A Study to Investigate Safety and Tolerability of NDX-3315 and NDX-3324 in Healthy Participants and Patients With Eosinophilic Esophagitis

An Open-label Phase 2 Study Assessing the Safety, Tolerability and Preliminary Diagnostic Performance of a Radioactive Imaging Agent, NDX-3315 and NDX-3324, in Healthy Adult Participants and Patients With Eosinophilic Esophagitis

An open-label phase 2 study to assess the safety and exploratory diagnostic performance of the oral radiopharmaceutical agent NDX-3315 and NDX-3324 in healthy participants and patients with eosinophilic esophagitis (EoE).

Study Overview

• Status: Completed
• Conditions: Eosinophilic Esophagitis
• Intervention / Treatment: Drug: NDX-3315; Drug: NDX-3324; Diagnostic test: SPECT/CT Imaging

Detailed Description

This study is a multi-site, Phase 2, open-label study of orally administered NDX-3315 or NDX-3324 and esophageal imaging in healthy participants and participants with EoE.

Study details include:

• The study duration or period will be up to around 10 weeks.
• Participants will receive either one or two doses of NDX-3315 or NDX-3324 depending on their assigned regimen arm. EoE participants will receive two doses; healthy participants will receive one dose. There will be a SPECT/CT scan performed at each dose.
• The visit frequency will be three site visits for healthy participants and four site visits for EoE participants followed by one follow-up phone call visit within the study period.

• Study Type: Interventional
• Enrollment (Actual): 34
• Phase: Phase 2

Contacts and Locations

Study Locations

• United States
  • Illinois
    • Chicago, Illinois, United States, 60611
      • Northwestern Univerisity
  • Pennsylvania
    • Philadelphia, Pennsylvania, United States, 19104
      • University of Pennsylvania
  • Utah
    • Salt Lake City, Utah, United States, 84132
      • University of Utah

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Healthy Participants:

  • Participants who are healthy as determined by medical evaluation including medical history, physical examination, laboratory tests, and electrocardiogram (ECG) assessment.

• EoE Participants:

  • Documented diagnosis of EoE (based on prior endoscopy with biopsies showing eosinophils ≥15 / HPF); AND
  • History (by patient report) of recurrent dysphagia and/or other related EoE symptoms (with intake of solids off anti-inflammatory therapy) prior to screening; dysphagia is defined as trouble swallowing solid food, or having solid food stuck, by patient report.

Exclusion Criteria:

• Medical Conditions:

  • Participant with presence of any other disease of the GI tract, including cancer, autoimmune esophageal disease, GERD which is symptomatic or uncontrolled, Barrett's esophagus, eosinophilic gastritis, enteritis, colitis, or proctitis; inflammatory bowel disease; or celiac disease. Known motility disorder of esophagus; achalasia or suspicion thereof.
  • Sleep apnea, if considered by the investigator a concern for the endoscopic procedure.
  • History of recurrent aspiration pneumonia.
  • History of bleeding disorders, liver cirrhosis or esophageal varices.
  • A current malignancy or previous history of cancer in remission for less than 5 years prior to Screening (participants will not be excluded if they had localized carcinoma of the skin that was resected for cure).
  • Participant with a Body Mass Index >40 m2/kg or inability to undergo a CT (or SPECT scan) due to weight limitations.
  • Participant is pregnant or nursing.

• Prior/Concomitant Therapy:

  • Participant who is on anticoagulation therapy that, in the investigator or Medical Monitor's opinion, cannot safely come off medication.
  • Use of chronic aspirin (with the exception of low-dose aspirin as long as the dose remains stable and not increased while on study), nonsteroidal agents, or anti-coagulants within 2 weeks prior to screening.
  • Use of systemic corticosteroids within 3 months or swallowed topical corticosteroids within 6 weeks prior to Screening visit.
  • Participant is being treated with systemic immunosuppression, carafate (sucralfate), or investigational agent of any kind within less than 3 months or 5 half-lives, whichever is longer, prior to Screening visit (this also includes investigational formulations of marketed products).

• Diagnostic Assessments:

  • Evidence of clinically significant abnormality in the hematological and biochemical assessments at Screening Visit, specifically: International Normalized Ratio (INR) >1.4; platelet count <80,000/μL and creatinine level >2 mg/dL.
  • ECG: QTcF ≥450 msec for males and QTcF ≥470 msec for females at the time of screening.

• Other Exclusion Criteria:

  • Any condition that would not permit adequate biopsies of the esophagus (e.g., esophageal varices, significant stricture precluding passage of a 9 mm endoscope, known allergy to sedative used for endoscopy).
  • Healthy Participants Only: A history or current diagnosis of allergic diseases (Should be discussed with Medical Monitor and PI to decide whether exclusionary), autoimmune disease, chronic rhinosinusitis or serum immunoglobulin E (IgE) level ≥100 kU/L. On any medications including NSAIDS and any over the counter (OTC) medications unless it is birth control or acne medications with the exception of Accutane, or if deemed acceptable to use by Medical Monitor and PI.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Participants Receiving NDX-3315; Participants receive NDX-3315 (delivered via oral syringe at ~ 1.5 mL per minute) using Regimen 5 (5 sips administered over approximately 5 minutes) or Regimen 10 (10 sips administered over approximately 10 minutes), followed by SPECT/CT imaging. Both healthy participants and participants with EoE are included.	Drug: NDX-3315; Oral solution; Diagnostic test: SPECT/CT Imaging; Participants undergo SPECT/CT imaging following administration of NDX-3315 or NDX-3324.
Experimental: Participants Receiving NDX-3324; Participants receive NDX-3324 (delivered via oral syringe at ~ 1.5 mL per minute) using Regimen 10 (10 sips administered over approximately 10 minutes) in a sitting reclined position, followed by SPECT/CT imaging. Both healthy participants and participants with EoE are included.	Drug: NDX-3324; Oral solution; Diagnostic test: SPECT/CT Imaging; Participants undergo SPECT/CT imaging following administration of NDX-3315 or NDX-3324.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The proportion of all participants with AEs following administration of NDX-3315 and NDX-3324	An adverse event (AE) is any untoward medical occurrence in a study participant administered a pharmaceutical product and that does not necessarily have causal relationship with this treatment.	From start of study drug administration up to End of Study (EOS) ( Up to 3 Weeks)
Absolute quantification of SPECT imaging	SPECT images will be analyzed for radioactive per region of interest(ROI) of the esophagus.	Up to 45 minutes after dose
Peak eosinophil counts per high-power field (HPF)	A blinded pathologist will perform peak eosinophil counts per high-power field (HPF) on biopsy specimens of the esophagus.	Up to 10 days after last dose
Determine Concordance of Outcomes	Determine concordance rate between; eMBP1 immunostaining score on biopsy specimens (esophagus) and; NDX-3315 and NDX-3324 absolute quantification of SPECT imaging of esophagus	Up to 10 Days After Last Dose

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
EoE Symptom Collection Questionnaire	A questionnaire will be used to collect study participant symptoms such as severity of EoE dysphasia as well as concerns about pain. Answers will have corresponding score ranging from 1-18, with 18 being the worst result.	Baseline (All participants), Day 1 (EoE participants only)
Partial Thromboplastin Time (PTT) as marker of pharmacodynamics (PD)	Blood samples will be collected to measure Partial Thromboplastin Time (PTT), which is a blood test that looks at how long it takes for blood to clot.	Baseline, 2 hours post-dose (Up to 1 Week)
Radioactivity of blood collected from participants exposed to NDX-3315 and NDX-3324.	Blood samples will be collected to measure radioactivity as counts per minute(cpm) and disintegrations per minute(dpm).	2.5 hours post-dose (Up to 1 Week)
Visual ratings of SPECT images	A blinded central reviewer will review SPECT images for uptake of NDX-3315 or NDX-3324 per region of interest(ROI) of the esophagus using a 5-point scale (0= no uptake to 4 = uptake similar to bowel), with 4 being the worst result.	Up to 45 minutes after dose
Deposition of eMBP1	A blinded immunostaining analyst will perform analysis of deposition of Eosinophil Major Basic Protein 1 (eMBP1) via immunostaining of biopsy specimens of the esophagus.	Up to 10 days after last dose
EoE Endoscopic Reference Score (EREFS)	The EoE-EREFS (Edema, Rings, Furrows, Exudates, Strictures) scores are used to measure the endoscopically identified EoE esophageal mucosal characteristics. The evaluation includes stricture (if applicable); exudates (absent, mild, severe); furrows (absent, present); edema (absent, present); crepe paper esophagus (absent, present), and overall general appearance incorporating all endoscopically-identified EoE findings (e.g., fixed rings, strictures, whitish exudates, furrowing, edema, and crepe paper mucosa). The EoE -EREFS score being used in this study has a range from 0-11, with 11 being the worst result.	Up to 10 days after last dose

Collaborators and Investigators

• Sponsor: NexEos Diagnostics, Inc.

Study record dates

Study Major Dates

• Study Start (Actual): January 20, 2023
• Primary Completion (Actual): May 22, 2025
• Study Completion (Actual): May 22, 2025

Study Registration Dates

• First Submitted: February 10, 2023
• First Submitted That Met QC Criteria: February 23, 2023
• First Posted (Actual): March 7, 2023

Study Record Updates

• Last Update Posted (Actual): May 14, 2026
• Last Update Submitted That Met QC Criteria: May 11, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Diagnostic; Eosinophilic Esophagitis; EoE
• Additional Relevant MeSH Terms: Pathologic Processes; Immune System Diseases; Digestive System Diseases; Gastrointestinal Diseases; Hypersensitivity, Immediate; Hypersensitivity; Eosinophilia; Leukocyte Disorders; Hematologic Diseases; Esophageal Diseases; Gastroenteritis; Esophagitis; Pathological Conditions, Signs and Symptoms; Hemic and Lymphatic Diseases; Disease; Eosinophilic Esophagitis
• Other Study ID Numbers: NDX-3315-1001

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No