This is a 2-part open-label, randomized, single-dose, 3-sequence, 3-period crossover, relative bioavailability, and food-effect study comparing different formulations of danicopan in healthy adult participants.

For both parts of this study, on Day 1 of each period, participants will receive a single oral dose of danicopan as either the prototype powder-in-capsule (PIC) formulation (1 or 2) under fed conditions, the prototype PIC formulation (1 or 2) under fasting conditions, or the tablet formulation under fed conditions.

Inclusion Criteria:

1. No clinically significant findings at screening (medical history, clinical laboratory profiles, and electrocardiograms).
2. Body mass index in the range of 18.0 to 32.0 kilograms (kg)/meter squared, inclusive, with a minimum body weight of 50.0 kg at screening.
3. Female participants of childbearing potential must either agree to abstinence or to use, with their male partner, a highly effective method of contraception .
4. Non-sterile male participants must agree to abstinence or use a highly effective method of contraception.

Exclusion Criteria:

1. History of any medical or psychiatric condition or disease that 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.
2. History or presence of drug or alcohol abuse within previous 2 years, current tobacco user, or positive drugs-of-abuse screen or alcohol screen at screening or Day -1 of Period 1.
3. History of meningococcal infection, or a first-degree relative with a history of meningococcal infection.
4. History of procedures that could alter absorption or excretion of orally administered drugs.
5. History of significant multiple and/or severe allergies or has had an anaphylactic reaction or significant intolerability to prescription or non-prescription drugs.
6. Body temperature ≥ 38.0°Celcius at screening or prior to first dosing or history of febrile illness, or other evidence of infection, within 14 days prior to (first) dosing.
7. Participation in any other investigational study drug trial in which receipt of an investigational study drug occurred within 5 half-lives (if known) or 30 days before first dosing, whichever is longer.
8. Donation of whole blood from 3 months prior to first dosing, or of plasma from 30 days before first dosing, receipt of blood products within 6 months prior to first dosing, or receipt of a vaccine within 30 days prior to first dosing.
9. Is a female with a positive pregnancy test or who is lactating.