SUVN-502 With Donepezil and Memantine for the Treatment of Moderate Alzheimer's Disease- Phase 2a Study

This is a phase 2a, proof-of-concept, 26-week, double-blind, multicenter, randomized,
parallel group, placebo-controlled study to compare the efficacy and safety of treatment with
SUVN-502 to placebo treatment in subjects with moderate Alzheimer's disease receiving
donepezil HCl (10 mg qd) and either memantine HCl (10 mg twice daily [bid]) or Namenda XR®
(28 mg qd) or the combination therapy, Namzaric™

The primary objective of the study is to evaluate the efficacy of a serotonin receptor
subtype 6 (5-HT6) antagonist, SUVN-502, compared to placebo, as adjunct treatment in subjects
with moderate Alzheimer's disease (Mini-Mental State Examination [MMSE] score of 12 to 20)
currently treated with the acetylcholinesterase inhibitor, donepezil hydrochloride (HCl), and
the N-methyl-D-aspartic acid (NMDA) antagonist, memantine HCl. Efficacy will be assessed by
the 11-item Alzheimer's Disease Assessment Scale for Cognitive Behavior (ADAScog-11) after 26
weeks of treatment.

Inclusion Criteria:

- Has a diagnosis of probable Alzheimer's disease based on the NINCDS-ADRDA criteria at
least 1 year prior to the screening visit.

- Has a score between 12 and 20 inclusive on the MMSE at the screening and baseline
visits.

- Has a MRI or CT scan performed within 12 months prior to screening with findings
consistent with the diagnosis of dementia due to Alzheimer's disease without any other
clinically significant comorbid pathologies.

- Must be receiving treatment with stable doses of donepezil HCl and memantine HCl for
at least 3 months prior to the screening visit

- Availability of an eligible and reliable caregiver

- Must be living in the community or an assisted living facility.

- Must be ambulatory or ambulatory aided (use of cane or walker).

- Is not pregnant or planning to become pregnant during the study.

- Subject (or subject's legally acceptable representative) and caregiver must sign an
Informed Consent to participate in the study.

Exclusion Criteria:

- Has a diagnosis of dementia due to other than Alzheimer's Disease

- Is taking cholinesterase inhibitors other than donepezil HCl or taking doses of
donepezil HCl other than 10 mg

- Is taking doses of memantine HCl other than 10 mg bid or Namenda XR® 28 mg qd.

- Has uncontrolled cardiac disease or hypertension.

- Has clinically significant renal or hepatic impairment.

- Has cancer or a malignant tumor, untreated thyroid disorder or has a history of
seizure disorder

- Is treated or likely to require treatment during the study, with any medications
prohibited by the study protocol.