We conducted an exploratory analysis of the influence of baseline neuropsychological (NP) profiles on the effect of EGb 761® (definition see editorial) in Alzheimer’s disease (AD). Using this perspective, we stratified the intent-to-treat data set collected during a 52-week, randomized, double-blind, placebo-controlled study with 120 mg EGb 761® based on cut-off points applied to naming and constructional praxis items of the Alzheimer’s Disease Assessment Scale-Cognitive subscale (ADAS-Cog). Mean changes over baseline and percentage of responders in each NP group and overall efficacy were analyzed, using the ADAS-Cog subscale as outcome measurements for assessing cognitive performance and the Geriatric Evaluation using the Relative’s Rating Instrument (GERRI) to measure social functioning. Three subgroups were identified: (1) right AD (RAD) subgroup, including 83 patients with primarily visual-constructional impairment; (2) left AD (LAD) with 25 patients showing predominant verbal deficits; (3) general AD (GAD) including 60 patients impaired in both cognitive domains. At the endpoint, the EGb 761® group of RAD showed an improvement of 1.7 points according to ADAS-Cog and 0.15 points according to GERRI, while the placebo group worsened by 1.3 and 0.02 points, respectively. The LAD patients worsened regardless of treatment; however, to a lesser degree in those receiving EGb 761® as assessed by the increase of 4.7 ADAS-Cog points and 0.13 GERRI points compared to 6.8 points and 0.20 points, respectively, for placebo. In GAD, the EGb 761® group showed minimal changes, whereas the placebo group slightly worsened on both assessments, resulting in favorable treatment differences of 1.6 ADAS-Cog points and 0.23 GERRI points. Retrospective analysis of overall efficacy indicated that a quantitative treatment effect favorable to EGb 761® could be observed in cognitive performance (p = 0.04) and social functioning (p = 0.02), even taking NP differences and baseline severity into account. However, qualitative EGb 761® effects could greatly depend on NP profiles - improvement could be expected with RAD patients, while EGb 761® effect should be considered more in terms of stabilization for GAD and delayed worsening for LAD population.
Key words
Ginkgo - EGb 761® - Alzheimer’s disease - Neuropsychological profiles
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