Presence of FLT3 Mutations Does Not Impair Stem Cell Mobilization and Feasibility of Autologous Peripheral Blood Stem Cell Transplantation in Acute Myeloid Leukemia

Clinical impact of SNP of P53 genes pathway on the adult AML patients

INTRODUCTION

Acute myeloid leukemia (AML) is a highly heterogeneous disease, with biologically and prognostically different subtypes.

AIM

To study the impact of p53, p21, and mdm2 gene polymorphisms on the clinical outcome in adult AML patients treated at the National Cancer Institute (NCI) - Cairo University.

METHODS

Forty-eight adult AML patients presented to the Medical Oncology Department, NCI, from April 2010 till November 2011. Clinical data and bone marrow samples were obtained. Molecular genetic analysis involving P53, MDM2, and P21 single-nucleotide gene polymorphisms was done using polymerase chain reaction-restriction fragment length polymorphism coupled analysis.

RESULTS

The mean age was 35.7 years. After a median follow-up period of 12 months, 28 patients (58.4%) achieved complete remission (CR) and the overall survival (OS) was 8.7 months. Patients with homozygous Arg/arg at codon 72 of P53 had a better median OS months than Arg/Pro and Pro/Pro (13.4 vs. 8.4 vs. 1.5 months, respectively; P = 0.045). P53/p21 combination had a better median OS and disease-free survival (DFS) of 12.1 and 13.7 months for wild type cases (GG + Ser/ser) and 20.3 and 20.7 months for patients with either variant genes (GC + Ser/arg) compared with 1.1 and 1.9 months for patients with both variant genes (CC + arg/arg), (P = 0.037 and 0.004). The presence of wild genotype of either P21 or MDM2 may abolish the effect of P53 homozygous variant genotype on the OS. Neither p21nor mdm2 polymorphism alone showed an impact on OS or DFS. CR was not affected by any of the three gene polymorphisms.

CONCLUSION

The p53 pathway gene polymorphisms may affect the OS of adult AML patients.

Chemosensitivity of nonleukemic clonogenic precursors in AML patients in complete remission: association with CD34(+) mobilization and with disease-free survival

A high number of CD34(+) cells in the peripheral blood during mobilization in patients with acute myeloid leukemia (AML) in complete remission (CR) is associated with a high relapse rate. The variability in chemoresistance of normal bone marrow precursors has been hypothesized as explanation for the variable CD34 mobilization in AML. In 37 patients with AML in CR, we determined the chemosensitivity of bone marrow clonogenic precursors to maphosphamide and etoposide, which was then correlated with the degree of CD34(+) mobilization. In an enlarged set of 49 patients, we also studied the importance of chemosensitivity of marrow precursors for disease-free survival and relapse incidence. Significant correlations were demonstrated between the peak number of CD34(+) cells and residual growth of colony-forming unit granulocyte-macrophage (CFU-GM) after maphosphamide (R = 0.550; p = 0.0003) and after etoposide (R = 0.793; p = 0.0003). It was possible to identify three groups of AML patients based on chemosensitivity. The mean CD34(+) peak was 33 × 10(6)/L in the hyperchemosensitive group, 141 × 10(6)/L in the normochemosensitive (p = 0.03), and 379 × 10(6)/L in the chemoresistant group (p = 0.002). Failed CD34(+) mobilization was observed in 72% of the hyperchemosensitive group, 23% of the normochemosensitive group, and 0% of the chemoresistant group (p = 0.001). Hyperchemosensitivity of CFU-GM, together with a low platelet count, were independent factors important in the failure of CD34(+) cell mobilization. A disease-free survival significantly inferior to that of all other patients was associated with chemoresistance of CFU-GM (log rank, p = 0.030) and with chemoresistance of burst-forming unit erythroid (BFU-E) (log rank, p = 0.033). Chemoresistance of CFU-GM (p = 0.048) and BFU-E (p = 0.017) was also associated with increase relapse incidence. Nonleukemic nature of these precursors was demonstrated studying minimal residual disease from single colony cells. In conclusion, we found that hyperchemosensitivity of normal nonleukemic CFU-GM is associated with a high risk of CD34(+) cell mobilization failure, while a chemoresistant pattern in CFU-GM and BFU-E is associated with poor disease-free survival and increased cumulative incidence of relapse.

Day 15 bone marrow driven double induction in young adult patients with acute myeloid leukemia: feasibility, toxicity, and therapeutic results

The strategy named double induction (DI) in acute myeloid leukemia (AML) consists of two courses of chemotherapy irrespective of the degree of cytoreduction in the bone marrow (BM) after the first course, unless severe complications prohibit its application. We describe treatment results from a series of 33 patients in whom DI was adopted only after demonstration of persistence of more than 10% blast cells at day 15 (D15) examination of BM. All patients received as induction idarubicin, cytarabine, and etoposide. As second induction, we administered the combination of fludarabine, intermediate dose cytarabine, and Granulocyte colony stimulating factor (G-CSF). The median blast count at D15 was 30 (15-90). Overall, 30 of 33 patients were judged as eligible to receive DI, reasons for exclusion being in all cases active infection in the context of severe pancytopenia. Nineteen patients (63%) had unfavorable karyotype and 11 (37%) normal karyotype; seven of these had Fms-like tyrosine kinase gene internal tandem duplication (FLT3/ITD) mutation. Overall, complete remission (CR) was achieved in 20/30 patients (67%), while eight patients (27%) were refractory and two died of infectious complications. All refractory patients had unfavorable cytogenetics. All patients achieving CR were programmed to receive allogeneic stem cell transplantation (allo-SCT), which was actually performed in 11 patients. Our study suggest that D15 driven DI represents a feasible and effective therapeutic strategy in young adult AML patients, improving therapeutic results and not compromising feasibility of allo-SCT. When compared with conventional DI, it offers the potential to avoid unnecessary toxicity in a consistent proportion of patients.

Autologous stem cell transplantation for elderly patients with acute myeloid leukaemia conditioned with continuous infusion idarubicin and busulphan

Different studies have suggested the potential utility of autologous stem cell transplantation (ASCT) in acute myeloid leukaemia (AML) of the elderly with encouraging results in selected patients. However, while the introduction of peripheral blood stem cells (PBSC) has consistently reduced morbidity and mortality of the procedure, relapse still represents the major cause of ASCT failure. One possibility to ameliorate therapeutic results could rely on the adoption of conditioning regimens specifically designed for AML. We report therapeutic results from a series of 40 AML patients older than 60 years (median age 67 years) autografted in first complete remission (CR), after conditioning with continuous infusion (c.i.) high dose idarubicin and busulphan. Fourty patients (median age: 67 years) received 2 days c.i. idarubicin at 20 mg/m(2)/day, followed by 3 days oral or intravenous busulphan (4 mg/kg/day) as conditioning. No case of transplant-related mortality occurred. Cardiac toxicity was absent, while 31 patients (77%) had grade 3-4 mucositis. After a median follow-up of 25 months, median disease free and overall survival (OS) for the whole patient population were 13 and 22 months, respectively. Three patients died while in CR from causes unrelated to AML. Better results were achieved in patients with intermediate karyotype as opposed to those with adverse cytogenetics. Our data confirm the feasibility of a conditioning regimen based on high-dose idarubicin plus busulphan in older selected AML patients and suggest clinical improvement in patients with normal cytogenetics.