A Dose-Optimization Study for the Initial Treatment of Dysplastic Barrett's Esophagus With trūFreeze™ Spray Cryotherapy

This is an adaptive dose-escalation clinical trial using trūFreeze™ spray cryotherapy for
the treatment of dysplastic Barrett's Esophagus in a clinical setting.

Participants will be enrolled in cohorts of up to 15. Each cohort will receive a similarly
dosed spray cryotherapy treatment, based on outcomes from the previous cohort. Participants
will receive one treatment with spray cryotherapy per the protocol and will then be followed
clinically. During the next scheduled clinical endoscopy, participants will be assessed for
percent regression of disease following the spray cryotherapy treatment. A determination
will be made regarding effectiveness of each dose based on the number of subjects that
achieve the primary outcome criterion (>= 50 percent BE segment regression).

The first cohort of up to 15 participants will receive an upper endoscopy in which
systematic images of the esophagus will be taken for the research study and will then
receive a treatment with spray cryotherapy using the trūFreeze™ system. These participants
will have a clinical follow-up endoscopy scheduled approximately 2 months after the initial
spray cryotherapy procedure. During the follow-up endoscopy, physicians will be asked to
provide an estimate of the percent regression of disease as well as systematic images of the
esophagus. These images will be sent to a central panel of masked experts who will assess
percent regression of disease compared to images taken prior to the first ablation
procedure.

Interim reviews of potential dose effectiveness will occur when 7 and 11 participants have
completed the follow-up visit. If during an interim review at least 5 participants
experience a sub-therapeutic response, the dose will be considered sub-therapeutic as not
meeting the definition of "fully effective," the cohort will be closed to new enrollment,
and enrollment on a new cohort at the next higher dose will begin. If during an interim
review less than 5 participants experience a sub-therapeutic response, enrollment on that
cohort will continue.

If/when enrollment on a cohort reaches 15 participants a decision will be made regarding the
effectiveness of the dose. If a dose is found to be "ineffective" or "partially effective,"
then a new cohort of individuals will be enrolled at a prescribed higher starting dose. If a
dose is found to be "fully effective," then a confirmatory cohort will be enrolled at the
same dose to confirm results. Enrollment will continue until a "fully effective" therapeutic
dose of spray cryotherapy is identified and confirmed in two cohorts of 15 participants
each.

Inclusion Criteria:

- English speaking males or females aged 18 to 80 who are candidates for sedated
endoscopy with treatment of BE.

- At least 3 centimeters segment length of Barrett's Esophagus (BE) with or without
circumferential involvement (i.e. CxM3) and with high grade or low grade dysplasia
based on pathology results from 4 quadrant biopsies taken every 1-2 centimeter
throughout the BE. All readings of dysplasia will be confirmed by an expert
pathologist.

- Willing to undergo spray cryotherapy and judged by patient's physician as an
appropriate candidate for this therapy.

- Able to read, comprehend, and complete the informed consent form

Exclusion Criteria:

- Bleeding disorder or other contraindication of spray cryotherapy.

- History of partial or complete esophagectomy.

- Current or past diagnosis of invasive esophageal cancer (previous intramucosal cancer
is allowable, if removed by endoscopic mucosal resection with histologically
confirmed negative lateral and deep margins).

- Pregnant women

- Contraindication to endoscopic spray cryotherapy as outlined in the directions for
use for the device

- Previous endoscopic ablation treatment (such as radiofrequency ablation (RFA) or
photodynamic therapy (PDT)).

- Previous chest external beam radiation therapy.

- Previous wide-area endoscopic resection or submucosal dissection. Previous focal
mucosal resection is permitted (maximum 2 previous EMR's of 2cm or less removed
representing less than 25% of the circumference of the esophagus removed).