Phase II trial of 17-AAG in melanoma patients

描述（由申请人提供）：40-67%的黑色素瘤肿瘤含有并激活BRAF突变（几乎总是V599E）。BRAF的上游，N-RAS的激活突变见于另外5-36%的黑色素瘤。因此，在大多数黑色素瘤中可以看到MARK通路的激活突变。这些观察结果以及许多体外和动物研究表明，MARK通路对黑色素瘤的生长至关重要。我们的总体目标是干扰黑色素瘤的MARK通路作为一种治疗策略。BRAF的正常折叠依赖于HSP90，有证据表明突变的BRAF甚至更依赖于HSP90。17-AAG对HSP90的抑制导致细胞系和异种移植模型中BRAF的耗竭和细胞生长的抑制。在17-AAG缺失的黑色素瘤中，其他感兴趣的HSP90客户蛋白是CDK4和AKT。在各种癌症类型中使用17-AAG的I期研究已经确定每周450 mg/m2的剂量是最有希望的II期剂量。虽然很少有黑色素瘤患者被纳入这些I期试验，但已经报道了一些临床反应。我们建议在转移性黑色素瘤患者中进行17-AAG的II期试验，剂量为450mg /m2/周x每8周6次。两组各25名患者将接受治疗，一组为野生型BRAF，另一组为突变型BRAF。该试验将在MSKCC（牵头机构）、新泽西癌症研究所和H.Lee Moffitt癌症中心进行。具体目标#1：确定每个队列的临床反应率，并验证突变BRAF的肿瘤对17-AAG更敏感的假设。具体目标#2：验证17-AAG治疗可以通过消耗肿瘤内BRAF和/或下游蛋白（如phospho-ERK， CDK4和cyclin D1）的储存来破坏MAPK途径的假设。为了解决这个问题，我们将在前10名患者治疗前和第一次17-AAG治疗后18-48小时进行肿瘤活检。采用Western blot和免疫组织化学对肿瘤进行分析。第二个目的是确定对MAPK通路的影响是否与临床反应或肿瘤中突变BRAF的存在相关。我们还打算通过表达阵列谱分析活检。作为一项探索性分析，我们将比较治疗前与治疗后标本的表达模式，临床反应性肿瘤与无反应性肿瘤，突变型BRAF与野生型BRAF肿瘤。

DESCRIPTION (provided by applicant): Between 40-67% of melanoma tumors contain and activating BRAF mutations (almost always V599E). Upstream of BRAF, activating mutations in N-RAS are seen in another 5-36% of melanomas. Thus, activating mutations in the MARK pathway are seen in most melanomas. These observations along with many in vitro and animal studies indicate that the MARK pathway is critical for melanoma growth. Our overall objective is to interfere with the MARK pathway in melanoma as a treatment strategy. BRAF depends on HSP90 for proper folding and there is evidence that mutated BRAF is even more dependent on HSP90. Inhibition of HSP90 by 17-AAG results in depletion of BRAF in cell lines and in xenograft models and inhibition of cell growth. Other HSP90 client proteins of interest in melanoma depleted by 17-AAG are CDK4 and AKT. Phase I studies using 17-AAG in a variety of cancer types have defined a weekly dose of 450 mg/m2 as the most promising phase II dose. Although few melanoma patients have been included in these phase I trials, some clinical responses have been reported. We propose a phase II trial of 17-AAG in patients with metastatic melanoma at a dose of 450 mg/m2/week x 6 every 8 weeks. Two cohorts of 25 patients each - one cohort with wild-type BRAF and one cohort with mutant BRAF - will be treated. The trial will be conducted at MSKCC (lead institution), Cancer Inst. of New Jersey, and H.Lee Moffitt Cancer Center. Specific aim #1: Determine the clinical response rate in each cohort and test the hypothesis that tumors with mutant BRAF will be more sensitive to 17-AAG. Specific aim #2: Test the hypothesis that treatment with 17-AAG can disrupt the MAPK pathway by depleting intra-tumor stores of BRAF and/or downstream proteins such as phospho-ERK, CDK4 and cyclin D1. To address this, we will obtain tumor biopsies in the first 10 patients pre-treatment and 18-48 hr following the first 17-AAG treatment. Tumors will be analyzed by Western blot and immunohistochemistry. A secondary aim is to determine if effects on the MAPK pathway correlate with clinical responses or with the presence of mutated BRAF in the tumor. We also intend to analyze the biopsies by expression array profiling. As an exploratory analysis, we will compare expression patterns in pre-treatment vs. post-treatment specimens, clinically responding tumors vs. non-responding tumors, and mutant BRAF vs. wild-type BRAF tumors.