[Assessment of benefits of drug therapies: memantine for Alzheimer's disease as an example]. / Zur Bewertung des Nutzens medikamentöser Therapieoptionen am Beispiel von Memantin bei Alzheimer Demenz.

After the approval of a drug, which represents a first assessment, independent institutions and medical professional associations provide further evaluations. Here, the question is to be asked whether common or diverging evaluation methods exist that can have an impact on the result. In principle, two methods are used: meta-analyses and responder analyses. Meta-analyses and the resulting effect sizes have to be interpreted according to the field of application (for example, the type and severity degree of a disease) with medical expertise. Omitting this can lead to incorrect evaluations and to a discrepancy of evaluation results. In the case of memantine, the merely biometric evaluation of meta-analyses performed by the IQWiG led to a denial of the benefit, while the same data, considering clinical routine, led professional associations to recommend memantine for moderate to severe Alzheimer´s disease. In contrast to meta-analyses, responder analyses directly show the benefit of a therapy option in the presence of significant group differences, as the selected responder criteria are based on the indication. The corresponding results of the responder analyses on memantine were also acknowledged by the IQWiG and led to a positive evaluation of memantine. This discrepancy of evaluation results illustrates the fact that statistical procedures are necessary when evaluating drug and non-drug therapy options but, that the interpretation of the results with medical expertise is essential.

Memantine in everyday clinical practice: a comparison of studies in Germany and Greece.

BACKGROUND/AIMS: Results from German and Greek non-interventional studies were compared to investigate possible differences concerning efficacy, tolerability and compliance between both countries. METHODS: In two open-label, multicentre, non-interventional studies, 4,305 patients with mild to severe Alzheimer's disease (AD) were treated with daily doses of 20 mg memantine for 6 months. Efficacy was assessed using the Mini-Mental State Examination (MMSE) and instrumental activities of daily living (IADL) scales. Safety and tolerability were recorded. RESULTS: After 6 months, the patients showed an improvement of their cognitive performance by 2 MMSE points compared to baseline (p < 0.001). MMSE values were improved in 67.4% of the patients, while 15.1% remained stable, and MMSE deteriorated in 17.5% only. The ability to perform IADL increased, as is indicated by lower values (baseline: 70.5; after 6 months: 66.6 points). Improvement of cognition and IADL was nearly identical in both countries. Treatment discontinuation was significantly more frequent in the Greek population, mainly due to non-adherence (9.4% of the safety population). 345 adverse events were recorded in 245 patients (6.3%), and they were significantly associated with country and age. CONCLUSION: The results correspond to those of clinical trials and support the efficacy and good tolerability of memantine in a realistic setting. Differences between the countries were observed regarding the baseline characteristics of patients (more female, older and more severe patients in Germany as well as less pretreatment with cholinesterase inhibitors) and regarding premature discontinuation and reported adverse drug reactions, which were both higher in Greece.