Evaluating The Efficacy And Safety Of Donepezil Hydrochloride (Aricept) In The Treatment Of The Cognitive Dysfunction Exhibited By Children With Down Syndrome, Aged 6 To 10

Subjects residing in the community or in facilities that have consistent and reliable caregivers who can provide efficacy information about the subjects.

The subjects must be expected to complete all procedures scheduled during the Screening and Baseline visits including all efficacy and safety parameters. Subjects who are verbal and able to be understood most of the time are preferred, but those who use other forms of communication, signs, symbol boards or devices to supplement his/her communication ability may be enrolled provided they meet the VABS-II/PCRF receptive and expressive score criteria mentioned above.

Subjects must have a parent, or other reliable caregiver who agrees to accompany the subject to all clinic visits, provide information about the subject as required by the protocol, and ensure compliance with the medication schedule.

The parent or caregiver must be a constant and reliable informant with sufficient contact with the subject to have detailed knowledge of the subject's adaptive functioning in order to be able to complete the VABS-II/PCRF accurately. The same individual should complete the form at every visit if possible.

Subjects should be in good general health with no medical conditions that are considered both clinically significant and unstable.

Clinical laboratory values within normal limits or abnormalities considered not clinically significant by the investigator and sponsor.

Subjects with stable Type I (insulin-dependent) or Type II diabetes are eligible provided they are monitored regularly prior to and during the study to ensure adequate glucose control. (Adequacy of control is based on the investigator's judgment, but should be guided primarily by a glycosylated hemoglobin \[hemoglobin A1c\] \<8.0 at screening; other information, including records of home monitoring and the screening fasting glucose may support this judgment.)

Subjects with thyroid disease also may be included in the study provided they are euthyroid and stable on treatment for at least 1 month prior to screening.

Subjects with a history of seizure disorder are allowed provided that they are on stable treatment for at least 3 months and have not had a seizure within the past 6 months.

Subjects should be independent in ambulation or ambulatory aided (i.e., walker or cane, to wheelchair); vision and hearing (eyeglasses and/or hearing aid permissible) sufficient for achieving VABS-II/PCRF minimum receptive raw scores of \>= 25 and expressive scores of \>= 61 and for cooperating with secondary efficacy evaluations and study examinations.

Age range: Subjects \<6 or \>10 years at the screening visit.

Subjects with active or clinically significant conditions that will, in the investigator's judgment, affect absorption, distribution or metabolism of the study medication (e.g., inflammatory bowel disease, gastric or duodenal ulcers or severe lactose intolerance); controlled celiac disease is allowed.

Subjects with a known hypersensitivity to piperidine derivatives or cholinesterase inhibitors.

Subjects currently receiving cholinesterase inhibitors or who have received them in the 3 months prior to screening or with prior use \>3 months prior to screening who stopped for lack of efficacy or tolerability or simply to enroll the subject in this study. Also excluded are subjects who participated in the Phase II study E2020-A001-219 (A2501059). In addition, subjects may not have taken any other investigational medications (including memantine) within 3 months prior to screening.

What this study is about