Bioavailability Study of 2 Oral Formulations of ALXN1840

A Phase 1, Randomized, 2-period, 2-sequence, Crossover With Parallel-group Extension, Open-label Study to Compare the Relative Bioavailability of 2 Oral Formulations of ALXN1840 in Healthy Adult Participants

The study will assess the relative bioavailability of 2 different formulations of ALXN1840 in healthy participants.

This is a two-way crossover study consisting of 2 dosing periods assessing a test and reference formulation of ALXN1840. A dose-proportionality parallel group design extension period will be conducted following completion of the two-way crossover period of the study and will assess 5 different ascending doses of ALXN1840. There will be at least a 14-day washout following doses between Periods 1 and 2 and also at least a 14-day washout following the dose in Period 2 and the following dose in the Dose-Proportionality Extension Period.

Safety will be assessed throughout the study.

Inclusion Criteria:

• No clinically significant history or presence of electrocardiogram findings
• Body weight ≥50 to ≤100 kilograms (kg) and body mass index 18 to <32 kg/meter squared for all participants
• Willing and able to follow protocol-specified contraception requirements

Exclusion Criteria:

• History or presence of clinical and/or laboratory disorders
• Abnormal blood pressure, defined as supine blood pressure ≤90/60 millimeters of mercury (mmHg) or >140/90 mmHg
• Lymphoma, leukemia, or any malignancy within the past 5 years
• Alanine aminotransferase, aspartate aminotransferase, or total bilirubin > upper limit of normal
• Serum copper or serum ceruloplasmin below lower limit of normal
• Hemoglobin <130 grams (g)/liter (L) for males and hemoglobin <115 g/L for females
• Significant allergies
• Smoker