The Outcome of Allogeneic Hematopoietic Cell Transplantation for Children with FMS-Like Tyrosine Kinase 3 Internal Tandem Duplication–Positive Acute Myelogenous Leukemia

Prognosis of relapse after hematopoietic cell transplant (HCT) for treatment of leukemia or myelodysplastic syndrome (MDS) in children

We studied 232 consecutive children transplanted between 1990 and 2011 with relapse after first hematopoietic cell transplant (HCT). Kaplan-Meier survival and hazard ratios for mortality were calculated for factors known at time of relapse using Cox proportional hazards models. The median (range) age at time of first HCT was 10.9 (0.5-20.9) years, time to relapse was 6.1 (0.2-89.5) months after HCT, and age at relapse was 11.7 (0.7-23.6) years. The 3-year overall survival (OS) after relapse was 13% (95% confidence interval (CI): 9%, 18%).The median (range) follow-up for the 18 surviving patients was 7.2 (3.0-24.4) years after relapse. The remaining 214 died after a median of 3 months (0.02-190.4). OS was not significantly different for patients with ALL as compared to AML. Fifty-one patients proceeded to second transplant of whom nine survive. Factors associated with improved survival included late relapse (>12 months), ALL in first CR at the time of first transplant and chemotherapy-based first conditioning regimens. These results can be used to counsel patients at the time of relapse after first transplant and as a baseline for comparison as to the effectiveness of newer therapies which are greatly needed for treatment of post-transplant relapse.

Midostaurin approved for FLT3-mutated AML

Midostaurin was recently approved by the US Food and Drug Administration for the treatment of FLT3-mutant acute myeloid leukemia (AML). This is the first drug to receive regulatory approval for AML in the United States since the year 2000. Midostaurin is a small-molecule kinase inhibitor with activity against the receptor tyrosine kinase FLT3, and its approval will hopefully mark the beginning of an era of targeted agents for the treatment of molecularly defined subtypes of AML.

Anti-Tumor and Immune Enhancing Activities of Rice Bran Gramisterol on Acute Myelogenous Leukemia

Background

Acute myelogenous leukemia (AML) is a cancer of the blood that most commonly affects human adults. The specific cause of AML is unclear, but it induces abnormality of white blood cells that grow rapidly and accumulate in bone marrow interfering with the production and functions of the normal blood cells. AML patients face poor prognosis and low quality of life during chemotherapy or transplantation of hematopoietic stem cells due to the progressive impairment of their immune system. The goal of this study is to find natural products that have the potential to delay growth or eliminate the abnormal leukemic cells but cause less harmful effect to the body’s immune system.

Methods and Findings

The unsaponified fraction of Riceberry rice bran (RBDS) and the main pure compound, gramisterol, were studied for cytotoxicity and biological activities in WEHI-3 cells and in the leukemic mouse model induced by transplantation of WEHI-3 cells intraperitoneally. In the in vitro assay, RBDS and gramisterol exerted sub-G1 phase cell cycle arrest with a potent induction of apoptosis. Both of them effectively decreased cell cycle controlling proteins (cyclin D1 and cyclin E), suppressed cellular DNA synthesis and mitotic division, and reduced anti-apoptosis Bcl-2 protein, but increased apoptotic proteins (p53 and Bax) and activated caspase-3 enzyme in the intrinsic cell death stimulation pathway. In leukemic mice, daily feeding of RBDS significantly increased the amount of immune function-related cells including CD3⁺, CD19⁺, and CD11b⁺, and elevated the serum levels of IFN-γ, TNF-α, IL-2, and IL-12β cytokines, but suppressed IL-10 level. At the tumor sites, CD11b⁺ cells were polarized and became active phagocytotic cells. Treatment of mice normal immune cells with gramisterol alone or a combination of gramisterol with cytokines released from RBDS-treated leukemic mice splenocytes culture synergistically increased pSTAT1 transcriptional factor that up-regulated the genes controlling cell survival and function. Phosphorylation of STAT1 was absent in WEHI-3. Instead, similar treatments significantly decreased pSTAT3 signaling that regulates transcription of genes controlling tumor growth and proliferation.

Conclusions

Rice bran gramisterol possesses a promising anti-cancer effect against a tumor of white blood cells and induces the production of anti-cancer immune-related cytokines. Gramisterol induces cell cycle arrest and apoptosis via suppression of pSTAT3 signaling control of tumor cells’ growth and progression. Gramisterol increased IFN-γ production and prevented the dysfunctional immune system of leukemic mice by enhancing pSTAT1 transcription signal controlling proliferation and functions of hematopoietic cells in the spleen. Together with IFN-γ, gramisterol efficiently facilitates leukemic mice immune system modulation leading to improvement of the AML condition. Administration of RBDS containing gramisterol potentiates immune recovery of leukemic mice and extends their survival. This finding encourages the medicinal application of rice bran gramisterol as a palliative treatment or an alternative agent for future drug development against AML.

Gemtuzumab Ozogamicin Reduces Relapse Risk in FLT3/ITD Acute Myeloid Leukemia: A Report from the Children's Oncology Group

PURPOSE

Gemtuzumab ozogamicin (GO), a calicheamicin-conjugated mAb against CD33, has been used in the treatment of acute myeloid leukemia (AML). We evaluated the impact of the addition of GO to standard chemotherapy and hematopoietic stem cell transplant (HCT) in patients withFLT3/ITD.

EXPERIMENTAL DESIGN

We analyzed children withFLT3/ITD-positive AML (n= 183) treated on two consecutive Children's Oncology Group AML trials (NCT00070174andNCT00372593). Outcomes were assessed forFLT3/ITD patients receiving standard chemotherapy with or without GO (GO vs. No-GO, respectively), and the impact of consolidation HCT for high-riskFLT3/ITD patients [highFLT3/ITD allelic ratio (ITD-AR)].

RESULTS

For allFLT3/ITD patients, complete remission (CR) rates for the GO versus No-GO cohorts were identical (64% vs. 64%;P= 0.98). Relapse rate (RR) after initial CR was 37% for GO recipients versus 59% for No-GO recipients (P= 0.02), disease-free survival (DFS) was similar (47% vs. 41%;P= 0.45), with higher treatment-related mortality (TRM) in GO recipients (16% vs. 0%;P= 0.008). Among high-riskFLT3/ITD patients with high ITD-AR, those who received HCT in first CR with prior exposure to GO had a significant reduction in RR (15% vs. 53%;P= 0.007), with a corresponding DFS of 65% versus 40% (P= 0.08), and higher TRM (19% vs. 7%;P= 0.08).

CONCLUSIONS

CD33 targeting with HCT consolidation may be an important therapeutic strategy in high-riskFLT3/ITD AML and its efficacy and associated toxicity warrant further investigation.

FLT3 mutational status is an independent risk factor for adverse outcomes after allogeneic transplantation in AML

Allogeneic HCT has been increasingly used in the setting of FLT3 mutated AML. However, its role in conferring durable relapse-free intervals remains in question. Herein, we sought to investigate FLT3 mutational status on transplant outcomes. We conducted a retrospective cohort study of 262 consecutive AML patients who underwent first-time allogeneic HCT (2008-2014), of whom 171 had undergone FLT3-ITD mutational testing. FLT3 mutated AML was associated with nearly twice the relapse risk (RR) compared with those without FLT3 mutation 3 years post-HCT (63% vs. 37%, P<0.001), and with a shorter median time to relapse (100 vs. 121 days). FLT3 mutational status remained significantly associated with this outcome after controlling for patient, disease, and transplant-related risk factors (P<0.05). Multivariate analysis showed a significant association of FLT3 mutation with increased 3-year RR (HR 3.63, 95% CI: 2.13, 6.19, P<0.001), and inferior disease-free survival (HR 2.05, 95% CI: 1.29, 3.27, P<0.01) and overall survival (HR 1.92, 95% CI: 1.14, 3.24, P<0.05). These data demonstrate high risk of early relapse after allogeneic HCT for FLT3 mutated AML that translates into adverse disease-free and overall survival outcomes. Additional targeted and coordinated interventions are needed to maintain durable remission after allogeneic HCT in this high-risk population.

Different aspects of stem cell procedures in children with poor responding AML: when is HSCT the best answer?

Acute myeloid leukemia in children is a heterogeneous disease with different morphological and cytogenetic features. New diagnostic tools and treatments, improved supportive care and the use of genomic tissue typing in selecting donors for hematopoietic stem cell transplantation (HSCT) adds to increased survival rates. Candidates to HSCT in first complete remission are patients with cytogenetic or molecular unfavorable prognostic markers, or blasts >15% after first induction. The use of minimal residual disease can also identify children benefiting from HSCT in first complete remission and the patients post HSCT with signs of relapse. The outcome and cure rate of acute myeloid leukemia, still remains poor and new diagnostic tools and treatments strategies need to be evaluated. In this management perspective, future management of novel minimal residual disease tools are discussed, conditioning therapies, as well as different transplantation procedures including haplo-transplantation and haplo-identical natural killer cell transplantation, but also altered graft-versus-host-disease treatments.

Adverse health events and late mortality after pediatric allogeneic hematopoietic SCT-two decades of longitudinal follow-up

Treatment-related late toxicities after pediatric allogeneic hematopoietic SCT (allo-HSCT) are increasingly important as long-term survival has become an expected outcome for many transplanted children and adolescents. In a retrospective cohort study, we assessed long-term health outcomes in 204 allo-HSCT survivors transplanted in childhood or adolescence (<20 years) between 1978 through 2000 after a median follow-up time of 12 (range 4-28) years. Data on conditioning regimen, adverse health events (AE) and growth and hormonal substitutions (hormone replacement therapies (HRTs)) were obtained from medical records. AEs were graded retrospectively according to Common Terminology Criteria for Adverse Events v3.0. Late deaths (⩾48 months after allo-HSCT) were evaluated separately. Multivariate analysis demonstrated that chronic GVHD (P<0.000) and longer follow-up time (P<0.05) correlated with AEs, whereas CY-based conditioning was inversely correlated (P<0.002). TBI and longer follow-up duration predicted more severe AEs (P<0.001 and P<0.001, respectively). HRTs were more frequent after TBI. Diabetes type II, dyslipidemia and hypertension were detected in 9, 7 and 7% of the survivors, respectively. Late deaths (n=22) were most frequently due to pulmonary failure (n=7), followed by secondary malignancy (n=5). The occurrence of AEs after pediatric allo-HSCT is high and likely to increase during extended follow-up, particularly in patients who have received TBI.