Study of ENP-501 in Peanut-Allergic and Non-Allergic Participants

April 23, 2026 updated by: N-Fold, LLC

A Phase 1/2, Randomized, Double-Blind, Placebo-Controlled, Dose Escalation and Expansion Study of ENP-501 in Non-Peanut Allergic Participants and Participants With a Known Peanut Allergy

This is a Phase 1/2 study to evaluate the safety and clinical activity of ENP-501 in non-peanut allergic (NPA) healthy participants and participants with an established peanut allergy (PA)

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
68

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • Colorado
      • Aurora, Colorado, United States, 80045
        • Recruiting
        • Research Site 001

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Child
  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

Part 1:

  • 14-50 years of age (inclusive)
  • Otherwise medically healthy and able to participate in the study
  • Able to perform spirometry testing in accordance with the American Thoracic Society (ATS) guidelines (2019)
  • All women of child-bearing potential, agree to either abstain from sexual activity or agree to use an adequate method of contraception for the duration of the study and for 30 days after the last dose of investigational product
  • Signed and dated written informed consent from the participant and/or parent or guardian
  • Signed and dated assent from participant under 18 in accordance with local IRB regulations
  • Willing and able to avoid peanut and peanut contaminants for the duration of the trial

Part 1 Cohort 1 only (NPA Participants)

  • No known clinical history of peanut allergy with regular exposure to peanuts in daily life, i.e ingests peanuts without symptoms
  • Negative Skin Prick Test (SPT) (wheal diameter of <3 mm) to peanut

Part 1 Cohort 2 only (PA Participants)

  • A documented clinical history of peanut allergy, which includes the development of symptoms (e.g., urticaria, flushing, rhinorrhea and sneezing, throat tightness or hoarseness, wheezing, vomiting) verified by a physician

  • At least two of the three following requirements:

    1. Positive Skin Prick Test (SPT) (wheal diameter of ≥ 8 mm) to peanut
    2. An elevated serum peanut specific IgE level ≥ 7 kUA/L (ImmunoCAP®)
    3. An Ara-h2 IgE level of ≥ 2 kUA/L (ImmunoCAP®)

Part 2:

  • 14 to 50 years of age (inclusive)
  • A documented clinical history of peanut allergy, which includes the development of symptoms (e.g., urticaria, flushing, rhinorrhea and sneezing, throat tightness or hoarseness, wheezing, vomiting) verified by a physician

  • At least two of the three following requirements at screening:

    1. Positive SPT (wheal diameter of ≥ 3 mm) to peanut
    2. Serum peanut-specific IgE level ≥ 0.7 kUA/L (ImmunoCAP®)
    3. An Ara-h2 IgE level of ≥ 0.5 kUA/L (ImmunoCAP®) within 1 year of enrollment
  • Participant must be willing and able to complete a DBPCFC at screening and EOT (24-hours after last dose) and experience dose-limiting symptoms at or before the 300 mg challenge dose of peanut protein during a Double Blind, Placebo Controlled Food Challenge (DBPCFC) conducted in accordance with Practical Issues in Allergology, Joint United States/European Union Initiative (PRACTALL) guidelines
  • Otherwise medically healthy and able to participate in the study
  • Able to perform spirometry testing in accordance with the ATS guidelines (2019)
  • All women of child-bearing potential, agree to either abstain from sexual activity or agree to use an adequate method of contraception for the duration of the study and for 30 days after the last dose of investigational product
  • Signed and dated written informed consent from the participant and/or parent or guardian
  • Signed and dated assent from participant under 18 in accordance with local IRB regulations
  • Willing and able to avoid peanut and peanut contaminants for the duration of the trial

Exclusion Criteria:

  • History of severe anaphylactic event requiring mechanical ventilation or use of intravenous (IV) vasopressor drugs
  • Clinically significant screening electrocardiogram (ECG) abnormality or corrected QTcF >/= 450 msec at Screening
  • FEV1 value < 80% predicted at Screening
  • Any hospitalization in the past year for asthma, >1 course of oral steroids for asthma in the past 6 months, or any emergency room visit in the past 6 months for asthma
  • Poorly controlled atopic dermatitis
  • Eosinophilic gastrointestinal disease
  • Use of oral or IV corticosteroids within 30 days of Screening
  • Use of tricyclic antidepressants within 6 months of Screening
  • Inability to discontinue antihistamines for at least 5 half-lives before skin testing
  • Use of omalizumab or other immunomodulatory therapy (not including corticosteroids) or biologic therapy within one year of Screening
  • Use of any food allergen-specific or other non-traditional form of allergen immunotherapy within one year of Screening
  • Use of immunosuppressive drugs within 30 days of Screening
  • Use of ß-blockers (oral)
  • Evidence of clinically significant neurologic, cardiac, pulmonary, hepatic, rheumatologic, autoimmune, or renal disease by history, physical examination, and/or laboratory studies including urinalysis
  • Pregnant or breast-feeding (if female)
  • Behavioral, cognitive, or psychiatric disease that in the opinion of the Investigator affects the ability of the participant to understand and cooperate with the study protocol
  • Known allergy to inactive ingredients of investigational product (active or placebo)
  • Participation in another interventional clinical trial within 30 days of Screening or within 5 half-lives of the other IP
  • Residing at the same address as another participant in this or any peanut immunotherapy study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Placebo Comparator: Placebo
Drug: Placebo
  • Part 1: Participants will receive buccal administrations of placebo daily for 6-14 weeks
  • Part 2: Participants will receive buccal administrations of placebo daily for 52 weeks following achieving the 2000 µg target dose
Experimental: ENP-501
Drug: ENP-501
  • Part 1: Participants will receive buccal administrations of ENP-501 daily for 6-14 weeks
  • Part 2: Participants will receive buccal administrations of ENP-501 daily for 52 weeks following achieving the 2000 µg target dose

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
Number of Participants with Treatment-Emergent Adverse Events (TEAEs) as Assessed by NCI CTCAE v 5.0 in Part 1
Time Frame: Up to 22 Weeks
Up to 22 Weeks
Number of Participants with Treatment-Emergent Serious Adverse Events (TESAEs) as Assessed by NCI CTCAE v 5.0 in Part 1
Time Frame: Up to 22 Weeks
Up to 22 Weeks
Number of Participants with Dose Limiting Toxicities (DLTs) as Assessed by NCI CTCAE v 5.0 in Part 1
Time Frame: Up to 22 Weeks
Up to 22 Weeks
Number of Participants with Systemic Reactions as Assessed by NCI CTCAE v 5.0 in Part 1
Time Frame: Up to 22 Weeks
Up to 22 Weeks
Number of Participants with changes in Clinical Laboratory Values in Part 1
Time Frame: Up to 22 Weeks
Up to 22 Weeks
Number of Participants with changes in Physical Examination in Part 1
Time Frame: Up to 22 Weeks
Up to 22 Weeks
Number of Participants with changes in Vital Signs in Part 1
Time Frame: Up to 22 Weeks
Up to 22 Weeks
Proportion of Participants Tolerating ≥1043 mg Cumulative Peanut Protein Without Dose-Limiting Symptoms at End of Treatment (EOT) Visit Double-Blind Placebo-Controlled Food Challenge (DBPCFC) Compared to Placebo in Part 2
Time Frame: Up to 72 Weeks
Up to 72 Weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Time Frame
Number of Participants Able to Tolerate 2000 µg Dose of ENP-501 Without Experiencing Dose-Limiting Toxicity (DLT) in Part 1
Time Frame: Up to 22 Weeks
Up to 22 Weeks
Change in Total IgE Levels in Part 1
Time Frame: Screening and Week 22 (EOS)
Screening and Week 22 (EOS)
Change in Ara h 1-Specific IgE Levels in Part 1
Time Frame: Screening and Week 22 (EOS)
Screening and Week 22 (EOS)
Change in Ara h 2-Specific IgE Levels in Part 1
Time Frame: Screening and Week 22 (EOS)
Screening and Week 22 (EOS)
Change in Ara h 3-Specific IgE Levels in Part 1
Time Frame: Screening and Week 22 (EOS)
Screening and Week 22 (EOS)
Change in Ara h 1-Specific IgG4 Levels in Part 1
Time Frame: Screening and Week 22 (EOS)
Screening and Week 22 (EOS)
Change in Ara h 2-Specific IgG4 Levels in Part 1
Time Frame: Screening and Week 22 (EOS)
Screening and Week 22 (EOS)
Change in Ara h 3-Specific IgG4 Levels in Part 1
Time Frame: Screening and Week 22 (EOS)
Screening and Week 22 (EOS)
Change in Wheal Diameter on Skin Prick Test (SPT) to Peanut in Part 1
Time Frame: Screening and Week 22 (EOS)
Screening and Week 22 (EOS)
Proportion of Participants Tolerating at Least 443 mg Cumulative Dose of Peanut Protein Without Dose-Limiting Symptoms at EOT Visit DBPCFC Compared to Placebo in Part 2
Time Frame: Up to 72 Weeks
Up to 72 Weeks
Proportion of Participants Tolerating at Least 2043 mg Cumulative Dose of Peanut Protein Without Dose-Limiting Symptoms at EOT Visit DBPCFC Compared to Placebo in Part 2
Time Frame: Up to 72 Weeks
Up to 72 Weeks
Proportion of Participants Tolerating 4043 mg Cumulative Dose of Peanut Protein Without Dose-Limiting Symptoms at EOT Visit DBPCFC Compared to Placebo in Part 2
Time Frame: Up to 72 Weeks
Up to 72 Weeks
Maximum Severity of Symptoms Occurring at Each Challenge Dose of Peanut Protein During the Exit DBPCFC in Part 2
Time Frame: Up to 72 Weeks
Up to 72 Weeks
Number of Participants Able to Tolerate the 2000 µg Dose of ENP-501 in Part 2
Time Frame: Up to 72 Weeks
Up to 72 Weeks
Change in Total IgE Levels in Part 2
Time Frame: Screening and Week 72 (EOS)
Screening and Week 72 (EOS)
Change in Ara h 1-Specific IgE Levels in Part 2
Time Frame: Screening and Week 72 (EOS)
Screening and Week 72 (EOS)
Change in Ara h 2-Specific IgE Levels in Part 2
Time Frame: Screening and Week 72 (EOS)
Screening and Week 72 (EOS)
Change in Ara h 3-Specific IgE Levels in Part 2
Time Frame: Screening and Week 72 (EOS)
Screening and Week 72 (EOS)
Change in Ara h 1-Specific IgG4 Levels in Part 2
Time Frame: Screening and Week 72 (EOS)
Screening and Week 72 (EOS)
Change in Ara h 2-Specific IgG4 Levels in Part 2
Time Frame: Screening and Week 72 (EOS)
Screening and Week 72 (EOS)
Change in Ara h 3-Specific IgG4 Levels in Part 2
Time Frame: Screening and Week 72 (EOS)
Screening and Week 72 (EOS)
Change in Wheal Diameter on Skin Prick Test (SPT) to Peanut in Part 2
Time Frame: Screening and Week 72 (EOS)
Screening and Week 72 (EOS)
Number of Participants with Treatment-Emergent Adverse Events (TEAEs) as Assessed by NCI CTCAE v 5.0 in Part 2
Time Frame: Up to 72 Weeks
Up to 72 Weeks
Number of Participants with Treatment-Emergent Serious Adverse Events (TESAEs) as Assessed by NCI CTCAE v 5.0 in Part 2
Time Frame: Up to 72 Weeks
Up to 72 Weeks
Number of Participants with TEAEs leading to discontinuation as Assessed by NCI CTCAE v 5.0 in Part 2
Time Frame: Up to 72 Weeks
Up to 72 Weeks
Number of Participants with Systemic Reactions as Assessed by NCI CTCAE v 5.0 in Part 2
Time Frame: Up to 72 Weeks
Up to 72 Weeks
Number of Participants with changes in Clinical Laboratory Values in Part 2
Time Frame: Up to 72 Weeks
Up to 72 Weeks
Number of Participants with changes in Physical Examination in Part 2
Time Frame: Up to 72 Weeks
Up to 72 Weeks
Number of Participants with changes in Vital Signs in Part 2
Time Frame: Up to 72 Weeks
Up to 72 Weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
N-Fold, LLC

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
CBCC Global Research

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 16, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 1, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 1, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 4, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 4, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 12, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 24, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 23, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • ENP-501-001

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings