Evaluate the Neurological Effects of EryDex on Subjects With A-T

A Multi-center, Randomized, Double-blind, Placebo-controlled Trial to Evaluate the Neurological Effects of EryDex on Subjects With Ataxia Telangiectasia (NEAT)

This is an international, multi-center, randomized, prospective, double-blind, placebo-controlled, Phase 3 study, designed to assess the effect of EryDex (dexamethasone sodium phosphate [DSP] in autologous erythrocytes), administered by intravenous (IV) infusion once every 28 days, on neurological symptoms of patients with Ataxia Telangiectasia (A-T).

The EryDex System (EDS) is a combination product that is used to load dexamethasone sodium phosphate (DSP) into autologous erythrocytes (EryDex) which is infused into the patient.

In the placebo arm, the subjects will receive autologous erythrocytes prepared with the EDS process using a placebo solution.

Upon completion of all screening assessments for eligibility, subjects meeting all selection criteria at baseline will be randomized in a 1:1 fashion to EryDex or placebo. Approximately 86 subjects 6- to 9-years-old, approximately 43 per group, will be randomized. Approximately 20 subjects 10 years of age and above, 10 per treatment group, may also be enrolled.

Inclusion Criteria:

• Clinical diagnosis of A-T
• In autonomous gait or is helped by periodic use of a support
• Genetic confirmation of A-T
• Body weight ≥15 kg

Exclusion Criteria:

• Participation in another clinical study
• Immune impairment
• History of severe impairment of the immunological system
• Current neoplastic disease or previous neoplastic disease not in remission for at least 2 years
• Severe or unstable pulmonary disease
• Uncontrolled diabetes
• Current chronic or acute significant renal and/or hepatic impairment
• Any previous oral or parenteral steroid use within 6 weeks before Baseline. Treatment with inhaled or intranasal steroids for asthma or allergies, as well as use of topical steroids will be permitted
• A disability that may prevent the subject from completing all study requirements