Study of ALXN1101 in Neonates With Molybdenum Cofactor Deficiency (MOCD) Type A

Inclusion Criteria:

- Male or female neonatal patient (1 to 28 days of age [inclusive] at the time of
ALXN1101 administration, with day 1 of age corresponding to the day of birth)

- Diagnosis of MoCD Type A, based on

- Prenatal genetic diagnosis, or

- Onset of clinical and/or laboratory signs and symptoms consistent with MoCD Type A
(eg, seizures, exaggerated startle response, high-pitched cry, axial hypotonia, limb
hypertonia, feeding difficulties, elevated urinary sulfite and/or SSC, elevated
xanthine in urine or blood, or low or absent uric acid in the urine or blood) within
the first 28 days after birth

- Parent or legal guardian must have signed the informed consent form (ICF) prior to any
study procedures being performed

Exclusion Criteria:

- Diagnosis other than MoCD Type A (may be determined after the initiation of study
drug)

- Condition that is considered by the treating physician to be a contraindication to
therapy, including evidence of abnormalities on brain imaging not attributable to MoCD
Type A, or that might otherwise interfere with the patient's participation in the
study, pose any additional risk for the patient, or confound patient assessments

- Antenatal and/or postnatal brain imaging prior to initiation of treatment with
ALXN1101 that indicates cortical or subcortical cystic encephalomalacia, clinically
significant intracranial hemorrhage, or other abnormalities on brain imaging
determined by the treating physician to be clinically significant

- Modified Glasgow Coma Scale (mGCS) for Infants and Children score of less than 7 for
more than 24 hours (This criterion does not apply to children less than 1 day in age).