Phase III Randomized, Placebo-Controlled Clinical Trial of Donepezil for Treatment of Cognitive Impairment in Breast Cancer Survivors After Adjuvant Chemotherapy (WF-97116).

Purpose: To test efficacy of donepezil, a cognitive enhancer, to improve memory in breast cancer survivors who report cancer-related cognitive impairment 1-5 years postchemotherapy.

Patients And Methods: Adult female BCS exposed to ≥4 cycles of adjuvant chemotherapy 1-5 years before enrollment who reported cancer-related cognitive impairment were eligible. Participants, enrolled at sites affiliated with the Wake Forest NCI Community Oncology Research Program (NCORP) Research Base, were randomly assigned to receive 5 mg of donepezil once daily for 6 weeks titrated to 10 mg once daily for 18 weeks or placebo. Cognition and self-report cognitive functioning was assessed at baseline, 12, 24 (end of intervention), and 36 (washout) weeks postrandomization. Mixed-effects repeated measures analysis of covariance models were used to assess treatment differences in immediate recall (primary outcome) on the Hopkins Verbal Learning Test-Revised (HVLT-R) and other cognitive domains (secondary outcomes) with covariates of treatment, time, time by treatment interaction, baseline outcome level, age stratification, and an unstructured covariance matrix to account for within participant correlation over time.

Results: Two hundred seventy-six BCS from 87 NCORP practices (mean age, 57.1, standard deviation [SD], 10.5) who were at a mean of 29.6 months (SD, 14.2) postchemotherapy were randomly assigned to donepezil (n = 140) or placebo (n = 136). At 24 weeks, treatment groups did not differ on HVLT-R scores (donepezil mean = 25.98, placebo = 26.50, = .32). There were no statistically significant differences between treatments at 12, 24, or 36 weeks for attention, executive function, verbal fluency, processing speed, or self-reported cognitive functioning. Endocrine therapy and menopausal status did not affect results.

Conclusion: BCS 1-5 years after completing chemotherapy with documented memory problems, randomly assigned to 24 weeks of 5-10 mg of donepezil once daily, did not perform differently at the end of treatment on tests of memory, other cognitive functions, or subjective functioning than those randomly assigned to placebo.