This is a single-arm long-term extension study that will enroll participants with PNH who have completed participation in Alexion-sponsored clinical studies with danicopan as an add on therapy to a C5i.

The total duration of the study will be up to 3 years. Eligible participants must complete all study assessments on the parent protocol before starting this study. All participants entering this study will receive danicopan as an add-on to a background C5i therapy. The only allowed C5i therapies are eculizumab and ravulizumab.

Key Inclusion Criteria:

• All participants who completed their participation in an Alexion sponsored clinical study with danicopan as an add on to a C5i treatment.
• Patient is capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the informed consent form and in this protocol.
• Documentation of vaccination for Neisseria meningitidis: All participants must be revaccinated as per national vaccination guidelines or local practice for vaccination use with complement inhibitors.

Key Exclusion Criteria:

• Any medical condition (for example, cardiac, pulmonary, renal, oncologic, or psychiatric) that, in the opinion of the Investigator, might interfere with participation in the study, pose any added risk to the participant, or confound the assessment of the participant.
• Patient has been permanently discontinued from danicopan in the parent study for any reason other than enrollment into this LTE study.
• Female participants who are pregnant, breastfeeding, or intending to conceive during the course of the study.

Alexion has a public commitment to allow requests for access to study data and will be supplying a protocol, CSR, and plain language summaries.