This Phase 1, first-in-human study will evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of CLYM116 in healthy volunteers.

CLYM116 is a humanized monoclonal antibody that selectively binds to a proliferation inducing ligand (APRIL). This is a Phase 1, randomized, double-blind, placebo-controlled, single-center study designed to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and immunogenicity of CLYM116 in adult normal healthy volunteers (NHVs). The study will enroll up to 48 subjects, across up to five cohorts.

Inclusion Criteria:

• Healthy adult males and females aged 18-60 years, inclusive
• Body mass index (BMI) between 18 and 32 kg/m² and weight between 45 and 110 kg
• Clinically normal medical history, physical exam, ECG, and laboratory results (or abnormalities deemed not clinically significant)
• Willing and able to comply with study procedures and provide informed consent
• Women of childbearing potential must use highly effective contraception and have negative pregnancy tests
• Men must use contraception and refrain from sperm donation for 4 months post-dose
• Completion of COVID-19 vaccination according to local guidelines, as well as influenza vaccination (within 12 months)

Exclusion Criteria:

• Prior treatment with investigational drugs within 30 days or 5 half-lives
• Previous or current hypogammaglobulinemia
• Current presence of allergic reactions considered clinically significant
• Positive tests for HIV, hepatitis B/C, syphilis, or tuberculosis
• Tobacco use (>2 cigarettes/day), alcohol abuse, or drug abuse
• Recent live vaccination (within 21 days) or any non-live vaccine (within 14 days)