Sponsor had determined that the benefit-risk profile of adrabetadex was not favorable and the clinical development program for adrabetadex was discontinued.

This study was amended from expanded access to a clinical trial. Information will be collected about long-term safety and effectiveness of adrabetadex shots in the spine every 2 weeks.

Participants who were already taking adrabetadex will receive their stable dose. Participants who have not ever taken it will start by receiving 400 mg.

Participants will receive treatment every 2 weeks until their doctor finds it does not help them anymore, they withdraw, or the study is stopped for any reason. Participants will not receive additional study treatment after their participation in this protocol.

Inclusion Criteria:

To be included in the study, a participant must meet the following criteria:

• Is male or female and at least 4 years of age at time of screening.
• Has a confirmed diagnosis of NPC and exhibits neurologic symptoms.
• Has written informed consent/assent to participate.
• Has the ability to undergo LP and IT drug administration.
• If taking miglustat (Zavesca®), must have been on a stable dose for the past 6 weeks and be willing to remain on a stable dose for the duration of participation in the study, or discontinue miglustat use at least 6 weeks before entry into the study (Day 1).
• If has a history of seizures, the condition is adequately controlled as per protocol requirements.
• Agrees to discontinue any investigational treatments (other than adrabetadex) for at least 1 month before first dose on Day 1.
• If engaging in heterosexual sex, agrees to use a protocol-defined method of contraception throughout the study, and until 30 days after completing the study.
• Has a responsible adult who the investigator determines is able and willing to comply with study requirements and a parent/guardian who will accompany the participant to study visits.

Exclusion Criteria:

Participants will be excluded from the study if they meet any of the following criteria:

• Weighs less than 15 kg.

• Has a history of hypersensitivity reactions to any product containing 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) or has a history of hypersensitivity reactions or allergy to anesthesia/sedation.

• Has received treatment with any investigational product (other than adrabetadex) within 1 month prior to Day 1 of treatment.

• Is pregnant or nursing.

• Has systemic infection or uncontrolled psychosis.

• Has known history of a bleeding disorder.

• Has used anticoagulants within 2 months of entry into the study.

• Per protocol, or in the opinion of the investigator:

  1. has laboratory values that would preclude participation
  2. has suspected infection of the central nervous system (CNS)
  3. has a spinal deformity that could impact performance of repeated LPs
  4. has a serious skin infection in the lumbar region or evidence of obstructive or normal pressure hydrocephalus
  5. is unable to comply with the study requirements
  6. has a medical condition that might increase the risk of participation