A pilot intervention study for the use of VEGF-targeted Fluorescence Near-Infrared (NIR) Endoscopy in (pre)malignant Esophageal Lesions

Esophageal cancer is with approximately 500.000 new esophageal cancer cases
annually, the eight most commonly diagnosed type of cancer globally. Esophageal
cancer is associated with a high mortality, estimated at approximately 400.000
deaths annually, and therefore the fifth leading cause of cancer associated
deaths worldwide. Next to this, the incidence of esophageal adenocarcinoma
(EAC) has shown to rise dramatically over the past few decades.

To improve detection of esophageal (pre)malignant lesions during surveillance
endoscopy of patients at risk of developing malignancies, for example in
Barrett*s Esophagus (BE), there is a need for better endoscopic visualization
and the ability for targeted biopsies. Optical molecular imaging of neoplasia
associated biomarkers could form a promising technique to accommodate this
need. It is known that the biomarker Vascular Endothelial Growth Factor (VEGF)
is overexpressed in dysplastic and neoplastic areas in BE segments versus
normal tissue and has proven to be a valid target for molecular imaging. The
University Medical Center Groningen (UMCG) developed a fluorescent tracer by
labeling the VEGF-targeting humanized monoclonal antibody bevacizumab,
currently used in anti-cancer therapy, with the fluorescent dye IRDye800CW. We
hypothesize that when bevacizumab-IRDye800CW is administered, it accumulates in
VEGF expressing high grade dysplasia (HGD) and esophageal adenocarcinoma (EAC),
enabling early cancer visualization using a newly developed flexible
Near-Infrared (NIR) fluorescence endoscopic platform. We want to test this
hypothesis in this pilot intervention study.

The primary objective of this pilot intervention study is to determine the
sensitivity of the fluorescent tracer bevacizumab-IRDye800CW using a flexible
NIR fluorescence endoscope in identifying (pre)malignant esophageal lesions
during endoscopy.

The in vivo fluorescent signal of early carcinoma (HGD and superficial EAC),
measured with the NIR fluorescence endoscopic platform, will be analyzed. The
accumulation of bevacizumab-IRDye800CW and the VEGF expression levels will be
analyzed ex vivo in the resected mucosal specimen. To assess the primary
objective, these results will be compared.

This study should support future studies using bevacizumab-IRDye800CW and
flexible NIR fluorescence endoscopy for the purpose of improving surveillance
strategies in high risk populations of developing gastrointestinal dysplasia
and adenocarcinoma, such as patients with known BE.


Secundaire objectives:
- To collect safety data of Bevacizumab-IRDye800CW.
- To investigate the correlation between fluorescence intensity and the grade
of VEGF expression in (pre)malignant lesions of the esophagus.
- To evaluate if there is a correlation between in vivo fluorescence intensity
and grade of ex vivo VEGF expression .
- To evaluate the degree of in vivo fluorescence intensity and ex vivo grade of
VEGF expression for the different stages of esophageal dysplasia-carcinoma
sequence.

The current study is a non-randomized, non-blinded, prospective, single center
pilot intervention study to determine whether optical molecular imaging using
bevacizumab-IRDye800CW and the newly developed NIR fluorescence endoscope can
identify (pre)malignant esophageal lesions.

A selected group of patients, with prior diagnosed HGD or superficial EAC and
therefore candidate for endoscopic therapy using a endoscopic mucosal resection
(EMR) technique, will receive topical administration of the VEGF-targeting
fluorescent tracer bevacizumab-IRDye800CW.

Patients will undergo the endoscopic procedures clustered in one
endoscopy-session: topical tracer application with use of spray-catheter (under
white-light inspection) followed by NIR fluorescence endoscopy (fiber-bundle
and CLE probe; both inserted subsequently through working channel of
white-light endoscope). Afterwards the standard therapeutic endoscopic mucosal
resection (EMR) will be performed. Next to this, biopsies of normal squamous
epithelium and, if present, the BE segment will be taken for study purposes
only. These specimens will be analysed ex vivo, using immunohistochemistry and
RNA and DNA analysis.

Patients included in this study will undergo an endoscopic procedure including
the standard endosocpic treatment (EMR) as well as VEGF-targeted fluorescence
imaging. All patients will receive the same consecutive endoscopic procedures
performed by the same gastroenterologist.

The procedure will start by topically spraying the fluorscent tracer
(bevacizumab-800CW) onto the esophageal mucosa. After several minutes of
incubation, excessive product will be rinsed. NIR-imaging will take place, by
using a NIR fiber-bundle and CLE-probe which can be subsequently inserted
through the working channel of the WL-endoscope. Subsequently, during normal
WLE imaging, the EMR procedure will be carried out. Next tot this, a maximum of
sixteen biopsies will be taken.

According to standard EMR-protocol, patients will be hospitalized the evening
prior to the procedure. As described in the standard EMR-protocol, fasting will
start at midnight prior to the procedure . EMR specimens and biopsies will be
analyzed ex vivo, using specimen procedures consisting of formalin fixed
paraffin embedded and frozen sections.

Time investment:
The study consists of one visit: consecutive fluorescence and white-light
endoscopy (EMR). The time investment of the participating subjects is
considered low; the endoscopy procedure will be prolonged slightly (aprox. 30
min) compared to a standard EMR procedure. According to standard EMR-protocol,
patients will be hospitalized the evening subsequent to the procedure. Due to
this, and the fact that the patients are under propofol sedation they will not
notice the slight prolongation of the procedure. Depending on the procedure and
occurrence of possible complication, patients sometimes have to stay
hospitalized a subsequent night. As according to standard protocol, fasting
will start at midnight prior to the procedure.

Risks:
The additional risks of participating in this study are mainly related to the
administration of Bevacizumab-IRDye800CW. Animal toxicological studies on
bevacizumab-IRDye800CW and preclinical tracer evaluation data showed no adverse
effects. The tracer has been safely intravenously administered to patients in
several trials ((NL37479.042.11; NL43407.042.13; NL45148.042.13). Adverse
Events may be expected after administration, based on our experience with
administrating a higher dose of unlabeled bevacizumab for therapeutic purposes.
Hypersensitivity reactions, wound-healing problems and hypertension can occur
after therapeutic dosages of intravenous bevacizumab. However, the expected
adverse events are temporal without clinical consequences and the risk is
considered minimal due to the low tracer dose used and topical administration.

The proposed endoscopy procedure is in intent equal to the therapeutic
endoscopic procedure, as the NIR-fiber and CLE-probe will be inserted through
the working channel of the WL-endoscope. Next to this, during the WLE procedure
max. 16 biopsies will be taken for study purposes only. This has in general a
minimal risk of bleeding. Though, if these complications occur, which is very
uncommon, the gastroenterologist has several tools to handle these problems
adequately.

Benefit:
The investigational endoscopy procedure does not have direct benefits for the
participating patients. However, the investigational procedure won*t interfere
with standard clinical care, since the fluorescence imaging will be performed
in serial with the white-light therapeutic endoscopy. Given the limited extra
time investment, the honorable minimal risks and the medical need for improved
diagnostic capabilities it seems therefore justified to ask to participate in
this study. Moreover, it is expected that this research will provide useful
information when considering future patient care and diagnostic endoscopy.
Hopefully, the results of this feasibility study will contribute to the
improvement of esophageal cancer detection and surveillance.