A Study of Subcutaneous Gefurulimab Using Prefilled Syringe Versus Autoinjector in Healthy Adult Participants

This is an open-label, randomized, parallel-group study.

The study consists of 2 periods: a Screening Period (up to 70 days), and an Evaluation Period of 92 days.

Separate randomization lists will be produced for each weight stratum (50 to < 70 kg, 70 to < 90 kg, and 90 to < 110 kg) and within each of the three weight strata, participants will be randomized 1:1:1:1:1:1 to one of the six combinations of device (prefilled syringe with needle safety device [PFS-SD] or autoinjector [AI]) and injection site (abdomen, thigh, or upper arm),

Participants will receive a single dose of 600 mg gefurulimab on Day 1, will be residential at the clinical unit until Day 5, will have visits on Day 8, quaque week (once a week) [qw] thereafter until Day 50, and quaque 2 week (once every two weeks) [q2w] from Day 50 until Day 92 during the Evaluation Period.

The total study duration is up to 162 days.

Inclusion criteria

• Participants must be 18 to 65 years of age inclusive, at the time of signing the informed consent.
• Body weight within ≥ 50 to < 110 kg and body mass index (BMI) within the range 18.5 to 30 kg/m2 (inclusive)
• Participants who are healthy as determined by medical evaluation with no clinically significant or relevant abnormalities as determined by medical history, physical examination, vital signs, 12-lead ECG, and clinical laboratory evaluation.
• QT interval corrected using Fridericia's formula (QTcF) ≤ 450 msec for male participants and ≤ 460 msec for female participants at Screening and prior to dosing on Day 1.
• Documented vaccination against meningococcal infection from serogroups A, C, W, and Y and serogroup B.
• Male and female participants should adhere to study-specific contraceptive methods.

Exclusion criteria

• History of any Neisseria meningitidis infection.
• History or presence of cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrinological, hematological, or neurological disorders.
• Abnormal blood pressure as determined by the Investigator.
• History of latent or active TB (Tuberculosis) or exposure to endemic areas.
• Allergy to monoclonal antibodies.
• Clinically significant multiple or severe drug allergies, intolerance to topical corticosteroids, or severe posttreatment hypersensitivity reactions.
• Lymphoma, leukemia, or any malignancy within the past 5 years except for basal cell or squamous epithelial carcinomas of the skin that have been resected with no evidence of metastatic disease for 3 years.
• Current or chronic history of liver disease.
• Known hepatic or biliary abnormalities.
• Active systemic bacterial, viral, or fungal infection within 14 days prior to dosing.
• History of allergy or intolerance to penicillin or cephalosporin.
• History of clinically significant allergic reaction (eg, anaphylaxis or angioedema) to any product.
• Live vaccine(s) within 1 month prior to Screening or plans to receive such vaccines during the study.
• Evidence of human immunodeficiency virus (HIV) infection (positive HIV type 1 or type 2 antibody).
• Evidence of hepatitis B infection (positive hepatitis B surface antigen [HBsAg] or positive total hepatitis B core antibody [HBcAb] with negative surface antibody [anti-HBs]), or hepatitis C viral infection (positive HCV RNA).
• Female participants who have a positive pregnancy test at Screening or Admission.
• Positive prestudy drug/alcohol screen; positive result may be repeated once.