Timed-sequential chemotherapy with concomitant granulocyte colony-stimulating factor for newly diagnosed de novo acute myelogenous leukemia

Timed-sequential chemotherapy as induction and/or consolidation regimen for younger adults with acute myelogenous leukemia

Increasing the intensity of induction chemotherapy has generated considerable recent interest in the treatment of acute myeloid leukemia. Achieving complete remission is a sine qua non condition for prolonged disease-free survival and may affect long-term outcome. In this setting, administering a repeat course of induction shortly after completion of the first course, known as timed-sequential chemotherapy (TSC), has been tested and may lead to an improved long-term outcome. Whether these results are due to the biologic recruitment of cell cycle-specific agents is unknown. However, this strategy to intensify induction may lead to more profound myelosuppression and to potential toxicities. Here we review the results of timed-sequential chemotherapy, used as induction regimen in de novo, relapsed or refractory AML or used as post-remission therapy, and compare them with those from other types of regimens.

Timed sequential induction chemotherapy and risk-adapted postremission therapy for acute myelogenous leukemia

Cytogenetic analysis at the time of diagnosis predicts outcome in patients with acute myelogenous leukemia (AML). For those patients with favorable risk cytogenetics, stem cell transplant can be delayed until the time of relapse. For those patients with nonfavorable cytogenetic risk profiles, stem cell transplant may be required for optimal survival benefit. We treated patients with de novo AML and age less than 60 years first with etoposide, mitoxantrone, cytarabine, and G-CSF (EMA-G) to induce remission. Patients in complete remission were assigned to treatment with chemotherapy alone if they had favorable risk cytogenetics defined as the identification of a core-binding factor translocation. Patients with any other cytogenetic profile were assigned to treatment with either autologous or allogeneic stem cell transplant depending on the availability of an HLA-matched donor. Following EMA-G, 33 of 40 patients (83%) achieved CR. Of the 25 patients who actually were treated with postremission chemotherapy, 21 were treated with their assigned risk-adapted therapy. Of the 33 patients in remission, 5 year relapse-free survival (RFS) and overall survival (OS) was 46 and 38%, respectively. Our intensive and risk-adapted, stem cell transplant approach to the treatment of patients with AML requires a better definition of risk and does not appear to substantially improve results compared with more standard approaches.

Increased C-kit intensity is a poor prognostic factor for progression-free and overall survival in patients with newly diagnosed AML

C-kit, a tyrosine kinase receptor, is expressed on most myeloid blasts and is thought to be important in the pathogenesis of AML. Activation of the c-kit receptor leads to phosphorylation and activation of downstream signaling proteins, which are important for cell survival and proliferation. Here, we discuss the prognostic impact of c-kit intensity, measured using the mean fluorescent index (MFI) in patients with newly diagnosed AML. On multivariate analysis, c-kit MFI>20.3 correlated with a decreased progression-free survival and overall survival, independent of known prognostic factors (age, white blood count at diagnosis and cytogenetics). Whether inhibiting c-kit in patients with AML will alter prognosis is the basis of ongoing clinical trials.

The role of timed sequential chemotherapy in adult acute myelogenous leukemia

Consecutive trials of timed sequential chemotherapy (TSC) have been conducted in adults with acute myelogenous leukemia. The rationale for TSC was based on the observation that leukemic cells can be recruited synchronously into the cell cycle after initial intensive therapy, at which time they may become more susceptible to killing by chemotherapeutic agents. Achieving complete remission is essential for prolonged disease-free survival and may affect long-term outcome. TSC has led to higher rates of complete remission and has improved long-term outcomes. This article reviews the results of important trials in which TSC was used as an induction regimen in de novo, relapsed, or refractory acute myelogenous leukemia or as postremission therapy.

Homoharringtonine in combination with cytarabine and aclarubicin resulted in high complete remission rate after the first induction therapy in patients with de novo acute myeloid leukemia

To assess the efficacy and toxicity of HAA regimen (homoharritonine 4 mg/m2/day, days 1-3; cytarabine 150 mg/m2/day, days 1-7; aclarubicin 12 mg/m2/day, days 1-7) as an induction therapy in the treatment of de novo acute myeloid leukemia (AML), 48 patients with newly diagnosed AML, aged 35 (14-57) years, were entered into this clinical study. The median follow-up was 26 months. Eighty-three percent of patients achieved complete remission (CR), and the first single course of induction HAA regimen resulted in CR rate of 79%. The CR rate of 100, 82 and 33% were achieved in patients with favorable, intermediate and unfavorable cytogenetics, respectively. For all patients who achieved CR, the median time from the initiation of the induction therapy to the evaluation of the remission status was 32 days. For all patients, the estimated 3 years overall survival (OS) rate was 53%, whereas for patients with M5, the estimated OS rate at 3 years was 75%. The toxicities associated with HAA regimen were acceptable, and the most common toxicity was infection. This study suggested that HAA regimen might be a well-tolerable, effective induction regimen in young adult patients with AML.

Role of cytokines in the treatment of acute leukemias: a review

Myeloid growth factors, such as granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor, have been used to decrease the duration of chemotherapy-induced neutropenia and thereby reduce the incidence and severity of infections in various regimens used to treat acute myeloid leukemia and acute lymphoblastic leukemia. These growth factors have also been used to recruit dormant myeloid leukemia cells into the S phase of cell cycle in order to increase their susceptibility to the antileukemic effects of agents such as cytarabine. Multiple prospective randomized trials have examined the benefit and safety of the addition of growth factors before, during, and after chemotherapy. A reduction in the duration of neutropenia has been the most consistent finding; this has not been associated with stimulation of leukemia cells, the main concern of using this strategy. Unfortunately, few studies have reported a benefit in prolonging the duration of disease-free survival or overall survival. Other cytokines, including interleukins and thrombopoietin, have also been evaluated for their theoretical ability to recruit immune mechanisms to eradicate residual leukemia burden after chemotherapy, and to stimulate platelet production. In this review, we summarize the clinical experience with these growth factors in treating acute leukemias.