18F ML-10 for Early Detection of Response of Brain Metastases to WBRT

Overview

The purpose of this study is to evaluate the potential of \[18F\]-ML-10 to serve as a non-invasive imaging tool for the early detection of apoptosis in brain metastases in response to radiation therapy. Such early detection may improve clinical management of patients with brain metastases, as it may help early identification of non-responders, and subsequently potentially lead to optimization of radiation dose, early decision on focal irradiation of selected, non-responsive lesions, or early referral of the patient to surgery. The experimental design of the present study aims to evaluate the potential of non-invasive PET examination with \[18F\]-ML-10, to provide the clinician early in the course of treatment, via non-invasive molecular imaging of radiation-induced apoptosis, information on tumor responsiveness, that is currently available only several weeks to months after completion of the radiotherapy.

Early assessment of the efficacy of anti-cancer therapy is highly desirable and an unmet need in clinical oncology. Currently, treatment efficacy is mostly measured by following tumor size by anatomical imaging (CT scan or MRI). However, changes in tumor size may be observed only after several weeks to several months after completion of treatment. Meanwhile, in cases where there is no response, the patient is unnecessarily exposed to treatment's side effects, and precious time may be lost before the initiation of an alternative, potentially more beneficial line of therapy. Therefore, there is an urgent and serious need for better tools for monitoring of tumor response to anti-cancer treatments. To address this need, \[18F\]-ML-10, a novel small molecular-weight probe (MW 205) was developed for clinical detection of apoptosis in vivo by positron emission tomography (PET). \[18F\]-ML-10 is a member of the ApoSense family of compounds, a novel class of molecular probes for molecular imaging of cell death. The first clinical indication for which \[18F\]-ML-10 is being developed is imaging of apoptosis in clinical oncology to monitor tumor response to radiation therapy. Previous preclinical and clinical studies have substantiated the safety of \[18F\]-ML-10, its very high stability in vivo, its favorable biodistribution profile, and its efficacy in clinical detection of cell death. In preclinical studies, the selective retention of \[18F\]-ML-10 in the focus of the neurovascular cell death in cerebral ischemia was demonstrated in respective animal models. 18F-ML-10 has been examined in two clinical trials in Uppsala Imanet, Sweden, and has been found safe in administration to healthy subjects and to elderly subjects with acute ischemic cerebral stroke. In these clinical trials, \[18F\]-ML-10 was also found efficacious in the clinical imaging of apoptosis, being either physiological apoptosis as observed in the testes in young healthy males, and pathological cell death, as observed in the brains of patients with acute ischemic cerebral stroke.