Efficacy of Pomalidomide in HHT-related bleeding

描述(申请人提供)：遗传性出血性毛细血管扩张症(HHT)是一种罕见的遗传性出血性疾病，由Eng、ALK1或Smad4突变引起。HHT的发病机制涉及脑、肺、肝和粘膜等多种组织和器官的动静脉畸形(AVM)的形成。这些脆弱的动静脉动静脉畸形极易出血。在HHT的许多临床表现中，复发性鼻出血和胃肠道(小肠)出血最常见；出血是慢性的，导致对输血和肠外铁质的依赖，并显著降低生活质量。对HHT的出血表现的治疗是支持性的，因为没有令人信服的导致AVM持续消退的有效、无毒的治疗方法。PI对4例小肠AVM严重消化道出血的患者的经验以及大量轶事报道表明，沙利度胺可导致AVM的消退，并阻止HHT患者的出血。然而，沙利度胺不受专利保护，不是由制造商提供用于临床试验，也不是由仿制药制造商生产的。因此，我们建议设计泊马度胺的III期试验，泊马度胺是第三代沙利度胺类似物，具有更强的抗血管生成活性和改善的安全性，用于HHT相关出血患者。我们希望在一项由行业资助的15名患者的初步研究中证明这项试验的可行性，并激活泊马度胺用于这一适应症，所有患者都将在U34开始之前被纳入其中。我们已经组建了一个多学科、多机构的方案开发团队，将与U24临床试验资源合作计划这项研究。这项建议的目标是1)开发一项随机、安慰剂对照的III期研究，以评估泊马度胺治疗HHT相关性鼻出血和/或胃肠道出血的有效性和安全性，以及2)计划在泊马度胺治疗之前和期间从HHT患者那里获得的血液和血浆组分的储存库，该库将用于确定泊马度胺和其他药物的反应生物标志物。这项建议利用创新的规划策略来开发一种新型药物的临床试验，该药物可能会导致治疗HHT患者出血的新范例。

DESCRIPTION (provided by applicant): Hereditary Hemorrhagic Telangiectasia (HHT) is a rare, inherited bleeding disorder caused by mutations in Eng, ALK1 or Smad4. The pathogenesis of HHT involves formation of arteriovenous malformations (AVM) in several tissues and organs including the brain, lung, liver and mucosal membranes. These fragile AVMs are highly prone to bleeding. Of the many clinical manifestations of HHT, recurrent epistaxis and gastrointestinal (small bowel) bleeding are most common; bleeding is chronic, leads to dependence on transfusion and parenteral iron, and significantly impairs quality of life. Treatment for the bleeding manifestations of HHT is supportive, since no effective, non-toxic therapy that causes consistent regression of AVMs has been convincingly demonstrated. The PI's experience with four patients with severe gastrointestinal bleeding from small bowel AVMs, as well as numerous anecdotal reports, suggests that thalidomide causes regression of AVMs and arrests bleeding in patients with HHT. However, thalidomide is not patent protected, is not supplied by the manufacturer for clinical trials and is not produced by manufacturers of generics. Therefore, we propose to design a phase III trial of pomalidomide, a third generation thalidomide analogue with greater anti-angiogenic activity and an improved safety profile, in patients with HHT-related bleeding. We expect to demonstrate feasibility for this trial and activit of pomalidomide for this indication in a 15 patient, industry- funded pilot study in which all patients will be enrolled prior to initiation of this U34. We have assembled a multi-disciplinary, multi-institutional protocol development team that will work with the U24 Clinical Trials Resource to plan the study. Goals of this proposal are 1) To develop a randomized, placebo-controlled phase III study to assess the efficacy and safety of pomalidomide in HHT-related epistaxis and/or gastrointestinal bleeding, and 2) To plan a repository of blood and plasma fractions obtained from patients with HHT before and during pomalidomide therapy that will be used for defining biomarkers of response to pomalidomide and other agents. This proposal utilizes innovative planning strategies to develop a clinical trial of a novel agent that may lead to a new paradigm for treatment of bleeding in patients with HHT.