Evaluate Efficacy and Safety of Repeat Subcutaneous Doses of FB825 in Adults With Moderate-to-Severe Atopic Dermatitis

Inclusion Criteria:

Subjects must meet all of the following criteria to be included in the study:

1. The subject is male or female between 18 and 65 years of age at the time of givinginformed consent.

2. Body weight equal to or greater than 40 Kg at the time of screening.

3. The subject has a physician-confirmed diagnosis of moderate-to-severe atopicdermatitis based on 12 months history of symptoms designated by Hanifin and Rajkacriteria.

4. Eczema Area and Severity Index (EASI) score ≥16 at screening and baseline visits.

5. Validated Investigator Global Assessment for Atopic Dermatitis (vIGA-AD) score ≥ 3 (5-point scale) at the screening and baseline visits.

6. ≥10 % body surface area (BSA) of AD involvement at the screening and baselinevisits.

7. Baseline pruritus numerical rating scale (NRS) average score for maximum itchintensity of ≥ 3, based on the average of daily pruritus NRS scores for maximum itchintensity reported during the 7 days prior to randomization.

8. History of inadequate response to a stable (4 weeks) regimen of topicalcorticosteroids (TCS) or topical calcineurin inhibitors (TCI) as treatment for ADwithin 6 months before the screening visit. (The TCS should belong to medium to highpotency strength and has been applied for at least 4 weeks or for the maximumduration recommended by product prescribing information.)

• An inadequate response is defined as the inability to achieve and maintainremission or a low disease activity state (comparable to vIGA-AD 0=clear to 2=mild).

• Subjects with systemic treatment for AD in the past 6 months were alsoconsidered as inadequate responders to topical treatments.

9. Patients must be applying stable doses of an additive-free, basic bland emollienttwice-daily for at least 1 week immediately before the baseline visit. Note: See exclusion criterion #13 for limitations regarding emollients.

10. Female subjects must have a negative serum pregnancy test at screening. All subjectsof childbearing potential and his/her sexual partner must meet 2 following conditionor acceptable methods of birth control throughout the study.

• Oral, injectable, or implanted hormonal contraceptives

• Condom with a spermicidal form, gel, film, cream, or suppository

• Occlusive cap (diaphragm or cervical/vault caps) with a spermicidal foam, gel,film, cream, or suppository

• Intrauterine device

• Intrauterine system (for example, progestin-releasing coil) or be surgicallysterile (i.e., hysterectomy, bilateral tubal ligation, bilateral oophorectomy,or vasectomy)

• Postmenopausal (defined as amenorrhea 12 consecutive months and documentedserum follicle stimulating hormone level per laboratory standard) Note: Thesubject must utilize the method of effective contraception during study periodas well as 16 weeks or 5 half-lives following the last dosing of FB825.

11. The subject is able to provide written informed consent.

12. The subject agrees to and is capable of adhering to scheduled visits, the treatmentplan, laboratory tests, other study procedures, and all protocol requirements.

Exclusion Criteria:

• Subjects to whom any of the following applies will be excluded from the study:

1. Female subjects who are pregnant or lactating

2. The subject with positive test results for HBeAg or HCV RNA should be excludedas they are indications of active hepatitis B virus and hepatitis C virusreplication.

3. A positive human immunodeficiency virus (HIV) test (e.g., HIV Ag/Ab combo test)at screening or a history of HIV infection.

4. The subject has a history of alcohol or drug abuse within one year prior toscreening that would impair or risk the patients' full participation in thestudy, in the opinion of the investigator.

5. The subject has a clinically significant, currently active or severegastrointestinal, cardiovascular, nervous system, psychiatric, metabolic,renal, hepatic, respiratory (with the exception of uncomplicated allergicrhinitis and allergic asthma), inflammatory, immunological, endocrine,diabetes, obesity [BMI≥35] or infectious disease and is ineligible toparticipate in the study as judged by the investigator.

6. The subject has a clinically significant history, as determined by theinvestigator, of drug allergies or hypersensitivity such as, but not limitedto, sulfonamides and penicillin, or a drug allergy witnessed in a previousstudy with experimental drugs.

7. The subject has any history of a previous anaphylactic reaction.

8. The subject has any condition that, in the opinion of the investigator, wouldcompromise the study or the well-being of the subject or prevent the subjectfrom meeting or performing study requirements.

9. The subject has received TCS or TCI within 7 days prior to the baseline visit (Day 1).

10. The subject has received any immunoglobulin products or blood products within 3months prior to baseline visit.

11. The subject has received a biologic product (including investigational biologicproduct) within 5 half-lives or 3 months, whichever is longer, before baselinevisit.

12. The subject has received an investigational drug within 8 weeks or within 5half-lives (if known), whichever is longer, before baseline visit.

13. Initiation of treatment of AD with prescription moisturizers or moisturizerscontaining additives such as ceramide, hyaluronic acid, urea, or filaggrindegradation products during the screening period.

14. Initiation of treatment of AD with sedative anti-histamine products during thescreening period (patients may continue using stable doses of non-sedativeanti-histamine).

15. The subject is a member of the professional or ancillary personnel involved inthe study.

16. The subject regular use (≥2 visits per week) of a tanning booth/parlor within 4weeks prior to the baseline visit.

17. The subject has received cell-based immunotherapy treatment within 3 monthsprior to baseline visit.

18. The subject has used any of the following classes of medication (prescriptionor over-the-counter) within specific time frames before the study drugtreatment:

• Systemic corticosteroids within 4 weeks.
• Leukotriene modifiers within 4 weeks.
• Cyclosporine within 4 weeks, or other immunosuppressants (e.g. gold salts,methotrexate, azathioprine) within 4 weeks.
• IFN-γ within 12 weeks, or other immunomodulating drugs within 4 weeks.
• Allergen immunotherapy within 1 year.
• JAK inhibitor within 4 weeks.

19. The subject has received phototherapy within 4 weeks before the study drugtreatment.

20. The subject has received live vaccine within 12 weeks before the study drugtreatment.

21. The subject has presence of skin comorbidities that may interfere with studyassessments.

22. The subject has known or suspected history of immunosuppression, includinghistory of opportunistic infections (e.g., TB) per investigator's judgment.

23. The subject has active chronic or acute infection requiring treatment withsystemic antibiotics, antivirals, antiparasitics, antiprotozoals, orantifungals within 2 weeks before the baseline visit, or superficial skininfections within 1 week before the baseline visit.Note: Patients with resolved infection may be rescreened.

24. The subject has history of malignancy within 5 years before the screeningperiod, except completely treated in situ carcinoma of the cervix, completelytreated and resolved non-metastatic squamous or basal cell carcinoma of theskin.

25. The subject has planned or anticipated the use of any prohibited medicationsand procedures during the entire study period.

26. The subject has planned or anticipated major surgical procedure during theentire study period.

27. High risk of parasite infection. Evidence of parasitic infection designated ashaving the following two items: • Risk factors for parasitic disease include living in an endemic area,experiencing chronic gastrointestinal symptoms, traveling to regions wheregeohelminthic infections are endemic within the last 6 months, and/or havingchronic immunosuppression).AND • Evidence of parasitic colonization or infection found during stool evaluationfor ova and parasites.Note: stool ova and parasite evaluation will only be conducted in patients withrisk factors and an eosinophil count more than twice the upper limit of normal.