Treatment-related mortality is common among children with acute lymphoblastic leukemia (ALL) treated in poor-resource settings. We applied a simplified flow-cytometric assay to identify patients with precursor B-cell ALL (B-ALL) at very low risk (VLR) of relapse and treated them with a reduced-intensity treatment plan (RELLA05). VLR criteria include favorable presenting features (age ≥1 and <10 years), white blood cell (WBC) count of <50 × 109/L, lack of extramedullary leukemia, and minimal residual disease (MRD) levels of <0.01% on remission induction day 19. Except for two doses of daunorubicin, treatment for patients with VLR B-ALL consisted of a combination of agents with a relatively low myelotoxicity profile, including corticosteroids, vincristine, L-asparaginase, methotrexate, and 6-mercaptopurine. Cyclophosphamide, systemic cytarabine, and CNS radiotherapy were not used. Of 454 patients with ALL treated at the Instituto de Medicina Integral Fernando Figueira in Recife, Brazil, between December 2005 and June 2015, 101 were classified as having VLR B-ALL. There were no cases of toxic death or treatment abandonment during remission induction. At a median follow-up of 6.6 years, there were eight major adverse events: six relapses, one treatment-related death (from septicemia) during remission, and one secondary myeloid leukemia. The estimated 5-year event-free and overall survival rates were 92.0% ± 3.9% and 96.0% ± 2.8%, respectively. The 5-year cumulative risk of relapse was 4.24% ± 2.0%. The treatment was well tolerated. Episodes of neutropenia were of short duration. Patients with B-ALL selected by a combination of presenting features and the degree of early response can be successfully treated with a mildly myelosuppressive chemotherapy regimen.

中文翻译：

---

小儿淋巴细胞白血病的降低剂量强度治疗：累西腓 RELLA05 试点研究的长期结果

在资源贫乏地区接受治疗的急性淋巴细胞白血病 (ALL) 儿童中，治疗相关死亡率很常见。我们应用了一种简化的流式细胞仪检测来识别复发风险极低 (VLR) 的前体 B 细胞 ALL (B-ALL) 患者，并采用降低强度的治疗计划 (RELLA05) 对其进行治疗。VLR 标准包括良好的表现特征（年龄≥1 岁和 <10 岁），白细胞 (WBC) 计数 <50 × 109/L，无髓外白血病，缓解时最小残留病 (MRD) 水平 <0.01%诱导第 19 天。除了两剂柔红霉素外，VLR B-ALL 患者的治疗由骨髓毒性相对较低的药物组合组成，包括皮质类固醇、长春新碱、L-天冬酰胺酶、甲氨蝶呤和 6-巯基嘌呤。环磷酰胺，未使用全身阿糖胞苷和中枢神经系统放疗。2005 年 12 月至 2015 年 6 月期间，在巴西累西腓的费尔南多菲盖拉综合医学研究所治疗​​的 454 名 ALL 患者中，101 名患者被归类为 VLR B-ALL。在缓解诱导期间没有出现中毒性死亡或放弃治疗的病例。在中位随访 6.6 年时，发生了 8 起主要不良事件：6 起复发、1 起缓解期间与治疗相关的死亡（败血症）和 1 起继发性髓性白血病。估计的 5 年无事件生存率和总生存率分别为 92.0% ± 3.9% 和 96.0% ± 2.8%。5 年累积复发风险为 4.24% ± 2.0%。治疗耐受性良好。中性粒细胞减少症的发作持续时间很短。