Nitrous Oxide For Endoscopic Ablation of Refractory Barrett's Esophagus (NO FEAR-BE) (NO FEAR-BE)


About this study

The purpose of this multicenter, prospective, single arm, non-randomized clinical trial to evaluate the safety and efficacy of the C2 CryoBalloon Focal Ablation System (CbFAS) for the treatment of persistent dysplasia or intestinal metaplasia (IM) in the tubular esophagus after 3 or more radiofrequency ablations (RFA) for dysplastic BE, or <50% eradication of Barrett's Esophagus (BE) after 2 RFA treatments.

Participation eligibility

Participant eligibility includes age, gender, type and stage of disease, and previous treatments or health concerns. Guidelines differ from study to study, and identify who can or cannot participate. There is no guarantee that every individual who qualifies and wants to participate in a trial will be enrolled. Contact the study team to discuss study eligibility and potential participation.

Inclusion Criteria:

  • History of BE with LGD or HGD confirmed with biopsy, or resected intramucosal cancer (IMC) with low risk of recurrence defined as EMR/ESD pathology results negative for: positive margin, >T1a stage, poorly differentiated carcinoma, and lymphovascular invasion.
  • Prior treatment with RFA who meet either of the following criteria at the enrolling EGD:
  • History of at least 3 RFA treatments, with one of the following:
    • Residual BE Prague C1 - C3; and/or 
    • Residual BE >M1 - M8; and/or 
    • One or more islands of residual BE >1 cm in diameter;
    • Any residual dysplasia in tubular esophagus.
  • History of at least 2 RFA treatments and < 50% eradication of BE, as judged by estimation of the treating physician.
  • 18 or older years of age at time of consent.
  • Provides written informed consent. 
  • Willing to undergo an alternative approved standard of care treatment for their condition. 
  • Willing and able to comply with study requirements for follow-up. 
  • No prior history of balloon or spray cryotherapy esophageal treatment. Prior APC is allowable.

Exclusion Criteria:

  • Dysplasia or IM confined only to the gastric cardia (BE Prague C0M0).
  • Pre-existing esophageal stenosis/stricture preventing advancement of a therapeutic endoscope during screening/baseline EGD. Subjects are eligible if the stenosis/stricture is dilated to at least 15mm, but baseline treatment may need to be delayed per protocol.
  • Symptomatic, untreated esophageal strictures.
  • Any endoscopically-visualized abnormalities such as ulcers, masses or nodules during screening/baseline EGD. Subjects with nodular dysplasia or ImCAIMC identified during screening/baseline EGD may be treated with EMR or ESD and return for baseline treatment in this study at least 6 weeks later given that:
    • Follow-up endoscopy must be negative for nodular dysplasia (visually clear of nodular dysplasia).
    • Patients with ImCAIMC must be at low risk for recurrence, confirmed by EMR/ESD pathology results negative for: positive margin, >T1a stage, poorly differentiated carcinoma, and lymphovascular invasion.
  • EMR or ESD < 6 weeks prior to baseline treatment.
  • Untreated invasive esophageal malignancy, including margin-positive EMR/ESD.
  • Active reflux esophagitis grade B or higher assessed during screening/baseline EGD.
  • Severe medical comorbidities precluding endoscopy, or limiting life expectancy to less than 2 years in the judgment of the endoscopist.
  • Uncontrolled coagulopathy.
  • Inability to hold use of anti-coagulation medications or non-aspirin anti-platelet agents (APAs) for the duration recommended per ASGE guidelines for a high risk endoscopy procedure.
  • Active fungal esophagitis.
  • Known portal hypertension, visible esophageal varices, or history of esophageal varices. 
  • General poor health, multiple co-morbidities placing the patient at risk, or otherwise unsuitable for trial participation.
  • Pregnant or planning to become pregnant during period of study participation. 
  • Patient refuses or is unable to provide written informed consent. 
  • Prior esophageal surgery with the exception of uncomplicated nissen fundoplication.



Participating Mayo Clinic locations

Study statuses change often. Please contact the study team for the most up-to-date information regarding possible participation.

Mayo Clinic Location Status Contact

Rochester, Minn.

Mayo Clinic principal investigator

Prasad Iyer, M.D.

Closed for enrollment

Contact information:

Michele Johnson P.T.A., CCRP


More information


Publications are currently not available

Study Results Summary

Not yet available

Supplemental Study Information

Not yet available


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