Efficacy of EsoGuard Assay on Esophageal Surface Cells Collected With EsoCheck vs EGD for the Diagnosis of BE or EAC

This is a two phase multicenter study to assess the operating characteristics of the

EsoGuard diagnostic assay panel performed on esophageal mucosal cells collected using the

EsoCheck cell collection device in known "Cases" of disease (i.e., patients with a

history of Barrett's Esophagus (BE) with and without varying degrees of dysplasia or

intramucosal adenocarcinoma [IMC]) and in patients with no known history of these

conditions. The latter are presumed to be "Controls", though this final determination is

made as part of study conduct, not at the time of enrollment.

The study is divided into a Run-In phase and an Efficacy phase. The assignment of a

patient to one or the other of these two phases will be made based on two pieces of

information: 1) the Final Study Diagnosis (as defined below) and 2) the current tally

versus the pre-determined target number of patients already assigned to each of the

subgroups (e.g., non-dysplastic Barrett's Esophagus (NDBE), high grade dysplasia {HGD])

for each phase. Patients will first be enrolled into the Run-In phase subgroups. Only

once the targeted enrollment for a given Run-In phase subgroup has been reached,

subsequent patients with a particular diagnosis will be assigned to the appropriate

Efficacy Phase subgroup, until the targeted total number is reached. Run In phase data

will be maintained in a separate database from Efficacy phase data. Study conduct is

identical in both phases; however, data from each phase will be segregated and analysis

of each phase will be used solely for its predetermined purpose without any co-mingling

of data. Once assigned, no patient, or their data, will be re-assigned or moved from

being a Run-In phase patient to being an Efficacy phase patient, or from the Run-In phase

database to the Efficacy phase database, or vice versa.

The Run-In phase will enroll the initial 60 short segment NDBE (also known as short

segment Barrett's Esophagus [SSBE]) and 25 long segment NDBE (also known as long segment

Barrett's Esophagus [LSBE]) Cases, the initial 10 low grade dysplasia [LGD] Cases, the

initial 3 high grade dysplasia [HGD] Cases, and the initial 2 intramucosal adenocarcinoma

[IMC] Cases, as well as the initial 100 Controls. The Efficacy phase will enroll 54 Cases

each with a Final Study Diagnosis of NDBE, LGD, HGD, and IMC, and 54 Controls.

Run-In phase data will be used solely to derive the optimal numerical cutoffs by which to

score mVIM and mCCNA1 (which are two genes where the methylated DNA changes are located)

positivity or negativity. These cutoffs serve as the key inputs into an algorithm by

which an overall EsoGuard result of positive versus negative is determined. The setting

of these cutoffs will be done by Sponsor personnel with full access to all Run-In phase

data; the goal will be to optimize overall EsoGuard assay sensitivity and specificity for

its intended use as a screening test in the at-risk population. The assay, once validated

and locked, will be used to analyze patients' distal esophageal cells obtained in both

the Efficacy phase of this Case Control study as well as in a separate Screening study

(PR-1039/EG-CL-101) to be conducted in parallel. Only Run-In phase data will be used to

set cutoffs. The mVIM and mCCNA1 (i.e., genes with methylated DNA changes) cutoffs will

be set and then the EsoGuard assay re validated and "locked", all before any Efficacy

phase distal esophageal cells specimens collected from study patients will undergo

EsoGuard analysis.

Sponsor personnel will have open access to all Run-In phase data during the enrollment of

the Run-In phase in order to determine if the data from patients enrolled to date is

sufficient to inform adequately the setting of cutoffs. If Sponsor so determines, it may

elect to terminate enrollment in the Run-In phase early (i.e., prior to enrolling the 100

Cases and 100 Controls listed above). If early termination of the Run-In phase is

elected, all patients enrolled subsequent to the date Sponsor makes this election will be

entered into the Efficacy phase and such subsequent patients will count towards the

Efficacy phase enrollment objectives.

As well, should Sponsor complete the intended Run-In phase enrollment of 100 Cases and

100 Controls but determine, upon its assessment of the resulting data, that data from

additional Cases could improve the setting of cutoffs, Sponsor may decide to enroll up to

100 additional Run-In phase Cases. These 100 Cases may be in whatever distribution of

disease Sponsor elects (i.e., ranging from NDBE through to IMC). In order to augment the

Run-In phase patient counts, the Sponsor will set updated targets for enrollment of each

Run-In phase subgroup and will assign patients to each Run-In subgroup to be augmented,

based on patients' Final Study Diagnosis and on whether the updated subgroup target has

been met. When each updated subgroup enrollment target has once again been met,

subsequent patients with that subgroup diagnosis will be enrolled into the Efficacy

phase.