Inclusion Criteria:

1. Male or female, 18 years or older
2. Documented Barrett's esophagus with high-grade dysplasia with diagnosis confirmed by the Pathology Department at the University of Chicago
3. Laboratory parameters within the range given in the protocol.

Exclusion criteria.

1. Patients with high-grade dysplasia of the esophagus who on ultrasound of the esophagus have invasion through the muscularis mucosa
2. Patients who do not tolerate repeated endoscopy
3. Patients who are allergic to 852A or any component in its vehicle
4. Patients with autoimmune disease such as rheumatoid arthritis, ulcerative colitis or Crohn’s disease which could be worsened by stimulating the innate immune system
5. Pregnant patients, and vulnerable patients who cannot or will not use contraceptives
6. Males who have a sexual partner who is pregnant or a vulnerable partner who cannot or will not use contraceptives.
7. Cardiac ischemia, cardiac arrhythmias or congestive heart failure uncontrolled by medication
8. History of, or clinical evidence of, a condition which, in the opinion of the investigator, could confound the results of the study or put the subject at undue risk
9. Uncontrolled intercurrent or chronic illness
10. Active hepatitis B or C with evidence of ongoing viral replication
11. Hyperthyroidism
12. Uncontrolled seizure disorder
13. Active coagulation disorder not controlled with medication
14. HIV positive
15. Congenital long QT syndrome or abnormal baseline QTc interval after Bazett’s correction
16. Laboratory values outside of the acceptable range as given in protocol.