A 2-Period Crossover Study of BPN14770 in Adults Males With Fragile X Syndrome

A total of 30 subjects will be enrolled. The study consists of a screening period of up to 28 days prior to initial treatment, followed by two double-blind treatment periods, each 12 weeks long. A final follow-up visit or phone contact for safety is planned one week after the conclusion of Period 2. Eligible subjects will be randomized in a blinded, balanced (1:1) fashion to receive either 25 mg BPN14770 capsules or matching placebo capsules during Period 1, followed by the opposite treatment during Period 2. One capsule will be taken twice daily during both double-blind periods. Subjects will return to the clinic at the end of Weeks 2, 6, and 12 of each study period. Cognitive and behavioral evaluations will be repeated at Weeks 6 and 12 of each Period. Additionally, patients will be monitored for adverse events via a telephone call at the end of Week 1 of each Period, and one week following completion of Period 2 or following early discontinuation. During clinic visits, adverse effects will be assessed, and laboratory measures, vital signs, and ECGs will be performed. Suicidality risk will also be evaluated at each clinic visit; if a concern is detected, the subject will be referred for further evaluation and treatment. Cognitive and behavioral assessments will be performed during each clinic visit. Pharmacodynamic measures of CNS function will be obtained to evaluated effects of the drug in the brain. Pharmacokinetic samples will be collected to confirm that study drug is present and to estimate plasma exposure at Week 12 of each Period.