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.
This is a multinational, multicenter, open-label, rater-blinded prospective Phase II study which will assess the safety and efficacy of N-Acetyl-L-Leucine (IB1001) for the treatment of Ataxia-Telangiectasia (A-T).~There are two phases to this study: the Parent Study, and the Extension Phase.~The Parent Study evaluates the safety and efficacy of N-Acetyl-L-Leucine (IB1001) for the symptomatic treatment of A-T.~The Extension Phase evaluates the long-term safety and efficacy of IB1001 for the neuroprotective, disease-modifying treatment of A-T.