FDA approves memantine (Namenda) for Alzheimer's Disease
ROCKVILLE, MD., October 17, 2003 -- The FDA has approved memantine (Namenda), for treatment of moderate to severe Alzheimer's Disease. This is the first drug approved for the treatment of patients with this severity of disease.
Previous treatments for Alzheimer's Disease have been studied in less severely affected (mild to moderate) patients. Memantine's mechanism of action is different from that of the drugs currently available for treating this 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 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 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 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).
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. Memantine will be marketed under the trade name Namenda by Forest Labs of Jersey City, N.J.
Posted: October 2003