Investigation of plaque vulnerability: Identification of atherosclerotic plaque angiogenesis using Bevacizumab-800CW and optoacoustic imaging: a single center proof of concept study
(CAROTID-OPTOLIGHT)

This project consists of the realization followed by the clinical validation of
a procedure dedicated to detect vulnerable atherosclerotic plaques in
symptomatic carotid stenosis. If in the future it would be possible to detect a
symptomatic carotid atherosclerotic plaque non-invasively (i.e. those plaques
resulting in cerebrovascular accidents and/or transient ischemic accidents),
this would strongly improve risk assessment among this large cohort of
patients. At the moment, indications for intervention are primarily based on
degree of stenosis, and not on degree of vulnerability. Symptomatology is
considered, but clinicians are not capable of predicting the consequences of a
first event, while two thirds of all patients with a major stroke are not
preceded by previous minor symptoms. Previous trials (NASCET and ECST) showed a
significant absolute risk reduction for symptomatic patients with a stenotic
lesion of the internal carotid artery greater than 70% after the performance of
a carotid endarterectomy (CEA; excision of the atherosclerotic plaque).
However, surgery can be associated with significant morbidity and even
mortality. On the other hand, reliable prediction prior to surgery whether an
atherosclerotic plaque is going to become symptomatic could also prevent
unnecessary surgery, which again significantly reduces morbidity and mortality.
In literature and our preliminary ex vivo data with a nuclear imaging tracer
89Zr-Bevacizumab, it appears that vulnerable atherosclerotic plaques (i.e.
those likely to become symptomatic) have an increased rate of angiogenesis at
the site of the rupture (i.e. the site of the vulnerable plaque) which expose
highly upregulated Vascular Endothelial Growth Factor-A (VEGF-A) production as
part of the inflammatory response within the plaque and subsequently which can
be visualized with a tracer targeting specifically VEGF-A.
An intraoperative near-infrared fluorescence (NIRF) imaging camera, among a NIR
fluorescence endoscopy system, and the use of the optical contrast agent
Bevacizumab-800CW in now more than 250 patients has been evaluated for its
feasibility to detect tumor lesions in patients with colorectal cancer, colon
polyps, Barret*s esophagus, peritoneal carcinomatosis of colorectal cancer
origin and breast cancer. These studies showed that bevacizumab-800CW is safe
in clinical use and feasible to detect even small tumor lesions with a high
sensitivity. While Bevacizumab-800CW can also detect the soluble ligand VEGF-A,
as shown by ex vivo analyses of excised CEA specimen, we aim to investigate
whether systemic administered Bevacizumab-800CW can be applied to patients
preoperative for the detection of vulnerable plaques by non-invasive
optoacoustic imaging and subsequently ex vivo mesoscopic imaging for validation
purposes. The primary objective for the proposed study is to achieve
pre-operative detection of the atherosclerotic plaque for patients with a
symptomatic carotid artery stenosis by non-invasive optoacoustic imaging. In
this study we will introduce the following concept: a preoperative non-invasive
optoacoustic-scan guided by the Bevacizumab-800CW targeted VEGF-A. This will
help us to detect if and at what time point within the atherosclerotic plaque
there is an upregulation of angiogenesis which can cross-correlated by ex vivo
analyses of characteristics of the vulnerable plaque (i.e. atheroma, foam
cells, influx of activated macrophages and angiogenesis as a result of
pro-inflammatory responses present in the plaque). The end-goal of the proposed
dual pre- and intra-operative imaging procedure is to prove that the
symptomatic carotid atherosclerotic plaque can be accurately and safely
detected by VEGF-A targeted optical imaging agents. In addition, this study
serves as a step-up to a larger non-invasive VEGF-A targeted optical imaging
study expanding the detection technology by using a new non-invasive
multispectral optoacoustic detection system. Ultimately, VEGF-A targeted
imaging in carotid stenosis could be used to predict vulnerability of the
atherosclerotic plaque non-invasively in order to select those patients who
will benefit the most of a surgical procedure.

* To investigate whether it*s feasible to detect within the carotid artery the
carotid plaques using optoacoustic imaging with the innovative MSOT Acuity Echo
in patients with symptomatic carotid stenosis.
* To investigate whether the VEGF-targeted optical imaging agent
Bevacizumab-800CW is able to detect VEGF upregulation as a characteristic of
the vulnerable plaque in carotid tissue by means of pre-operative
Bevacizumab-800CW optoacoustic imaging in patients with symptomatic carotid
stenosis cross-correlated by ex vivo microscopic analysis.v

Study design: Interventional phase 1 technical feasibility study:
non-randomized, open label, uncontrolled with single group proof of concept
study. This study will be carried out at the University Medical Center
Groningen, Department of Surgery and Department of Nuclear Medicine and
Molecular Imaging. Further analysis of sections of the plaques will be done at
the Department of Pathology at the UMCG and by the Helmholtz Institute,
Biomedical Research Centre, München.

Burden - Time-investment: for most surgeries, patients are usually submitted
one day prior to planned surgery. Patients will have to visit the UMCG one
extra time for the tracer injection and the imaging procedure three days
preoperative.
The burden associated with participation consists of: an intravenous injection
of Bevacizumab-800CW 3 days before the surgical procedure. Additionally, the
optoacoustic imaging procedure will take around 20-30 minutes.
Burden * Extra procedures: Patients will undergo intravenous injection of
Bevacizumab and have to undergo one extra imaging procedure preoperative. The
estimated time for imaging preoperative is 20-30 minutes.
Risks: The possible most likely adverse event for injection of
Bevacizumab-800CW is a short elevation of blood pressure or an allergic and/ or
anaphylactic reaction, as described in the IMPD. Most adverse events are
transient and mild (nausea, vomiting, flushing, chest discomfort).
Risk * Medical Device: The optoacoustic imaging device uses a class IV laser
and therefore is a risk for cornea and skin. Several measurements described
below, are taken to reduce the risk of injuries to an absolute minimum.
Benefit: Patients will have no direct benefit from this study.