Phase 3 Randomized Placebo Controlled Clinical Trial of Donepezil

Inclusion Criteria

• Women ≥18 years old with history of invasive breast cancer
• Must have completed at least 4 cycles of adjuvant/neo-adjuvant cytotoxic chemotherapy between 1 and 5 years prior to registration (Ongoing herceptin or other chronic human epidermal growth factor receptor 2 (HER2) directed therapies are allowed).
• Patients receiving ongoing hormonal therapy for breast cancer must be on the same hormonal agent for at least 3 months prior to study registration and plan to continue for the duration of the study (9 months)
• Use of psychotropic medications (anti-depressants, anxiolytics, sleeping aids, narcotics) is permitted (patient will be asked to list any that have been taken within the last 3 days on the recent medication sheet) if dose is stable over previous 12 weeks. Patients who were previously on one of these psychotropic medications and have subsequently discontinued the drug must have been off the medication for at least 4 weeks prior to enrollment. Patients who have been on a psychotropic medication for at least 12 weeks but have recently switched to a medicine in the same class (for example, switching from one selective serotonin reuptake inhibitor (SSRI) antidepressant to a different SSRI antidepressant) need to be on a stable dose of the new medication for at least 4 weeks prior to enrollment to be eligible.
• Self-reported cognitive problem plus a measured memory deficit (score 460 milliseconds will make the patient ineligible.
• Pregnant women are excluded from this study. Following informed consent, women of child-bearing potential will be screened with a serum or urine pregnancy test within 10 days of enrollment. The effects of donepezil on the developing human fetus at the recommended therapeutic dose are unknown. For this reason and because donepezil is known to be teratogenic, women of child-bearing potential must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her study physician immediately.
• It is unknown whether donepezil is excreted in breast milk, for this reason women who are currently breast-feeding are not eligible for this study.
• On another intervention study involving medication at the time of enrollment or during participation in this study. (Exception: Patients will remain eligible for this study if they are also enrolled on the Alliance for Clinical Trials in Oncology study (NCT02927249): Aspirin in Preventing Recurrence of Cancer in Patients with HER2 Negative Stage II-III Breast Cancer After Chemotherapy, Surgery, and/or Radiation Therapy. Studies that involve only blood draws or questionnaires are also permitted.)
• Use of investigational drugs likely to affect cognition within 30 days prior to pre-screening visit.