Memantine and Cholinesterase Inhibitors: Complementary Mechanisms in the Treatment of Alzheimer’s Disease

This review describes the preclinical mechanisms that may underlie the increased therapeutic benefit of combination therapy—with the N-methyl-d-aspartate receptor antagonist, memantine, and an acetylcholinesterase inhibitor (AChEI)—for the treatment of Alzheimer’s disease (AD). Memantine, and the AChEIs target two different aspects of AD pathology. Both drug types have shown significant efficacy as monotherapies for the treatment of AD. Furthermore, clinical observations indicate that their complementary mechanisms offer superior benefit as combination therapy. Based on the available literature, the authors have considered the preclinical mechanisms that could underlie such a combined approach. Memantine addresses dysfunction in glutamatergic transmission, while the AChEIs serve to increase pathologically lowered levels of the neurotransmitter acetylcholine. In addition, preclinical studies have shown that memantine has neuroprotective effects, acting to prevent glutamatergic over-stimulation and the resulting neurotoxicity. Interrelations between the glutamatergic and cholinergic pathways in regions of the brain that control learning and memory mean that combination treatment has the potential for a complex influence on disease pathology. Moreover, studies in animal models have shown that the combined use of memantine and the AChEIs can produce greater improvements in measures of memory than either treatment alone. As an effective approach in the clinical setting, combination therapy with memantine and an AChEI has been a welcome advance for the treatment of patients with AD. Preclinical data have shown how these drugs act via two different, but interconnected, pathological pathways, and that their complementary activity may produce greater effects than either drug individually

Memantine in patients with Alzheimer's disease receiving donepezil: new analyses of efficacy and safety for combination therapy

Introduction: Memantine and cholinesterase inhibitors potentially offer additional benefits in Alzheimer's disease (AD) when used together. This study assessed the efficacy and safety of combination treatment with memantine added to stable donepezil in patients with moderate to severe AD, and in a subset with moderate AD. Methods: Post hoc meta-analyses of data combined from two 24-week, randomised, double-blind, placebo-controlled trials of memantine 20 mg/day versus placebo, added to a stable cholinesterase inhibitor, were conducted. Data were included for all patients receiving donepezil 10 mg/day with Mini-Mental State Examination (MMSE) scores < 20 (n = 510). Efficacy was assessed using measures of cognition, function, and global status. Furthermore, marked clinical worsening, defined as concurrent deterioration from baseline in the three main efficacy domains, and safety, measured by treatment-emergent adverse events, were assessed. Analyses were performed for patients with moderate to severe AD (MMSE 5-19; MOD-SEV subgroup), and also for patients with moderate AD (MMSE 10-19; MOD subgroup; n = 367). Results: At week 24, in the MOD-SEV subgroup, patients receiving memantine added to donepezil significantly outperformed those receiving placebo added to donepezil in measures of cognition (P < 0.0001), function (P = 0.02), and global status (P = 0.010), with standardised mean differences (SMDs) of 0.36, 0.21, and 0.23, respectively (all last observation carried forward). Similarly, in the MOD subgroup, significant benefits were observed for cognition (P = 0.008), function (P = 0.04) and global status (P = 0.008), with SMDs of 0.28, 0.21, and 0.28, respectively. Significantly fewer patients receiving memantine added to donepezil showed marked clinical worsening than those receiving placebo added to donepezil, in both subgroups (MOD-SEV: 8.7% versus 20.4%, P = 0.0002; MOD: 5.9% versus 15.0%, P = 0.006). The incidence of adverse events was similar between treatment groups. Conclusions: These results support and extend previous evidence that combination treatment with memantine added to stable donepezil in patients with moderate AD, and in those with moderate to severe AD, is associated with significant benefits in reducing 24-week decline in cognition, function and global status. Combination treatment produces substantially reduced rates of marked clinical worsening, has good safety and tolerability, and generates effect sizes that are both statistically significant and clinically meaningful

Safety and efficacy of repeat long-term incobotulinumtoxinA treatment for lower limb or combined upper/lower limb spasticity in children with cerebral palsy

PURPOSE: The open-label phase 3 ‘Treatment with IncobotulinumtoxinA in Movement Open-Label’ (TIMO) study investigated longer-term safety and efficacy of incobotulinumtoxin A in children/adolescents with cerebral palsy (CP). METHODS: Patients on standard treatment, with unilateral or bilateral lower limb (LL) or combined upper limb (UL)/LL spasticity received four incobotulinumtoxinA injection cycles (16 or 20 Units/kg bodyweight total [maximum 400 or 500 Units] per cycle depending on ambulatory status/clinical pattern treated), each followed by 12–16 weeks’ observation. Treatment for pes equinus was mandatory; flexed knee or adducted thigh were options for unilateral treatment and/or ULs for unilateral/bilateral treatment. The primary endpoint was safety; changes in Ashworth Scale and Gross Motor Function Measure-66 scores, and Global Impression of Change Scale scores at week 4 of each injection cycle were also evaluated. RESULTS: IncobotulinumtoxinA (≤500 Units for ≤98 weeks) was safe, well-tolerated, and effective across all endpoints for multipattern treatment of LL and combined LL/UL spasticity in ambulant/nonambulant children/adolescents with CP. Treatment effects increased with each injection cycle. No new/unexpected safety concerns were identified. CONCLUSION: IncobotulinumtoxinA showed a good safety and tolerability profile, with efficacy over multiple clinical presentations. As an adjunct treatment, it offers an effective, individualized treatment option for pediatric CP-related spasticity