N-Acetyl-L-Leucine for Ataxia-Telangiectasia (A-T)

The primary purpose of the study is to evaluate the safety and efficacy of N-Acetyl-L-Leucine (IB1001) in the treatment of A-T investigating the efficacy in terms of improving symptoms, functioning, and quality of life against the defined endpoints in patients with A-T.

Patients will be assessed during three study phases: a baseline period, a 6-week treatment period, and a 6-week post-treatment washout period. If within 6 weeks prior to the initial screening visit, a patient has received any of the prohibited medications defined in the eligibility criteria (irrespective of the preceding treatment duration) a wash-out study-run in of 6 weeks is required prior to the first baseline assessment.

All patients will receive the study drug during this study.

For each individual patient, the study lasts for approximately 3.5 - 4 months during which there are 6 study visits to the study site.

This Extension Phase allows patients who have completed the Parent Study to, at the discretion of the Principal Investigator (PI), continue treatment with N-Acetyl-L-Leucine (IB1001). Patients will receive treatment with IB1001 for two one-year treatment periods, separated by a 6-week washout. All patients will receive the study drug during the treatment period. For each individual patient, the Extension Phase lasts for approximately 25.5 months, during which there are 6 visits to the study site.