Study of Danicopan as Add-on Treatment to Ravulizumab or Eculizumab in Pediatric Participants With PNH Who Have Clinically Significant Extravascular Hemolysis

Inclusion Criteria:

• Confirmed diagnosis of PNH.

• CS-EVH defined by: Anemia: Hgb ≤ 10.5 g/dL, and absolute reticulocyte count ≥ 100 × 109/L

• Treated with ravulizumab or eculizumab for at least 12 weeks immediately precedingDay 1, the dose received should be stable during this period, and there should be noanticipated changes in dosage or interval during the first 12 weeks of this study.

• all participants must be vaccinated against meningococcal infection from serogroupsA, C, W, and Y and serogroup B within 3 years prior to, or at least 14 days prior toDay 1

• vaccinated against Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae

Exclusion Criteria:

• Platelet count < 30000/μL or there is a need for platelet transfusions.

• ANC < 500/μL.

• Clinically significant laboratory abnormalities related to liver function,including:

• ALT > 2 × ULN or ALT > 3 × ULN for participants with documented liver ironoverload defined by serum ferritin values ≥ 500 ng/mL.

• Direct bilirubin > 2 × ULN, unless, in the Investigator's opinion, is due tohemolysis or Gilbert's syndrome based on medical history.

• Current evidence of biliary cholestasis.

• Known aplastic anemia or other bone marrow failure that requires HSCT or othertherapies, including anti-thymocyte globulin and immunosuppressants unless thedosage of immunosuppressant has been stable for at least 12 weeks before Day 1 andis expected to remain stable through Week 12.

• History of a major organ transplant (eg, heart, lung, kidney, liver) or HSCT.

• Known or suspected complement deficiency.

• Active bacterial or viral infection, a body temperature > 38°C on 2 consecutivedaily measures, evidence of other infection, or history of any febrile illnesswithin 14 days prior to first study intervention administration.