Resistance Suppression for P. Aeruginosa using Novel Combination Therapy Modeling

描述(申请人提供)：铜绿假单胞菌是ICU发病率和死亡率的主要原因，特别是在呼吸机相关性肺炎患者中。许多分离株具有多重耐药性，一些分离株对目前存在的所有抗感染药物都具有抗药性。目前还没有新的抗生素在临床开发中(在人类中)具有新的作用机制来对抗假单胞菌。考虑到与新药开发相关的周期时间，很可能在5-7年内不会出现对这种病原体具有新作用机制的抗生素。因此，我们必须创造关于如何最好地抑制这种病原体的抗生素耐药性的新知识。这将有助于在我们等待新药物的同时保存我们现有的药物。此外，当具有新作用机制的药物可用时，它们可以以最佳方式开发以抑制耐药性，无论是作为单一疗法还是联合治疗。在这项应用中(具体目标#1)，我们假设我们可以通过在我们的中空纤维感染模型(HFIM)中研究这种病原体，并将一个大型数学模型与HFIM数据相匹配来确定这些剂量和时间表，从而确定用于抑制耐药性的单一疗法的最佳剂量和给药时间表。我们进一步假设，不同的耐药机制将改变最佳剂量和方案。我们建议研究野生型铜绿假单胞菌PAO-1的等基因突变，每个突变都包含一个明确的抗性机制。这些发现将通过使用蒙特卡罗模拟(MCS)与人类联系起来。在具体目标2中，我们建议检查联合化疗中的药物。我们开发了一种全新的数学模型，可以描述两种药物联合化疗对铜绿假单胞菌分离株的影响。该模型是一种混合模型，允许将该模型与两种制剂的浓度-时间过程进行拟合，并将该模型与由多种制剂组合对存在的敏感和较不敏感的生物体种群随时间产生的不同变化相匹配。对该系统参数的稳健识别将允许计算出抑制耐药性的最佳组合方案。如上所述，这种方案将通过使用MCS与MAN连接起来。HFIM是一种体外系统。在具体的目标#3中，我们还将在中性粒细胞减少的小鼠肺炎模型中验证这些最优和非最优方案，使用与在AIMS#1和#2中体外研究的相同菌株。在检验这一点时，我们将对方案使用“人性化”剂量，以便小鼠和人类药代动力学之间的差异不会导致不正确的推断。无论是单一疗法还是联合疗法，都会这样做。将设计和进行前瞻性验证实验。结果将与体外研究结果进行比较，并与人类建立联系。在这样做的过程中，将为抑制耐药突变群体放大的药物方案定义强有力的原则。铜绿假单胞菌是重症监护病房中的一种重要病原体，通常对我们治疗性医疗机构中的许多甚至所有药物都具有耐药性。由于至少在7年内不会有具有独特作用机制的药物对假单胞菌有效，因此必须学习如何使用我们现有的药物，以抑制耐药性的出现，并保持这些药物对我们的患者有效。我们计划通过以下方式做到这一点：1)了解在我们的中空纤维感染模型(HFIM)中添加假单胞菌活性药物以抑制耐药性的最佳方式，并描述不同耐药机制对此过程的影响2)了解如何在HFIM中联合使用这些药物以最佳地抑制耐药性出现3)在铜绿假单胞菌肺炎小鼠模型中验证HFIM的体外研究结果。

DESCRIPTION (provided by applicant): Pseudomonas aeruginosa is a major cause of morbidity and mortality in the ICU, particularly among patients with Ventilator-Associated Pneumonia. Many isolates are multi-drug resistant and some isolates are resistant to all currently extant anti-infective agents. There are currently no new antibiotics in clinical development (in man) with novel mechanisms of action against Pseudomonas. Given the cycle time associated with new drug development, it is likely that no antibiotics with new mechanisms of action for this pathogen will arise for 5 - 7 years. Thus, we must generate new knowledge about how best to suppress antibiotic resistance for this pathogen. This will help preserve our current drugs while we await new agents. Also, when agents with new mechanisms of action become available they can be developed in an optimal fashion for resistance suppression, both as monotherapy and in combination. In this application (Specific Aim #1), we hypothesize that we can identify optimal doses and schedules of administration for monotherapy for resistance suppression by studying this pathogen in our Hollow Fiber Infection Model (HFIM) and fitting a large mathematical model to the HFIM data to identify these doses and schedules. We further hypothesize that different resistance mechanisms will alter optimal doses and schedules. We propose to study isogenic mutants of the wild-type P. aeruginosa PAO-1 isolate, each containing a defined resistance mechanism. These findings will be bridged to man through use of Monte Carlo simulation (MCS). In Specific Aim #2, we propose to examine drugs in combination chemotherapy. We have developed a completely novel mathematical model that allows description of the impact of two drug combination chemotherapy on isolates of P. aeruginosa. This model is a mixture model and allows the fitting of the model to the concentration-time course of both agents as well as to fit the model to the disparate changes over time wrought by the combination of agents on the susceptible and less-susceptible populations of organisms present. Robust identification of the parameters of this system will allow calculation of optimal combination regimens for resistance suppression. Such regimens will be bridged to man through the use of MCS, as above. The HFIM is an in vitro system. In Specific Aim #3, we will also validate these optimal and non-optimal regimens in a neutropenic mouse pneumonia model, employing the same isolates studied in vitro in Aims #1 and #2. In examining this, we will use "humanized" dosing for the regimens, so that differences between mouse and human pharmacokinetics will not drive an improper inference. This will be done for both mono- and combination therapy. Prospective validation experiments will be designed and carried out. Results will be compared with the in vitro findings and also bridged to man. In so doing robust principles will be defined for drug regimens that will suppress amplification of resistant mutant populations. Pseudomonas aeruginosa is a pathogen of major importance in the Intensive Care Unit and is often resistant to many or even all of the drugs in our therapeutic armamentarium. As no agents with a unique mechanism of action active against Pseudomonas are expected for at least 7 years, it is imperative to learn how to use our currently available agents in a way that suppresses emergence of resistance and keeps these agents active for our patients. We plan to do this by 1) understanding the optimal way to dose Pseudomonas-active drugs in our hollow fiber infection model (HFIM) to suppress resistance and delineate the impact of different resistance mechanisms on this process 2) understand how to administer these drugs in combination in the HFIM to optimally suppress resistance emergence 3) validate the in vitro findings from the HFIM in a mouse model of Pseudomonas aeruginosa pneumonia.