overall survival after intensified post-remission therapy in this age group.

Relapse is the major cause of treatment failure in acute lymphoblastic leukemia (ALL), yet there is no established treatment for relapsed ALL. To improve the induction remission rate, we modified the dose of idarubicin in the original Children's Cancer Group (CCG)-1884 protocol, and retrospectively compared the results. Twenty-eight patients diagnosed with relapsed ALL received induction chemotherapy according to the CCG-1884 protocol. Complete remission (CR) rate in all patients after induction chemotherapy was 57%. The idarubicin 10 mg/m2/week group showed CR rate of 74%, compared with the 22% CR rate of the idarubicin 12.5 mg/m2/week group (p=0.010). Remission failure due to treatment-related mortality (TRM) was 44% and 5.2% in the idarubicin 12.5 mg/m2/week and 10 mg/m2/week groups, respectively (p=0.011). Overall survival (OS) and 4-yr event-free survival (EFS) were 12.8% and 10.3%, respectively. OS and 4-yr EFS were higher in the idarubicin 10 mg/m2/week group (19.3% and 15.6%) than in the 12.5 mg/m2/week group (0% and 0%). In conclusion, a modified dose of idarubicin from 12.5 mg/m2/week to 10 mg/m2/week resulted in an improved CR rate in the treatment of relapsed ALL, which was due to lower TRM. However, despite improved CR rate with modified dose of idarubicin, survival rates were unsatisfactory.

The meningeal involvement is rare in acute promyelocytic leukemia. We experienced a 39-year-old woman who achieved complete remission with all-trans retinoic acid, idarubicin and cytarabine therapy. Several months later, she complained of non-specific headache. Her complete blood cell count was normal, but magnetic resonance image of brain revealed focal meningeal enhancement and cerebrospinal fluid showed leukemic promyelocytes and PML/RARA rearrangement. Bone marrow study showed hematologic, cytogenetic and molecular remission. She was treated with intrathecal and systemic chemotherapy and whole brain radiotherapy. The patient has survived for 68 months since the last systemic chemotherapy.

We report a case of reversible encephalopathy syndrome in a 16-year-old girl with acute myelogenous leukemia (AML), who is undergoing during consolidation chemotherapy composed of BH-AC (N4-behenoyl-1-beta-D-arabinofuranosyl cytosine) and idarubicin. On the 6th day of chemotherapy, she was in a drowsy state following generalized tonic clonic seizure lasting 20 minutes. MR images revealed extensive cortical and subcortical white matter brain edema. Alertness returned over the 24 hr following by the discontinuation of BH-AC and intravenous administration of diphenylhydantoin, although she complained of intermittent headaches and visual disturbance. She gradually recovered from these symptoms during subsequent 7 days. Previously noted abnormal signal intensities have nearly disappreared on follow-up MRI obtained on the 22nd day after the first seizure. She was discharged without any neurologic sequela. This case suggests that BH-AC, a derivative of cytosine arabinoside (1-beta-D-arabinofuranosylcytosine) could be a cause of reversible encephalopathy syndrome.

Patients with acute myelocytic leukemia (AML) have varied outlooks for survival after the diagnosis. To identify pretreatment prognostic indicators in AML, we analyzed 132 cases of AML seen at our hospital between June, 1989 and December, 1994. The median age of the patients was 40 years (range, 15-81). There were 63 male and 69 female patients. One hundred eight patients (82%) received induction chemotherapy which was based on cytarabine plus anthracyclines. Sixty six patients achieved complete remission (CR) and the CR rate among the patients given induction chemotherapy was 61%. The median duration of CR was 11.2 months. After median follow up of 6.6 months (range 0.5-51.4), 26 patients (39%) remain in continuous CR. The median duration of overall survival of the patients was 6.7 months. After median follow up of 10.6 months (range, 0.1-52.7), 41 patients (31%) are alive. Variables affecting duration of CR included the age of the patients, performance status of the patients, percentage of blast in the peripheral blood, hemoglobin level, percentage of blast in the bone marrow, FAB subtype, and CD7 marker positivity. Variables affecting survival duration included age of the patients, performance status of the patients, absolute blast count (ABC) in the peripheral blood, bone marrow cellularity, the percentage of blast in the bone marrow, and CD5 marker positivity. Multivariate analysis showed that the age of the patients and percentage of blast in the bone marrow were significant independent indicators for overall survival of the patients. Further studies utilizing cytogenetics and molecular characteristics of leukemic cell are warranted to better define the prognostic factors of patients with AML.

The involvement of central nervous system is rare in acute promyelocytic leukemia (APL). We report a APL patient of a 41 yr-old Korean male who presented with fever and petechia. Complete molecular remission was achieved with all-trans retinoic acid (ATRA), idarubicin, and cytarabine. Ten months later, he complained of a mild headache. The results of the physical examination and the complete blood counts were normal. The examination of cerebrospinal fluid showed the presence of promyelocyte. Bone marrow studies showed cytogenetic remission but with molecular relapse. He was treated with intrathecal and systemic chemotherapy.

Because cladribine can increase cytarabine triphosphate levels, we tested a cladribine—cytarabine combination in the St. Jude AML97, trial in which this combination was administered before standard chemotherapy to 96 children with acute myeloid leukemia (AML) or myelodysplastic syndrome. Patients received a 5-day course of cladribine (9 mg/m2/dose) and cytarabine either as daily 2-hour infusions (500 mg/m2/dose) (arm A) or a continuous infusion (500 mg/m2/day) (arm B). Ara-CTP levels and inhibition of DNA synthesis increased from day 1 to day 2, but were not different between the two arms. In addition, the median blast percentages at day 15 did not differ between arms A and B, but patients treated in arm A had shorter intervals between the initiation of the first and second courses of therapy. Thus, although there were trends towards better CR rates and overall survival for patients treated in arm B, the reduced efficacy of arm A may have been partially compensated by more intense timing of therapy for that group. For all patients, 5-yr event-free survival and overall survival estimates were 44.1% ± 5.4 % and 50.0% ± 5.5%. Our results suggest that cladribine in combination with continuous-infusion cytarabine is effective therapy for childhood AML.

We report a 41 year old male with sickle cell disease who developed a myelodysplastic syndrome and acute myeloid leukemia with complex karyotype involving chromosomes 5, 7 and 17 after 15 years of hydroxyurea treatment. He responded poorly to induction chemotherapy with cytarabine/idarubicin followed by high dose cytarabine and succumbed to neutropenic sepsis. Multiple systematic reviews, observational studies and clinical trials were conducted to identify the toxicity profile of hydroxurea. Only six cases of leukemia/myelodysplastic syndrome were identified in patients with sickle cell anemia treated with hydroxyurea. Subsequently, it was concluded that hydroxyurea is not leukemogenic. However, it was noted that most of the published studies had only up to 9 years of follow-up. Our patient was started on hydroxyurea in 1990, before the widespread use of the drug and took hydroxyurea for 15 years. His presentation may reflect an outcome otherwise not yet observed because of the short follow-up of prior studies. We believe that the leukemogenic risk of hydroxyurea should be discussed with the patients and their families. Studies evaluating the adverse effects of hydroxyurea should have longer follow-up before definitive conclusions are drawn.

OBJECTIVE:

To evaluate the outcomes of acute myeloid leukemia patients who were older than 60 years of age at the time of diagnosis following the implementation of a treatment algorithm based on age, performance status, and cytogenetic results.

METHODS:

We retrospectively compared the results of 31 elderly acute myeloid leukemia patients (median age of 74 years) who were treated according to the new algorithm.

RESULTS:

Fifteen patients with a good performance status and no unfavorable karyotypes were treated with either intensive cytotoxic chemotherapy (<70 years, nine cases) or adapted etoposide, 6-thioguanine and idarubicine (>70 years, six cases); 16 cases with a poor performance status or unfavorable cytogenetics received supportive care only. Six patients achieved a complete remission and two achieved a partial remission after chemotherapy. There were three toxic deaths during induction, two in the adapted etoposide, 6-thioguanine and idarubicine group and one in the intensive cytotoxic chemotherapy group. The overall median survival time was 2.96 months, 1.3 months in the supportive care group, and 4.6 months in the treatment group.

CONCLUSIONS:

Our results illustrate the importance of treatment guidelines adapted to local resources in an attempt to improve the survival of elderly acute myeloid leukemia patients in developing countries.

Purpose

To determine the possibility of synergistic anti-leukemic activity and the underlying molecular mechanisms associated with cytarabine combined with valproic acid (VPA) [a histone deacetylase inhibitor (HDACI) and an FDA-licensed drug for treating both children and adults with epilepsy] in pediatric acute myeloid leukemia (AML).

Experimental Design

The type and extent of anti-leukemic interactions between cytarabine and VPA in clinically relevant pediatric AML cell lines and diagnostic blasts from children with AML were determined by MTT assays and standard isobologram analyses. The effects of cytarabine and VPA on apoptosis and cell cycle distributions were determined by flow cytometry analysis and caspase enzymatic assays. The effects of the two agents on DNA damage and Bcl-2 family proteins were determined by Western blotting.

Results

We demonstrated synergistic antileukemic activities between cytarabine and VPA in 4 pediatric AML cell lines and 9 diagnostic AML blast samples. t(8;21) AML blasts were significantly more sensitive to VPA and showed far greater sensitivities to combined cytarabine and VPA than non-t(8;21) AML cases. Cytarabine and VPA cooperatively induced DNA double strand breaks, reflected in induction of γH2AX and apoptosis, accompanied by activation of caspases 9 and 3. Further, VPA induced Bim expression and shRNA knockdown of Bim resulted in significantly decreased apoptosis induced by cytarabine, and by cytarabine plus VPA.

Conclusions

Our results establish global synergistic antileukemic activity of combined VPA and cytarabine in pediatric AML and provide compelling evidence to support the use of VPA in the treatment of children with this deadly disease.