Phase 1/2 Open Single-arm Monocentric Study Evaluating the Tolerance and Interest of Transient Opening of the Blood-Brain Barrier by Low Intensity Pulsed Ultrasound With the SONOCLOUD® Implantable Medical Device in Mild Alzheimer's Disease Patients (MMSE 20-26)

Detailed Summary

In Alzheimer's disease (AD) an imbalance between the production and clearance of the ß-amyloid peptide is hypothesized as the driving event of the disease. The decreased clearance of Aß could be partly linked to a progressive dysfunction of the brain vasculature and of the blood brain barrier (BBB). Among many possible explanations for these failures of the multiple clinical trials evaluating innovative drugs in AD, one is the lack of target engagement, as none of these drugs is able to readily cross BBB. This barrier acts as a wall that actively and passively prevents the crossing of molecules between the blood and the brain parenchyma compartments. Only 0.3% of intravenously injected anti-Aß immunoglobulins reach the brain despite a half-life of 15-20 days. Low intensity Focal ultrasound associated to microbubble injection can open the BBB in a non invasive way. These openings are reversible in 2 hours to 2 days depending on the intensity of the ultrasound. Ultrasound opening of the BBB was initially used in a transgenic mouse model of AD to increase the brain delivery of an anti-Aß antibody. In this article, the Aß load was reduced in ultrasound treated brain region. Surprisingly it was then demonstrated that the simple opening of the BBB without any adjunct anti-Aß treatment was able to drive the same Aß clearance effects. This is probably linked to endogenous antibodies that are able to penetrate the brain parenchyma and target Aß plaques. Four opening sessions elicited positive promnesic effects in these mice. Our group conceived and developed a mean to easily, reproductively and innocuously open the BBB. A unique extra-dural ultrasound emitter (sonoCloud®) is surgically implanted in the skull under local anesthesia. It emits low intensity contact ultrasound (LICU) that are not deterred by bone and thus are able to open the BBB.Preclinical studies show the SonoCloud® device is safe and efficient as it allowed reproducible and repeatable opening of the BBB in rabbits, dogs and non human primates. Drugs up to 2000 Kilo Daltons (kDa) are able to cross the BBB to reach the brain parenchyma in which the concentration of Carboplatin was increased by 700% in the BBB opened region. No adverse event was evidenced both clinically, by EEG, Evoked potential, MRI, 18 Fluorodeoxyglucose (FDG) PET and histology in the primates after 7 bi-monthly sessions of LICU BBB opening. SonoCloud® and its external generator have been certified by the academic start-up CarThéra (APHP, UPMC). Our multidisciplinary skills (neurology, neurosurgery, neuroimaging, basic science departments in the same University hospital setting) and our previous experience of BBB opening in Man give us the unique opportunity to translate this procedure from neuro-oncology to AD which could 1) Have a positive effect on brain lesion load and symptoms by itself and 2) allow anti-AD (or more broadly, central nervous system) drugs to engage their targe

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