Monitoring and modulating the trajectory of eosinophilic esophagitis.

Current treatments of eosinophilic esophagitis (EoE) aim to eliminate esophageal mucosal inflammation and attenuate, stabilize, or reverse stricture formation. However, our ability to study the long-term course of esophageal strictures in patients with EoE is hampered by the short-term existence of this disease. It is unclear to what degree of control of inflammation is needed to prevent stricture formation. Additionally, identified phenotypes of EoE may ultimately dictate different levels of concern and time intervals for developing fibrosis. Currently, multiple methods are used to monitor patients' disease progression to fibrosis, as symptoms alone do not correlate with disease activity. Endoscopic findings and mucosal histology are used to monitor disease activity, but these focus on improvements in inflammation with inconsistent evaluation of underlying fibrosis. The use of functional lumen impedance planimetry, barium esophagraphy, and endoscopic ultrasound continues to expand in EoE. The rapid advancements in EoE have led to an armamentarium of measuring tools and therapies that holistically characterize disease severity and response to therapy. Nevertheless, our ability to evaluate gross esophageal fibrosis and stricture formation from a transmural rather than mucosal view should be a focus of future investigations because it is essential to monitoring and modulating the trajectory of EoE.

Questionnaire for diagnosis and response to therapy in rumination syndrome.

Rumination is a behavioral disorder characterized by regurgitation of food without retching. It is diagnosed clinically by the Rome Criteria and treated primarily by diaphragmatic breathing. Despite diagnosis and follow-up being based on symptomatic responses to therapies, there are no published or validated questionnaires. To address this care-gap, a rumination questionnaire was developed and reviewed by two expert esophagologists and five patients diagnosed with rumination. Ultimately, an eight-point questionnaire with scoring ranging from -1 to 10 was finalized. This newly developed questionnaire was implemented on five additional patients diagnosed clinically with rumination syndrome with improvement after interventions noted.

Quality Indicator Development for the Approach to Ineffective Esophageal Motility: A Modified Delphi Study.

GOALS: Develop quality indicators for ineffective esophageal motility (IEM). BACKGROUND: IEM is identified in up to 20% of patients undergoing esophageal high-resolution manometry (HRM) based on the Chicago Classification. The clinical significance of this pattern is not established and management remains challenging. STUDY: Using RAND/University of California, Los Angeles Appropriateness Methods, we employed a modified-Delphi approach for quality indicator statement development. Quality indicators were proposed based on prior literature. Experts independently and blindly scored proposed quality statements on importance, scientific acceptability, usability, and feasibility in a 3-round iterative process. RESULTS: All 10 of the invited esophageal experts in the management of esophageal diseases invited to participate rated 12 proposed quality indicator statements. In round 1, 7 quality indicators were rated with mixed agreement, on the majority of categories. Statements were modified based on panel suggestion, modified further following round 2's virtual discussion, and in round 3 voting identified 2 quality indicators with comprehensive agreement, 4 with partial agreement, and 1 without any agreement. The panel agreed on the concept of determining if IEM is clinically relevant to the patient's presentation and managing gastroesophageal reflux disease rather than the IEM pattern; they disagreed in all 4 domains on the use of promotility agents in IEM; and had mixed agreement on the value of a finding of IEM during anti-reflux surgical planning. CONCLUSION: Using a robust methodology, 2 IEM quality indicators were identified. These quality indicators can track performance when physicians identify this manometric pattern on HRM. This study further highlights the challenges met with IEM and the need for additional research to better understand the clinical importance of this manometric pattern.

A Delphi Method for Development of a Barrett's Esophagus Question Prompt List as a Communication Tool for Optimal Patient-physician Communication.

BACKGROUND METHODS: The question prompt list content was derived through a modified Delphi process consisting of 3 rounds. In round 1, experts provided 5 answers to the prompts "What general questions should patients ask when given a new diagnosis of Barrett's esophagus" and "What questions do I not hear patients asking, but given my expertise, I believe they should be asking?" Questions were reviewed and categorized into themes. In round 2, experts rated questions on a 5-point Likert scale. In round 3, experts rerated questions modified or reduced after the previous rounds. Only questions rated as "essential" or "important" were included in Barrett's esophagus question prompt list (BE-QPL). To improve usability, questions were reduced to minimize redundancy and simplified to use language at an eighth-grade level (Fig. 1). RESULTS: Twenty-one esophageal medical and surgical experts participated in both rounds (91% males; median age 52 years). The expert panel comprised of 33% esophagologists, 24% foregut surgeons, and 24% advanced endoscopists, with a median of 15 years in clinical practice. Most (81%), worked in an academic tertiary referral hospital. In this 3-round Delphi technique, 220 questions were proposed in round 1, 122 (55.5%) were accepted into the BE-QPL and reduced down to 76 questions (round 2), and 67 questions (round 3). These 67 questions reached a Flesch Reading Ease of 68.8, interpreted as easily understood by 13 to 15 years olds. CONCLUSIONS: With multidisciplinary input, we have developed a physician-derived BE-QPL to optimize patient-physician communication. Future directions will seek patient feedback to distill the questions further to a smaller number and then assess their usability.

Roles of swallowing and belching in different phenotypes of gastroesophageal reflux disease.

BACKGROUND: The contributions of swallowing and belching to specific gastroesophageal reflux disease (GERD) phenotypes are unclear. METHODS: This study retrospectively analyzed esophageal pH/impedance studies, comparing reflux events preceded by gastric belching (GB), supragastric belching (SGB), air swallowing, and liquid/solid swallowing based on reflux position, lower esophageal sphincter (LES) pressure, and acid exposure time (AET). KEY RESULTS: 20 GERD patients and 10 controls were studied. Upright GERD patients and controls had a higher proportion of reflux events with a preceding swallow or belch (0.64, 0.64) than the supine group (0.38, p = 0.043). The upright group and controls trended toward a higher proportion of reflux events preceded by overall swallowing (0.61, 0.50) and air swallowing (0.55, 0.48) than the supine group (0.32, 0.31 p = 0.064, p = 0.11), but the three groups had similar rates of liquid/solid swallowing (0.032, 0.024, 0.017, p = 0.69). LES pressure did not correlate with reflux events preceded by swallowing (R2 = 0.021, p = 0.44). There was a higher rate of events preceded by gastric belching in the control group (0.14) than in the upright (0.032) and supine groups (0.066, p = 0.049). LES pressure did not correlate with the rate of events preceded by belching (R2 = 0.000093, p = 0.96). Normal AET patients had a higher rate of events preceded by GB (0.12) than those with increased acid exposure (0.030, p = 0.0083), but the two groups had similar rates of preceding air (0.43, 0.47, p = 0.68), liquid/solid (0.018, 0.032, p = 0.30), and overall swallowing (0.44, 0.53, p = 0.38). CONCLUSIONS AND INFERENCES: Swallowing more than belching is a dominant mechanism for reflux irrespective of GERD position, LES pressure, and AET.

Barrier Dysfunction in Eosinophilic Esophagitis.

PURPOSE OF REVIEW: Compelling evidence over the past decade supports the central role of epithelial barrier dysfunction in the pathophysiology of eosinophilic esophagitis (EoE). The purpose of this review is to summarize the genetic, environmental, and immunologic factors driving epithelial barrier dysfunction, and how this impaired barrier can further promote the inflammatory response in EoE. RECENT FINDINGS: Common environmental exposures, such as detergents, may have a direct impact on the esophageal epithelial barrier. In addition, the effects of IL-13 on barrier dysfunction may be reduced by 17ß-estradiol, Vitamin D, and the short chain fatty acids butyrate and propionate, suggesting novel therapeutic targets. There are many genetic, environmental, and immunologic factors that contribute to epithelial barrier dysfunction in EoE. This leads to further skewing of the immune response to a "Th2" phenotype, alterations in the esophageal microbiome, and penetration of relevant antigens into the esophageal mucosa, which are central to the pathophysiology of EoE.

H influenzae LPS colocalization with Toll-like receptor 4 in eosinophilic esophagitis.

Background: Patients with eosinophilic esophagitis (EoE) have a unique esophageal microbiome with increased presence of Haemophilus influenzae, but its role in the disease is unclear. Objective: Microbiome-derived bacterial LPS activation of Toll-like receptors (TLR) is a potential mechanism for inducing inflammation in other chronic inflammatory diseases, but it has not been studied in EoE. Our aim was therefore to study microbiome-derived bacterial LPS activation of TLRs in EoE. Methods: We studied 10 patients with active EoE, 9 patients with inactive EoE, and 10 control patients. Esophageal biopsy samples from the controls, patients with active EoE (>15 eosinophils/hpf), and patients with inactive EoE were immunostained for the presence of H influenzae LPS, presence of TLR4, and colocalization of LPS and TLR4. Staining intensity was measured by using confocal laser microscopy and scored on a scale from 0 to 3 as the average score assigned by 2 blinded observers. Results: H influenzae LPS was detected by positive staining in 20 of the 29 patients (69.0%), including 9 of the 10 patients with active EoE (90.0%), 8 of the 9 patients with inactive EoE (89.9%), and 3 of the 10 controls (30%); its level was greater in the patients with active EoE than in the controls (P = .063). TLR4 was detected by positive staining in 19 of the 29 patients (65.5%), including 9 of the 10 patients with active EoE (90.0%), 4 of the 9 patients with inactive EoE (44.4%), and 6 of the 10 controls (60.0%); its level was higher in the patients with active EoE than in those with inactive EoE (P = .096). The result of testing for colocalization of LPS and TLR4 was positive in 8 of 10 patients with active EoE (80.0%), 1 of 9 patients with inactive EoE (11.1%), and 1 of 10 control patients (10.0%), with greater colocalization of H influenzae LPS and TLR4 staining density in the samples from patients with active EoE than in the controls or the patients with inactive EoE (P = .009 and P = .018, respectively). Conclusion: Esophageal microbiome-rich H influenzae LPS colocalizes to TLR4 in active EoE. These data lend further support to a role for the esophageal microbiome in modulating the activity of EoE.

Development of a model to identify patients who do not need oesophageal biopsies when eosinophilic oesophagitis is suspected.

BACKGROUND: Predictive models for eosinophilic oesophagitis (EoE) may not fully rule in the diagnosis. AIM: To develop a reverse model that predicts against EoE to eliminate the need for oesophageal biopsies. METHODS: In this two-centre study, a predictive model was developed (Mayo Clinic) and validated (University of North Carolina [UNC]). Cross-sectional data from consecutive adult patients without prior EoE who underwent upper enoscopy with oesophageal biopsies were used. EoE cases had ≥15 eosinophils/high-power field while controls had no eosinophils. Data were collected on patient clinical and endoscopic features. Multiple variable logistic regression was used to identify predictors of non-EoE status while maintaining specificity ≥95%. A secondary model was developed to predict against the need for endoscopy in patients suspected of having EoE without alarm symptoms. RESULTS: The Mayo and UNC cohorts consisted of 345 (EoE = 94, non-EoE = 251) and 297 patients (EoE = 84, non-EoE = 213), respectively. A primary model based on clinical and endoscopic features predicted against EoE with c-statistic 0.92 (95% CI: 0.88-0.96), specificity 95%, and sensitivity 65%. This model was validated (UNC) with c-statistic 0.87 (95% CI: 0.82-0.92). A simplified scoring system was created and a threshold of ≥12 points excluded EoE with 95% specificity and 50% sensitivity. A secondary model based on clinical characteristics alone predicted against EoE with c-statistic 0.86 (95% CI: 0.82-0.90), specificity 95% and sensitivity 39% and validated (UNC) with c-statistic 0.78 (95% CI: 0.71-0.85). CONCLUSION: A simplified scoring system accurately identified a group of patients with a low likelihood of EoE where unnecessary oesophageal biopsies can be avoided, potentially resulting in resource and cost savings.

Pooled Phase 2 and 3 Efficacy and Safety Data on Budesonide Oral Suspension in Adolescents with Eosinophilic Esophagitis.

OBJECTIVES: The objective of this study was to evaluate the efficacy and safety of budesonide oral suspension (BOS) in adolescents with eosinophilic esophagitis (EoE). METHODS: This post hoc analysis pooled data from two 12-week, randomized, double-blind, placebo-controlled studies of BOS 2.0 mg twice daily (b.i.d.) (phase 2, NCT01642212; phase 3, NCT02605837) in patients aged 11-17 years with EoE and dysphagia. Efficacy endpoints included histologic (≤6, ≤1, and <15 eosinophils per high-power field [eos/hpf]), dysphagia symptom (≥30% reduction in Dysphagia Symptom Questionnaire [DSQ] scores from baseline), and clinicopathologic (≤6 eos/hpf and ≥30% reduction in DSQ scores from baseline) responses at week 12. Change from baseline to week 12 in peak eosinophil counts, DSQ scores, EoE Histology Scoring System (EoEHSS) grade (severity) and stage (extent) total score ratios (TSRs), and total EoE Endoscopic Reference Scores (EREFS) were assessed. Safety outcomes were also examined. RESULTS: Overall, 76 adolescents were included (BOS, n = 45; placebo, n = 31). Significantly more patients who received BOS than placebo achieved histologic responses (≤6 eos/hpf: 46.7% vs 6.5%; ≤1 eos/hpf: 42.2% vs 0.0%; <15 eos/hpf: 53.3% vs 9.7%; P < 0.001) and a clinicopathologic response (31.1% vs 3.2%; P = 0.003) at week 12. More BOS-treated than placebo-treated patients achieved a dysphagia symptom response at week 12 (68.9% vs 58.1%; not statistically significant P = 0.314). BOS-treated patients had significantly greater reductions in EoEHSS grade and stage TSRs ( P < 0.001) and total EREFS ( P = 0.021) from baseline to week 12 than placebo-treated patients. BOS was well tolerated, with no clinically meaningful differences in adverse events versus placebo. CONCLUSIONS: BOS 2.0 mg b.i.d. significantly improved most efficacy outcomes in adolescents with EoE versus placebo.

A perspective on the clinical relevance of weak or nonacid reflux.

BACKGROUND: Advances in ambulatory esophageal reflux monitoring that incorporated impedance electrodes to pH catheters have resulted in better characterization of retrograde bolus flow in the esophagus. With pH-impedance monitoring, in addition to acid reflux episodes identified by pH drops below 4.0, weakly acid reflux (WAR, pH 4-7) and nonacid reflux (NAR, pH >7.0) are also recognized, although both may be included under the umbrella term NAR. However, despite identification of ambulatory pH-impedance monitoring, data on clinical relevance and prognostic value of NAR are limited. The Lyon Consensus, an international expert review that defines conclusive metrics for gastroesophageal reflux disease (GERD), identifies NAR as "supportive" but not conclusive for GERD. PURPOSE: This review provides perspectives on whether NAR fulfills three criteria for clinical relevance: whether NAR sufficiently explains pathogenesis of symptoms, whether it is associated with meaningful manifestations of GERD, and whether it can predict treatment efficacy.

Eosinophilic Esophagitis Histologic Scoring System: Correlation with Histologic, Endoscopic, and Symptomatic Disease and Clinical Use.

BACKGROUND: The eosinophilic esophagitis histologic scoring system (EoEHSS) was developed to enhance the diagnostic standard of peak eosinophil count (PEC) in evaluating disease activity in EoE. AIMS: (1) Correlate the EoEHSS and PEC to measures of symptomatic and endoscopic disease activity, (2) Correlate EoEHSS grade and stage subcomponents to clinical, radiology, and endoscopic markers of fibrotic disease, (3) Evaluate EoEHSS remission in asymptomatic patients with PEC < 15 eosinophils per high powered field (eos/hpf). METHODS: Secondary analysis of prospective cohort data of 22 patients with EoE that underwent dietary therapy and endoscopy at 3 time points. Active disease was defined by EoEHSS grade or stage > 0.125, symptomatic disease by EoE symptom activity index > 20, endoscopic disease by endoscopic reference score > 2, and histologic disease by PEC ≥ 15 eos/hpf. EoEHSS remission was defined by esophageal inflammation (EI) grade of 0-1, EI stage of 0, total grade ≤ 3, and total stage ≤ 3. RESULTS: EoEHSS grade and stage did not correlate with symptomatic disease but did with endoscopic and histologic disease. PEC showed similar correlation pattern. Abnormal grade and stage had strong sensitivity (87-100%) but poor specificity (11-36%) to detect symptomatic, endoscopic, and histologic disease activity. Lamina propria fibrosis was evaluated in 36% of biopsies and did not correlate with minimum esophageal diameter. Out of 14 patients who were in complete symptomatic, endoscopic, and histologic remission, 8 met criteria for EoEHSS remission. CONCLUSION: The positive and negative correlations of EoEHSS to specific measures of symptomatic, histologic, and endoscopic activity suggest that it provides complementary information in EoE.

Esophageal Lichen Planus: A Descriptive Multicenter Report.

GOALS: To better understand the characteristics, treatment approaches, and outcomes of patients with esophageal lichen planus (ELP). BACKGROUND: ELP is a rare, often unrecognized and misdiagnosed disorder. Data on this unique patient population are currently limited to small, single-center series. STUDY: A multicenter, retrospective descriptive study was conducted of adults diagnosed with ELP over a 5-year period, between January 1, 2015, and October 10, 2020, from 7 centers across the United States. RESULTS: Seventy-eight patients (average age 65 y, 86% female, 90% Caucasian) were included. Over half had at least 1 extraesophageal manifestation. Esophageal strictures (54%) and abnormal mucosa (50%) were frequent endoscopic findings, with the proximal esophagus the most common site of stricture. Approximately 20% had normal endoscopic findings. Topical steroids (64%) and/or proton pump inhibitors (74%) dominated management; endoscopic response favored steroids (43% vs. 29% respectively). Almost half of the patients required switching treatment modalities during the study period. Adjunctive therapies varied significantly between centers. CONCLUSIONS: Given its at times subtle clinical and endoscopic signs, a high index of suspicion and biopsy will improve ELP diagnosis, especially in those with extraesophageal manifestations. Effective therapies are lacking and vary significantly. Prospective investigations into optimal treatment regimens are necessary.

Development and modification of a dysphagia question prompt list to improve patient-physician communication: Incorporating both esophageal expert and patient perspectives.

BACKGROUND: Question prompt lists (QPLs) are structured sets of disease-specific questions, intended to encourage question-asking by patients and enhance patient-physician communication. To date, a dysphagia-specific QPL has not been developed for patients with esophageal dysphagia symptoms. We aim to develop a dysphagia-specific QPL incorporating both esophageal expert and patient perspectives, applying rigorous methodology. METHODS: The QPL content was generated applying a two-round modified Delphi (RAND/UCLA) method among 11 experts. In round one, experts provided five answers to the prompts: "What general questions should patients ask when being seen for dysphagia?" and "What questions do I not hear patients asking but, given my experience, I believe they should be asking?" In round two, experts rated proposed questions on a 5-point Likert scale. Responses rated as "essential" or "important", determined by an a priori median threshold of ≥4.0, were accepted for inclusion. Subsequently, 20 patients from Stanford Health Care were enrolled to modify the preliminary QPL, to incorporate their perspectives and opinions. Patients independently rated questions applying the same 5-point Likert scale. At the end, patients were encouraged to propose additional questions to incorporate into the QPL by open-endedly asking "Are there questions we didn't ask, that you think we should?" KEY RESULTS: Eleven experts participated in both voting rounds. Of 85 questions generated from round one, 60 (70.6%) were accepted for inclusion, meeting a median value of ≥4.0. Questions were combined to reduce redundancy, narrowing down to 44 questions. Questions were categorized into the following six themes: 1. "What is causing my dysphagia?"; 2. "Associated symptoms"; 3. "Testing for dysphagia"; 4. "Lifestyle modifications"; 5. "Treatment for dysphagia"; and 6. "Prognosis". The largest number of questions covered "What is causing my dysphagia" (27.3%). Twenty patients participated and modified the QPL. Of the 44 questions experts agreed were important, only 30 questions (68.2%) were accepted for inclusion. Six patients proposed 10 additional questions and after incorporating the suggested questions, the final dysphagia-specific QPL created by esophageal experts and modified by patients consisted of 40 questions. CONCLUSIONS & INFERENCES: Incorporating expert and patient perspectives, we developed a dysphagia-specific QPL to enhance patient-physician communication. Our study highlights importance of incorporating patient perspective when developing such a communication tool. Further studies will measure the impact of this communication tool on patient engagement.

Development of a Practical Guide to Implement and Monitor Diet Therapy for Eosinophilic Esophagitis.

Dietary therapy for short- and long-term management of eosinophilic esophagitis is an effective yet poorly understood and underutilized treatment strategy. Despite several prospective trials demonstrating the efficacy of dietary therapies, successful clinical implementation is hampered by the need for a multidisciplinary approach including dietitian support and provider expertise. The availability of these resources is not readily available to most gastroenterologists. Without standardized guidance on starting or completing the diet for gastrointestinal providers and/or consulting dietitians, provider attitudes toward dietary therapy vary greatly depending on familiarity and knowledge gaps in using diet therapy. This review aims to summarize evidence in support of dietary therapy in eosinophilic esophagitis while providing guidance on initiation and implementation of dietary therapy for providers.

Safety of an investigational formulation of budesonide (budesonide oral suspension) for eosinophilic oesophagitis: an integrated safety analysis of six phase 1-3 clinical trials.

BACKGROUND: Questions remain regarding the safety of swallowed topical corticosteroids in eosinophilic oesophagitis (EoE). AIM: To assess the safety of an investigational formulation of budesonide (budesonide oral suspension; BOS) from six trials. METHODS: Safety data were integrated from six trials (healthy adults: SHP621-101 [phase 1]; patients with EoE: MPI 101-01 and MPI 101-06 [phase 2]; SHP621-301, SHP621-302 and SHP621-303 [phase 3]) for participants who received ≥1 dose of study drug (BOS 2.0 mg twice daily [b.i.d.], BOS any dose [including BOS 2.0 mg b.i.d.] and placebo). Adverse events (AEs), laboratory testing, bone density and adrenal AEs were assessed. Exposure-adjusted incidence rates were calculated for AEs and AEs of special interest (AESIs). RESULTS: Overall, 514 unique participants were included (BOS 2.0 mg b.i.d., n = 292; BOS any dose, n = 448; placebo, n = 168). The BOS 2.0 mg b.i.d., BOS any dose and placebo groups totalled 93.7, 122.4 and 25.0 participant-years of exposure (PY), respectively. Proportions of treatment-emergent AEs (TEAEs) and AESIs (any) reported were higher for BOS than placebo; however, most were mild/moderate in severity. The most commonly reported AESIs (exposure-adjusted incidence rates [per 100 PY]) in the BOS 2.0 mg b.i.d., BOS any dose and placebo groups were infections (133.5, 154.4 and 136.2, respectively) and gastrointestinal AEs (84.3, 80.9 and 92.1, respectively). Adrenal AEs were more frequent with BOS 2.0 mg b.i.d. and BOS any dose than placebo (44.8, 34.3 and 24.0, respectively). TEAEs and AESIs related to study drug or leading to discontinuation were infrequent. CONCLUSIONS: BOS was well-tolerated; most TEAEs with BOS were mild/moderate in severity. GOV NUMBERS: SHP621-101 (no clinical trials registration number), MPI 101-01 (NCT00762073), MPI 101-06 (NCT01642212), SHP621-301 (NCT02605837), SHP621-302 (NCT02736409) and SHP621-303 (NCT03245840).

One-food versus six-food elimination diet therapy for the treatment of eosinophilic oesophagitis: a multicentre, randomised, open-label trial.

BACKGROUND: Empirical elimination diets are effective for achieving histological remission in eosinophilic oesophagitis, but randomised trials comparing diet therapies are lacking. We aimed to compare a six-food elimination diet (6FED) with a one-food elimination diet (1FED) for the treatment of adults with eosinophilic oesophagitis. METHODS: We conducted a multicentre, randomised, open-label trial across ten sites of the Consortium of Eosinophilic Gastrointestinal Disease Researchers in the USA. Adults aged 18-60 years with active, symptomatic eosinophilic oesophagitis were centrally randomly allocated (1:1; block size of four) to 1FED (animal milk) or 6FED (animal milk, wheat, egg, soy, fish and shellfish, and peanut and tree nuts) for 6 weeks. Randomisation was stratified by age, enrolling site, and gender. The primary endpoint was the proportion of patients with histological remission (peak oesophageal count <15 eosinophils per high-power field [eos/hpf]). Key secondary endpoints were the proportions with complete histological remission (peak count ≤1 eos/hpf) and partial remission (peak counts ≤10 and ≤6 eos/hpf) and changes from baseline in peak eosinophil count and scores on the Eosinophilic Esophagitis Histology Scoring System (EoEHSS), Eosinophilic Esophagitis Endoscopic Reference Score (EREFS), Eosinophilic Esophagitis Activity Index (EEsAI), and quality of life (Adult Eosinophilic Esophagitis Quality-of-Life and Patient Reported Outcome Measurement Information System Global Health questionnaires). Individuals without histological response to 1FED could proceed to 6FED, and those without histological response to 6FED could proceed to swallowed topical fluticasone propionate 880 µg twice per day (with unrestricted diet), for 6 weeks. Histological remission after switching therapy was assessed as a secondary endpoint. Efficacy and safety analyses were done in the intention-to-treat (ITT) population. This trial is registered on ClinicalTrials.gov, NCT02778867, and is completed. FINDINGS: Between May 23, 2016, and March 6, 2019, 129 patients (70 [54%] men and 59 [46%] women; mean age 37·0 years [SD 10·3]) were enrolled, randomly assigned to 1FED (n=67) or 6FED (n=62), and included in the ITT population. At 6 weeks, 25 (40%) of 62 patients in the 6FED group had histological remission compared with 23 (34%) of 67 in the 1FED group (difference 6% [95% CI -11 to 23]; p=0·58). We found no significant difference between the groups at stricter thresholds for partial remission (≤10 eos/hpf, difference 7% [-9 to 24], p=0·46; ≤6 eos/hpf, 14% [-0 to 29], p=0·069); the proportion with complete remission was significantly higher in the 6FED group than in the 1FED group (difference 13% [2 to 25]; p=0·031). Peak eosinophil counts decreased in both groups (geometric mean ratio 0·72 [0·43 to 1·20]; p=0·21). For 6FED versus 1FED, mean changes from baseline in EoEHSS (-0·23 vs -0·15; difference -0·08 [-0·21 to 0·05]; p=0·23), EREFS (-1·0 vs -0·6; difference -0·4 [-1·1 to 0·3]; p=0·28), and EEsAI (-8·2 vs -3·0; difference -5·2 [-11·2 to 0·8]; p=0·091) were not significantly different. Changes in quality-of-life scores were small and similar between the groups. No adverse event was observed in more than 5% of patients in either diet group. For patients without histological response to 1FED who proceeded to 6FED, nine (43%) of 21 reached histological remission; for patients without histological response to 6FED who proceeded to fluticasone propionate, nine (82%) of 11 reached histological remission. INTERPRETATION: Histological remission rates and improvements in histological and endoscopic features were similar after 1FED and 6FED in adults with eosinophilic oesophagitis. 6FED had efficacy in just less than half of 1FED non-responders and steroids had efficacy in most 6FED non-responders. Our findings indicate that eliminating animal milk alone is an acceptable initial dietary therapy for eosinophilic oesophagitis. FUNDING: US National Institutes of Health.