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REGN20423

Phase 1

Atopic Dermatitis | Small molecule | Dermatology |Regeneron Pharmaceuticals, Inc.|Trials Updated: Oct 7, 2026

REGN20423 development status

Highest phase Phase 1
Registered trials 1 across 1 sponsor since Apr 2026

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindCONTROLLEDDMC
Total Trials1
Total Enrollment144

FDA Designations

No designations recorded

REGN20423 clinical trials

REGN20423 · 1 trial · 2 indications

Phase 1 1
NCT07527923First-in-Human Trial to Assess REGN20423 in Healthy Adult Participants and Adult Participants With Atopic DermatitisHealthy Volunteer
RECRUITING144 Analytics
PHASE1RECRUITING
First-in-Human Trial to Assess REGN20423 in Healthy Adult Participants and Adult Participants With Atopic Dermatitis
Healthy VolunteerUnlock trial analytics

Study Endpoints

Primary Endpoints

Occurrence of Treatment Emergent Adverse Events (TEAEs)
Up to 69 weeks
Severity of TEAEs
Up to 69 weeks

Secondary Endpoints

Concentrations of REGN20423 in serum
Up to 57 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
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Study Design & Arms

AllocationRANDOMIZED
MaskingQUADRUPLE
ModelSEQUENTIAL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Part AEXPERIMENTAL -
Part BEXPERIMENTAL -

Interventions

NameTypeDescription
REGN20423DRUGAdministered per the protocol
PlaceboOTHERAdministered per the protocol
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Eligibility Criteria

Age Range18 Years to 65 Years
SexALL
Healthy VolunteersYes
Study Sites7

Part A: Enrolls healthy participants Part B: Enrolls participants with atopic dermatitis Key Inclusion Criteria: Part A: 1. 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 s...

Countries:United StatesBelgium
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Recent Changes (Last 90 Days)

LOWOct 7, 2026NCT07527923lastUpdatePostDate: changed
LOWOct 7, 2026NCT07527923lastUpdatePostDate: changed
LOWSep 25, 2026NCT07527923lastUpdatePostDate: changed
LOWSep 25, 2026NCT07527923lastUpdatePostDate: changed

Frequently asked questions about REGN20423

What is REGN20423?

REGN20423 is an investigational small molecule drug being developed by Regeneron Pharmaceuticals for the treatment of atopic dermatitis. It is currently in Phase 1 clinical development and has not been approved by any regulatory agency. Regeneron is evaluating it in a first-in-human study that includes both healthy adult volunteers and adults with atopic dermatitis.

What is REGN20423 used for?

REGN20423 is being studied for the treatment of atopic dermatitis, a chronic inflammatory skin condition. It is an investigational therapy and is not approved for any indication. The ongoing Phase 1 trial enrolls adults with atopic dermatitis alongside healthy adult volunteers to evaluate the drug in a controlled, double-blind setting.

Who is developing REGN20423?

REGN20423 is being developed by Regeneron Pharmaceuticals, Inc., which trades on the Nasdaq under the ticker REGN. Regeneron is the sponsor of the Phase 1 first-in-human trial evaluating the drug in healthy volunteers and adults with atopic dermatitis.

What phase is REGN20423 in?

REGN20423 is in Phase 1 clinical development. It is an investigational small molecule and has not received FDA approval. The single registered trial is a first-in-human Phase 1 study that is currently recruiting participants, with no completed trials reported for this asset.

What clinical trials is REGN20423 in?

REGN20423 is being evaluated in one clinical trial, NCT07527923, titled a first-in-human trial to assess REGN20423 in healthy adult participants and adult participants with atopic dermatitis. The Phase 1 study is recruiting, is randomized, double-blind, and controlled, and plans to enroll 144 participants across the United States and Belgium.

Who can enroll in the REGN20423 trial?

The REGN20423 Phase 1 trial, NCT07527923, enrolls adults 18 years of age and older of any sex, including healthy volunteers and participants with atopic dermatitis. It is a randomized, double-blind, controlled first-in-human study being conducted in the United States and Belgium, with a planned enrollment of 144 participants.