Single Arm Study of ALXN1210 in Complement Inhibitor Treatment-Naïve Adult and Adolescent Patients With Atypical Hemolytic Uremic Syndrome (aHUS)

Inclusion Criteria:

1. Male or female ≥ 12 years of age and weighing ≥ 40 kg at the time of consent.

2. Evidence of thrombotic microangiopathy (TMA), including low platelet count, hemolysis
(breaking of red blood cells inside of blood vessels), and decreased kidney function

3. Documented meningococcal vaccination not more than 3 years prior to, or at the time
of, initiating study drug. Patients who receive a meningococcal vaccine less than 2
weeks before initiating ALXN1210 treatment must receive treatment with appropriate
prophylactic antibiotics until 2 weeks after vaccination. Patients who have not been
vaccinated prior to initiating ALXN1210 treatment should receive prophylactic
antibiotics prior to and for at least 2 weeks after meningococcal vaccination.
Patients < 18 years of age must have been vaccinated against Haemophilus influenzae
type b (Hib) and Streptococcus pneumoniae according to national and local vaccination
schedule guidelines.

4. 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. ADAMTS13 deficiency (Activity < 5%)

2. Shiga toxin-related hemolytic uremic syndrome (STEC-HUS)

3. Positive direct Coombs test

4. Pregnancy or breastfeeding

5. Identified drug exposure- related hemolytic uremic syndrome (HUS)

6. Bone marrow transplant (BMT)/hematopoietic stem cell transplant (HSCT) within last 6
months prior to start of Screening

7. HUS related to known genetic defects of cobalamin C metabolism

8. Systemic sclerosis (scleroderma), systemic lupus erythematosus (SLE), or
antiphospholipid antibody positivity or syndrome

9. Chronic dialysis (defined as dialysis on a regular basis as renal replacement therapy
for ESKD)