FROM THE JOURNAL OF CLINICAL ONCOLOGY
Adult brain tumor survivors taking donepezil, a drug approved for the treatment of Alzheimer’s disease, showed significant improvements in the cognitive functions of memory, motor speed, and dexterity, compared with those taking a placebo. However, improvements in the primary outcome of composite cognitive function were similar for the two arms, investigators reported.
The study results were published online April 20 in the Journal of Clinical Oncology.
Patients with greater pretreatment deficits saw greater improvements in cognitive functioning with donepezil treatment, reported Stephen Rapp, Ph.D., professor of psychiatry and behavioral medicine at Wake Forest School of Medicine, Winston-Salem, N.C., and associates.
“This suggests that treatment with a daily dose of donepezil can provide benefit to some adult long-term brain tumor survivors after PBI or WBI [partial- or whole-brain irradiation], particularly those with greater pretreatment cognitive impairment,” they wrote (J. Clin. Oncol. 2015 Apr. 20 [doi: 10.1200/JCO.2014.58.4508]).
The phase III trial enrolled 198 primary or metastatic brain tumor survivors who underwent fractionated PBI or WBI at least 6 months previously. Patients received either donepezil at 5 mg daily for 6 weeks, followed by 10 mg daily for 18 weeks if well tolerated, or placebo for 24 weeks. Composite cognitive scores improved for both arms and did not differ significantly. Donepezil treatment resulted in significantly greater improvements in memory (recognition, P = .027; discrimination, P = .007) and motor speed and dexterity (P = .016).
Donepezil was generally well tolerated, except for diarrhea in 25% of the active arm vs. 9% in the placebo arm (P = .005). The study retention rate was 74% at 24 weeks for both groups.
Although enrolled patients had a high level of cognitive impairment relative to noncancer controls, with 91% having at least one test score at least 1.5 standard deviations below the normal comparison group, scores across most measures varied widely from significantly lower to higher than the comparison group. This heterogeneity may underlie the less than significant improvement observed with the study treatment. Patients with greater cognitive deficits saw greater benefits.
“This indicates that brain tumors and their treatments, including cranial irradiation, are associated with clinically significant cognitive impairment among some but not all patients. In future studies, demonstrable cognitive impairment should be an inclusion criterion for enrollment,” Dr. Rapp and associates wrote.