Open-Label Extension Study of Diazoxide Choline in Patients With Prader-Willi Syndrome

Key Inclusion Criteria:

- Successful completion of clinical study C601

- Provide voluntary, written informed consent (parent(s) / legal guardian(s) of
patient); provide voluntary, written assent (subjects, as appropriate)

Key Exclusion Criteria:

- Positive urine pregnancy test (in females of child-bearing potential) or females who
are pregnant or breastfeeding, and/or plan to become pregnant or to breast-feed during
or within 90 days after study participation

- Any new disease, condition, or circumstance which would prevent, in the opinion of the
Investigator, the patient from completing all study visits and assessments required by
the protocol (e.g., an anticipated change of care setting)