Phase II trial to assess the safety and efficacy of clofarabine in combination with low-dose cytarabine in elderly patients with acute myeloid leukemia

Previous studies have shown that clofarabine plus low-dose cytarabine (LDAC) could induce roughly 60 % of complete remissions (CR) with acceptable toxicity and induction mortality in elderly acute myeloid leukemia (AML) patients not suitable for intensive chemotherapy. The Programa Español de Tratamientos en Hematología group conducted a trial for patients diagnosed with untreated AML aged 60 years and older, using the combination of clofarabine (20 mg/m²?×?5 days) plus low-dose cytarabine (20 mg/m²?×?14 days). The protocol was flexible regarding the use of antifungal and antibacterial prophylaxis, and outpatient induction therapy was allowed. Although the planned recruitment goal was 75 patients, only 11 patients were enrolled (median age, 74 years) after observing high toxicity and unacceptable mortality (46 and 73 % at 4 and 8 weeks, respectively). The response assessment showed three CR (27 %), three resistant diseases (27 %), and five induction deaths (46 %). Induction was administered in an outpatient modality in five patients, while antifungal and antibacterial prophylaxis was not given in seven and five patients, respectively. In our context, induction therapy with the combination of clofarabine (20 mg/m²) plus LDAC was associated with high toxicity and unacceptable mortality in elderly AML patients, leading to the early interruption of the trial. Tight patients’ clinical monitoring, follow-up, and intensive supportive care seem crucial to achieve at least acceptable clinical outcomes in elderly AML patients receiving clofarabine plus LDAC. This trial is registered at www.clinicaltrials.gov as no. NCT01193400.     

Allogeneic hematopoietic cell transplantation in acute myeloid leukemia

Allogeneic hematopoietic cell transplantation (HCT) is a curative treatment modality for select patients with acute myeloid leukemia (AML), functioning as a restorative agent following intensified chemo- and/or radiotherapy and also engendering the disease-directed immunologic threat of graft-versus-leukemia effect. Advancements in conditioning regimen intensity, donor availability, and supportive care have broadened the eligibility for allogeneic HCT, reduced rates of transplant related mortality, and improved outcomes over time. There are still obstacles to transplant in AML, offering opportunities for ongoing discovery, including poor recipient fitness, insufficient donor availability for certain populations, and limited access to care. Relapse remains the most common cause of treatment failure and a high priority area of investigative efforts. Post-transplant maintenance and novel applications of cellular therapeutics are expected to usher in a new era of promise for successful HCT in AML and will aim to overcome the remaining barriers impeding favorable outcomes for these patients.     

Maintenance therapy after allogeneic hematopoietic cell transplantation for acute myeloid leukemia

With improvements in the safety of allogeneic hematopoietic cell transplantation, disease recurrence following the procedure is now the most frequent reason for treatment failure. Administration of maintenance therapy after transplantation is one way to try and prevent recurrence. This paper provides a brief review of the topic.     

Phase I study of oral clofarabine consolidation in adults aged 60 and older with acute myeloid leukemia

Clofarabine has shown activity and tolerability in older patients with acute myeloid leukemia (AML). We investigated the safety and tolerability of an oral formulation of clofarabine for consolidation therapy of patients aged 60 and older with AML. In this phase I study, twenty‐two patients older than 60 years with AML in first complete remission were treated once daily with oral clofarabine for 14 or 21 days of a 28‐day cycle, for up to five cycles. Dose escalation from 1 mg to 6 mg daily using a 3 + 3 design was used to determine dose‐limiting toxicities (DLT), the maximum tolerated dose (MTD), and tolerability of oral clofarabine. No DLTs or Grade 3–4 nonhematologic toxicities were observed. The primary toxicities were hematologic, including uncomplicated grade 3–4 neutropenia (50%) and thrombocytopenia (50%). Given that myelosuppression necessitating dose delays/reductions was observed more commonly at higher doses, the recommended phase II dose is 2 mg daily for 21 of 28 days. At doses equal to or greater than 2 mg, the median relapse‐free survival was 28.35 months. Oral clofarabine was well‐tolerated with encouraging activity in patients older than 60 years. Further investigation of oral clofarabine as a consolidation and/or maintenance therapy in AML for older individuals is warranted. ( ClinicalTrials.gov :NCT00727766). Am. J. Hematol. 89:487–492, 2014. © 2014 Wiley Periodicals, Inc.     

Effectiveness of allogeneic hematopoietic cell transplantation for older patients with acute myeloid leukemia

Outcomes with conventional chemotherapy for older patients with acute myeloid leukemia (AML) remain disappointing, with few cures. For younger patients with AML, allogeneic hematopoietic cell transplantation (HCT) offers the best chance for cure, but this strategy is seldomly used for older patients. With recently improved methodologies, transplantation has become increasingly safe, suggesting that its use in older patients be reconsidered. This report will address four issues: the current frequency of transplantation for AML according to patient age; the impact of patient age on transplant outcomes; the comparative outcomes of transplantation versus chemotherapy for older patients with AML; and possible methods to improve the outcome of allogeneic HCT in older patients with AML.     

Role of allogeneic and autologous hematopoietic stem cell transplantation in acute myeloid leukemia

Most younger patients with acute myeloid leukemia will enter remission of disease. Prevention of relapse is now the central therapeutic issue. A number of factors predict the risk of relapse, the most powerful of which is cytogenetics. Both allogeneic and autologous transplantation have been extensively used as remission consolidation, but intensive chemotherapy has also provided improved results such that the choice of consolidation treatment is not clear. Recent prospective trials of allogeneic and autologous transplantation with careful analysis have not always shown a survival benefit, although both approaches have significantly reduced relapse risk. In analysis where relapse risk is taken into account based on cytogenetics, there is little evidence of the benefit of transplantation in good-risk patients, partly because patients in this group who relapse can then undergo successful salvage therapy. The results are still uncertain in standard-risk patients, so transplantation should continue to be used in the context of a trial. Poor-risk patients have a higher failure rate after transplantation, and for these patients novel approaches are required.     

Allogeneic hematopoietic cell transplantation in patients with acute myeloid leukemia and pulmonary mucormycosis

Mucormycosis is a serious invasive fungal infection in immunocompromised patients. Patients undergoing treatment for hematologic malignancies are predominantly prone to the pulmonary manifestation of mucormycosis. Historically, allogeneic hematopoietic cell transplantation (HCT) in patients suffering from pulmonary mucormycosis (PM) was considered contraindicated owing to mortality rates up to 90%. We present 3 patients with acute myeloid leukemia and PM who were treated with radical surgical debridement combined with high‐dose liposomal amphotericin B (LAB), and subsequently underwent successful allogeneic HCT. To date, all 3 patients are in complete remission and show no signs of mucormycosis. Allogeneic HCT in patients with PM seems feasible provided that the infectious focus is completely removed surgically and adequate antifungal pharmacotherapy, such as high‐dose LAB or posaconazole, is established.     

异基因造血干细胞移植治疗AML1/ETO(+)急性髓系白血病的疗效

目的:分析AML1/ETO(+)急性髓系白血病进行异基因造血干细胞移植后的临床疗效。方法:总结北京市道培医院2003年11月-2009年1月完成的24例AML1/ETO(+)急性髓系白血病患者进行异基因造血干细胞移植后的资料,使用Kaplan-Meier统计方法计算总体存活率、无白血病存活率和累积复发率,使用Logrank统计方法进行单因素分析。结果:24例患者移植后1年的总体存活率为(86.47±7.29)%,2年和3年的总体存活率为(69.00±10.77)%;移植后1年的无白血病存活率为(73.89±9.21)%,2年和3年的无白血病存活率为(67.17±10.54)%;移植后1、2年时的累积复发率分别为(27.75±8.09)%和(31.46±11.13)%。在单因素分析中,移植类型(同胞全合/单倍体/无关供者)、自确诊白血病到进行移植的时间间隔(12个月和12个月2组)、确诊时有无附加染色体异常、确诊时有无髓外浸润、确诊时的缓解状态(CR1和CR2/复发2组)等对总体存活率的影响均差异无统计学意义(均P0.05)。结论:异基因造血干细胞移植对AML1/ETO(+)急性髓系白血病患者具有良好疗效,是具有高危因素患者的治疗选择之一。     

Neoplastic meningitis in patients with acute myeloid leukemia scheduled for allogeneic hematopoietic stem cell transplantation

We analyzed the frequency of neoplastic meningitis in patients with acute myeloid leukemia prior to allogeneic hematopoietic stem cell transplantation at our institution. Between 1996 and 2009, cerebrospinal fluid samples of 204 adult patients were examined during pre-transplant work-up for cell counts and, if abnormal, morphologically. We found blasts in cerebrospinal fluid samples of 17 patients with either persistent (n=9) or newly diagnosed (n=8) neoplastic meningitis. All patients proceeded to transplant. The proportion of patients with central nervous system involvement was significantly higher in patients with refractory disease at the time of transplantation compared with patients responding to prior systemic therapy (19% vs. 4.6%; P=0.003). Since most of the patients with central nervous system involvement were asymptomatic, cerebrospinal fluid evaluation should be considered at least in patients with refractory acute myeloid leukemia.     

Phase I/II study of the hypoxia-activated prodrug PR104 in refractory/relapsed acute myeloid leukemia and acute lymphoblastic leukemia

We previously demonstrated vast expansion of hypoxic areas in the leukemic microenvironment and provided a rationale for using hypoxia-activated prodrugs. PR104 is a phosphate ester that is rapidly hydrolyzed in vivo to the corresponding alcohol PR-104A and further reduced to the amine and hydroxyl-amine nitrogen mustards that induce DNA cross-linking in hypoxic cells under low oxygen concentrations. In this phase I/II study, patients with relapsed/refractory acute myeloid leukemia (n=40) after 1 or 2 prior treatments or acute lymphoblastic leukemia (n=10) after any number of prior treatments received PR104; dose ranged from 1.1 to 4 g/m². The most common treatment-related grade 3/4 adverse events were myelosuppression (anemia 62%, neutropenia 50%, thrombocytopenia 46%), febrile neutropenia (40%), infection (24%), and enterocolitis (14%). Ten of 31 patients with acute myeloid leukemia (32%) and 2 of 10 patients with acute lymphoblastic leukemia (20%) who received 3 g/m² or 4 g/m² had a response (complete response, n=1; complete response without platelet recovery, n=5; morphological leukemia-free state, n=6). The extent of hypoxia was evaluated by the hypoxia tracer pimonidazole administered prior to a bone marrow biopsy and by immunohistochemical assessments of hypoxia-inducible factor alpha and carbonic anhydrase IX. A high fraction of leukemic cells expressed these markers, and PR104 administration resulted in measurable decrease of the proportions of hypoxic cells. These findings indicate that hypoxia is a prevalent feature of the leukemic microenvironment and that targeting hypoxia with hypoxia-activated prodrugs warrants further evaluation in acute leukemia. The trial is registered at clinicaltrials.gov identifier: 01037556.     

Autologous stem cell transplantation for acute myeloid leukemia

Autologous bone marrow transplant (ABMT) and stem cell transplantation (ASCT) are important treatment modalities for acute myeloid leukemia (AML). The role of ASCT in first remission patients remains controversial. Phase II and phase III studies demonstrate that patients with favorable-risk cytogenetics benefit from ASCT, with reduction in relapse and improvement in leukemia-free survival (LFS). Patients with poor-risk cytogenetics do not appear to benefit significantly from ASCT and should preferentially be treated with allogeneic transplant. The role of ASCT for patients with intermediate risk disease is uncertain. It appears that ASCT in first remission will improve disease-free survival compared to standard chemotherapy. Sufficient patients who relapse after chemotherapy treatment can be salvaged with ASCT in second remission such that the beneficial effect on overall survival is blunted. ASCT produces equivalent results to ABMT but with reduced morbidity. The collection of stem cells during recovery from intensive dose consolidation therapy appears to be an attractive strategy that can increase the percentage of patients who are able to receive their intended transplant. Consolidation therapy prior to stem cell collection and transplant has been shown to decrease the relapse rate and improve outcomes, but the optimal nature of this consolidation therapy is unknown. For patients with AML in second remission, ABMT/ASCT offers a substantial salvage rate, and is particularly effective for patients with acute promyelocytic leukemia.     

异基因造血干细胞移植治疗高危恶性血液病

目的 分析HLA配型相合同胞供者异基因造血干细胞移植（allo-HSCT）治疗高危恶性血液病的疗效及影响疗效的相关因素。方法 回顾性分析90例有高危因素的恶性血液病患者,其中急性髓细胞白血病（AML）43例,急性淋巴细胞性白血病（ALL）28例,急性混合细胞性白血病（AHL）2例;移植前处于第1次完全缓解期（CR1）11例,均为Ph染色体阳性,第二次及以上CR期23例,未缓解／复发39例;骨髓增生异常综合征（MDS）-难治性贫血伴原始细胞增多或难治性贫血伴原始细胞增多一转化型17例。预处理方案采用全身照射加环磷酰胺（CY／TBI）方案11例,白消安加环磷酰胺方案79例。干细胞来源包括骨髓移植（BMT）27例,外周血造血干细胞移植（PBSCT）30例,BMT＋PBSCT33例;移植物抗宿主病（GVHD）预防采用经典环孢素A加短程甲氨蝶呤（MTX）。平均随访时间为15个月。结果 至随访终点,62．2％（56／90）存活,55．5％（50／90）无病存活,31．1％（28／90）复发。HSCT后预计4年累积总体生存率（OS）为45．5％,无病生存率（DFS）为34．9％。移植前处于CR、未缓解／复发和MDS患者HSCT后4年的累积0s分别为54．0％、28．2％和70．1％（P=0．027）。发生0～Ⅰ和Ⅱ～Ⅳ度GVHD的患者HSCT后的4年OS分别为57．6％和26．7％（P=0．015）,而患者性别、年龄、移植前有无脑膜白血病、预处理方案、干细胞来源均不是OS,DFS及复发的影响因素。多因素分析表明,移植前处于CR期者长期生存率明显提高,而ALL长期生存率明显低于AML／MDS。结论 对有高危因素的血液系统恶性肿瘤患者,选择allo—HSCT可使部分患者延长无病生存乃至根治。移植前处于CR期者长期生存率明显提高,ALL复发率明显高于AML／MDS。对于急性白血病挽救性治疗争取在取得CR后移植;对于MDS患者一经诊断,无需化疗,可尽早移植。     

Autologous stem cell transplantation for advanced acute myeloid leukemia

We studied the efficacy of a two-step approach to autologous stem cell transplantation for patients with advanced acute myeloid leukemia. Step 1 consisted of consolidation chemotherapy using cytarabine 2000 mg/m(2) twice daily for 4 days plus etoposide 40 mg/kg by continuous infusion over the same 4 days. Peripheral blood stem cells were collected under granulocyte colony-stimulating factor (G-CSF) stimulation during recovery from this chemotherapy. Step 2, autologous stem cell transplantation, utilized the preparative regimen of oral busulfan 16 mg/kg followed by etoposide 60 mg/kg i.v. During step 1, there were no treatment-related deaths among 28 patients, but two patients did not proceed to transplantation because of failure of mobilization. A median CD34+ dose (x10(6)/kg) of 13.6 was collected. Of 26 patients undergoing autologous transplant, there was one treatment-related death and 12 relapses. With a median follow-up of 5.4 years, 5 year event-free survival (EFS) of all patients entered is 54%. The most important prognostic factor was cytogenetic changes. All seven patients with t(15,17) remained in long-term remission whereas EFS for other patients was 38%. We conclude that this two-step approach to autologous transplantation produces excellent stem cell yields, allows a high percentage of patients to receive the intended therapy, and provides effective treatment.