The main purpose of this study is to evaluate how eltrekibart is absorbed by the body when it is given under the skin to healthy participants.

The study will last about 17 weeks.

Inclusion Criteria:

• Are overtly healthy as determined by medical evaluation including medical history and physical examination
• Have a minimum body weight of 45 kilograms (kg).
• Have a body mass index (BMI) within the range of 18.5 to 28.5 kilograms per square meter (kg/m²), inclusive

Exclusion Criteria:

• Have multiple severe allergies to prescription or nonprescription drugs

• Are immunocompromised

• Have had any of the following types of infection within 3 months prior to the screening visit:

  • Serious, that is, requiring hospitalization, or intravenous or equivalent oral antibiotic treatment

  • Opportunistic infections Note: Herpes zoster is considered active and ongoing until all vesicles are dry and crusted over

  • Chronic, that is, duration of symptoms, signs, or treatment of 6 weeks or longer, or

  • Recurring, including, but not limited to:

    • herpes simplex,
    • herpes zoster,
    • recurring cellulitis, or
    • chronic osteomyelitis.

• Are currently pregnant or are intending to become pregnant or to breastfeed at any time in the study or within 16 weeks after receiving the single dose of study intervention.