Phase 1a/1b Study of TRB-061 in Healthy Participants & Atopic Dermatitis Patients

This Phase 1a/1b randomized, double-blind, placebo-controlled study evaluates the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of subcutaneously (SC) administered TRB-061 in healthy adults and patients with moderate-to-severe atopic dermatitis (AD).

Part 1 (SAD): Healthy participants receiving single doses or placebo. Part 2 (MAD): Healthy participants receiving multiple doses (3 doses over 8 weeks) of TRB-061 or placebo.

Part 3 (MAD+): Participants with moderate-to-severe AD receiving repeated doses (4 doses over 12 weeks) of TRB-061 or placebo.

The study comprises three sequential parts:

Part 1 (SAD): Healthy adults will receive single-ascending doses of TRB-061 or placebo in cohorts of 8 (6 active, 2 placebo). Safety data will be reviewed before dosing the remaining participants. Follow-up lasts 12 weeks post-dosing.

Part 2 (MAD): Two cohorts of healthy adults will receive multiple doses of TRB-061 or placebo every 4 weeks (Q4W) over 8 weeks. Follow-up lasts 10 weeks post-last dose.

Part 3 (MAD+): Participants with moderate-to-severe AD will be randomized (1:1:1) to receive one of two doses of TRB-061 or placebo for 12 weeks. Responders will be followed for 36 weeks post-treatment. Non-responders will complete the study at 16 weeks. Placebo non-responders may receive 12 weeks of active treatment with a 12-week follow-up.

Eligibility Criteria:
Inclusion Criteria:

1. Male or female participants aged 18 to 70 years, inclusive, at the time of informed consent.
2. Body weight ≥50 kg and body mass index (BMI) between 18.5 and 35.0 kg/m², inclusive.
3. Participant is in good general health as determined by the investigator, based on medical history, physical examination, and clinical laboratory tests.
4. For healthy participants (Parts 1 and 2): no clinically significant abnormalities in laboratory results, ECGs, or physical exams at screening.
5. For participants in Part 3: diagnosis of moderate-to-severe atopic dermatitis for at least 12 months before screening.
6. Must be nonpregnant and nonlactating with negative pregnancy tests at screening and prior to dosing.
7. Must be a non-smoker or ≤5 cigarettes per week for the past 6 months.

Exclusion Criteria:

1. History of any clinically significant disease or disorder which, in the opinion of the investigator, may put the participant at risk or interfere with study results.
2. History or presence of any condition requiring systemic immunosuppressive or immunomodulatory therapy within a defined period before screening.
3. Use of any biologic agent (e.g., monoclonal antibodies) within 3 months or 5 half-lives (whichever is longer) before Day 1.
4. Participation in another investigational drug trial within 30 days or 5 half-lives of the investigational product (whichever is longer) before Day 1.
5. History of hypersensitivity or allergic reaction to any component of the study drug or placebo formulation.
6. Known active or latent tuberculosis (TB) infection or history of incomplete TB treatment.
7. Positive test at screening for hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) RNA, or human immunodeficiency virus (HIV).
8. Active infection or history of serious infections within 4 weeks prior to Day 1.
9. History of malignancy (except treated and cured non-melanoma skin cancers or cervical carcinoma in situ).
10. Pregnant or breastfeeding women, or women planning to become pregnant during the study or within a specified time after the last dose.
11. Clinically significant ECG abnormalities (e.g., QTcF \>470 ms) or other cardiac risk factors.
12. Abnormal laboratory values at screening
13. Use of live vaccines within 4 weeks before Day 1.
14. Use of systemic corticosteroids, immunosuppressants, or immunomodulatory drugs within protocol-defined washout periods.
15. Active COVID-19 infection or symptoms, or positive COVID-19 test at screening.
16. History of alcohol or drug abuse within the past year.
17. Use of tobacco/nicotine products beyond protocol-allowed limits.
18. Positive cotinine test at check-in.
19. Any other reason, in the opinion of the investigator or sponsor, that would make the participant unsuitable for participation in the study.