This study will evaluate the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of single ascending doses of AZD6912 administered subcutaneously (SC) in healthy participants.

In this First-In-Human (FiH) study, eligible participants will be randomly assigned to 6 cohorts in a 3:1 ratio to receive either a single dose of AZD6912 SC or placebo. The first 2 participants in each cohort will be dosed as a sentinel pair, with one receiving AZD6912 SC and the other receiving placebo.

The study will comprise of, a screening period of 70 days, a treatment period where participants will stay at the Clinical Unit from the day before study intervention administration until at least 240 hours and will be discharged on Day 11. Outpatient visits would start weekly from Day 15, then bi-weekly from Day 43, 4-weekly from Day 99, and 6-weekly from Day 155, with additional follow-up visits approximately every 4 weeks as needed until complement activity returns to the normal range.

The study will last approximately 25 months, including the optional Japanese cohorts, with each participant participating for about 38 weeks or longer until complement activity returns to normal range (per local laboratory).

Inclusion Criteria:

• Females must have a negative pregnancy test.

• Contraceptive use by males and females should be consistent with local regulations.

• Have a body mass index (BMI) between 18 and 30 kg/m2 inclusive and weigh at least 50 kg.

• For optional Japanese participants only:

  • Participants must be of Japanese descent defined as: first generation (born to 2 Japanese parents and 4 Japanese grandparents).
  • Born in Japan, and not have lived outside Japan for more than 5 years.
  • Lifestyle, including diet, must not have significantly changed since leaving Japan.

Exclusion Criteria:

• History of any clinically important disease or disorder.
• Current or recurrent disease of clinical significance that could affect clinical assessments or clinical laboratory evaluations.
• Any clinically important illness, medical/surgical procedure or trauma within 4 weeks of the first administration of study intervention.
• History of congenital or acquired immunodeficiency or complement deficiency or an underlying condition that predisposes to infection.
• History of any Neisseria infection, unexplained, recurrent infections, or infection requiring treatment with systemic antibiotics.
• Evidence of hepatitis B infection (positive for HBsAg or positive for anti-HBcAb) or hepatitis C viral infection (HCV Abs or hepatitis C RNA positive) or HIV infection (positive for HIV type 1 or type 2 Abs).
• Participants testing positive for COVID-19 prior to dosing.
• Any cardiac abnormalities.
• A CAP activity < 60% at screening.
• Known or suspected history of drug abuse, history of alcohol abuse or smoking.

Qualified researchers can request access to anonymized individual patient-level data from AstraZeneca group of companies sponsored clinical trials via the request portal Vivli.org. All requests will be evaluated as per the AZ disclosure commitment: https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure. "Yes", indicates that AZ are accepting requests for IPD, but this does not mean all requests will be approved.

AstraZeneca will meet or exceed data availability as per the commitments made to the EFPIA/PhRMA Data-Sharing Principles. For details of our timelines, please refer to our disclosure commitment at https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

When a request has been approved AstraZeneca will provide access to the anonymized individual patient-level data via secure research environment Vivli.org. A Signed Data Usage Agreement (non-negotiable contract for data accessors) must be in place before accessing requested information.