The purpose of this study is to determine the absolute bioavailability of SC administered cizutamig in healthy adult participants.

This is a randomized, double-blind, Phase 1 study designed to determine the absolute bioavailability of SC administered cizutamig in healthy adult participants. The study will enroll participants in SC and IV cohorts.

Inclusion Criteria:

1. 18-65 years of age
2. Body mass index 18-30 kg/m2 and weight 55-100 kg
3. Individuals in good health
4. Meets vaccination requirements as defined by the protocol
5. Agree to abstain from consumption of alcohol within 48-hrs of study visits
6. Agree to the use of highly effective contraception as defined by the protocol

Exclusion Criteria:

1. Active Infection
2. Inadequate clinical laboratory parameters at Screening
3. Receipt of or inability to discontinue any excluded therapies
4. Individuals who will decline blood products
5. Individuals with immediate household contacts with young children (eg, ≤ 6 years old) or immunocompromised persons
6. History of drug or alcohol abuse within last 12 months
7. Individuals who are hypersensitive to intravenous immunoglobulin (IVIg)
8. History of severe allergic or anaphylactic reactions to mAb therapy (or recombination antibody-related fusion proteins) or any constituents of study drug
9. Major surgery requiring the use of general anesthesia within 12 weeks prior to Screening or planned or expected major surgery during the study period (from Screening to the individual's last visit)
10. Blood donation or significant blood loss within 30 days prior to screening
11. Individuals considered to be part of a vulnerable population (eg, incarceration)
12. Individuals that in the opinion of the Investigator, are not suitable for participation in the trial
13. Inability to comply with protocol-mandated requirements