The primary purpose of this study is to evaluate whether the drug EI-001 can help improve vitiligo symptoms. EI-001 is a novel antibody drug that affects the immune system to decrease uncontrolled inflammation. EI-001 has been investigated in human cell cultures, animal studies, and in a Phase 1 healthy volunteer study. The results so far show that EI-001 is a tolerable and potential new treatment for immune diseases such as vitiligo.

Inclusion Criteria:

• Able to understand and voluntarily sign the informed consent form (ICF).
• Male or female, aged 18-65 years at the time of consent.
• BMI 18-38 kg/m² and weight ≥ 40 kg at consent. Clinically diagnosed non-segmental vitiligo (NSV) for at least 3 months, and meets one of the following:
• Inadequate response to approved treatments:
• Topical therapy (e.g., corticosteroids, calcineurin inhibitors, or JAK inhibitors) ≥ 3 months,
• Phototherapy ≥ 6 months, or Oral therapy (e.g., corticosteroids, calcineurin inhibitors) ≥ 3 months.
• Or unable to use these treatments due to contraindications, intolerance, or unsuitability.
• Depigmentation extent meeting all of the following:

Facial BSA (F-BSA) ≥ 0.5%, Facial VASI (F-VASI) ≥ 0.5, Total BSA (T-BSA) between 5% and 60%, Total VASI (T-VASI) ≥ 5.

• Agree to discontinue all vitiligo treatments from screening until final follow-up.
• If not previously vaccinated against zoster, agree to complete vaccination before Day 1.
• Contraception
• Not applicable to females of non-childbearing potential (surgically sterile or postmenopausal ≥12 months, confirmed by FSH at screening).

Exclusion Criteria:

• Non-eligible skin conditions: Other types of vitiligo (e.g., segmental) or other depigmentation disorders (e.g., piebaldism, leprosy, post-inflammatory hypopigmentation, tinea versicolor, etc.), or ≥30% leukotrichia on face or body.
• Psychiatric risk
• Recent vitiligo treatments
• Surgical treatments or depigmenting agents (e.g., monobenzone)
• High-dose steroids
• Pregnancy or lactation
• Abnormal Medical conditions
• Prohibited prior therapies
• Cardiac abnormalities
• Abnormal chest X-ray
• Renal impairment
• Clinically significant abnormal laboratory results at screening, per investigator judgment.
• Viral infections:
• Hypersensitivity: Known allergy or severe reaction to EI-001 or its excipients.
• Compliance concerns: Any condition that would make it difficult for the subject to follow the study schedule, receive treatment, attend visits, or could interfere with study objectives, data interpretation, or participant safety.