This is a Phase 1 bridging study being conducted to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of ALXN2050 after both single- and multiple-dosing in healthy participants of Japanese descent.

Key Inclusion Criteria:

• Medically healthy with no clinically significant or relevant abnormalities as determined by medical history, physical or neurological examination, vital signs, 12-lead electrocardiogram, screening clinical laboratory profiles.

• 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 greater than 5 years;
  • Lifestyle, including diet, must not have significantly changed since leaving Japan.

• Participants must be able to speak, read, and understand the Japanese and English languages.

• Body mass index within the range 18.5 to 30.0 kilograms (kg)/meter squared, inclusive, with a minimum body weight of 50.0 kg at Screening.

Key Exclusion Criteria:

• History of any medical or psychiatric condition or disease that, in the opinion of the Investigator or designee, might limit the participant's ability to complete or participate in this clinical study, confound the results of the study, or pose an additional risk to the participant by their participation in the study.
• History of significant multiple and/or severe allergies.
• Any previous procedure that could alter absorption or excretion of orally administered drugs.
• Participation in another investigational drug or investigational device study within 5 half-lives (if known) or 30 days prior to the first dose of study intervention, whichever is longer.
• Body temperature ≥ 38.0°Celcius, at Screening or prior to the first dose of study intervention.
• History of drug or alcohol abuse within 2 years prior to the first dose of study intervention or positive drugs-of-abuse or alcohol screen at Screening or Day -1; current tobacco/nicotine users or smokers or a positive cotinine test at Screening.
• Donation of whole blood from 3 months prior to the first dose of study intervention, or of plasma from 30 days prior to the first dose of study intervention; receipt of blood products within 6 months prior to the first dose of study intervention.