The Food and Drug Administration (FDA) today approved memantine (NAMENDA), for treatment of moderate to severe Alzheimers Disease. It's the first drug approved for the treatment of patients at higher severity levels of the disease.
Previous treatments for Alzheimers Disease have been studied in less severely affected (mild to moderate) patients. Memantines mechanism of action is different from that of the drugs currently available.
"The approval of memantine is good news for Alzheimers Disease patients," FDA Commissioner Mark McClellan, M.D., Ph.D., said. "This is the first drug shown to have an effect on the symptoms of moderate to severe Alzheimers Disease, and shows a low incidence of minor side effects."
Alzheimers Disease, which affects about 4.5 million Americans, is a degenerative condition affecting memory, judgment and the ability to reason. The new drug an is thought to work by blocking the action of the chemical glutamate.
Although memantine helps treat the symptoms of Alzheimers Disease in some patients, there is no evidence that it modifies the underlying pathology of the disease.
The first two double-blind studies, each about six months long, 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 Alzheimers 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 Alzheimers Disease and also showed a statistically significant advantage of memantine over placebo.
The studies utilized 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 Alzheimers 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 utilized 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 percent), headache (six percent), and constipation (six percent).
FDAs 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 Alzheimers Disease. Memantine will be marketed under the trade name Namenda by Forest Labs of Jersey City, N.J.