Memantine is not an effective treatment for cognitive impairment and dementia in people older than 40 years with Down’s syndrome, according to research published in The Lancet.
Researchers, led by Marisa Hanney, bemoaned the ‘striking absence’ of evidence for this patient group, while suggesting that therapies effective for Alzheimer’s disease were not necessarily effective for Down’s syndrome patients.
“Prevalence of Alzheimer’s disease in people with Down’s syndrome is very high, and many such individuals who are older than 40 years have pathological changes characteristic of Alzheimer’s disease,” wrote Hanney et al.
Following the success of memantine in transgenic mice, researchers aimed to assess the safety and efficacy of the drug on Down’s syndrome patients.
The randomised, double-blind trial included adults (>40 years) with karyotypic or clinically diagnosed Down’s syndrome, with and without dementia, at four learning disability centres in the UK and Norway.
Patients were given either mematine (88) or placebo (85) for 52 weeks and the primary outcome was change in cognition and function, measured with DAMES scores and the adaptive behaviour scale.
The primary outcome was change in cognition and function, measured with Down’s syndrome attention, memory, and executive function scales [DAMES] scores and the adaptive behaviour scale (ABS) parts I and II.
Of the patients receiving memantine, 72 [82%] had DAMES data and 75 [85%] had ABS data at 52 weeks, while of those receiving placebo 74 [87%] had DAMES and 73 [86%] ABS.
“Both groups declined in cognition and function but rates did not differ between groups for any outcomes,” noted Hanney et al.
“After adjustment for baseline score, there were non-significant differences between groups of −4·1 (95% CI −13·1 to 4·8) in DAMES scores, −8·5 (—20·1 to 3·1) in ABS I scores, and 2·0 (—7·2 to 11·3) in ABS II scores, all in favour of controls.
“Ten (11%) of 88 participants in the memantine group and six (7%) of 85 controls had serious adverse events (p=0·33). Five participants in the memantine group and four controls died from serious adverse events (p=0·77).”
As a result, Hanney et al concluded: “Despite promising indications, memantine is not an effective treatment.”