First-in-Human Trial to Assess REGN20423 in Healthy Adult Participants and Adult Participants With Atopic Dermatitis

NCT07527923 | Not Yet Recruiting Phase 1 FDA Drug

• 2 other identifiers: R20423-HV-25552025-524205-32-00
• Study Type: interventional
• Target: 136
• Locations: 0 countries
• Sites: N/A

Brief Summary

This clinical trial will evaluate REGN20423, an investigational medicine that has not previously been studied in humans and is used only in clinical studies. The study will assess the safety, how the body processes the medicine, and the dose levels that may work best. It will also test whether REGN20423 can help treat adults with atopic dermatitis. This is a two-part study: Part A includes healthy adult participants. Part B includes adults with atopic dermatitis. The Study is Looking at:

• What side effects REGN20423 might cause
• How much REGN20423 is in the blood at different times
• How well REGN20423 works in adults with atopic dermatitis
• Whether the body makes antibodies against REGN20423
• How the body changes after having REGN20423, which can help researchers understand why REGN20423 works better in some people than others
• What the best dose of REGN20423 is

Conditions

Healthy Volunteer; Atopic Dermatitis

Keywords

Eczema; Inflammatory skin disease

Outcome Measures

Primary Outcomes (2)

• Occurrence of Treatment Emergent Adverse Events (TEAEs)

  Up to 52 weeks

• Severity of TEAEs

  Up to 52 weeks

Secondary Outcomes (25)

• Concentrations of REGN20423 in serum

  Up to 52 weeks

• Absolute values from baseline of total Interleukin 13 (IL-13)

  Up to 52 weeks

• Absolute values from baseline of total Immunoglobulin E (IgE)

  Up to 52 weeks

• Absolute values from baseline of total eosinophil counts in blood

  Up to 52 weeks

• Absolute values from baseline of total periostin

  Up to 52 weeks

Study Arms (2)

Part A

EXPERIMENTAL

Drug: REGN20423; Other: Placebo

Part B

EXPERIMENTAL

Drug: REGN20423; Other: Placebo

Interventions

REGN20423 DRUG

Administered per the protocol

Part A; Part B

Placebo OTHER

Administered per the protocol

Part A; Part B

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Part A:
• Is judged by the investigator to be in good health based on medical history, physical examination, vital signs, Electrocardiograms (ECGs), and laboratory safety testing at screening and prior to initial dose of study intervention
• Has a BMI within 18 to 31 kg/m² (inclusive) at the screening visit
• Part B:
• Has a history of AD for at least 6 months at screening
• Has EASI score ≥5 at both the screening and baseline visits
• Has IGA score ≥2 at both the screening and baseline visits

You may not qualify if:

• Part A:
• Hospitalized (\>24 hours) for any reason within 30 days prior to the screening visit
• Hypersensitivity to the study treatment or any of its excipients
• History of clinical parasite infection, except treated trichomoniasis
• Received a live attenuated vaccine within 1 month prior to the first screening visit or anticipates need for a live attenuated vaccine during the study
• History of alcohol or drug abuse as determined by the investigator
• Part B:
• Known or suspected history of immunosuppression
• Presence of skin comorbidities at screening that may interfere with study assessments
• Inability to discontinue medications and treatments prior to baseline and during the study per the Excluded Medications and Treatments list
• Uncontrolled chronic disease that might require bursts of oral corticosteroids during the study

Sponsors & Collaborators

• Regeneron Pharmaceuticals: lead

MeSH Terms

Conditions

Dermatitis, Atopic; Eczema; Dermatitis

Condition Hierarchy (Ancestors)

Skin Diseases, Genetic; Genetic Diseases, Inborn; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Skin Diseases; Skin and Connective Tissue Diseases; Skin Diseases, Eczematous; Hypersensitivity, Immediate; Hypersensitivity; Immune System Diseases

Study Officials

• Clinical Trial Management

  Regeneron Pharmaceuticals

  STUDY DIRECTOR

Central Study Contacts

Clinical Trials Administrator

CONTACT

844-734-6643; clinicaltrials@regeneron.com

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: SEQUENTIAL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: Part A is sequential Part B is parallel

Study Record Dates

• First Submitted: April 7, 2026
• First Posted: April 14, 2026
• Study Start: May 4, 2026
• Primary Completion (Estimated): June 9, 2028
• Study Completion (Estimated): June 9, 2028
• Last Updated: April 14, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, CSR, ANALYTIC CODE
• Time Frame: When Regeneron has: * received marketing authorization from major health authorities (e.g., FDA, European Medicines Agency (EMA), Pharmaceuticals and Medical Devices Agency (PMDA), etc.) for the product and indication or has globally discontinued development of the product for all indications on or after April 2020 and has no plans for future development * made the study results publicly available (e.g., scientific publication, scientific conference, clinical trial registry) * the legal authority to share the data, and * ensured the ability to protect participant privacy
• Access Criteria: Qualified researchers can submit a proposal for access to individual patient or aggregate level data from a Regeneron-sponsored clinical trial through Vivli. Regeneron's Independent Research Request Evaluation Criteria can be found at: https://www.regeneron.com/sites/default/files/Regeneron-External-Data-Sharing-Policy-and-Independent-Research-Request-Evaluation-Criteria.pdf