FDA approves memantine for Alzheimer's disease

Alzheimer's disease, which affects about 4.5 million Americans, is a degenerative condition affecting memory, judgment and the ability to reason. The new drug - an N-methyl-D-asparate (NMDA) antagonist - is thought to work by blocking the action of the chemical glutamate.

Although memantine helps treat the symptoms of Alzheimer's disease in some patients, there is no evidence that it modifies the underlying pathology of the disease.

FDA commissioner Mark McClellan said: "The approval of memantine is good news for Alzheimers' disease patients. This is the first drug shown to have an effect on the symptoms of moderate to severe Alzheimer's disease and shows a low incidence of minor side effects."

The first two double-blind studies, each of about six months duration, were conducted in the United States and involved about 250 and about 400 patients, respectively. The larger study was carried out in patients already taking donepezil, a drug already approved for the treatment of Alzheimer's disease.

Both studies showed that patients on memantine experienced less deterioration in their symptoms compared to patients treated with placebo during the study.

The third study, conducted in nursing homes in Latvia, was a 12-week double blind study in 166 patients with severe Alzheimer's disease and also showed a statistically significant advantage of memantine over placebo.

The studies utilised a variety of measures to evaluate the effectiveness of memantine. For the two studies conducted in the United States, the measures included the severe impairment battery (SIB) to assess attention, orientation, language, memory, and social interactions, and the modified Alzheimer's disease cooperative study - activities of daily living (ADCS-ADL) scale, which assessed the ability of patients to eat, dress, bathe, travel, shop and perform household chores.

The third study utilised the behavioral rating scale for geriatric patients (BGP), which assessed day-to-day functioning and the clinical global impression of change (CGI-C), which assessed the overall condition of the patients.

The most frequently reported adverse events were dizziness (seven per cent), headache (six per cent) and constipation (six per cent).

The FDA's peripheral and central nervous system drugs advisory committee this past September unanimously agreed that memantine is effective and safe for the treatment of moderate to severe Alzheimer's disease.oliticians were almost inevitably involved. As a result the best people and the best contracts could not always be chosen.