Development of a dual MDM2/XIAP inhibitor with a high therapeutic index for childhood cancers

项目摘要 急性淋巴细胞白血病（ALL）和神经母细胞瘤（NB）是儿童最常见的癌症。 目前的治疗方案往往与严重的副作用有关。因此，有一个强大的未满足 医学需要开发具有更高治疗指数的靶向药物以改善治疗结果。 癌蛋白MDM 2和XIAP是肿瘤中重要的细胞存活蛋白。MDM 2和XIAP升高 表达与疾病进展和不良治疗结果相关。他们代表着非常有吸引力的 癌症药物靶点。虽然存在几种MDM 2-p53和XIAP抑制剂，但它们都没有进入市场。 UTHSC和埃默里大学最近的一项合作导致了小分子MX69的发现和专利申请， 52作为MDM 2/XIAP双重抑制剂。MX69-52与MDM 2 RING结构域结合，并破坏其与 XIAP IRES，导致MDM 2和XIAP的同时抑制，导致癌细胞凋亡。MX69- 52的MTD ≥200 mg/kg，并且在15 mg/kg时对白血病异种移植模型有效，这表明大的 治疗指数SEAK Therapeutics获得了这一专利支架的许可，旨在开发最有效的 异构体混合物MX69-52中的异构体，即MX69- 52 d，作为儿科癌症的更有效药物。 SEAK Therapeutics在本I期SBIR中建议将MX 69 - 52 d作为可行的临床药物进行表征和风险降低 候选人，并为这种方法提供概念证明。 目标1。生成足够量的最有效的光学异构体MX69- 52 d，并测定其 绝对结构。Milcantine：（1）生产500 mg MX 69 - 52 d（纯度≥ 98%）;（2）明确 确定了MX69- 52 d的绝对结构，以实现立体特异性合成的未来发展。 目标二。确认MX69- 52 d对MDM 2/XIAP的双重抑制作用，并评价其潜在脱靶效应 针对一组重要的生理目标我们将确认MX69- 52 d保持其 作用与其异构体混合物MX 69 -52相似。我们还将绘制其潜在的脱靶效应， Cerep的Safety 47面板。Mild：（3）证实了MX69- 52 d在两种细胞中的双重MDM 2/XIAP抑制能力。 生物化学和细胞分析;（4）确定了10 µM时对生理学重要靶标的潜在相互作用 (e.g., GPCR、离子通道、转运蛋白），以进一步降低MX69- 52 d的风险。 目标3：确定MX69- 52 d的最大耐受剂量（MTD）和药代动力学（PK）参数， 评价其在异种移植模型中的抗癌活性，并评估其对正常人的潜在体内毒性。 细胞/组织。我们将使用两只小鼠来评估MX69- 52 d的改善的功效和治疗指数。 儿科癌症的模型。Mild：（5）MX69- 52 d的MTD（≥200 mg/kg）和PK参数;（6） 在≤20 mg/kg剂量下显示抗癌疗效，无急性毒性。 这项工作的成功将为第二阶段SBIR奠定基础，重点是开发MX69- 52 d或 通过IND前研究改进类似物，目标是开发一种更有效的儿科癌症药物。

PROJECT SUMMARY Acute lymphoblastic leukemia (ALL) and neuroblastoma (NB) are the most common cancers in children. Currently treatment options are often associated with severe side effects. Therefore, there is a strong unmet medical need to develop targeted-drugs with higher therapeutic indexes for improved treatment outcome. The oncoproteins MDM2 and XIAP are important cell-survival proteins in tumors. Elevated MDM2 and XIAP expression is associated with disease progression and poor treatment outcomes. They represent very attractive cancer drug targets. While several MDM2-p53 and XIAP inhibitors exist, none of them made to the market yet. A recent collaboration at UTHSC and Emory led to the discovery and patenting of the small molecule MX69- 52 as a MDM2/XIAP dual inhibitor. MX69-52 binds to the MDM2 RING domain and disrupts its interaction with XIAP IRES, resulting in simultaneous inhibition of both MDM2 and XIAP, leading to cancer cell apoptosis. MX69- 52 has an MTD ≥200 mg/kg and is effective against leukemia xenograft models at 15 mg/kg, suggesting a large therapeutic index. SEAK Therapeutics licensed this patented scaffold and aims to develop the most potent isomer within the isomeric mixture MX69-52, namely MX69-52d, as a more effective drug for pediatric cancers. SEAK Therapeutics proposes in this Phase I SBIR to characterize and de-risk MX69-52d as a viable clinical candidate and to provide proof of concept for this approach. Aim 1. Generate sufficient amounts of the most potent optical isomer MX69-52d and determine its absolute structure. Milestones: (1) produce 500 mg of MX69-52d (purity ≥ 98%); (2) unambiguously determined the absolute structure of MX69-52d to enable future development of a stereo-specific synthesis. Aim 2. Confirm MDM2/XIAP dual inhibition by MX69-52d and evaluate its potential off-target effects against a panel of physiologically important targets. We will confirm that MX69-52d maintains its mode of action similar to that of its isomeric mixture MX69-52. We will also map its potential off-target effects using Cerep’s Safety47 panel. Milestones: (3) confirmed dual MDM2/XIAP inhibitory abilities of MX69-52d in both biochemical and cellular assays; (4) identified potential interactions at 10 µM on physiologically important targets (e.g., GPCRs, ion channels, transporters) to further de-risk MX69-52d. Aim 3. Determine maximum tolerated dose (MTD) and pharmacokinetic (PK) parameters of MX69-52d, evaluate its anticancer activities in xenograft models, and assess its potential in vivo toxicity to normal cells/tissues. We will evaluate the improved efficacy and therapeutic index of MX69-52d using two mouse models of pediatric cancers. Milestones: (5) the MTD of MX69-52d (≥200 mg/kg) and PK parameters; (6) demonstrated anti-cancer efficacy without acute toxicities at ≤20 mg/kg. Success of this work will set the stage for a Phase II SBIR focusing on the development of MX69-52d or an improved analog through pre-IND studies, with the goal to develop a more effective drug for pediatric cancers.