A Phase 3, Open-Label Study of ALXN1210 in Children and Adolescents With Paroxysmal Nocturnal Hemoglobinuria (PNH)

Inclusion Criteria:

1. Patients from birth up to < 18 years of age and weighing ≥ 5 kg at the time of
consent.

2. PNH diagnosis confirmed by documented by high-sensitivity flow cytometry

3. Presence of 1 or more of the following PNH-related signs or symptoms within 3 months
of Screening: fatigue, hemoglobinuria, abdominal pain, shortness of breath (dyspnea),
anemia, history of a major adverse vascular event (including thrombosis), dysphagia,
or erectile dysfunction; or history of pRBC transfusion due to PNH.

4. LDH level ≥ 1.5 × ULN for patients not being treated with eculizumab at screening and
LDH level ≤ 1.5 × ULN for patients taking eculizumab.

5. Documented meningococcal vaccination not more than 3 years prior to dosing, and
vaccination against Streptococcus pneumoniae and Haemophilus influenzae

6. Female patients of childbearing potential must use highly effective contraception
starting at screening and continuing until at least 8 months after the last dose of
ALXN1210

Exclusion Criteria:

1. History of Bone Marrow transplantation

2. History of or ongoing major cardiac, pulmonary, renal, endocrine, or hepatic disease
that, in the opinion of the investigator or sponsor, would preclude participation.

3. Unstable medical conditions (eg, myocardial ischemia, active gastrointestinal bleed,
severe congestive heart failure, anticipated need for major surgery within 6 months of
randomization, coexisting chronic anemia unrelated to PNH)

4. Females who are pregnant, breastfeeding or who have a positive pregnancy test at
screening or Day 1

5. Participation in another interventional clinical study or use of any experimental
therapy within 30 days before initiation of study drug on Day 1 in this study or
within 5 half-lives of that investigational product, whichever is greater.