STUDY OF MAB 216 WITH CHEMOTHERAPY FOR THE TREATMENT OF PEDIATRIC PATIENTS

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。主要目标：1。估计复发性或难治性急性淋巴细胞白血病（ALL）儿童单克隆抗体216（mAb 216）的最大耐受剂量（MTD），间隔一周分两次给药。2.确定按照该方案给予的mAb 216作为单药和与阿托斯汀联合给药的剂量限制性毒性（DLT）。3.表征mAb 216在复发性或难治性ALL儿童中的药代动力学行为。次要目标：1。在I期研究范围内明确定义mAb 216的抗肿瘤活性。2.评估mAb 216在复发性或难治性ALL患者中的生物活性。 ALL是儿童期最常见的恶性肿瘤。大约80%的儿童ALL是B细胞谱系的，尽管使用当前的治疗方法，近80%的ALL儿童将被治愈，但对于剩余的患者组，需要新的和不同的治疗策略仍然是治疗挑战。对白血病原始细胞表现出特异性但不与化疗药物共享毒性特征的试剂对于设计抗白血病治疗的新策略将是特别有利的。 我们的研究已经发现，从ALL、非霍奇金淋巴瘤（NHL）患者活检、B细胞系和正常人B细胞获得的恶性B细胞在体外被VH 4 -34基因（可变重链区）编码的单克隆抗体（mAb）的子集杀死，并且VH 4 -34编码的Ab的细胞毒性对B细胞具有高度特异性。由于人mAb 216是测试的mAb中细胞毒性最强的，因此已将其用于进一步研究。重要的是，用标记的mAb 216和标记的抗CD 34染色的正常骨髓的流式细胞术分析显示，216不与干细胞反应，因此尽管正常的外周B细胞将在体内被mAb 216处理杀死，但它们将重新增殖。此外，体外研究已经证明mAb 216对来自诊断患有ALL的儿童的前B细胞的细胞毒性。 还测试了mAb 216与单一化疗剂组合的体外细胞毒性。将来自不同基因型和表型的ALL原始细胞的细胞系与mAb 216单独或与长春新碱、柔红霉素或L-天冬酰胺酶联合孵育。所有这些化学治疗剂增加了用单一药剂化学治疗或单独的mAb 216观察到的细胞毒性程度。然而，长春新碱与mAb 216的组合特别引人注目，导致比单独使用长春新碱或mAb 216所观察到的细胞毒性增强一个数量级。 通过RAID计划，NCI及其承包商在家兔中进行了mAb 216单独给药和与阿托斯汀联合给药的药代动力学（PK）和毒性研究。在组织病理学检查中，未观察到药物相关变化。单克隆抗体216本身在给药后3天引起血小板计数的剂量相关性降低，并且在20 mg/kg剂量下平均WBC计数降低，主要是由于中性粒细胞减少。到第8天，血小板和WBC计数均恢复，血清化学参数无显着变化。根据毒理学研究的结果，RAID研究者得出结论，当与阿曲斯汀联合给药时，在mAb 216的计划临床剂量（100-400 mg/m2/剂）下，预期不会出现持续全身毒性。 虽然这是mAb 216在儿科患者中的第一个I期试验，但另一种VH 4 -34衍生抗体HA-1A已在儿童中进行了测试。在这些研究中，没有报告认为与HA-1A“肯定”或“很可能”相关的不良事件。虽然不确定，但这些结果表明mAb 216在儿科患者中可能耐受良好。考虑到将有资格在本I期研究中接受治疗的患者人群的高风险性质，本试验设计的目的是：1）允许在复发性ALL患者中测试mAb 216作为单药; 2）确定mAb 216作为单药给药时的PK; 3）确定该抗体作为单药的毒性特征;和4）评估该抗体的体内细胞毒性。临床前细胞毒性数据强烈表明，mAb 216单独使用时可显示临床疗效。然而，有令人信服的证据表明，mAb 216，当与化疗药物，特别是阿曲斯汀，介导的协同程度的细胞毒性对B-祖细胞白血病母细胞。因此，本临床试验的研究设计将提供关于mAb 216单独使用以及与化疗药物联合使用时的临床影响的重要信息。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Primary Aims: 1. Estimate the maximum tolerable dose (MTD) of monoclonal antibody 216 (mAb 216), administered in two doses one week apart, to children with relapsed or refractory acute lymphoblastic leukemia (ALL). 2. Determine the dose-limiting toxicities (DLT) of mAb 216 given on this schedule, as a single agent and in combination with Vincristine. 3. Characterize the pharmacokinetic behavior of mAb 216 in children with relapsed or refractory ALL. Secondary Aims: 1. Preliminarily define the anti-tumor activity of mAb 216 within the confines of a Phase I study. 2. Assess the biologic activity of mAb 216 in patients with relapsed or refractory ALL. Goals ALL is the most common malignancy of childhood. Approximately 80% of childhood ALL is of B-cell lineage, and although with current therapy nearly 80% of children with ALL will be cured, for the remaining group of patients the need for new and different treatment strategies continues to be a therapeutic challenge. Agents that demonstrate specificity for leukemic blasts, but which do not share a toxicity profile with chemotherapy drugs, would be particularly advantageous for designing new strategies of anti-leukemia therapy. Our research has found that malignant B cells obtained from ALL, non-Hodgkin's lymphoma (NHL) patient biopsies, B-cell lines and normal human B-cells are killed in vitro by a subset of monoclonal antibodies (mAbs) encoded by the VH4-34 gene (variable heavy region), and that cytotoxicity of VH4-34 encoded Abs are highly specific for B cells. Because human mAb 216 was the most cytotoxic of the tested mAbs, it has been used for further study. Importantly, flow cytometry analysis of normal bone marrow stained with labeled mAb 216 and labeled anti CD34 showed that 216 does not react with stem cells, so although the normal peripheral B cells would be killed in vivo by mAb 216 treatment, they will repopulate. Furthermore, in vitro studies have demonstrated mAb 216's cytotoxicity on pre-B cells from children diagnosed with ALL. In vitro cytotoxicity of mAb 216 in combination with single chemotherapeutic agents has also been tested. Cell lines which have been derived from ALL blasts of different genotype and phenotype, were incubated with mAb 216 alone or in combination with vincristine, daunomycin, or L-asparaginase. All of these chemotherapeutic agents increased the degree of cytoxicity seen with either single agent chemotherapy or mAb 216 alone. However, the combination of vincristine with mAb 216 was particularly striking, resulting in enhanced cytoxicity an order of magnitude greater than that seen with either vincristine or mAb 216 alone. Through the RAID program, the NCI and its contractors have performed in rabbits, pharmacokinetic (PK) and toxicity studies of mAb 216 alone and when given in combination with Vincristine. On histopathologic examination, no drug-related changes were noted. By itself, three days after administration, mAb 216 produced a dose-related decrease in platelet count, and mean WBC counts were decreased at a 20 mg/kg dosage, primarily due to neutropenia. Both platelet and WBC counts recovered by Day 8, and there were no significant changes in serum chemistry parameters. Based on the results of toxicology studies, RAID investigators concluded that sustained systemic toxicity is not expected at the planned clinical doses (100-400 mg/m2/dose) of mAb 216 when given in combination with Vincristine. While this is the first Phase I trial of mAb 216 in pediatric patients, another VH4-34 derived antibody, HA-1A, has been tested in children. In those studies, there were no adverse events reported that were felt to be "definitely" or "probably related" to HA-1A. While not definitive, these results suggest that mAb 216 may be well tolerated in pediatric patients. Given the high risk nature of the patient population who will be eligible for treatment on this Phase I study, it is the intent of this trial design to: 1) allow testing of mAb 216 as a single agent in patients with relapsed ALL; 2) to determine the PK of mAb 216 when administered as a single agent; 3) to determine the toxicity profile of this antibody as a single agent; and 4) to assess the in vivo cytotoxicity of this antibody. The preclinical cytotoxicity data strongly suggest that mAb 216 may demonstrate clinical efficacy when used alone. However, there is compelling evidence that mAb 216, when used in combination with chemotherapy agents, particularly Vincristine, mediates a synergistic degree of cytoxicity against B-progenitor leukemic blasts. The study design of this clinical trial will therefore provide important information about the clinical impact of mAb 216 when used alone as well as in combination with chemotherapeutic agents.