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 proposed indication for which
[18F]-ML-10 is being developed is for early assessment of response of solid tumors to
radiation and chemoradiation 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.
Additional Phase 2 study demonstrated the suitability and safety of 18F-ML-10, designed
to serve as a PET radiotracer for early detection of cellular apoptosis of brain
metastases in response to WBRT. The relationship between the early change in 18F-ML-10
uptake by the tumor, observed during or upon completion of treatment, and subsequent
tumor shrinkage as observed by MRI eight weeks after the completion of WBRT, was
demonstrated.18F-ML-10 demonstrated a good safety profile with no drug-related AEs or any
effect on safety parameters.