A Randomized , Double Blind, Placebo Controlled, 3-Arm Parallel Design Study to Evaluate the Effects of BPN14770 in Patients With Early Stage Alzheimer's Disease

• Males or females between the ages of 55 and 85 years with a clinical diagnosis of early stage AD, defined according to the following criteria assessed during Screening and at Baseline :

‣ Clinical Dementia Rating (CDR) score of 0.5 or 1, with Memory Box score of 0.5 or greater

⁃ MMSE score of 20 or greater

⁃ RBANS DMI score ≤ 85 Note: PET imaging for amyloid is not required for diagnosis, which will be made on clinical grounds.

• Currently receiving a stable (at least 2 months) dose regimen of donepezil or another cholinesterase inhibitor for treatment of Alzheimer's disease. Doses of these drugs may not be changed during the trial.

• Note: Memantine is not permitted during the trial and must be discontinued at least 3 weeks prior to Baseline.

• Modified Hachinski Ischemia score \< 4.

• Body mass index (BMI) \< 38 kg/m2, inclusive, and body weight of \>48 kg (105 pounds) at screening.

• Female subjects must be at least two years post-menopausal (subjected reported menopausal status), surgically sterile (bilateral tubal ligation, hysterectomy, or bilateral oophorectomy at least 6 months prior to first study drug administration), or willing to either (1) utilize hormonal contraception plus one barrier method or (2) use two barrier methods of contraception (e.g. diaphragm and spermicide) from initial screening until one month after taking the final dose. An intrauterine device (IUD) is considered a barrier method of contraception in this study. Male subjects must be willing to inform female partners of their participation in the study and must agree to use adequate contraceptive methods (vasectomy performed at least 6 months prior to first study drug administration, or use at least one barrier method of birth control).

• Able to understand and comply with the study procedures, voluntarily agree to participate in this study, and provide written informed consent prior to start of any study-specific procedures.

• All subjects must have a caregiver who is willing and able to ensure compliance with study medications, visits, and study procedures.