The goal of this Phase Ia clinical trial is to evaluate the safety, tolerability, and pharmacokinetics of EB070 injection following single ascending subcutaneous doses in healthy adult volunteers.

The main questions it aims to answer are:

Is EB070 injection safe and well tolerated at increasing single subcutaneous dose levels in healthy subjects?

What are the pharmacokinetic characteristics of EB070 after single-dose administration?

This is a single-center, randomized, double-blind, placebo-controlled, single ascending-dose (SAD) study. A total of 36 healthy volunteers will be enrolled and assigned to one of five dose cohorts (21 mg, 75 mg, 225 mg, 450 mg, or 600 mg). Subjects in each cohort will be randomized in a 3:1 ratio to receive a single subcutaneous injection of EB070 or placebo.

A sentinel dosing strategy will be applied. In the 21 mg cohort, one subject will initially receive EB070. In the remaining cohorts, two sentinel subjects (one receiving EB070 and one receiving placebo) will be dosed first. Dose escalation and enrollment of the remaining subjects will proceed after evaluation of safety and tolerability within 48 hours after dosing.

Participants will:

Undergo screening assessments prior to dosing

Receive a single subcutaneous injection of EB070 or placebo

Stay in the Phase I unit for approximately 3 days for safety monitoring and pharmacokinetic and anti-drug antibody (ADA) sample collection

Return for scheduled outpatient visits for PK, ADA, and safety assessments through Day 113

Safety will be assessed throughout the study by monitoring adverse events, vital signs, physical examinations, 12-lead ECGs, and laboratory tests. Pharmacokinetic parameters and anti-drug antibodies (ADA) will be evaluated as secondary outcomes.

Inclusion Criteria:

• Age: 18 to 60 years old.
• Sex: Healthy male and female participants.
• Body weight: ≥50 kg for males and ≥45 kg for females; body mass index (BMI = weight [kg] / height [m²]) between 18 and 26 kg/m².
• Participants of reproductive potential (both male and female) must agree to use reliable contraception (hormonal, barrier method, or abstinence) during the study and for at least 3 months after study completion. Female participants of childbearing potential must have a negative pregnancy test (β-HCG) at screening and baseline and must not be breastfeeding.
• Informed consent: Participants must have been adequately informed about the study, voluntarily sign the informed consent form, and be willing and able to comply with study procedures.

Exclusion Criteria:

• Abnormal findings at screening in physical examination, vital signs, 12-lead ECG, or laboratory tests (including hematology, urinalysis, blood biochemistry, coagulation function, and thyroid function) deemed clinically significant by the investigator.
• Positive serology for any of the following: hepatitis B surface antigen, hepatitis C antibody, syphilis antibody, or HIV antigen/antibody.
• History of any clinically significant disease affecting the respiratory, digestive, cardiovascular, hematologic/lymphatic, nervous, psychiatric, genitourinary, endocrine, hepatic, renal, dermatologic, or metabolic systems, or any other condition that could interfere with study results.
• Blood pressure at screening: systolic ≥140 mmHg or <90 mmHg, or diastolic ≥90 mmHg or <50 mmHg.
• Planned major surgery during the study, or major surgery within 1 month prior to randomization.
• History of chronic infection, particularly bacterial, viral, fungal, or parasitic infection within 1 month prior to randomization.
• Known allergy to EB070 or any excipients, history of hypersensitivity to antibody-based biologics, or history of specific allergic conditions (e.g., allergic conjunctivitis, allergic asthma, atopic dermatitis), or any clinically significant food, drug, insect bite, foreign protein, or monoclonal antibody allergy as judged by the investigator.
• Alcohol abuse: ≥28 standard drinks per week within 1 year prior to randomization, or frequent drinking (>14 standard drinks/week) within 6 months prior to randomization; or failed breath alcohol test (>0 mg/100 mL) at screening or Day 1. (One standard drink contains 14 g alcohol, e.g., 360 mL beer, 45 mL 40% liquor, or 150 mL wine.)
• Smoking ≥5 cigarettes per day or equivalent tobacco use (e.g., nicotine gum/lozenges) within 3 months prior to randomization, inability to abstain during the study, or positive urine cotinine test at screening or Day 1.
• Participation in any clinical trial of an investigational drug within 3 months prior to randomization (or within 5 half-lives, whichever is longer).
• Use of any medications or dietary supplements (prescription, over-the-counter, herbal, or traditional Chinese medicine) within 14 days prior to randomization, or within 5 half-lives of the study drug.
• Use of any biologic products within 3 months prior to randomization (or within 5 half-lives, whichever is longer).
• Administration of live or attenuated vaccines within 1 month prior to randomization or planned during the study.
• History of substance abuse (e.g., morphine, cannabis, methamphetamine, MDMA, ketamine) within 1 year prior to randomization, or positive urine drug screen at screening or Day 1.
• Blood donation or significant blood loss (≥400 mL) within 3 months prior to randomization, or planned donation during the study or within 3 months after study completion.
• History of syncope or needle phobia, or inability to tolerate blood draws.
• Positive interferon-gamma release assay (T-SPOT.TB). Subjects without tuberculosis history or symptoms may be included if results are within twice the upper limit of normal.
• Any other condition that the investigator judges makes the participant unsuitable for the study.