Biomarkers for predicting response to Hsp90 therapy

描述（由申请人提供）：背景：用于Hsp90患者选择的诊断分析——一个未满足的医疗需求：如今，制药公司将药物推向市场往往是不够的。监管机构和保险公司还要求制药公司开发测试，以确定哪些患者更有可能从这种药物中受益，从而使其他患者免受不必要的副作用和费用。2011年7月，FDA向业界发布了伴随诊断分析的指导意见，其中包括希望该测试与药物同时获得批准。这对于临床研究中或即将进入临床评估的近20种Hsp90抑制剂尤其重要，其中精确确定患者群体尤其难以捉摸。对于Hsp90抑制剂，目前患者的选择是基于Hsp90依赖性癌客户蛋白（即HER2和mutALK）的存在，但对于大多数肿瘤来说，驱动转化的Hsp90依赖性癌客户蛋白难以识别。为了预测个体患者的反应性，人们需要以逐个肿瘤的方式定义Hsp90的癌蛋白客户，然后了解伴侣-客户复合物的组成和功能，以及它们所涉及的分子网络，这是一项艰巨的技术挑战。假设：我们在这里提出了一个简单的替代方案：我们建议在每个肿瘤中测量一种Hsp90物种的丰度，即允许存在异常肿瘤驱动客户的“致癌Hsp90”，而不是测量肿瘤驱动客户网络。当肿瘤依赖于Hsp90-癌蛋白网络生存时，这些蛋白变得依赖于“致癌Hsp90”的功能和稳定性。这种共生的相互依赖表明，肿瘤对Hsp90癌蛋白的依赖等于对“致癌Hsp90”的依赖。测量后者的丰度是前者的读数，因此是Hsp90治疗富集的潜在生物标志物。方法：但是如何测量这种“致癌Hsp90”物种呢？它的丰度并不仅仅取决于Hsp90的表达，但是某些Hsp90抑制剂，如由Chiosis实验室开发的PU-H71，目前正在MSKCC和NCI临床中心进行临床评估，特异性地与这种“致癌Hsp90”物种相互作用。因此，标记的PU-H71衍生物可以用作测量其存在度和丰度的工具。事实上，我们已经创建了荧光和放射性标记版本的PU-H71，我们分别优化用于流式细胞术（液体肿瘤）或正电子发射断层扫描（PET）成像（实体肿瘤）。这些工具与“致癌性Hsp90”特异性相互作用，为临床中该Hsp90物种的定量提供了一种手段。在这里，我们建议(a)进行探索性分析，以验证“致癌Hsp90”物种作为Hsp90抑制剂治疗患者选择的生物标志物，(b)证明使用两种化学工具，PU-FITC和124I-PU-H71，以无创测量该生物标志物的存在和丰度。具体来说，我们计划：(1)在体外液体和实体肿瘤的临床前模型中确定所提出的生物标志物预测对Hsp90抑制剂有反应的癌症亚群的能力（Guzman和Chiosis）。(2)通过液体肿瘤中的PU-FITC标记和实体肿瘤中的124I-PU-H71摄取和保留来测定体内液体肿瘤和实体肿瘤的临床前模型，确定“致癌Hsp90”是否预测抗肿瘤活性（Guzman， Lewis和Chiosis）。(3)对提出的生物标志物进行临床探索性研究(Dunphy, Lewis, Guzman， Chiosis与临床同事Gerecitano（1期，PI)， Modi和Hudis（乳腺癌，2期），Roboz, Tallman （AML， 1期，2期PI）和Larson（核医学）合作）。这种肿瘤敏感性与生物标志物谱的探索性相关性分析，一旦在后续的大型临床研究中得到验证，将最终提供一种预测肿瘤对Hsp90抑制剂反应的方法。最终目标是提供一种方法，通过分析“致癌性Hsp90”的存在和丰度，通过多参数流式细胞术在液体癌症中使用PU-FITC测量，通过PET在实体肿瘤中使用124I-PU-H71放射性示踪成像来测量，从而为患者选择未来的Hsp90抑制剂治疗提供常规方法。意义：据我们所知，这是首次报道的无创伴诊技术，对Hsp90治疗的患者选择具有潜在的预测能力。在描述的两种形式中，该分析提出了液体癌症和实体肿瘤的解决方案。由于这些检测提供了临床医生从未获得过的数据，它们有望帮助加快Hsp90抑制剂在癌症中的开发，并为临床决策提供Hsp90靶向药物的信息。因此，他们可以彻底改变Hsp90抑制剂的临床开发和使用，以个性化的、针对患者的方式。

DESCRIPTION (provided by applicant): Background: Diagnostic assay for Hsp90 patient selection -an unmet medical need: These days it is often not enough for pharmaceutical companies to bring a drug to market. Regulators and insurers are also requiring companies to develop tests to pinpoint which patients are more likely to benefit from the drug, thereby sparing other patients from needless side effects and expense. The FDA issued guidance to the industry on companion diagnostic assays in July 2011, including its preference for having the test ready for approval at the same time as the drug. This is especially important for the almost 20 Hsp90 inhibitors in clinical studies or about to enter clinical evaluation, where pinpointing th patient population has been especially elusive. For Hsp90 inhibitors, patient selection is currently based on the presence of an Hsp90-dependent oncoclient protein (i.e. HER2 and mutALK), but for most tumors the Hsp90-adicted onco-client protein(s) that drive transformation are difficult to identify. To predict an individual patient's responsiveness, one would need to define, in a tumor-by-tumor manner, the Hsp90's oncoprotein clientele and then understand the make-up and function of chaperone-client complexes, together with the molecular networks in which they are involved, a daunting technical challenge. Hypothesis: We propose here a simple alternative: instead of measuring the network of tumor-driving Hsp90 clientele, we propose to measure in each tumor the abundance of an Hsp90 species, the "oncogenic Hsp90", that allows for the existence of the aberrant tumor-driving clientele. While the tumor becomes addicted to survival on a network of Hsp90-oncoproteins, these proteins become dependent on "oncogenic Hsp90" for functioning and stability. This symbiotic interdependence suggests that addiction of tumors to Hsp90 oncoproteins equals addiction to "oncogenic Hsp90". Measuring the abundance of the latter is a read-out of the first, and therefore a potential biomarker for Hsp90 therapy enrichment. Approach: But how to measure this "oncogenic Hsp90" species? Its abundance is not dictated by Hsp90 expression alone, however certain Hsp90 inhibitors, such as PU-H71 developed by the Chiosis lab and currently in clinical evaluation at MSKCC and the NCI Clinical Center, specifically interact with this "oncogenic Hsp90" species. Labeled derivatives of PU-H71 therefore can be used as tools to measure its presence and its abundance. Indeed, we have created both a fluorescent and a radiolabeled version of PU-H71 that we optimized for use in flow cytometry (for liquid tumors) or positron emission tomography (PET) imaging (for solid tumors), respectively. These tools interact specifically with the "oncogenic Hsp90" and provide a means for the quantification of this Hsp90 species in clinic. Here we propose to (a) conduct exploratory analyses towards validation of the "oncogenic Hsp90"species as a biomarker for patient selection on Hsp90 inhibitor therapy and (b) demonstrate the use of the two chemical tools, PU-FITC and 124I-PU-H71, to non-invasively measure the presence and abundance of this biomarker. Specifically, we plan: (1) To determine in in vitro preclinical models of liquid and solid tumors the ability of the proposed biomarker to predict the subset of cancers that will respond to Hsp90 inhibitors (Guzman and Chiosis). (2) To determine in in vivo pre-clinical models of liquid and solid tumors whether the "oncogenic Hsp90", as measured by PU-FITC labeling in liquid tumors and by 124I-PU-H71 uptake and retention in solid tumors, predicts for anti-tumor activity (Guzman, Lewis and Chiosis). (3) To conduct an exploratory study of the proposed biomarker in clinic (Dunphy, Lewis, Guzman, Chiosis in collaboration with clinical colleagues Gerecitano (Phase 1, PI), Modi and Hudis (breast cancer, Phase 2), Roboz, Tallman (AML, Phase 1,2 PIs) and Larson (nuclear medicine)). This exploratory correlation analysis of tumor sensitivity vs biomarker profile, once validated in follow- up large clinical studies, will ultimately provide an assay for predictive response of tumors to Hsp90 inhibitors. The ultimate goal is to provide a means by which patient selection for future Hsp90 inhibitor treatment would be routinely performed by analysis of the presence and abundance of the "oncogenic Hsp90" as measured by multiparameter flow cytometry using PU-FITC in liquid cancers and by PET using 124I-PU-H71 radiotracer imaging in solid tumors. Significance: To our knowledge, these are the first reported non-invasive companion diagnostic technologies with potential predictive power for patient selection in Hsp90 therapy. In the two described forms, the assay proposes a solution for both liquid cancers and solid tumors. Because the assays offer data never- before available to clinicians, they promise to help accelerate the development of Hsp90 inhibitors in cancers and to inform clinical decision-making with Hsp90-targeted agents. They could therefore, revolutionize the clinical development and the use of Hsp90 inhibitors in an individualized, patient-specific manner.