A Phase I Study of HXN5003 in Healthy Participants and Patients With Moderate-to-Severe Atopic Dermatitis

A Phase I, Multicenter, Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Safety, Tolerability, Pharmacokinetics, Immunogenicity, and Efficacy of HXN5003 in Healthy Participants and Patients With Moderate-to-Severe Atopic Dermatitis

This is a Phase I, multicenter, randomized, double-blind, placebo-controlled study evaluating HXN5003 in healthy participants and patients with moderate-to-severe atopic dermatitis (AD).

The study consists of two parts: Part A (single ascending dose in healthy participants) and Part B (multiple ascending dose in AD patients).

The primary objectives are to assess the safety, tolerability, pharmacokinetics (PK), immunogenicity, and preliminary efficacy of HXN5003.

Study Overview

• Status: Not yet recruiting
• Conditions: Moderate-to-Severe Atopic Dermatitis; Health Adult Subjects
• Intervention / Treatment: Drug: HXN5003; Drug: HXN5003; Drug: Placebo; Drug: Placebo

• Study Type: Interventional
• Enrollment (Estimated): 68
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Tong Gang; Phone Number: (86)13918569690; Email: tonggang@helixon.com

Study Locations

• China
  • Zhejiang
    • Hangzhou, Zhejiang, China, 310006
      • Affiliated Hangzhou First People's Hospital, School of Medicine, Westlake University
      • Contact: Liming Wu; Phone Number: 13750837205; Email: 18957118053@163.com
      • Contact: Ying Wang; Phone Number: (86)-18367124548; Email: nancywangying@163.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Participants must be able to understand and comply with the study requirements and voluntarily sign the informed consent form (ICF).
2. (Healthy Participants) Male or female participants aged 18 to 50 years (inclusive) at the time of signing the ICF.
3. (Healthy Participants) Male participants weighing ≥ 50.0 kg and female participants weighing ≥ 45.0 kg, with a body mass index (BMI) between 19.0 and 26.0 kg/m² (inclusive).
4. (Patients with AD) Male or female participants aged 18 to 70 years (inclusive)
5. (Patients with AD) Participants must have documented AD history, moderate-to-severe disease, and inadequate response to topical therapy at screening.

Exclusion Criteria:

1. Presence of any clinically significant disease at randomization, as judged by the investigator.
2. History of severe drug allergy or systemic anaphylactic reactions, such as anaphylactic shock, laryngeal edema, etc.
3. Known or suspected history of immunosuppression, or history of invasive opportunistic infections, including infections that are unusually frequent, recurrent, or prolonged in duration as judged by the investigator, even after resolution of the infection.
4. Participants who have resided long-term in regions with high prevalence of Human Herpesvirus-8 (HHV-8), such as Africa or the Mediterranean coastal areas.
5. History of malignancy or malignant disease, with the exception of surgically excised cutaneous squamous cell carcinoma in situ, basal cell carcinoma, and cervical carcinoma in situ that have been in complete remission for more than 5 years without any evidence of recurrence.
6. Female participants who are breastfeeding or pregnant, or women of childbearing potential with a positive serum pregnancy test result at screening.
7. Participants with a chronic active infection or a condition that would seriously interfere with study drug administration at baseline within 4 weeks prior to randomization; or a superficial skin infection requiring treatment within 1 week prior to randomization; or an acute illness within 48 hours prior to randomization.
8. (Patients with AD) Other than AD, A history of clinically significant disease which is poorly controlled or could pose a safety risk to the participant or confound the safety assessment, as judged by the Investigator to compromise participant safety in the study.
9. (Patients with AD) Positive results in any of the following infectious disease screening tests: 1）History of active tuberculosis, or positive result at screening (T-SPOT.TB or QuantiFERON-TB Gold); 2）Positive for hepatitis B; 3）Positive hepatitis C antibody; 4）Positive Treponema pallidum antibody; 5）History of HIV infection, or positive HIV antibody.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Part A Single Ascending Dose (SAD); Healthy participants will receive a single subcutaneous dose of HXN5003	Drug: HXN5003; Healthy participants will be enrolled sequentially into one of four ascending dose cohorts and will receive a single subcutaneous dose of HXN5003.; Drug: HXN5003; AD participants will be enrolled sequentially into one of two ascending dose cohorts and will receive multiple subcutaneous doses of HXN5003.
Placebo Comparator: Part A Placebo (SAD); Healthy participants will receive a single subcutaneous dose of placebo	Drug: Placebo; Healthy participants will be enrolled sequentially into one of four ascending dose cohorts and will receive a single subcutaneous dose of placebo.; Drug: Placebo; AD Participants will be enrolled sequentially into one of two ascending dose cohorts and will receive multiple subcutaneous doses of placebo.
Experimental: Part B Multiple Ascending Dose (MAD); AD participants will receive multiple subcutaneous doses of HXN5003	Drug: HXN5003; Healthy participants will be enrolled sequentially into one of four ascending dose cohorts and will receive a single subcutaneous dose of HXN5003.; Drug: HXN5003; AD participants will be enrolled sequentially into one of two ascending dose cohorts and will receive multiple subcutaneous doses of HXN5003.
Placebo Comparator: Part B Placebo (MAD); AD participants will receive multiple subcutaneous doses of placebo	Drug: Placebo; Healthy participants will be enrolled sequentially into one of four ascending dose cohorts and will receive a single subcutaneous dose of placebo.; Drug: Placebo; AD Participants will be enrolled sequentially into one of two ascending dose cohorts and will receive multiple subcutaneous doses of placebo.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Part A Adverse events	Incidence, severity, and causal relationship of Adverse Events (AEs)	Up to day 197
Part B Adverse Events	Incidence, severity, and causal relationship of Adverse Events (AEs)	Up to day 281

Collaborators and Investigators

• Sponsor: Helixon Biotechnology (Suzhou) Co., Ltd

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): October 1, 2027
• Study Completion (Estimated): January 1, 2028

Study Registration Dates

• First Submitted: August 30, 2026
• First Submitted That Met QC Criteria: August 30, 2026
• First Posted (Actual): September 3, 2026

Study Record Updates

• Last Update Posted (Actual): September 3, 2026
• Last Update Submitted That Met QC Criteria: August 30, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: HXN5003-A1-102

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: No
• Studies a U.S. FDA-regulated device product: No