Study of Danicopan in Participants With Paroxysmal Nocturnal Hemoglobinuria (PNH)

Inclusion Criteria: * Currently untreated PNH participants with PNH Type III erythrocyte and/or granulocyte clone size ≥10% and anemia (hemoglobin \<12 grams/deciliter) with adequate reticulocytosis (as determined by the Investigator). * LDH ≥1.5 x the upper limit of normal. * Platelets ≥50,000/microliter without the need for platelet transfusions. * Documentation of vaccination for Neisseria meningitidis, Haemophilus influenza, and Streptococcus pneumoniae, or willingness to receive vaccinations during the screening period. * Negative pregnancy test for females prior to dosing and throughout the study. Exclusion Criteria: * History of a major organ transplant (for example, heart, lung, kidney, liver) or hematopoietic stem cell/marrow transplant. * Participants who had received another investigational agent within 30 days or 5 half-lives of the investigational agent prior to study entry, whichever is greater. * Participants who had received eculizumab at any dose or interval within the past 75 days before study entry. * Participants with known or suspected complement deficiency. * Participants with active bacterial infection or clinically significant active viral infection, a body temperature \>38°Celsius, or other evidence of infection on Day 1, or with a history of febrile illness within 14 days prior to first study drug administration. * History of meningococcal infection, or a first-degree relative or household contact with a history of meningococcal infection. * Females who were pregnant, nursing, or planning to become pregnant during the study or within 90 days of study drug administration or participants with a female partner who was pregnant, nursing, or planning to become pregnant during the study or within 90 days of study drug administration.