• Percentage change of F-VASI relative to baseline in week 24

Primary Objectives: - Evaluate the efficacy of EI-001 compared to baseline Secondary Objectives: - Evaluate the long-term safety and tolerability of EI-001 compared to placebo - Evaluate the efficacy of EI-001 compared to placebo Exploratory Objectives: - Evaluate the pharmacokinetic (PK) characteristics of EI-001 - Analyze the PD (proliferative) effect of EI-001 - Evaluate the immunogenicity of EI-001

EI-001

EI-001

Intravenous infusion

100 mg/10 mL

• Percentage change of F-VASI relative to baseline in week 24

1. Must be able to understand and be willing to sign the participant consent form.

2. Must be a male or female aged 18 to 65 years at the time of consent signing.

3. Must have a body mass index between 18 and 38 kg/m² and weigh at least 40 kg at the time of signing the consent form.

4. Clinically diagnosed with non-segmented vitiligo (NSV), with a recorded history of NSV (at least 3 months), and meeting one or both of the following criteria:

a. Inadequate response to approved or recognized therapies, including any of the following:

i. Received at least 3 months of topical treatment (corticosteroids, calcineurin inhibitors, or JAK inhibitors (JAKI)) with unsatisfactory results;

ii. Received at least 6 months of phototherapy without satisfactory results;

iii. Received at least 3 months of clinically recognized oral treatment (corticosteroids or calcineurin inhibitors) without satisfactory results.

b. Contraindicated, intolerant, or unsuitable for approved or recognized treatments (such as topical treatment [corticosteroids, calcineurin inhibitors, or JAKI], phototherapy, or clinically recognized oral treatment [corticosteroids or calcineurin inhibitors]);

5. Depigmented areas include:

a. Facial body surface area (F-BSA) ≥ 0.5%, and
b. Facial vitiligo area score index (F-VASI) ≥ 0.5, and
c. 5% ≤ Total surface area (T-BSA) ≤ 60%, and
d. Total vitiligo area score index (T-VASI) ≥ 5.

6. Agree to discontinue all medications and procedures for treating vitiligo from screening to the final safety follow-up visit.

7. If not previously vaccinated against shingles, agree to complete the vaccination before Day 1 of the trial.

8. Agree to use the following contraceptive methods:

a. Female and male subjects of fertility must agree to use appropriate contraceptive methods with a success rate of at least 99% from the screening period until 90 days after the last dose of the trial intervention to avoid pregnancy.

b. During this period, male subjects must avoid donating sperm. During this period, female subjects must avoid donating oocytes.

c. Subjects should be informed of permitted contraceptive methods with a success rate of at least 99%, and confirm that they fully understand.

Note: This standard does not apply to women who are infertile (e.g., those who have undergone surgical sterilization with hysterectomy and/or bilateral oophorectomy, or women who have reached menopause; menopause is defined as the absence of menstruation for at least 12 months prior to screening, and confirmed by FSH test values ​​at the time of screening).

1. Other forms of vitiligo (e.g., segmented vitiligo) or other skin depigmentation disorders (e.g., piebaldism, pityriasis alba, leprosy, post-inflammatory hypopigmentation, progressive macular hypomelanosis, nevus anemicus, chemical vitiligo, tinea versicolor), or a prevalence of ≥30% of facial or body hair (including albinism).

2. A lifelong history of any serious or recurrent suicidal behavior, or any mental illness, including recent or ongoing suicidal ideation or behavior (with some intention but no specific plan, or with a specific plan and intention), and answer "yes" to one of the following two questions (based on the Columbia Suicide Severity Assessment Scale):

- Question 1: Have you ever had suicidal thoughts and intended to act on them?

Or,

- Question 2: Have you started thinking about or considering specific methods of suicide? Do you intend to carry out this plan?

3. Use of the following for vitiligo treatment:

a. Received laser or phototherapy (phototherapy), including tanning beds, within 8 weeks prior to Day 1;

b. Use of dihydroxyacetone (commonly found in self-tanning products) within 8 weeks prior to Day 1;

c. Melanocyte-keratinocyte transplantation or other vitiligo surgical treatment;

d. Use of depigmenting agents such as hydroquinone monobenzyl ether, including Benoquin® (benzophenone), before Day 1.

4. Use of ≥ 10 mg/day of intravenous systemic steroid therapy (prednisone or equivalent) for a condition other than vitiligo within 6 months prior to Day 1.

5. Pregnant, considering pregnancy, or breastfeeding women.

6. The following concomitant conditions or history of other medical conditions:

a. Any clinically significant medical condition other than vitiligo, as determined by the trial administrator, that is not adequately controlled without proper treatment and may pose additional safety risks to the subject or may interfere with the assessment of safety or efficacy in this trial.

b. Active acute or chronic skin infection requiring treatment with systemic antibiotics, antivirals, antiparasitics, antiprotozoal drugs, or antifungals within 8 weeks prior to Day 1, or a superficial skin infection within 2 weeks prior to Day 1.

Note: Subjects may be re-screened after infection resolution.

c. Any other active skin disease or condition that may affect the assessment of the course or severity of non-segmented vitiligo (NSV) in this trial.

d. History of hospitalization, parenteral antimicrobial therapy, or a clinically significant systemic infection as determined by the trial administrator within 6 months prior to Day 1.

e. Previous infection with Pneumocystis jirovecii, tuberculosis (TB), nontuberculous mycobacteria (NTM), or other bacterial, fungal, or viral infections deemed unsuitable for participation in this trial by the trial administrator.

f. Current shingles infection, history of disseminated herpes simplex, or a history of shingles.

g. A history of malignant tumors (including melanoma, lymphoma, and leukemia) within 5 years prior to Day 1, excluding successfully treated non-metastatic squamous cell carcinoma of the skin, basal cell carcinoma, or localized carcinoma in situ of the cervix.

h. A history of alcohol or drug abuse within 6 months prior to Day 1, which the trial administrator determines would affect participation in the trial or adherence to the trial protocol.

i. A history of major trauma or major surgery within 1 month of the initial study intervention.

j. A history of severe infusion-related reactions (IRR) to previous medications, which the trial administrator determines are unsuitable for this study intervention.

7. Use of medications or investigational drugs during the following periods prior to Day 1 (initial administration of the study intervention):

a. For any local or systemic JAKI, < 12 weeks or 5 half-lives (if known), whichever is longer.

b. For any experimental or experimental treatment, < 12 weeks or 5 half-lives (if known), whichever is longer.

c. For biologics that induce systemic immunosuppression or immunomodulation (e.g., adalimumab, etanercept, infliximab, golimumab, certolizumab, ustekinumab, secukinumab, brodalumab, ixekizumab, risankizumab, guselkumab, bimekizumab, iscalimab, bermekimab, rituximab, anakinra), < 12 weeks or 5 half-lives (if known), whichever is longer.

d. Individuals who received a live or attenuated vaccine within 8 weeks prior to Day 1, or who are scheduled to receive a live or attenuated vaccine during the trial or within 12 weeks of the last investigational dose.

e. < 8 weeks of systemic immunosuppression or immunomodulatory small molecule drugs (e.g., oral or injectable corticosteroids, methotrexate, cyclosporine, dapsone, azathioprine) or therapies, including chemotherapy, radiation therapy, or other drugs known to suppress immune function, except for prior medications listed as permissible in the trial protocol.

Note 1: Inhaled or intranasal spray corticosteroids are permitted.

Note 2: Oral corticosteroids may be used for non-dermatological conditions (e.g., asthma exacerbation, bronchitis) for a duration not exceeding 7 days, with the approval of the trial administrator and the trial sponsor.

Note 3: Topical corticosteroids for non-vitiligo skin diseases (e.g., atopic dermatitis or psoriasis) are permitted in areas not treated for vitiligo. The total area of ​​other skin diseases outside the vitiligo treatment area must not exceed 10% of the body surface area (BSA).

f. < 3 weeks of any oral or topical PDE-4 inhibitors (e.g., apremilast, criboroxetine).

g. Any topical medication applied to vitiligo lesions for less than 2 weeks.

h. Any over-the-counter (OTC) medication used to treat vitiligo for less than 2 weeks.

i. Herbal preparations of unknown nature or known beneficial effects on vitiligo for less than 1 week.

8.12-lead electrocardiogram showing:

a. Clinically significant abnormalities requiring treatment (e.g., acute myocardial infarction, severe tachycardia or bradycardia), or conditions indicating serious underlying cardiac disease (e.g., cardiomyopathy, Wolf-Parkinson-White syndrome).

b. Confirmed QTcF prolongation (>450 ms).

9. Abnormal findings on chest screening imaging (e.g., chest X-ray), including but not limited to: lesions suggestive of active tuberculosis or a history of inactive tuberculosis, suspected or confirmed nontuberculous mycobacterial infection, Pneumocystis pneumonia, other infections, heart failure, or malignancy. A chest X-ray will be performed within 4 weeks prior to day 1 of screening.

10. Impaired renal function (beyond mild impairment) is defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m² at screening. The eGFR formula is as follows:
eGFR = 142 × min(SCr/κ,1)α × max(SCr/κ,1) - 1.200 × 0.9938 × age × 1.012 [for females]

11. If any abnormal laboratory values ​​listed in the table below are found during the screening period, you will be excluded from the trial.

Laboratory Parameter Exclusion Criteria

Hematology
a. Platelet count < Upper limit of normal (ULN)
b. Hemoglobin < 100 g/L
c. Neutrophil count (ANC) < 1.5 × 10⁹/L
d. White blood cell count (WBC) < 3 × 10⁹/L or > 10 × 10⁹/L

Liver
e. Alanine transaminase (ALT) ≥ 2 × Upper limit of normal (ULN)
f. Aspartate transaminase (AST) ≥ 2 × Upper limit of normal (ULN)

g. Total bilirubin ≥ 1.5 × Upper limit of normal (ULN)

Note: Unless clinically diagnosed as Gilbert's syndrome

Kidney
h. Serum creatinine > 1.25 × Upper limit of normal (ULN)

Coagulation
i. Prothrombin time (PT) > Upper limit of normal (ULN)

j. International Normalized Ratio (INR)

> Upper limit of normal (ULN)

12. B present Evidence of hepatitis B virus (HBV) or hepatitis C virus (HCV) infection or reactivation risk, such as: positive hepatitis B surface antigen (HBsAg), or positive HBV DNA test when HBsAg is negative and hepatitis B core antibody (HBcAb) is positive, or positive HCV RNA test when hepatitis C antibody (HCV antibody) is positive.

Note: Individuals without a history of hepatitis B virus (HBV) infection, who have been vaccinated against HBV, and whose only evidence of exposure is a positive hepatitis B surface antigen (HBsAg) antibody test (HBsAb positive) are eligible to participate in this trial.

13. Individuals with a history of HIV or a positive HIV serological test during the screening period, or those with known immunodeficiency diseases (including primary immunodeficiency diseases and acquired immunodeficiency syndromes), and any disease that causes significant impairment of the immune system.

14. Evidence of active or latent Mycobacterium tuberculosis (TB) infection, defined as follows:

a. A positive or inconclusive IGRA test performed on Day 1 or within the preceding 12 weeks will result in exclusion; a negative result is required to qualify unless other criteria described herein are met. Acceptable IGRA testing methods include QuantiFERON®-TB Gold (QFT-G), QuantiFERON®-TB Gold In-Tube (QFT-GIT), and T-SPOT®-TB. IGRA testing may be waived if the subject has received a documented and adequate course of treatment for latent or active TB infection.

b. History of latent or active TB infection.

c. Currently receiving treatment for latent or active tuberculosis infection.

15. Any of the following conditions exist:

a. Positive for Epstein-Barr virus (EBV) or cytomegalovirus (CMV);

b. Positive for Coccidioides serological test;

c. Currently having an active histoplasmosis or blastomycosis;

d. Currently having or actively infected with Salmonella, Shigella, or Campylobacter.

16. Known allergy or severe reaction to EI-001 or its excipients.

17. In the investigator's judgment, unable or unlikely to adhere to the dosing schedule and trial evaluation.

18. Any situation, in the investigator's judgment, that may affect the subject's full participation in the trial (including interventional dosing and necessary follow-up visits), impair the immune system, interfere with the trial objectives, pose a significant risk to the subject, or affect the interpretation of trial data.