Safety, PK, PD, and Clinical Activity of Orally Administered KT-621 in Adult Patients With Atopic Dermatitis (AD) (BroADen)

A Phase 1b Open-label, Multicenter, Single-arm Study to Evaluate the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Clinical Activity of Orally Administered KT-621 in Adult Participants With Moderate to Severe Atopic Dermatitis

This is a study to evaluate safety, tolerability, pharmacokinetics, pharmacodynamics, and clinical activity of orally administered KT-621 in adult male and female patients with moderate to severe atopic dermatitis (AD).

Study Overview

• Status: Completed
• Conditions: Atopic Dermatitis
• Intervention / Treatment: Drug: KT-621

• Study Type: Interventional
• Enrollment (Actual): 22
• Phase: Phase 1

Contacts and Locations

Study Locations

• United States
  • Alabama
    • Birmingham, Alabama, United States, 35244
      • Kymera Investigative Site
  • California
    • Fountain Valley, California, United States, 92708
      • Kymera Investigative Site
    • Santa Monica, California, United States, 90404
      • Kymera Investigative Site
  • Florida
    • Boynton Beach, Florida, United States, 33436
      • Kymera Investigative Site
    • Hollywood, Florida, United States, 33024
      • Kymera Investigative Site
    • Tampa, Florida, United States, 33613
      • Kymera Investigative Site
  • North Dakota
    • Fargo, North Dakota, United States, 58078
      • Kymera Investigative Site
  • Ohio
    • Dublin, Ohio, United States, 43016
      • Kymera Investigative Site
    • Springfield, Ohio, United States, 45505
      • Kymera Investigative Site
  • Oklahoma
    • Tulsa, Oklahoma, United States, 74136
      • Kymera Investigative Site
  • South Carolina
    • Charleston, South Carolina, United States, 29420
      • Kymera Investigative Site
  • Texas
    • San Antonio, Texas, United States, 78213
      • Kymera Investigative Site

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Participants aged 18 to 55 years (inclusive) at the time of screening
• Participants must be willing and able to comply with scheduled visits, treatment plan, laboratory tests, and other procedures
• Participants must have had chronic atopic dermatitis (AD) for at least 1 year before Screening.
• Moderate to very severe eczema as determined by Eczema Area and Severity Index (EASI) score of at least 16 at the baseline visit.
• A validated Investigator Global Assessment (vIGA) score of at least 3 at the baseline visit, indicating moderate to severe AD.
• At least 10% body surface area (BSA) of AD involvement at the baseline visit.
• Weekly average Peak Pruritus Numeric Rating Scale (NRS) of at least 4 at the baseline visit.
• Documented history within 6 months prior to baseline visit of either inadequate response or contraindication to topical medications for AD.
• Application of stable dose of moisturizer at least twice daily for at least 7 consecutive days immediately prior to the baseline visit.

Exclusion Criteria:

• Participants who have a clinically relevant history of respiratory, gastrointestinal (GI), renal, hepatic, hematological, lymphatic, endocrinological, neurological, cardiovascular, psychiatric, musculoskeletal, genitourinary, immunological, ophthalmological, or connective tissue diseases or disorders.
• Participants who have any surgical or medical procedure planned during participation in the study.
• Participants with a history of alcohol or substance abuse within the previous 2 years.
• Participants who have any known factor, condition, or disease that might interfere with treatment compliance, study conduct or interpretation of the results.
• Participants whose results from clinical laboratory safety tests are outside the local reference range at Screening.
• Participants who have been dosed with any investigational drug or device in a clinical study within 8 weeks or 5 half-lives (whichever is longer) of KT-621 administration.
• Participants with a history of lack of response to any medication targeting interleukin (IL)-4, IL-13, and/or janus kinase (JAK)- signal transducer and activator of transcription (STAT) pathways (e.g. dupilumab, tralokinumab, upadacitinib, abrocitinib) at approved doses after at least 16 weeks of therapy.
• Pregnant or breastfeeding women, or women planning to become pregnant or breastfeed during the study.
• Female participants of childbearing potential with a positive or undetermined pregnancy result at the Screening and baseline visits.
• Participants with a known sensitivity to any of the components of KT-621.
• Participants who are a member of the investigational team or his/her immediate family.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: KT-621; Each participant receives daily oral doses of KT-621 throughout the 28-day treatment period.	Drug: KT-621; Oral drug

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Incidence of adverse events (AEs)	From enrollment through the safety follow-up visit on Day 43
Incidence of treatment-emergent potentially clinically-significant abnormalities in electrocardiogram (ECG) results, vital signs, or laboratory test results from the serum chemistry, hematology (with differential), chemistry, or coagulation panels.	From enrollment through the safety follow-up visit on Day 43

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Plasma PK parameter estimates of KT-621 derived from plasma concentration-time data	Trough concentrations taken at each visit before dosing, post-dose concentrations taken after dosing at Days 1 and 15.	From baseline visit through the safety follow-up visit on Day 43

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
KT-621 concentrations in skin		From baseline visit through the safety follow-up visit on Day 43
Change in Eczema Area and Severity Index (EASI) score		From screening through the safety follow-up visit on Day 43
Proportion of participants who achieve a validated Investigator Global Assessment (vIGA) score of 0 or 1 at scheduled clinic visits	On a scale of 0 to 4, 0 being no inflammatory signs of AD, 4 being severe inflammatory signs of AD	From screening through the safety follow-up visit on Day 43
Change from baseline in the Peak Pruritus Numeric Rating Scale (NRS) score	Percent change from baseline	From baseline visit through the safety follow-up visit on Day 43
Change from baseline in levels of signal transducer and activator of transcription 6 protein, in skin and in whole blood		From baseline visit through the safety follow-up visit on Day 43
Change from baseline in the serum levels of Th2 biomarkers such as thymus and activation-regulated chemokine (TARC)		From baseline visit through the safety follow-up visit on Day 43
Change from baseline through Week 4 in the serum levels of proinflammatory cytokines		From baseline visit through the safety follow-up visit on Day 43
Change from baseline through Week 4 in messenger RNA transcriptome levels on the skin.		From baseline visit through the safety follow-up visit on Day 43

Collaborators and Investigators

• Sponsor: Kymera Therapeutics, Inc.

Study record dates

Study Major Dates

• Study Start (Actual): April 17, 2025
• Primary Completion (Actual): November 10, 2025
• Study Completion (Actual): November 10, 2025

Study Registration Dates

• First Submitted: April 9, 2025
• First Submitted That Met QC Criteria: April 17, 2025
• First Posted (Actual): April 25, 2025

Study Record Updates

• Last Update Posted (Actual): January 26, 2026
• Last Update Submitted That Met QC Criteria: January 22, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Phase 1; STAT6; STAT6 degrader; KT621; Targeted protein degrader
• Additional Relevant MeSH Terms: Genetic Diseases, Inborn; Immune System Diseases; Hypersensitivity, Immediate; Hypersensitivity; Skin Diseases; Skin Diseases, Genetic; Skin Diseases, Eczematous; Dermatitis; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Skin and Connective Tissue Diseases; Dermatitis, Atopic
• Other Study ID Numbers: KT621-AD-102

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