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

视网膜母细胞瘤(RB)是儿童最常见的眼内恶性肿瘤。最近推出的Intra- 动脉化疗(IAC)和玻璃体内注射，都使用了以马法兰为基础的方案，改善了全球 晚期RB患者的存活率，同时避免静脉化疗的全身毒性。然而， 马法兰对视网膜和视网膜血管系统有毒性，这两种治疗方法都与眼部多方面有关。 影响，可能导致终身失明。这项研究的目标是确定替代药物 对眼结构毒性较小，但对眼内RB仍有效，可通过IAC和玻璃体内使用 注射。在兔身上，我们已经建立了唯一的IAC小动物模型，并证明了良好的 马法兰的眼透入度和重复性药代动力学(Pk)。我们还开发了一种兔子模型 Rb同时产生视网膜肿瘤和从人类Rb细胞系生长的玻璃体种子，概括了这些特征 发现于晚期RB患者。使用这些新的模型，我们计划确定PK，视网膜/视网膜血管 已经获得FDA批准的选定的一组化疗药物的毒性概况和疗效。 专注于FDA批准的药物将使我们的发现迅速转化为临床实践。玻璃体和玻璃体 将计算每种药物在IAC或玻璃体内后的视网膜内药物浓度和PK曲线 注射，使用传统的质谱学和一种新的原位成像质谱学技术， 在范德比尔特开发的。一旦计算出PK曲线，每种药物的最大耐受剂量(MTD) IAC和重复玻璃体内注射的药物都将计算在内。功能性和结构性眼毒性 将使用一套全面的技术来衡量。一种稳健的贝叶斯连续重估方法 将采用临床研究设计。MTD随后将用于研究每种药物的疗效，由 IAC或玻璃体内注射，用于上述兔模型的RB治疗。在确认外管局之后 和有效靶剂量在我们的兔模型中，我们将使用切割来确认没有视网膜毒性 EDGE技术，允许随着时间的推移监测药物在可保留的体外人类视网膜组织中的毒性 活在支持性灌流液中进行功能评估。这确保了这些药物对人眼是安全的(而不是 只有兔子)。Daniels博士带来了眼部肿瘤生物学和遗传学方面的经验，以及 RB的IAC。他研究的长期目标是开发更安全、靶向通路的药物来治疗RB。 这项指导临床科学家研究职业发展奖(K08)将允许Daniels博士成为 由世界级的导师团队指导，他们在视网膜生物学、肿瘤生物学和 治疗学，以及抗肿瘤药物和眼内药物的临床前评估。通过一个 结合动手实验和教学，Daniels博士将发展必要的技能来使用 临床前研究的动物模型，视网膜毒性和有效性的体内评估，以及生物统计学，而 开发一个全面的药物测试平台，用于未来对新化合物的评估。

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.