Developing alternative approaches to reduce retinal toxicity and prevent vision loss in the treatment of intraocular retinoblastoma

视网膜母细胞瘤是儿童眼内最常见的恶性肿瘤。最近推出的内- 动脉化疗（IAC）和玻璃体内注射（均使用基于美法仑的方案）改善了地球仪 晚期RB患者的生存率，同时避免静脉化疗的全身毒性。然而，在这方面， 美法仑对视网膜和视网膜血管系统是有毒的，并且两种治疗都与许多眼侧 影响，可能导致终身视力丧失。这项研究的目的是确定替代药物， 对眼部结构的毒性较小，但对眼内RB仍有效，用于通过IAC和玻璃体内给药 注射在兔中，我们已经开发了唯一的IAC小动物模型，并已证明了良好的 美法仑的眼渗透性和可再现的药代动力学（PK）。我们还开发了一个兔子模型 RB的发展视网膜肿瘤和玻璃体种子从人类RB细胞系生长，重演的特点， 在晚期RB患者中发现。使用这些新的模型，我们计划确定PK，视网膜/视网膜血管 毒性特征和已经获得FDA批准的所选化疗剂组的功效。 专注于FDA批准的药物将使我们的研究结果迅速转化为临床实践。玻璃体和 将计算IAC或玻璃体内给药后每种药物的视网膜内药物浓度和PK曲线。 注射，使用传统的质谱和一种新的原位成像质谱技术， 是在范德比尔特发展起来的一旦计算了PK曲线，则计算每种药物的最大耐受剂量（MTD）。 将计算IAC和重复玻璃体内注射的药物。功能性和结构性眼毒性 将使用一个全面的技术小组来衡量。一种鲁棒的贝叶斯连续重评估方法 将采用临床研究设计。然后，MTD将用于每种药物的疗效研究， IAC或玻璃体内注射，用于治疗上述兔模型中的RB。在识别保险箱之后 和有效的靶剂量在我们的兔子模型体内，我们将确认没有视网膜毒性使用切割 该技术允许在离体人类视网膜组织中随时间监测药物毒性， 在支持性灌注液中存活以进行功能评估。这确保了这些药物对人眼是安全的（不 兔子）。丹尼尔斯博士带来了眼部肿瘤生物学和遗传学的经验，以及临床专业知识， IAC为RB。他的研究的长期目标是开发更安全的、靶向途径的药物来治疗RB。 这个指导临床科学家研究职业发展（K 08）奖将允许博士丹尼尔斯 由世界一流的导师团队指导，他们在视网膜生物学，肿瘤生物学和 治疗学，以及眼内药物和眼内药物的临床前评估。通过 实践实验和教学相结合，丹尼尔斯博士将开发必要的技能，在使用 用于临床前研究、视网膜毒性和疗效的体内评估以及生物统计学的动物模型， 开发一个全面的药物测试平台，可用于评估未来的新化合物。

Retinoblastoma (RB) is the most common intraocular malignancy in children. The recent introduction of intra- arterial chemotherapy (IAC) and intravitreal injections, both using melphalan-based regimens, has improved globe survival for eyes with advanced RB, while avoiding the systemic toxicities of intravenous chemotherapy. However, melphalan is toxic to the retina and retinal vasculature, and both treatments are associated with many ocular side effects, potentially resulting in life-long loss of vision. The goal of this research is to identify alternative drugs that are less toxic to the ocular structures but remain effective against intraocular RB, for use via IAC and intravitreal injection. In rabbits, we have developed the only small animal model of IAC, and have demonstrated excellent ocular penetration and reproducible pharmacokinetics (PK) for melphalan. We have also developed a rabbit model of RB that develops both retinal tumors and vitreous seeds grown from human RB cell lines, recapitulating features found in patients with advanced RB. Using these novel models, we plan to determine the PK, retinal/retinal vascular toxicity profiles, and efficacy of a selected group of chemotherapeutic agents that already have FDA-approval. Focusing on FDA-approved drugs will allow rapid translation of our findings into clinical practice. Both vitreous and intra-retinal drug concentrations and PK curves will be calculated for each drug following both IAC or intravitreal injection, using traditional mass spectrometry and a novel in situ imaging mass spectrometry technique that was developed at Vanderbilt. Once the PK curves have been calculated, the maximum tolerable dose (MTD) for each drug will be calculated for both IAC and for repeated intravitreal injections. Functional and structural ocular toxicity will be measured using a comprehensive panel of techniques. A robust Bayesian Continual Reassessment Method clinical study design will be employed. The MTD will then be used in studies of the efficacy of each drug, given by either IAC or intravitreal injection, for the treatment of RB in the above rabbit models. Following identification of safe and effective target doses in vivo in our rabbit model, we will confirm the absence of retinal toxicity using a cutting edge technology that allows drug toxicity to be monitored over time in ex vivo human retinal tissues that can be kept alive in a supportive perfusate for functional evaluation. This ensures that these drugs are safe for human eyes (not just rabbits). Dr. Daniels brings experience with ocular tumor biology and genetics, as well as clinical expertise with IAC for RB. The long-term goal of his research is to develop safer, pathway-targeted agents for the treatment of RB. This Mentored Clinical Scientist Research Career Development (K08) Award will allow Dr. Daniels to be mentored by a world-class team of mentors, who have extensive expertise in retinal biology, tumor biology and therapeutics, and in the preclinical assessment of antineoplastic agents and intraocular drugs. Through a combination of hands-on experimentation and didactics, Dr. Daniels will develop necessary skills in the use of animal models for preclinical studies, in vivo assessment of retinal toxicity and efficacy, and biostatistics, while developing a comprehensive drug-testing platform that can be used to assess novel compounds in the future.